found only in the heart, where it forms most of the heart wall.

cardiac muscle

Like skeletal muscle, cardiac muscle is _______, but its action is _________

1. striated

2. involuntary

how is cardiac muscle involuntary?

its alternating contraction and relaxation cannot be consciously controlled. The heart beats because it has a natural pacemaker that initiates each contraction;

located in the walls of hollow internal structures, such as blood vessels, airways, and most organs in the abdominopelvic cavity. It is also attached to hair follicles in the skin.

smooth muscle

Smooth muscle tissue gets its name from the fact that, under a microscope, it appears ________ or ________.

1. nonstriated

2. smooth

The action of smooth muscle is usually ___________, and, like cardiac muscle, some smooth muscle tissue has autorhythmicity

involuntary

Both cardiac muscle and smooth muscle are regulated by neurons that are part of the ____________ division of the nervous system (see Chapter 20) and by _________________

1. autonomic (involuntary)

2. hormones released by endocrine glands.

What are the four functions of smooth muscle?

1. Contractions move food, bile, and enzymes through the GI tract, gametes through the reproductive system, and urine through the urinary system--> contractions cause various types of organ movement, including propulsion of food through digestive tract, propulsion of urine through the urinary tract, and expulsion of a newborn through the uterus during labor

2. contractions of blood vessels help regulate the rate of blood flow

3. sphincters in hollow organs regulate the outflow of substances through hollow organs

4. contractions are usually involuntary

What are the two functions of cardiac muscle?

1. contractions pump blood through the body's blood vessels/ contractions pump blood to the body

2. contractions are involuntary

What are the four functions of skeletal muscle?

1. Moves skeletal bones --> Contractions in the belly of a muscle produce movement by exerting force on tendons (attached at origins and insertions) which pull on bones, drawing one towards the other

2. Contractions stabalize joints and help maintain posture and body positions

3. contractions produce heat, used to maintain body temperature

4. most contractions are voluntary

what are the 4 key functions of muscular tissue?

1. Producing body movements.

2. Stabilizing body positions

3. Storing and moving substances within the body.

4. Producing heat

Total body movements such as walking and running, and localized movements such as grasping a pencil, keyboarding, or raising your hand, rely on the integrated functioning of skeletal muscles, bones, and joints.

(a function of muscular tissue)

Producing body movements.

skeletal muscle contractions stabilize joints and help maintain body positions, such as standing or sitting. Postural muscles contract continuously when you are awake; for example, sustained contractions in neck muscles hold your head upright when you are listening intently to an anatomy lecture

(a function of muscular tissue)

Stabilizing body positions

Sustained contractions of ringlike bands of smooth muscles called sphincters may prevent outflow of the contents of a hollow organ. Temporary storage of food in the stomach or urine in the urinary bladder is possible because smooth muscle sphincters close off the outlets of these organs. Cardiac muscle contractions pump blood through the body's blood vessels. Contraction and relaxation of smooth muscle in the walls of blood vessels help adjust their diameter and thus regulate the rate of blood flow. Smooth muscle contractions also move food and substances such as bile and enzymes through the gastrointestinal tract, push gametes (sperm and oocytes) through the reproductive systems, and propel urine through the urinary system. Skeletal muscle contractions indirectly promote the flow of lymph throughout the body and aid the return of blood in veins to the heart.

(a function of muscular tissue)

Storing and moving substances within the body

As muscular tissue contracts, it also produces heat, a process called thermogenesis (ther′-mō-JEN-e-sis). Much of the heat released by muscle is used to maintain normal body temperature. Involuntary contractions of skeletal muscles, known as shivering, can dramatically increase the rate of heat production

(a function of muscular tissue)

Producing heat

Where is smooth tissue found?

1. within the walls of all hollow or tubular organs of the digestive, respitory, urinary, and reproductive tracts

2. within the walls of blood vessels, the iris, and ciliary muscles of the eye, in the skin of the scrotum and as thin bands called the arrector pilli associated with hair follicles in the skin

what are the four properties of muscle tissue?

1. Extreme excitability

2. contractability

3. Extensibility

4. Elasticity

a property of both muscle and nerve cells, is the ability to respond to certain stimuli by producing electrical signals called action potentials (impulses). Action potentials in muscles are referred to as muscle action potentials; those in nerves are called nerve action potentials or nerve impulses. Action potentials can travel along a cell's plasma membrane due to the presence of specific ion channels. Two main types of stimuli trigger action potentials in muscle cells: electrical and chemical. Autorhythmic electrical signals arise in the muscular tissue itself, as in the heart's pacemaker. Chemical stimuli, such as neurotransmitters released by neurons, hormones distributed by the blood, or even local changes in pH, can also trigger action potentials in muscle cells.

(one of the properties of muscle tissue)

Extreme excitability

the ability of muscular tissue to contract forcefully when stimulated by an action potential. When a skeletal muscle contracts, it generates tension (force of contraction) while pulling on its attachment points. In some muscle contractions, the muscle develops tension but does not shorten. An example is holding this book in your outstretched hand. In other muscle contractions, the tension generated is greater than resistance, so the muscle shortens and movement occurs. An example is lifting a book off a table

(one of the properties of muscle tissue)

contractability

the ability of muscular tissue to stretch, within limits, without being damaged. The connective tissue within the muscle limits the range of extensibility and keeps it within the contractile range of the muscle cells. Normally, smooth muscle is subject to the greatest amount of stretching. For example, each time your stomach fills with food, the muscle in the wall is stretched. Cardiac muscle also is stretched each time the heart fills with blood.

(one of the properties of muscle tissue)

Extensibility

the ability of muscular tissue to return to its original length and shape after contraction or extension.

(one of the properties of muscle tissue)

elasticity

what are the 3 ways that muscle tissue is categorized?

1. by its shape

2. the # of nuclei

3. the mechanism of stimulation

Where is cardiac tissue found?

in the wall of the heart in a muscular layer called the myocardium

what is #1?

skeletal muscle fiber (cell)

what is #2?

the nucleus (of skeletal muscle tissues)

what is #3?

striations (of skeletal muscle tissue)

where is skeletal muscle tissue located?

1. it attaches to bones via tendons

2. it is also found in the pharynx & the larynx, the chest, back, & abdominal walls, the face, the tongue, & the diaphragm

what is #1?

Smooth muscle fiber (cell)

what is #2?

nucleus of smooth muscle fiber

skeletal muscle is a separate organ composed of hundreds to thousands of skeletal muscle cells, also called __________

muscle fibers

muscle fibers have a ___________ shape

elongated

what is #2?

intercalated discs (of cardiac muscle tissue)

what is # 1?

the nucleus of cardiac muscle fiber

what is #3?

striations (of cardiac muscle tissue)

what is #4?

cardiac muscle fiber (cell)

what is #5?

gap junctions (of cardiac muscle tissue)

______________ surround muscle fibers and whole muscles, and carry the blood vessels and nerves that exert their effects on individual muscle fibers

Connective tissues

A skeletal muscle consists of __________________________________

individual muscle fibers (cells) bundled into fascicles and surrounded by three connective tissue layers.

what is #1?

skeletal muscle

(skeletal muscle tissue)

what is #2?

bone covered by periosteum

(skeletal muscle tissue)

what is #3?

tendon

(of skeletal muscle tissue)

what is #4?

Epimysium

(of skeletal muscle tissue)

what is #5?

Perimysium

(of skeletal muscle tissue)

what is #6?

Epimysium

(of skeletal muscle tissue)

what is #7?

Fasicle

(of skeletal muscle tissue)

what is #8?

Perimysium

(of skeletal muscle tissue)

what is #9?

Muscle fiber (cell)

(of skeletal muscle tissue)

what is #10?

Myofibril

(of skeletal muscle tissue)

What is #1?

Muscle fiber

(skeletal muscle)

what is #2?

Myofibrils

(skeletal muscle)

tough, glistening white dense regular connective tissue structures that attach the muscle belly to the bones, are minimally vascular, lack muscle cells, and consist primarily of parallel arrangements of collagen fibers

tendons

Which connective tissue coat surrounds groups of muscle fibers, separating them into fascicles?

Perimysium is the connective tissue layer that bundles groups of muscle fibers into fascicles.

The contractile elements of muscle fibers are the ___________, which contain overlapping thick and thin filaments.

myofibrils

(skeletal muscle)

Which structure shown here releases calcium ions to trigger muscle contraction?

The sarcoplasmic reticulum releases calcium ions to trigger muscle contraction.

(skeletal muscle)

Among the following, which is smallest: muscle fiber, thick filament, or myofibril? Which is largest?

Size, from smallest to largest: thick filament, myofibril, muscle fiber

(skeletal muscle)

Damage to a muscles cell's __________ will directly interfere with the production of the major energy source necessary for body movements.

mitochondria

_____________ is considered the motor protein because it can hydrolyze ATP.

myosin

Put the steps of the skeletal muscle and cardiac muscle contraction cycle in order:
1. Power stroke
2. Cross-bridges
3. Detachment
4. ATP hydrolysis

A. 1, 2, 3, 4

B. 4, 2, 1, 3

C. 3, 2, 1, 4

D. 3, 1, 4, 2

B. 4, 2, 1, 3

Skeletal muscle contractions will not occur (paralysis) if there is injury or damage of _________ neuron

somatic motor

Injury to an entire motor unit consists of

A. all of the sarcomeres that one motor neuron innervates

B. all of the myofibrils that one motor neuron innervates

C. all of the skeletal muscles that one motor neuron innervates

D. all of the muscle fibers that one motor neuron innervates

D. all of the muscle fibers that one motor neuron innervates

____________ an do work for a moderate length of time such as a 200 meter dash.

Fast oxidative-glycolytic fibers

A birth defect that caused developmental anomalies in all three types of muscle tissue most likely originated in the ______________ cells

mesenchymal cells

Connective tissue diseases will effect the _________________ of ______________ muscle

epimysium of skeletal muscle

The neurotransmitter in the neuromuscular junction is ______________

acetylcholine

To initiate the cross-bridge cycle, _________ must bind to troponin.

calcium

Red muscle fibers __________ than white muscle fibers.

A. contain relatively more mitochondria

B. have more capillaries

C. have more myoglobin

D. all of the choices are correct

D. all of the choices are correct

Which fibers tend to be pale or white in color?

A. all of the choices are correct

B. fast oxidative-glycolytic

C. fast glycolytic

D. slow oxidative

C. fast glycolytic

Marathon runners would be expected to have higher percentages of _________ compared to short-distance sprinters.

slow oxidative fibers

what is #1?

fascicle

(skeletal muscle)

what is #2?

muscle fiber

(skeletal muscle)

what is #3?

nucleus

(skeletal muscle)

what is #4?

endomysium

(skeletal muscle)

what is #5?

perimysium

(skeletal muscle)

what is #6?

somatic motor neuron

(skeletal muscle)

what is #7?

blood capillary

(skeletal muscle)

what is #8?

endomysium

(skeletal muscle)

what is #9?

sarcolemma

(skeletal muscle)

what is #10?

striations

(skeletal muscle)

what is #11?

sarcoplasm

(skeletal muscle)

what is #12?

myofibril

(skeletal muscle)

what is #13?

filament

(skeletal muscle)

Thin wrapping of mostly reticular fibers. This surrounding connective tissue helps to bind the muscle fibers together, yet it is loose enough to allow them to move freely over one another. In addition, the endomysium carries small blood vessels that supply the fibers with nutrients

the endomysium

groups of muscle fibers form bundles wrapped in a thicker layer of connective tissue.

a fascicle

dense irregular connective tissue covering that surrounds a fasicle

perimysium

a somewhat thicker covering of dense irregular connective tissue which binds all the fascicles together to form the muscle belly

epimysium

explain the continuous network of connective tissue

(skeletal muscle tissue)

So the tendons are a continuous mass of connective tissue that runs through the muscle as the endomysium, perimysium, and epimysium and emerges from the belly of the muscle as the tendons of origin and insertion at either end. This is what makes your muscles so incredibly strong. At its junction with the bone, the surface tissue of the tendon is continuous with the periosteum, while its deeper collagen fibers enter the bone to blend with the collagen of the osseous extracellular matrix. This strong, continuous network of connective tissue is essential to the function of the musculoskeletal system.

The various skeletal muscles of the body are further grouped together and protected by large dense irregular connective tissue sheets, called ______________ which wrap around groups of muscles much like a sock encircles your foot.

fascia

ex: For example, underneath the skin and subcutaneous layer in the free lower limbs a thin, tough, glistening sheet of dense irregular connective tissue called the fascia of the free lower limbs surrounds all the muscles.

• The most important components of a skeletal muscle are the ______________ themselves
• each mature __________________is a single cell with a hundred or more nuclei. Once fusion has occurred, the muscle fiber loses its ability to undergo cell division.
• most arise before birth and most of these cells last a lifetime

muscle fibers/ skeletal muscle fibers

During embryonic development, many myoblasts fuse lengthwise to form one ____________________. Once fusion has occurred, a skeletal muscle fiber loses the ability to _____________, but satellite cells retain this ability

1) skeletal muscle fiber

2) undergo cell division

The ____________ of the muscle fiber encloses sarcoplasm and myofibrils, which are striated

1. The multiple nuclei of a skeletal muscle fiber are located just beneath the _________

2. the plasma membrane of a muscle fiber

3. The cell membrane of a muscle fiber (cell), especially of a skeletal muscle fiber

sarcolemma

Fluid filled _______________ wraps around each myofibril.

Sarcoplasmic reticulum (SR)

1. The dramatic muscle growth that occurs after birth occurs by enlargement of existing muscle fibers, called ________________

2. An excessive enlargement or overgrowth of tissue without cell division.

3. due to increased production of myofibrils, mitochondria, sarcoplasmic reticulum, and other organelles.

4. It results from very forceful, repetitive muscular activity, such as strength training.

hypertrophy

1) an increase in the number of fibers.

2) An abnormal increase in the number of normal cells in a tissue or organ, increasing its size.

hyperplasia

1. Small, cylindrical invaginations of the sarcolemma of striated muscle fibers (cells) that conduct muscle action potentials toward the center of the muscle fiber.

2. Thousands of tiny invaginations of the sarcolemma that tunnel in from the surface toward the center of each muscle fiber. Because transverse tubules are open to the outside of the fiber, they are filled with interstitial fluid.

transverse tubules (t tubules)

_____________ propagate along the sarcolemma and through the transverse tubules, quickly spreading throughout the muscle fiber. This arrangement ensures that all the superficial and deep parts of the muscle fiber become excited by an action potential almost simultaneously.

Muscle action potentials

The sarcolemma surrounds the ___________________, the cytoplasm of a muscle fiber

sarcoplasm

explain the sarcoplasms role in providing the muscle with energy

The sarcoplasm includes a substantial amount of glycogen, a storage molecule that consists of a chain of linked glucose molecules. When the muscle requires energy and has already depleted its available glucose, glucose molecules from glycogen will be released and utilized for the synthesis of ATP.

1. the sarcoplasm contains a red-colored protein called ______________. This protein, found only in muscle, binds oxygen molecules that diffuse into muscle fibers from interstitial fluid.
2. releases oxygen when mitochondria need it for ATP production

myoglobin

1. At high magnification, the sarcoplasm appears stuffed with little threads. These small structures are the contractile elements of skeletal muscle, the ______________. ____________, which are about 2μm in diameter and extend the entire length of the muscle fiber, have prominent striations that make the whole muscle fiber look striped (striated).
2. A threadlike structure, extending longitudinally through a muscle fiber (cell) consisting mainly of thick filaments (myosin) and thin filaments (actin, troponin, and tropomyosin).

myofibrils

1. A fluid-filled system of membranous sacs that encircles each myofibril

2. A network of saccules and tubes surrounding myofibrils of a muscle fiber (cell), comparable to endoplasmic reticulum; functions to reabsorb calcium ions during relaxation and to release them to cause contraction.

3. This elaborate system is similar to smooth endoplasmic reticulum in nonmuscle cells

sarcoplasmic reticulum (SR)

In a ____________, the sarcoplasmic reticulum stores calcium ions (Ca²⁺). When triggered, Ca²⁺ will be released from the terminal cisterns into the sarcoplasm, which triggers muscle contraction.

relaxed muscle fiber

Within myofibrils are smaller protein structures called _____________

filaments

thin filaments are mostly composed of the protein __________

actin

thick filaments are mostly composed of the protein __________

myosin

Both thin and thick filaments are directly involved in the _____________

contractile process

1. The filaments inside a myofibril do not extend the entire length of a muscle fiber. Instead, they are arranged in compartments called ______________, the basic functional units of a myofibril
2. A contractile unit in a striated muscle fiber (cell) extending from one Z disc to the next Z disc

sarcomeres

Narrow, plate-shaped regions of dense protein material called ___________ separate one sarcomere from the next. Thus, a sarcomere extends from __________ to the _________.

1. Z discs
2. extends from one z disc to the next z disc

The dark, middle part of the sarcomere that extends the entire length of the thick filaments and also includes those parts of the thin filaments that overlap with the thick filaments

A band

• The lighter, less dense area of the sarcomere that contains the rest of the thin filaments but no thick filaments
• A Z disc passes through the center of each __________

I band

A narrow region in the center of each A band that contains thick filaments but no thin filaments

H zone

A region in the center of the H zone that contains proteins that hold the thick filaments together at the center of the sarcomere

M line

Myofibrils are built from 3 kinds of proteins:

(list them)

1. contractile proteins☛ which generate force during contraction
2. regulatory proteins☛ help switch the contraction process on and off
3. structural proteins ☛ keep the thick and thin filaments in the proper alignment, give the myofibril elasticity and extensibility, and link the myofibrils to the sarcolemma and extracellular matrix

what are the 2 contractile proteins? How can we identify them?

1. Myosin☛ the major component of thick filaments.
2. Actin☛ the major component of thin filaments

Contractile proteins (myosin and actin) _______________, and regulatory proteins (troponin and tropomyosin) _________________.

1. generate force during contraction

2. help switch contraction on and off

Which proteins connect to the Z disc? Which proteins are present in the A band? In the I band?

Actin and titin anchor into the Z disc. A bands contain myosin, actin, troponin, tropomysin, and titin; I bands contain actin, troponin, tropomysin, and titin.

what are the 2 regulatory proteins?

1. tropomyosin
2. troponin

give some info about tropomyosin and troponin (2 regulatory proteins)

1. are thin filaments

2. In relaxed muscle, myosin is blocked from binding to actin because strands of tropomyosin cover the myosin-binding site on actin. The tropomyosin strand, in turn, is held in place by troponin molecules. You will soon learn that when calcium ions (Ca²⁺) bind to troponin, it undergoes a change in shape; this change moves tropomyosin away from myosin-binding sites on actin, allowing myosin to bind to actin and muscle contraction to begin.

what are the 4 key structural proteins?

1. titin
2. myomesin
3. nebulin
4. dystrophin

A regulatory protein that is a component of the thin filament. When a skeletal muscle fiber is relaxed, tropomyosin covers the myosin-binding sites on actin molecules, thereby preventing myosin from binding to actin.

tropomyosin

regulatory protein that is a component of the thin filament. When calcium ions (Ca²⁺) bind to troponin, it undergoes a change in shape; this conformational change moves tropomyosin away from myosin-binding sites on actin molecules, and muscle contraction subsequently begins as myosin binds to actin.

troponin

Proteins that generate force during muscle contractions.

contractile proteins

A contractile protein that makes up the thick filament. A myosin molecule consists of a tail and two myosin heads, which bind to myosin-binding sites on actin molecules of a thin filament during muscle contraction.

myosin

A contractile protein that is the main component of the thin filament. On each actin molecule is a myosin-binding site where a myosin head of a thick filament binds during muscle contraction.

actin

Proteins that help switch the muscle contraction process on and off.

regulatory proteins

Proteins that keep the thick and thin filaments of the myofibrils in proper alignment, give the myofibrils elasticity and extensibility, and link the myofibrils to the sarcolemma and extracellular matrix.

structural proteins

an organ made up of fascicles that contain muscle fibers (cells), blood vessels, and nerves. The skeletal muscle is wrapped in epimysium.

skeletal muscle

a bundle of muscle fibers wrapped in perimysium.

fascicle

Long cylindrical cell covered by a vascular endomysium. The cell membrane, the sarcolemma, surrounds the sarcoplasm with its myofibrils, many peripherally located nuclei, mitochondria, transverse tubules, sarcoplasmic reticulum, and terminal cisterns. The fiber has a striated appearance.

muscle fiber (cell)

Threadlike contractile elements within the sarcoplasm of a muscle fiber that extend the entire length of the fiber; composed of filaments.

myofibril

Contractile proteins within myofibrils that are of two types: thick filaments composed of myosin and thin filaments composed of actin, tropomyosin, and troponin; the sliding of the thin filaments past the thick filaments produces muscle shortening.

filaments (myofilaments)

What part of the sarcolemma contains acetylcholine receptors?

The part of the sarcolemma that contains acetylcholine receptors is the motor end plate.

1. Even while at rest, a skeletal muscle exhibits ____________, a small amount of tautness or tension in the muscle due to weak, involuntary contractions of its motor units.
2. A sustained, partial contraction of portions of a skeletal or smooth muscle in response to activation of stretch receptors or a baseline level of action potentials in the innervating motor neurons.

muscle tone

Muscle contraction may either be ___________ or _____________

isotonic or isometric

1. the muscle remains almost constant while the muscle changes its length

2. these are used to produce body movements and for moving objects

3. two types are: concentric & eccentric

isontonic contraction

what are the 2 types of isotonic contractions?

1. concentric isotonic contraction

2. eccentric isotonic contraction

1. if the tension generated is great enough to overcome the resistance of the object to be moved, the muscle shortens and pulls on its tendon to produce movement and to reduce the angle at a joint
2. Picking up a book from a table involves ______________________ of the biceps brachii muscle in the arm. By contrast, as you lower the book to place it back on the table, the previously shortened biceps lengthens in a controlled manner while it continues to contract

Concentric isotonic contraction(s)

1. When the length of a muscle increases during a contraction, the contraction is a (an) _________________________
2. During an ____________, the tension exerted by the myosin cross-bridges resists movement of a load (the book, in this case) and slows the lengthening process. For reasons that are not well understood, repeated contractions like these (for example, walking downhill) produce more muscle damage and more delayed-onset muscle soreness than do concentric isotonic contractions.

Eccentric isotonic contraction(s)

1. the tension generated is not enough to exceed the resistance of the object to be moved and the muscle does not change its length.
2. An example would be holding a book steady using an outstretched arm.
3. These contractions are important for maintaining posture and for supporting objects in a fixed position
4. do not result in body movement, but energy is still expended ⫸ as you well know if you have ever tried to hold your anatomy book in an outstretched hand for any length of time. The book pulls the arm downward, stretching the shoulder and arm muscles. The _____________ of the shoulder and arm muscles counteracts the stretch
5. are important because they stabilize some joints as others are moved

isometric contractions ⤻

Most activities include both _________ and ________ contractions.

1. isotonic
2. isometric

Skeletal muscle fibers vary in their content of ____________, the red protein that binds oxygen in muscle fibers

myoglobin

Those with a high myoglobin content are called _____________, while those that have a low myoglobin content are called __________________

1. red muscle fibers
2. white muscle fibers

Red muscle fibers also contain more ________________ and are supplied by more ______________ than white muscle fibers.

1. mitochondria

2. blood capillaries

Skeletal muscle fibers are classified as one of 3 types: (list the 3 types)

1. slow oxidative fibers
2. fast oxidative-glycolytic fibers
3. fast glycolytic fibers.

1. also called type I fibers, appear dark red because they contain large amounts of myoglobin and many blood capillaries. Because they have many large mitochondria
2. these fibers generate ATP mainly by aerobic (oxygen-requiring) cellular respiration, which is why they are called oxidative fibers.
3. use ATP at a slow rate. As a result, these fibers have a slow speed of contraction.
4. are very resistant to fatigue and are capable of prolonged, sustained contractions for many hours.
5. These fibers are adapted for maintaining posture and for aerobic, endurance-type activities such as running a marathon.

slow oxidative (SO) fibers

type IIa fibers are typically the largest fibers. Like slow oxidative fibers, they contain large amounts of myoglobin and many blood capillaries, giving them a dark red appearance.

2. these fibers can generate considerable ATP by aerobic cellular respiration, which gives them a moderately high resistance to fatigue.

3. Because their intracellular glycogen level is high, they also generate ATP by anaerobic (oxygen-free) glycolysis.

4. fibers are “fast” because they use ATP at a fast rate, which makes their speed of contraction faster than SO fibers.

5. These fibers contribute to activities such as walking and sprinting.

Fast oxidative-glycolytic (FOG) fibers

1) type IIb fibers have low myoglobin content, relatively few blood capillaries and few mitochondria, and appear white in color. T

2) they contain large amounts of glycogen and generate ATP mainly by anaerobic (nonoxygen-requiring) cellular respiration (glycolysis).

3) Due to their ability to use ATP at a fast rate, __________ fibers contract strongly and quickly. These fast-twitch fibers are adapted for intense anaerobic movements of short duration, such as weight lifting or throwing a ball, but they fatigue quickly. Strength training programs that engage a person in activities requiring great strength for short times produce increases in the size, strength, and glycogen content of fast glycolytic fibers. The __________ fibers of a weight lifter may be 50 percent larger than those of a sedentary person or an endurance athlete because of increased synthesis of muscle proteins. The overall result is muscle enlargement due to hypertrophy of the __________ fibers.

Fast Glycolytic (FG) Fibers

Most skeletal muscles are a __________ of all three types of skeletal muscle fibers. The proportions vary somewhat, depending on the action of the muscle, the person's training regimen, and genetic factors.

mixture

1. The principal tissue in the heart wall

2. cannot be controlled voluntarily

3. display autorhythmicity--> the ability to repeatedly generate spontaneous action potentials.

4. these action potentials cause alternating contraction and relaxation of the heart muscle fibers

5. are shorter in length and less circular in transverse section

6. exhibit branching, which gives individual ______________ a “stair-step” appearance.

7. Usually one centrally located nucleus is present, although an occasional cell may have two nuclei

1. (overall) cardiac muscle tissue

2. (blank) cardiac muscle fibers

1. the ends of cardiac muscle fibers connect to neighboring fibers by irregular transverse thickenings of the sarcolemma referred to as intercalated discs
2. an irregular transverse thickening of the sarcolemma that contains desmosomes, which hold cardiac muscle fibers (cells) together, and gap junctions
3. contains: desmosomes & gap junctions

intercalated discs

1. aid in the conduction of muscle action potentials from one fiber to the next
2. cell junctions which allow muscle action potentials to spread from one cardiac muscle fiber to its neighbors

gap junctions

The intercalated discs contain ______________, which hold the cardiac muscle fibers together

desmosomes

Cardiac muscle tissue has an endomysium, but lacks a ___________ and ____________.

1. perimysium
2. epimysium

Cardiac muscle fibers display ______________, the ability to repeatedly generate spontaneous action potentials.

autorhythmicity

_____________ are larger and more numerous in cardiac muscle fibers than in skeletal muscle fibers.

Mitochondria

___________ muscle fibers have the same arrangement of actin and myosin, and the same bands, zones, and discs, as skeletal muscle fibers

Cardiac

The transverse (T) tubules of cardiac muscle are _________________ than those of skeletal muscle; there is one T tubule per sarcomere, located at the Z disc.

wider but less abundant

The _______________ of cardiac muscle fibers is somewhat smaller than the _____ of skeletal muscle fibers.

sarcoplasmic reticulum

Cardiac muscle differs from skeletal muscle in that cardiac muscle only has

A. transverse tubules

B. intercalated discs

C. nuclei

D. striations

B. intercalated discs

Which is likely to occur with someone who has an overworked heart?

A. mitochondria decrease in number

B. the lungs enlarge

C. the heart enlarges

D. the capillary network around the heart decreases

C. the heart enlarges

Which muscle tissue has the least amount of sarcoplasmic reticulum?

Smooth muscle tissue

Compared to other muscle tissues, smooth muscle differs in that it lacks ___________________

transverse tubules

Which gives rise to skeletal muscle

A. ectome

B. myotome

C. dermatome

D. sclerotome

B. myotome

Myotome gives rise to

A. arrector pili muscle

B. biceps brachii muscle

C. skin

D. vertebrae

B. biceps brachii muscle

With aging, skeletal muscle is replaced by ______________

fibrous connective tissue

Which muscle should decline in mass first as we age?

A. deltoid of shoulder

B. palmaris longus of forearm

C. biceps brachii of arm

D. rectus femoris of thigh

D. rectus femoris of thigh

In addition to muscle tissue, can you speculate as to what other tissue of the body is capable of responding to certain stimuli by producing action potentials?

A. epithelium

B. cartilage

C. bone

D. nervous

D. nervous

Once you begin to exercise, you notice your desire to turn on the air conditioning. This desire is the result of which property of muscle tissue?

thermogenesis

The process of exercising with progressively heavier resistance to strengthen the musculoskeletal system is known as

strength training

A genetic mutation that results in malformation of the actin protein will directly effect the function of which type(s) of muscle tissue? Select all that apply.

A. skeletal

B. smooth

C. cardiac

A. skeletal

B. smooth

C. cardiac

Human normally undergo a slow progressive loss of skeletal muscle mass after the age of 30.

A. True

B. False

A. True

Acetylcholine receptors are found along the ______________

motor end plate

During a contraction, the _________ band remain(s) unchanged in size.

A band

Muscle cells are innervated by somatic motor neurons in ______________

skeletal muscle

Skeletal muscle tissue formation begins during the fourth week of embryonic development as specialized mesodermal cells, called _____________, fuse together.

myoblasts

Strength training results in muscle cells that undergo _____________

hypertrophy

A genetic mutation that results in malformation of the myosin protein will directly effect the function of which type(s) of muscle tissue? Select all that apply.

A. skeletal

B. smooth

C. cardiac

A. skeletal

B. smooth

C. cardiac

The sliding filament theory describes the sliding of actin and ________________

myosin filaments

When acetylcholine binds to receptors on the motor end plate, ________ enters the sarcoplasm

sodium

Which muscle(s) is/are controlled by the somatic nervous system?

skeletal

The small amount of tautness or tension in the muscle due to weak, involuntary contractions of its motor units is known as muscle _____________

muscle tone

As muscles age, many changes can take place. Select all that apply.

A. decrease in strength

B. loss of muscle mass

C. decrease in flexibility

D. muscle hypertrophy

E. increase of reflex speed

A. decrease in strength

B. loss of muscle mass

C. decrease in flexibility

Diminished levels of oxygen found in skeletal muscle fibers can be a direct consequence of __________ protein defect.

myoglobin

Desmosomes and gap junctions form _________ in cardiac tissue.

intercalated discs

This fiber is smallest in diameter and the least powerful; it contracts slowly and is very resistant to fatigue.

slow oxidative

When muscle cells produce new thick and thin filaments, they get larger in size for example from weight training exercises. This process is referred to as ______________

hypertrophy

Striated muscle tissues develop from the embryonic ___________________

mesoderm

In terms of autorhythmicity, single-unit smooth muscle tissue is most like

a. cardiac muscle tissue

b. skeletal muscle tissue

a. cardiac muscle tissue

Which somatic region will develop into the vertebrae?

A. C

B. A

C. B

A. C

Neuromuscular junctions function when __________ are released into the synaptic cleft.

neurotransmitters

Over time, how is it possible for a weight lifter to become a marathon runner?

A. decrease the percentage of SO fibers

B. increase the percentage of SO fibers

C. decrease FOG fibers and increase FG fibers

D. increase the proportion of FG fibers

B. increase the percentage of SO fibers

Which muscle(s) is/are non-striated and involuntary?

smooth muscles

During a skeletal muscle contraction, which of the following structures shorten? Select all that apply.

A. sarcomere

B. myofibril

C. myosin

D. actin

E. muscle cell

F. fascicle

G. skeletal muscle

A. sarcomere

B. myofibril

E. muscle cell

F. fascicle

G. skeletal muscle

As one ages, the presence of slow oxidative fibers

A. slightly decreases

B. stays the same

C. decreases

D. increases

D. increases

Which benefits result from strength training? Select all that apply.

A. increase in muscle mass and strength

B. decrease in the amount of energy spent at rest

C. decrease in resting metabolic rate

D. increase mineral deposition into bone

A. increase in muscle mass and strength

D. increase mineral deposition into bone

When an action potential arrives are the synaptic end bulb, ________-gated calcium channels allow calcium to move ________.

1. voltage-gated
2. into the cell

When the doctor uses a reflex hammer and taps on the patellar tendon you respond by automatically "kicking out" i.e. extending your leg. As you age this patellar tendon reflex __________________

slows (hyporflexia)

In terms of mitochondria, cardiac muscle cells resemble

A. slow oxidative skeletal muscle cells

B. fast oxidative-glycolytic skeletal muscle cells

C. fast glycolytic skeletal muscle cells

A. slow oxidative skeletal muscle cells

Elderly persons often lose overall flexibility due to the conversion of fast glycolytic skeletal muscle fibers into fast oxidative glycolytic skeletal muscle fibers.

A. True

B. False

B. False

A state of decreased levels of calcium circulating in the blood (hypcalcemia) will not effect smooth muscle contractions.

A. True

B. False

B. False

A virus that invades the body and initiates muscle protein destruction leaves ________ muscle fibers most vulnerable to the virus.

red muscle fibers

Which somatic region is the dermatome?

Options:

1. A
2. B
3. C

1. A

The advantage of engaging in regular strength training at the gym versus taking anabolic steroids to build muscle mass include the following. Select all that apply.

A. Regular strength training increases basal metabolic rate and therefore better weight control.

B. Regular injections of anabolic steroids increases the chances of causing liver and kidney damage.

C. Regular injections of anabolic steroids increases the risk of heart disease.

D. Regular strength training increases bone deposition and therefore bone strength.

A. Regular strength training increases basal metabolic rate and therefore better weight control.

B. Regular injections of anabolic steroids increases the chances of causing liver and kidney damage.

C. Regular injections of anabolic steroids increases the risk of heart disease.

D. Regular strength training increases bone deposition and therefore bone strength.

As persons age, ATP will be expended more ____________ in skeletal muscle tissue.

slowly

_____________ can be caused by either electrical or chemical stimuli in muscles.

electrical excitability

As persons age there becomes a greater proportion of fast ___________ skeletal muscle fibers.

slow oxidative skeletal muscle fibers

As persons age more or less aerobic cellular respiration will be used to generate ATP in skeletal muscle tissue

more

When myosin heads pivot, they pull the thin filaments towards the ______________

M line

During contraction of a cardiac muscle cell

A. both the I and A bands lengthen

B. neither the H band nor the I band shortens

C. both the H and I bands shorten

D. the H band shortens while the A band lengthens

C. both the H and I bands shorten

Drugs that block the acetylecholine receptors located on muscle tissue sarcolemma would cause complete cessation of ______________ muscle contractions

skeletal

When muscle action potentials enter transverse tubules, ___________ __________(chemical symbol __________ ) is released from the sarcoplasmic reticulum.

1. Calcium
2. Ions, Cations
3. Ca,Ca++,Ca2+

Muscle action potentials arise at the _______________ junction when acetylcholine stimulates the sarcolemma.

neuromuscular

Lifting a cell phone off of a counter to your ear is an example of a/an __________________

concentric isotonic contraction

The _____________ filament mechanism is the process in which the myosin heads attach to a “walk” along the thin filaments.

sliding filament mechnism

The enzyme that breaks down acetylcholine in the synaptic cleft is _______________

acetylcholinesterase

The tension generated is not enough to exceed the resistance of the object to be moved and the muscle does not change its length in a/an ______________ contraction

isometric

When a skeletal muscle is not stimulated and not contracting, calcium ions are stored in the __________________

sarcoplasmic reticulum

When a sarcomere contracts, which bands/zones shorten?

H bands & I bands

Strength and endurance training can provide many health benefits. Select all that apply.

A. lengthened bones

B. injury prevention

C. improved physical form

D. increased fatigue and stress

E. stronger bones

F. increased flexibility

B. injury prevention

C. improved physical form

E. stronger bones

F. increased flexibility

For hypertrophy to occur in skeletal muscle fibers, which subcellular changes must be seen in a muscle cell? Select all that apply.

A. Myosin and actin will increase in numbers.

B. Muscle cells will increase in numbers.

C. The amount of sarcoplasm will increase.

D. The muscle cell will split and grow.

A. Myosin and actin will increase in numbers.

C. The amount of sarcoplasm will increase.

Which skeletal muscle fiber type will generate the most force during contraction?

fast glycotic fiber

Smooth muscle is so-named because of the absence of striations noted in its muscle cells. The absence of striations indicates that thin and thick filaments are consequently absent.

A. True

B. False

B. False

Which somatic region is the myotome?

1. A
2. C
3. B

3. B

Blood vessel diameter fluctuates between being constricted and being dilated. This is the primary contributor to blood pressure. In order for blood vessels (arterioles) to maintain a steady pressure, there must be a prolonged presence of what ion in the smooth muscle cell's cytosol?

calcium (Ca)

A tight ligature wrapped around the forearm can destroy muscle fibers which get replaced by fibrous connective tissue and leads to a permanent shortening (contracture) of the forearm muscles. Which feature of muscle tissue will be compromised by the presence of this scar tissue?

extensibility

As persons age, muscle tissue gets replaced by (select all that apply)

A. fat

B. fibrous connective tissue

C. bone tissue

D. lymph

E. adipose tissue

A. fat

B. fibrous connective tissue

E. adipose tissue

Pushing against an immovable object is an example of which strength-training exercise

A. isotonic

B. concentric

C. eccentric

D. isometric

D. isometric

The heart's autorhymicity is eliminated when a person exercises.

• true
• false

false

Which of the following anchors A in the figure to myomesin?

titin

After a contraction, calcium in the sarcoplasm must be removed in order for sarcomere relaxation. Where does the calcium get transported to and how?

where: it gets transported into sarcoplasmic reticulum;

how: it gets actively transported

Which of the following could help explain the decrease in muscle strength as your parents age from their twenties to their sixties? Select all that apply.

A. skeletal muscle is replaced by fibrous connective tissue

B. up to fifty percent loss of overall muscle mass

C. atrophy caused by loss of all skeletal muscle fiber types

D. regular aerobic work-outs at the gym

E. smooth muscle is replaced by adipose tissue

A. skeletal muscle is replaced by fibrous connective tissue

B. up to fifty percent loss of overall muscle mass

When individuals discuss white meat and dark meat, which fibers would be classified as dark meat? Select all that apply.

A. slow oxidative fibers

B. fast oxidative-glycolytic fibers

C. fast glycolytic fibers

A. slow oxidative fibers

B. fast oxidative-glycolytic fibers

By the end of the fifth week, approximately 30 days, ____________ somites are formed.

42-44 pairs of somites are formed

It is conceivable that 50% of your muscle mass could be lost up to ten years prior to your notice of loss in muscle strength.

• true
• false

true

Muscles of the upper limb develop from the embryonic ___________ while muscles of the lower limb develop from the embryonic _____________.

1. paraxial mesoderm
2. paraxial mesoderm

Which statement best describes smooth muscle?

A. No transverse tubules are present in smooth muscle.

B. Smooth muscle cells have well-developed sarcoplasmic reticulum.

C. Smooth muscle contains the same proteins as cardiac and skeletal muscle.

D. Smooth muscle consists of desmosomes in the form of intercalated discs.

A. No transverse tubules are present in smooth muscle.

______________ steroids are testosterone-like and can be abused by individuals to increase muscle size.

Anabolic steroids

Disruption of embryonic paraxial mesoderm formation will ultimately interfere with the further development of ________________

skeletal muscle

Calcium in cardiac muscle is stored in _________________

sarcoplasmic reticulum (SR)

Anabolic steroids, also known as androgenic steroids, promote growth and develop masculine characteristics. What type of actions do anabolic steroids have on skeletal muscles? Select all that apply.

A. have the same effect on the body as human growth hormone

B. inhibit breakdown of muscle tissue

C. increase protein synthesis

D. improve protein consumption

B. inhibit breakdown of muscle tissue

C. increase protein synthesis

A bands, I bands, H bands and sarcomeres are present in (select all that apply)

A. smooth muscle tissue

B. cardiac muscle tissue

C. skeletal muscle tissue

B. cardiac muscle tissue

C. skeletal muscle tissue

____________ allow you to respond super-quickly with short bursts of energy.

Fast glycotic fibers

Smooth muscle is so-named because of the absence of striations noted in its muscle cells. The absence of striations indicates that the actin and myosin proteins are consequently absent.

1. true
2. false

2. false

Dense bodies are connected to each other by ________________

intermediate filaments

___________ muscle stabalizes body positions

skeletal

Which muscle(s) is/are striated and voluntary?

skeletal

In smooth muscle, instead of pulling against Z discs, myofilaments pull against ___________ bodies.

dense bodies

Once calcium flows into a muscle fiber, the events of contraction are set into motion. Why does it take longer for calcium ions to reach the myofilaments in a smooth muscle fiber than it does in a skeletal muscle fiber?

because skeletal muscle fibers have transverse tubules to facilitate the flow of calciuum

Multiunit smooth muscle fibers that contract like skeletal muscle fibers, i.e. individually, do so because _______________

there are no gap junctions

A virus that invades the epimysium of skeletal muscle tissue will also be found within the epimysium of cardiac muscle tissue.

• true
• false

false

After death, rigor mortis occurs (muscles cannot contract or stretch) because cellular membranes become leaky and the calcium from the sarcoplasmic reticulum enters the sarcoplasm of the muscle. After 24 hours, however, the muscles relax again. In order for that to occur, what must be broken down?

cross-bridges

Smooth muscle tone is possible due to _________________

prolonged calcium presence in the sarcoplasm

____________ muscle is the only muscular tissue with good regeneration capability.

Smooth muscle

In terms of function, cardiac muscle contractions resemble ___________ smooth muscle contractions.

A. Single-unit

B. Multi-unit

A. Single-unit

When do muscle tissues stretch best?

A. The muscle cell temperature is warm.

B. The muscle cell temperature is cold.

C. The temperatures are the same as the external environment.

D. The temperature does not affect muscles' ability to stretch.

A. The muscle cell temperature is warm.

During senescence (aging) as more of the skeletal muscle fibers convert to slow oxidative skeletal muscle fibers, aerobic and strength training exercises are not recommended.

1. true
2. false

2. false

Which somatic region will develop into skeletal muscles?

1. C

2. A

3. B

3. B

Which of the following would you most likely expect to observe in a seventy-year old male patient? Assume no great fluctuations in weight or health.

A. a complete inability to perform any aerobic or strength training exercises

B. greater proportion of fibrous connective tissue compared to when he was thirty five years old

C. lesser proportion of adipose tissue as compared to when he was thirty-five years old

D. overall number of skeletal muscle fibers have been converted to cardiac and smooth muscle fibers

B. greater proportion of fibrous connective tissue compared to when he was thirty five years old

Which contributes to the loss of muscle mass with aging?

A. decreased strength

B. increased aerobic exercise

C. increased number of SO fibers

D. decreased physical activity

D. decreased physical activity

Age-related muscle mass loss can be reversed by chronic bed-rest.

• true
• false

false

Which somatic region becomes part of the integumentary region composed of dense irregular connective tissue?

1. A
2. B
3. C

1. A

Failure of the paraxial mesoderm to segment during embryonic development will affect further development of (select all that apply)

A. muscles of the back

B. muscles of the lower limb

C. the brain

D. dermis of the skin

E. chewing muscles

A. muscles of the back

B. muscles of the lower limb

D. dermis of the skin

E. chewing muscles

three athletes' muscle fibers were analyzed in their leg muscles. Which athlete is probably a sprinter?
Athlete 1 had 70% slow oxidative and 30% fast oxidative.
Athlete 2 had 58% slow oxidative and 42% fast oxidative.
Athlete 3 had 25% slow oxidative and 75% fast oxidative.

A. Athlete 1

B. Athlete 2

C. Athlete 3

C. Athlete 3

Three athletes' muscle fibers were analyzed in their leg muscles. Which athlete is probably a distance runner?
Athlete 1 had 70% slow oxidative and 30% fast oxidative.
Athlete 2 had 58% slow oxidative and 42% fast oxidative.
Athlete 3 had 25% slow oxidative and 75% fast oxidative.

A. Athlete 1

B. Athlete 2

C. Athlete 3

A. Athlete 1

Muscles that tire quickly and rely on anaerobic respiration will have contractions that are

A. moderate

B. fast

C. slow

B. fast

Fast glycolytic fibers produce more tension because they have more __________________

have more myosin and actin cross-bridges

___________ filaments of your postural muscles are composed of actin, nebulin, troponin and tropomyosin.

thin

The ability to store urine in the bladder or feces in the rectum prior to voiding is dependent upon _______________ muscle sphincters. Select all that apply.

A. nonstriated

B. striated

C. skeletal

D. smooth

A. nonstriated

B. striated

C. skeletal

D. smooth

In smooth muscle most of the calcium comes from __________________

interstitial fluid

______________ smooth muscle cells contract independently of each other and rarely contain gap junctions.

Multi-unit

A virus that invades the connective tissue of visceral smooth muscle will be discovered in the ________________

endomysium

In a maximally contracted muscle, which of the following disappears entirely? Select all that apply.

1. E
2. A
3. C
4. B
5. D

3. C

4. B

____________ has an intracellular cytoskeleton composed of intermediate filaments.

Smooth muscle

Goosebumps are caused by _______________

multi-unit smooth muscle

A drug that selectively binds the desmin protein will interfere with ___________________.

the contraction of smooth muscle cells

Increasing extracellular levels of calcium will have the least affect on __________________ muscle tissue when considering making the calcium available intracellularly for contraction.

smooth

Individuals who change their training regimen from sprinting to long-distance running will experience changes in muscle cell types from:

A. fast glycolytic into slow oxidative

B. fast glycolytic into fast oxidative-glycolytic

C. fast oxidative-glycolytic into fast glycolytic

D. slow oxidative into fast glycolytic

B. fast glycolytic into fast oxidative-glycolytic

Cardiac muscle contraction is initiated by an impulse received from somatic motor neurons.

• true
• false

false

Which property do cardiac and smooth muscle share?

A. gap junctions

B. sarcomeres

C. dense bodies

D. intercalated discs

A. gap junctions

Decreased levels of calcium (hypocalcemia) will have the most profound effect on ________________ muscle contraction.

smooth muscle contraction

Which part of the somite develops into the cervical, thoracic, lumbar, sacral and coccyx bones?

sclerotome

Damage to embryonic somites will inhibit the formation of the muscles responsible for chewing.

• true
• false

• false

Electrical signaling between cardiac cells is due to _____________--

gap junctions

Which somatic region will develop into the dermis?

1. A
2. B
3. C

1. A

Which of the following unique features of cardiac muscle cells accounts for synchronous contractions?

A. they are striated

B. they are involuntary

C. they have intercalated discs

D. they are nonstriated

C. they have intercalated discs

Disruption of the ________ of cardiac muscle tissue would interfere with the heart's ability to beat in synchronous fashion

gap junctions

The stomach, urinary bladder and small intestines will have

A. cardiac muscle

B. single-unit smooth muscle

C. skeletal muscle

D. multi-unit smooth muscle

B. single-unit smooth muscle

_________________ smooth muscle cells contract independently of each other.

Visceral, Single-unit

The inability to internalize signals from the outside of a cardiac muscle cell to the interior reflects a dysfunction of the cell's _____________.

transverse tubules

An Olympic athlete who trains for eight hours a day most likely develops a ___________ enlarged heart.

physiological

Examination of tissue obtained from a muscle biopsy reveals alternating light and dark protein bands. Deduce from where this biopsy was taken? Select all that apply.

A. the heart

B. the stomach

C. the bronchioles (airway)

D. a blood vessel

E. the gastrocnemius (calf muscle

A. the heart

E. the gastrocnemius (calf muscle

During fibrillation the chambers of the heart are unable to adequately relax and fill with blood. Which of the following describes how the healthy heart achieves optimal filling of its chambers?

A. by increasing the number of gap junctions used for each cardiac muscle contraction

B. by eliminating all of the calcium from the sarcoplasmic reticulum of cardiac muscle fibers

C. by allowing sustained contractions of cardiac muscle tissue (tetanus)

D. by maintaining cardiac muscle contractions longer than skeletal muscle contractions

D. by maintaining cardiac muscle contractions longer than skeletal muscle contractions

Action potentials in cardiac muscle tissue are generated by neurotransmitters (chemical messengers).

• true
• false

false

The actin and myosin myofilaments are arranged into sarcomeres in cardiac muscle tissue.

• true
• false

true

Intermediate filaments have a role in smooth muscle tissue analogous to the role of ________ in skeletal muscle tissue.

dystrophin

Smooth muscle contractions within a blood vessel serve to decrease the size of the vessel's opening (vasoconstriction). In this particular instance these smooth muscle contractions result in _____________ blood pressure within the blood vessel

higher

What can you do to slow down the typical progressive muscle mass declines associated with aging? Select all that apply.

A. lift weights

B. increase lipid intake

C. exercise aerobically

D .reduce protein intake

A. lift weights

C. exercise aerobically

Sarcomeres that display only D with no B and no C would be true of a muscle that is __________________

maximally contracted

_______________ is a structural protein that allows for a lot of the elasticity and extensibility exhibited in myofibrils.

titin

Which is a function of muscle? Select all that apply.

A. protection of underlying tissues

B. pushing eggs and sperm

C. storage of material in intestines

D. shivering

E. lubrication

F. maintaining postures

B. pushing eggs and sperm

C. storage of material in intestines

D. shivering

F. maintaining postures

Calcium plays an important role in successful skeletal muscle contractions. Identify all of the places where voltage-gated calcium channels occur that are relevant to skeletal muscle contractions. Select all that apply.

A. synaptic end bulbs

B. thin filaments

C. motor end plate

D. transverse tubule/sarcoplasmic reticulum interface

A. synaptic end bulbs

D. transverse tubule/sarcoplasmic reticulum interface

____________ is a structural protein that helps regulate the length and tension of thin filaments.

Nebulin

The contractile proteins in all three types of muscle tissue are ___________ and __________

actin & myosin

Which myofibril proteins of the slow oxidative skeletal muscle fibers generate force during a contraction?

contractile proteins

This fiber is intermediate in diameter, has lots of myoglobin, can contract quickly and has moderate resistance to fatigue.

fast oxidative-glycolytic

When you become a grandparent around age sixty-five, which of the following will be the first activity that noticeably becomes more difficult to do?

A. kissing your granddaughter goodnight

B. racing your grandson on bicycles

C. hugging your grandson

D. throwing a ball to your granddaughter

b. racing your grandson on bicycles

Much of the heat in the body is produced by __________ muscle

skeletal muscle

In an oxygen-depleted environment, which skeletal muscle fiber(s) will be least acutely effected?

fast glycotic

Myoglobin is most abundant in which skeletal muscle fiber type?

slow oxidative fiber

At what age would you most likely be if your muscle mass dropped from 60 pounds (27 kg) to 54 pounds (24.5 kg)?

1. 20 yrs
2. 70 yrs
3. 60 yrs
4. 45 yrs

2. 70 yrs

Frank wants to enter his triathlon but is unsure he is physically ready. He consults his A&P teacher about what type of muscle fibers he can develop. What explanation do you expect his teacher to give?

A. Repeated stimulation of endurance training activities will just cause hypertrophy in the fibers that are preexisting.

B. All fibers are genetically predetermined and cannot be changed.

C. Repeated stimulation of endurance training activities will help fast oxidative-glycolytic fibers develop from fast oxidative fibers.

D. Over time, with appropriate endurance training, all fibers can be changed in slow oxidative and fast oxidative-glycolytic

C. Repeated stimulation of endurance training activities will help fast oxidative-glycolytic fibers develop from fast oxidative fibers.

Assisted-living facilities (nursing homes) for the elderly should not provide a work-out room for their clients since exercise is not effective in older people.

• true
• false

false

When a skeletal muscle is stretched, the

A. A band will decrease

B. I band will increase

C. I band will decrease

D. A band will increase

B. I band will increase

Which somatic region develops to protect the spinal cord?

1. C
2. A
3. B

1. C

What do intercalated discs and the ligand gates on motor end plates have in common?

Both are involved in depolarization of the cellular membrane

What is the relationship between cardiac and skeletal muscle? Select all that apply.

A. Cardiac and skeletal muscle have different regulatory proteins used in muscle contraction.

B. In cardiac and skeletal muscle, myosin will hydrolyze ATP before crossbridges will form.

C. The method by which calcium is released from the sarcoplasmic reticulum is the same in cardiac and skeletal muscle.

D. In cardiac and skeletal muscle, crossbridges will not detach unless myosin binds to an ATP molecule.

B. In cardiac and skeletal muscle, myosin will hydrolyze ATP before crossbridges will form.

D. In cardiac and skeletal muscle, crossbridges will not detach unless myosin binds to an ATP molecule.

Harvey was recently diagnosed with myasthenia gravis, an autoimmune disease that causes the number of functional acetylcholine receptors in the motor end plate to decrease. Various drugs can be used to treat this condition. Which of the following mechanisms of such drugs would help relieve the symptoms?

A. calcium inhibitors

B. acetylcholine inhibitors

C. acetylcholinesterase inhibitors

D. sodium channel inhibitors

C. acetylcholinesterase inhibitors

Multiunit smooth muscle tissue contracts similarly to skeletal muscle fibers of ____________ motor units.

small

identify letter C

sarcoplasm

___ (#) terminal cisternae and the T-tubule compose a triad

2

Myosin attaches to thin filaments and slides them using _______________ as an energy source

ATP, adenosine triphosphate

____ (#) thin filaments are associated with every thick filament, i.e indicate how many.

2

An action potential propagating down the transverse tubule causes the terminal cisterns to release _________________

calcium

Three hearts are dissected from individuals with unknown histories. Two of the three hearts are enlarged. Select all of the possible reasons the two hearts may be enlarged.

A. They are from individuals who had low blood pressure histories.

B. They are from well-trained professional athletes.

C. They are from individuals with a history of heart disease.

D. They are from individuals who had arthritis issues.

B. They are from well-trained professional athletes.

C. They are from individuals with a history of heart disease.

Muscles that resist fatigue and rely on aerobic oxygen will have contractions that are

A. fast

B. quick

C. slow

C. slow

During the "World's Strongest Man" competition much attention was given to the winner of the giant log lift for setting a record of 212.5 kg (467.5 lbs). You speculate that this athlete has a greater proportion of _________ skeletal muscle fibers than any of the other fiber types.

fast glycotic

A man who has fallen from a ladder is now paraplegic (paralyzed from the waist down). Which type(s) of muscle fibers will be lost as a result? Select all that apply.

A. type IIb

B. slow oxidative

C. fast glycolytic

D. type IIa

E. type I

B. slow oxidative

D. type IIa

A cardiac event that has damaged the heart's pacemaker will have a direct effect on which of the following?

A. ability of the cardiac muscle to stretch

B. ability of the cardiac muscle to generate nerve impulses

C. autorhythmicity

D. chemical stimulation of the cardiac muscle

C. autorhythmicity

At twenty-five years of age, John weighed 180 pounds (81 kg) and had a total muscle mass of 76 pounds (34 kg). Approximately how old will John be when his total muscle mass measures 38 pounds (17 kg) given that his total weight has remained fairly constant through time?

A. eighty-five years old

B. sixty years old

C. forty-five years old

D. thirty years old

B. sixty years old

A genetic mutation that results in malformation of the actin protein will directly effect the function of which type(s) of muscle tissue? Select all that apply.

A. cardiac

B. smooth

C. skeletal

A. cardiac

B. smooth

C. skeletal

A genetic mutation that results in malformation of the myosin protein will directly effect the function of which type(s) of muscle tissue? Select all that apply.

A. cardiac

B. smooth

C. skeletal

A. cardiac

B. smooth

C. skeletal

A virus that destroyed somites would cease further development of the (select all that apply)

A. pharyngeal pouches

B. intermediate mesoderm

C. somitomeres

D. vertebrae

E. muscles that move the back

D. vertebrae

E. muscles that move the back

Failure of mesodermal cells to migrate during the embryonic period will not effect further development of muscle of the

A. bladder

B. stomach

C. heart

D. limbs

D. limbs

When muscles undergo resistance training there is trauma to the muscle cells. Which cells are present on the periphery to help repair the damaged area?

satellite cells

Which would have the lowest number of motor units?

A. postural muscles in the back

B. muscles of the upper arm

C. facial muscles

D. muscles in the toes

E. muscles moving the eyeball

A. postural muscles in the back

These fibers have a high amount of myoglobin, which gives them a reddish or pinkish coloration. Select all that apply.

A. slow oxidative fibers

B. fast oxidative-glycolytic fibers

C. fast glycolytic fibers

A. slow oxidative fibers

B. fast oxidative-glycolytic fibers

Aerobic exercises such as running and swimming will have which effect on skeletal muscle?

A. increase the number of mitochondria per cell

B. increase the number of fascicles

C. increase the number of motor units

D. increase the number of muscle cells

A. increase the number of mitochondria per cell

Perform these movements: blink your eye, squeeze your calf (soleus muscle), and squeeze your anal sphincter. Which contains fast twitch fibers?

A. anal sphincter muscles

B. calf muscles (soleus)

C. eye muscles

C. eye muscles

Long-distance running and biking will have what effect on skeletal muscle tissue?

A. Increase number of muscle cells per muscle cell

B. Increase number of mitochondria and myoglobin per muscle cell

C. Increase number of motor units

D. Increase number of fast glycolytic fibers

B. Increase number of mitochondria and myoglobin per muscle cell

An individual is often fatigued from strength training when she used to be able to withstand high-energy activities. The doctor orders biopsies from her muscles to test for mitochondrial myopathy. Which type of fiber should the doctor not biopsy?

A. fast oxidative

B. slow oxidative

C. fast oxidative-glycolytic

C. fast oxidative-glycolytic

Connective tissues in skeletal muscles function in

A. storing creatine phosphate

B. regulating frequency of muscle contractions

C. depolarizing the membrane

D. aligning the myofibrils with the muscle cell membrane

E. transmitting mechanical force

E. transmitting mechanical force

Stretching your muscles prior to strength training can be accomplished in less time during the __________ months.

summer

The muscles of athletes from various sports were analyzed during a physiology lab and only one had a high proportion of fast glycolytic fibers relative to slow oxidative fibers. Which type of sport does this athlete most likely participate in?

A. two of the choices are correct

B. long-distance swimmer

C. marathon runner

D. sprinter

D. sprinter

Muscle enlargement seen in body builders, for example, is a consequence of muscle _________________

hypertrophy

A single motor unit will innervate

A. a mixture of fiber types

B. FOG fibers only

C. one fiber type

D. FG fibers only

C. one fiber type

Which skeletal muscle fiber type would contain the most thick and thin filaments?

A. fast oxidative-glycolytic fiber

B. slow oxidative fiber

C. fast glycolytic fiber

C. fast glycolytic fiber

Which skeletal muscle fiber type can perform aerobic and anaerobic cellular respiration

A. slow oxidative fiber

B. fast glycolytic fiber

C. fast oxidative-glycolytic fiber

C. fast oxidative-glycolytic fiber

__________ will be most abundant in a marathon runner.

A. Fast oxidative-glycolytic fibers

B. FOG fibers

C. Fast glycolytic fibers

D. Slow oxidative fibers

D. Slow oxidative fibers

Low-intensity activity, such as standing, will recruit

A. None of the choices is correct.

B. slow oxidative fibers

C. fast glycolytic fibers

D. fast oxidative-glycolytic fibers

B. slow oxidative fibers

Which skeletal muscle fiber type is the first to be recruited for contractions?

slow oxidative fiber

_______________ allows the heart to stretch without tearing.

extensibility

___________, ____________, or _______________ muscle initiates its own contractions all throughout one's lifetime.

Cardiac, visceral, or smooth

Picking up a twenty ounce bottle of soda would primarily require the recruitment and activation of ______________ motor units.

slow oxidative

Which of the following words would best indicate the notion that energy for a skeletal muscle fiber is generated anaerobically?

A. fast

B. slow

C. oxidative

D. glycolytic

D. glycolytic

_____________ are better suited for a 400-800 meter run.

A. Fast oxidative-glycolytic fibers

B. Slow oxidative fibers

C. Slow oxidative fibers and fast glycolytic fibers

D. Fast glycolytic fibers

A. Fast oxidative-glycolytic fibers

Most body muscles contain _____________ that allow(s) them to exhibit a range of contractile speeds and fatigue resistance.

A. one fiber type

B. only SO and FOG fiber types

C. only FG and SO fiber types

D. a mixture of fiber types

D. a mixture of fiber types

Which location would be described if fast glycolytic was the most abundant skeletal muscle fiber type?

A. gastrocnemius

B. quadriceps femoris group

C. biceps brachii and triceps brachii

D. trapezius

C. biceps brachii and triceps brachii

The principal tissue in the heart wall is ________________

cardiac muscle tissue

How is cardiac muscle similar and different from skeletal muscle tissue? (list 1 way it is similar & 1 way it is different)

1. similar: it is striated like skeletal muscle tissue
2. different: its activity cannot be controlled voluntarily

• the ability to repeatedly generate spontaneous action potentials
• displayed by certain cardiac muscle fibers (as well as some smooth muscle fibers and nerve cells in the brain and spinal cord)

autorhythmicity

What is the effect that autorhythmicity has on the heart?

it generates these action potentials that cause alternating contraction and relaxation of the heart muscle fibers

what are 3 aspects of the structure of cardiac muscle fibers?

1. cardiac muscle fibers are shorter in length and less circular in the transverse section
2. They exhibit branching, which gives individual cardiac muscle fibers a “stair-step” appearance.
3. A typical cardiac muscle fiber is 50–100 μm long and has a diameter of about 14 μm

Are nuclei present in cardiac muscle fibers?

Usually one centrally located nucleus is present, although an occasional cell may have two nuclei

1. The ends of cardiac muscle fibers connect to neighboring fibers by irregular transverse thickenings of the sarcolemma referred to as __________________
2. An irregular transverse thickening of sarcolemma that contains desmosomes, which hold cardiac muscle fibers (cells) together, and gap junctions, which aid in conduction of muscle action potentials from one fiber to the next.

intercalated discs

1. hold cardiac fibers together

2. embedded in intercalated discs

desmosomes

What 2 things are apart of the intercalated discs?

1. desmosomes

2. gap junctions

1. Cell junctions that allow muscle action potentials to spread from one cardiac muscle fiber to its neighbors.

2. allow muscle action potentials to spread from one muscle fiber to its neighbors

3. embedded in intercalated discs

gap junctions

does cardiac muscle tissue have/ is it made up of all 3 types of connective tissue? (the -mysiums)

no, cardiac muscle tissue has an endomysium, but lacks a perimysium and epimysium

Cardiac muscle fibers display autorhythmicity, the ability to ___________________________________

repeatedly generate spontaneous action potentials

what is #1?

(cardiac muscle tissue)

desmosomes

what is #2?

(cardiac muscle tissue)

Mitochondrian

what is #3?

(cardiac muscle tissue)

sarcolemma

what is #4?

(cardiac muscle tissue)

nucleus

what is #5?

(cardiac muscle tissue)

cardiac muscle fiber

what is #6?

(cardiac muscle tissue)

gap junctions

what is #7?

(cardiac muscle tissue)

opening of transverse tubule

what is #8?

(cardiac muscle tissue)

gap junctions

What are the functions of intercalated discs in cardiac muscle fibers?

The intercalated discs contain desmosomes that hold the cardiac muscle fibers together and gap junctions that enable action potentials to be spread from one muscle fiber to another.

what is this structure?

desmosomes

what is this structure?

gap junctions

__________ are larger and more numerous in cardiac muscle fibers than in skeletal muscle fibers.

Mitochondria

Cardiac muscle fibers have the same arrangement of __________ and __________, and the same _________, ___________, and _________, as skeletal muscle fibers

1. actin and myosin
2. bands
3. zones
4. discs

The ________________ of cardiac muscle are wider but less abundant than those of skeletal muscle;

transverse (T) tubules

In cardiac muscle fibers, there is one T tubule per _________, located at the _______

1. sarcomere
2. Z disc

The sarcoplasmic reticulum of cardiac muscle fibers is ______________ than the SR of skeletal muscle fibers.

somewhat smaller

What is the major functional difference b/t cardial & skeletal muscle tissue?

Under normal resting conditions, cardiac muscle tissue contracts and relaxes about 75 times per minute ⭆This continuous, rhythmic activity is a major functional difference between cardiac and skeletal muscle tissue.

two main differences between skeletal & cardiac muscle?

1.

2.

1. continuous, rhythmic activity
2. source of stimulation

When can skeletal muscle tissue contract?

only when stimulated by acetylcholine released by an action potential in a somatic motor neuron

when can cardiac muscle contract?

cardiac muscle tissue can contract without extrinsic (outside) nervous or hormonal stimulation

what is cardiac muscle tissue's source of stimulation?

1. a conducting network of specialized cardiac muscle fibers within the heart

[Stimulation from the body's nervous system or endocrine system merely causes the conducting fibers to increase or decrease their rate of discharge]

Cardiac muscle tissue remains contracted _________________ than skeletal muscle tissue, allowing time for the chambers of the heart to relax and fill with blood between beat

10 to 15 times longer

cardiac muscle tissues contraction pattern permits the heart rate to increase significantly while preventing _________

tetanus

• sustained contraction which would stop blood flow within the heart.

tetanus

Like skeletal muscle, cardiac muscle fibers can undergo ___________ in response to an increased workload

hypertrophy

• called a physiological enlarged heart and it is why many athletes have enlarged hearts
• n increase in muscle mass due to an increase in muscle cell size
• an increase in the size of a muscle through an increase in the size of its component cells. It differs from muscle hyperplasia, which is the formation of new muscle cells. Depending on the type of training, the ______________ can occur through increased sarcoplasmic volume or increased contractile proteins.

hypertrophy

By contrast, a ________________ is related to significant heart disease

pathological enlarged heart

what is #1?

(cardiac muscle tissue)

myocardium

what is #2?

(cardiac muscle tissue)

pericardium

what is #3?

(cardiac muscle tissue)

endocardium

what is #1?

(cardiac muscle tissue)

nucleus

what is #2?

(cardiac muscle tissue)

sarcolemma

what is #3?

(cardiac muscle tissue)

transverse tubule

what is #4?

(cardiac muscle tissue)

mitochondrian

what is #5?

(cardiac muscle tissue)

sarcoplasmic reticulum

what is #6?

(cardiac muscle tissue)

thin filament (myosin)

what is #7?

(cardiac muscle tissue)

thick filament (actin)

what is #8?

(cardiac muscle tissue)

Z Discs

what is #9?

(cardiac muscle tissue)

I Band

what is #10?

(cardiac muscle tissue)

M line

what is #11?

(cardiac muscle tissue)

H zone

what is #12?

(cardiac muscle tissue)

A band

what is #13?

(cardiac muscle tissue)

sarcomere

how is smooth muscle tissue similar to cardiac muscle tissue?

it is activated involuntarily

what are the 2 types of smooth muscle tissue?

1. visceral smooth muscle tissue

2. multi-unit smooth muscle tissue

• More common type of smooth muscle tissue found in skin, walls of small arteries and veins, and walls of hollow viscera. Also called single-unit smooth muscle tissue
• is found in the skin, in wraparound sheets that form part of the walls of small arteries and veins, and in the walls of hollow viscera such as the stomach, intestines, uterus, and urinary bladder.
• Because the fibers connect to one another by gap junctions, muscle action potentials spread rapidly throughout the network. For example, when a neurotransmitter, hormone, or autorhythmic signal stimulates one fiber, the muscle action potential spreads to neighboring fibers, which then contract as a single unit.

visceral smooth muscle tissue

(a), one autonomic motor neuron synapses with several visceral smooth muscle fibers, and action potentials spread to neighboring fibers through gap junctions.

(b), three autonomic motor neurons synapse with individual multi-unit smooth muscle fibers. Stimulation of one multi-unit fiber causes contraction of that fiber only.

(c) Comparison between a relaxed and contracted smooth muscle fiber

histology of smooth muscle tissue

Smooth muscle fibers have thick and thin filaments but no ______________ and little ______________

1. transverse tubules
2. sarcoplasmic reticulum

Which type of smooth muscle is more like cardiac muscle than skeletal muscle, with respect to both its structure and function?

Visceral smooth muscle and cardiac muscle are similar in that both contain gap junctions, which allow action potentials to spread from one cell to its neighbors.

1. a kind of smooth muscle tissue that consists of individual fibers, each of which has its own motor neuron terminals
2. There are few gap junctions between neighboring fibers.
3. Less common type of smooth muscle tissue that consists of individual fibers, each of which has its own motor neuron terminals; found in walls of larger arteries, airways to the lungs, arrector pili muscle of hair follicles, muscles that control pupil diameter, and ciliary body that focuses the lens of the eye.

multi-unit smooth muscle tissue

As you just learned, stimulation of one visceral muscle fiber causes contraction of many adjacent fibers; in contrast, stimulation of one multi-unit smooth muscle fiber causes ____________________

contraction of that fiber only

What are 5 examples of parts of the body that contain multi-unit smooth muscle tissue?

1. The walls of large arteries
2. The airways to the lungs
3. The arrector pili muscles that attach to hair follicles
4. The muscles of the iris that adjust pupil diameter
5. The ciliary body that adjusts focus of the lens in the eye

Smooth muscle fibers are ______________ than skeletal muscle fibers

considerably smaller

A single relaxed smooth muscle fiber is ___________ long, _________ in the middle (3–8 μm), and _________ at each end

1. 30–200 μm
2. thickest in the middle
3. tapered at each end

Within each smooth muscle fiber is a single, ________, ___________________.

oval, centrally located nucleus

The ___________ of smooth muscle fibers contains both thick filaments and thin filaments, in ratios between about 1:10 and 1:15 respectively, but they are not arranged in orderly sarcomeres as in striated muscle.

sarcoplasm

1. filaments that contain the protein desmin and appear to have a structural rather than contractile role

2. Protein filament, ranging from 8 to 12 nm in diameter, that may provide structural reinforcement, hold organelles in place, and give shape to a cell.

intermediate filaments

Because the various intermediate filaments have no regular pattern of overlap, smooth muscle fibers _______________—thus the name smooth

do not exhibit striations

Smooth muscle fibers also lack _____________ and have little sarcoplasmic reticulum for storage of _____.

1. transverse tubules

2. sarcoplasmic reticulum

3. Ca²⁺

Smooth muscle tissue has an endomysium, but lacks a ___________ and ____________.

1. perimysium

2. epimysium