human anatomy chapter 9

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humans rely on muscles for (2)

1. Many of our physiological processes
2. Virtually all our dynamic interactions with the environment


three types of muscle tissue

1. skeletal muscle
2. cardiac muscle
3. smooth muscle


1. skeletal muscle functions

1. produce skeletal movement
2. maintain posture and body position
3. support soft tissue
4. regulate entering and exiting of material
5. maintain body temp.


2. cardiac muscle functions

1. Pushes blood through arteries and veins
2. Rhythmic contractions


3. Smooth muscle functions

1. Pushes fluids and solids along the digestive tract, for example
2. Involuntary contraction


Four basic properties that all muscle tissues share

1. excitability: The ability to respond to stimuli
2. contractility: The ability to shorten and exert a pull or tension
3. extensibility: The ability to continue to contract over a range of resting lengths
4. Elasticity: The ability to rebound toward its original length


Gross Anatomy of skeletal muscles is the study of... (4)

1. Overall organization of muscles
2. Connective tissue associated with muscles
3. Nerves associated with muscles
4. Blood vessels associated with muscles


Microscpoic anatomy of skeletal muscles is the study of... (3)

1. Myofibrils
2. Myofilaments
3. Sarcomeres


Gross Anatomy
Connective tissue of muscle

1. Epimysium
2. Perimysium
3. Endomysium


Gross Anatomy
Connective tissue of muscle
1. Epimysium
2. Perimysium
3. Endomysium

1. dense tissue that surrounds the entire muscle
2. dense tissue that divides the muscle into parallel compartments of fascicles
3. dense tissue that surrounds individual muscle fibers

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1. skeletal muscle (organ)
2. Muscle Fassicle (bundle of cells)
3. Muscle Fiber
4. Epimysium
5. Perimysium
6. Endomysium


Connective tissue of muscles

1. Tenconds: connect a muscle to a bone
2. Aponeuroses: Connect a muscle to a muscle


What converge to form tendons?(3)

1. Epimysium
2. Perimysium
3. Endomysium


Gross Anatomy
Nerves and Blood Vessels
1. Nerves....
2. There is a...
3. the nerve is...

1. Innervate the muscle
2. Chemical communication b/w a nerve and a muscle
3. "connected" to the muscle via the motor end plate---> this is the meuromuscular junction


Gross Anatomy
Nerves and Blood Vessels
4. Blood vessels...
5. they then...

4. Inntervate the endomysium of the muscle
5. branch to form coiled networks to accommodate flexion and extension of the muscle

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1. neuromuscular synapse
2. skeletal muscle fibers
3. Axons


Microanatomy of skeletal muscle fibers
1. Sarcolemma
2. Sarcoplasm
3. muscle fiber(3)

1. Membrane that surrounds the muscle cell
2. The cytosol of the muscle cell
3. A. Can be 30–40 cm in length
B. Multinucleated (each muscle cell has hundreds of nuclei)
C. Nuclei are located just deep to the sarcolemma


1. the sarcoplasm contains...
2. myofibrisl are responsible for...
3. myofibrils are attached to...
4. surrounding each myofibril is the...

1. myofibrils
2. the contraction of muscles
3. the sarcolemma at each end of the muscle cell
4. sarcoplasmic reticculum


1. Myofibrils are made of...
2. (these include...

1. myofilaments
2. A. Actin
B. Myosin


Sarcomere Organization
1. myosin
2. actin
3. both are arranged in...
4. all the myofilaments are arranged....

1. (Thick filament)
2. Thin Filament
3. repeating units called sarcomeres
4. parallel to the long axis of the cell


Sarcomere Organization
1. is...
2. approximately...
3. consists of...
4. this over lapping creates...

1. Main functioning unit of muscle fibers
2. 10,000 per myofibril
3. overlapping actin and myosin
4. the striations that gibe the skeletal muscle its identifiable characteristic


Sarcomere Organization
5. each Sarcomere consists of... (5)

A. Z line (Z disc)
B. I band
C. A band (overlapping A bands create striations)
D. H band
E. M line

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1. I band 4. H band
2. A band 5. thick filament
3. Z line 6. thin filament


Levels of organization
__A__ consists of __B__ -> Consists of __C__ -> consists of __D__ -> consists of __E__ -> consists of __F__ -> are made of __G__ and __H__

A. skeletal muscles B. Muscle fascicles
C. muscle fibers D. myofibrils
E. sarcomeres F. myofilaments
G. actin H. myosin

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1. skeletal mmuscle 4. myofibril
2. muscle fascicles 5. sarcomere
3. muscle fibers


1. twisted filament consisting of...
2. Each G actin molecule has an...
3. ____ bind to the active site on actin
4. ____: a protein that covers the the binding sites when the musle is relaxed
5. ___: holds tropomyosin in position

1. G Actin molecues
2. Active site
3. Myosin Cross- bridges
4. tropomyosin
5. troponin

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A. sarcomere B. H bank
c. myofibril D. Z line
E. M line F. Actin
G. Z line H. Titin
I. troponin J. Active Site
K. Tropomyosin L. G actin molecules


1. myosin filaments consist of...
2. Myosin is a ____. it is held in place by:
A. protein forming the...
B. a Core of...

1. an elongated tail and a globular head (cross-bridges)
2. stationary molecule
A. M line
B. Titin connecting to the Z lines


Muscle contraction
1. A contracting muscle ____ in length
2. Contraction is caused by
3. Contraction is triggered by
4. Muscle contraction requires the presence
5. When a muscle contracts, actin filaments
6. This sliding action is called the

1. shortens
2. interactions between thick and thin filaments within the sarcomere
3. the presence of calcium ions
4. ATP
5. slide toward each other
6. sliding filament theory


The sliding filament theory
Upon contraction:
1. The H band and I band
2. The zone of overlap gets
3. The Z lines move
4. The width of the A band

1. get smaller
2. larger
3. closer together
4. remains constant throughout the contraction


Events leading to muscle conraction
1. an ___travels down the axon of a nerve
2. _____from the end of the axon at the motor end plate
3. This ultimately causes the sarcoplasmic reticulum to
4. Calcium ions

1. impulse
2. acetylcholine is released
3. release its stored calcium ions
4. bind to troponin


Events leading to muscle contraction
5. This binding action causes a
6. This rotation
7. ____extend and bind to the binding sites on actin
8. the _____ thus sliding the actin myofilament
9. As the actin myofilaments are pulled toward each other, the

5. rotation of the troponin- tropomyosin complex
6. exposes the binding sites on the actin myofilament
7. myosin heads
8. cross-bridge pivot
9. muscle becomes shorter


Motor units and Muscle control
Motor units
1. Precise control (example)
2. Less precise control (example)

1. A motor neuron controlling two or three muscle fibers
A. the control over the eye muscles
2. A motor neuron controlling perhaps 2000 muscle fibers
A. the control over the leg muscles


Motor units and muscle control
Muscle tension Depends on

1. The frequency of stimulation
2. The number of motor units involved


Motor units and muscle control
1. Muscle tone
2. Muscle spindles

1. A. The tension of a muscle when it is relaxed
B. Stabilizes the position of bones and joints
2. These are specialized muscle cells that are monitored by sensory nerves



The net effect is an enlargement of the muscle


Muscle Atrophy

Discontinued use causes decreased muscle size and muscle tone


Three major types of skeletal muscle fibers

1. Fast Fibers (white fibers)associated with eye muscles
2. Intermediate Fibers (pink Fibers)
3. Slow fibers (red fibers)associated with leg muscles


features of fast fibers (7)

1. Large in diameter
2. Large glycogen reserves
3. Relatively few mitochondria
4. Muscles contract using anaerobic metabolism
5. Fatigue easily
6. Can contract in 0.01 second or less after stimulation
7. Produce powerful contractions


Features of slow fibers (6)

1. Half the diameter of fast fibers
2. Take three times longer to contract after stimulation
3. Can contract for extended periods of time
4. Contain abundant myoglobin (creates the red color)
5. Muscles contract using aerobic metabolism
6. Have a large network of capillaries


Features of intermediate fibers

1. Similar to fast fibers
A. Have low myoglobin content
B. Have high glycolytic enzyme concentration
C. Contract using anaerobic metabolism
2. Similar to slow fibers
A. Have lots of mitochondria
B. Have a greater capillary supply
C. Resist fatigue


Distribution of fast, slow, and intermediate fibers
1. Fast fibers (3)

A. High density associated with eye and hand muscles
B. Sprinters have a high concentration of fast fibers
C. Repeated intense workouts increase the fast fibers


Distribution of fast, slow, and intermediate fibers
2. Slow and intermediate fibers (4)

A. None are associated with the eyes or hands
B. Found in high density in the back and leg muscles
C. Marathon runners have a high amount
D. Training for long distance running increases the proportion of intermediate fibers


muscle classifications based on shape or arrangement of fibers (7)

1. Parallel muscle fibers
2. Convergent muscle fibers
3. Pennate muscle fibers
4. Unipennate muscle fibers
5. Bipennate muscle fibers
6. Multipennate muscle fibers
7. Circular muscle fibers


1. PArallel Muscle fibers

Muscle fascicles are parallel to the longitudinal axis
Biceps brachii and rectus abdominis

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A. Parallel muscle
B. PArallel muscle


2. Convergent Muscle Fibers

Muscle fibers form a broad area but come together at a common point
Pectoralis major

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D. Convergent muscle


3. Pennate Muscle Fibers
4. Unipennate muscle fibers

3. Muscle fibers form an oblique angle to the tendon of the muscle
4. All the muscle fibers are on the same side of the tendon
Extensor digitorum

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E. Unipennate muscle


5. Bipennate muscle fiber

5. Muscle fibers are on both sides of the tendon
Rectus Femoris

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F. Bipennate Muscle


6. Multipennate muscle fibers

6. The tendon branches within the muscle
Deltoid muscle

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G. multipennate muscle


7. Circular muscle fibers
B. examples

7. Muscle fibers form concentric rings
A. Sphincter muscles
B. Orbicularis oris and orbicularis oculi

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H. circular muscle


Muscle Terminology
1. Origin
2. Insertion
3. Action

1. Point of muscle attachment that remains stationary
2. Point of muscle attachment that is movable
3. The function of the muscle upon contraction


Muscles can be grouped according to their primary actions into four types:

1. Prime Movers (agonists)
2. Antagonists
3. Synergists
4. Fixators


1. Prime Movers (agonists)
2. Antagonists
3. Synergists
4. Fixators

1. Responsible for producing a particular movement
2. Actions oppose the action of the agonist
3. Assist the prime mover in performing an action
4. Agonist and antagonist muscles contracting at the same time to stabilize a joint


1. Prime Movers (agonists) examples
2. Antagonists examples
3. Synergists examples
4. Fixators examples

1. Biceps brachii – flexes the lower arm
2. Triceps brachii – extends the lower arm
3. Latissimus dorsi and teres major – contract to move the arm medially over the posterior body
4. Flexor and extensor muscles contract at the same time to stabilize an outstretched hand


Muscles can be named for

1. Specific body regions or location
2. Shape of the muscle
3. Orientation of the muscle fibers
4. Specific or unusual features
5. Its origin and insertion points
6. Primary function
7. References to occupational or habitual action


Specific body regions or locations
1. brachialis
2. tibialis anterior

1. associated with the brachium of the arm
2. associated with the anterior tibia


Shape of the muscle
1. trapezius
2. Deltoid

1. trapezoid shape
2. triangular shape


Orientation of the muscle fibers
1. Rectus femoris
2. External oblique

1. straight muscle of the leg
2. muscle on outside that is oriented with the fibers at an angle


Specific or unusual features
1. Biceps brachii
2. Teres Major

1. two origins
2. long, big, rounded muscle


Origin and insertion points
1. Sternocleidomastoid
2. Genioglossus

1. points of attachment are sternum, clavicle, and mastoid process
2. points of attachment are chin and tongue


Primary functions
1. Flexor carpi radialis
2. Adductor longus

1. a muscle that is near the radius and flexes the wrist.
2. a long muscle that adducts the leg


References to occupational or habitual actions
1. Buccinator
2. Sartorius

1. the buccinator area moves when playing a trumpet
2. derived from the Latin term (sartor), which is in reference to “tailors.” Tailors used to cross their legs to form a table when sewing material


Levers and Pulleys: A Systems Design for Movement
1. most of the time, upon contraction, a muscle causes...
2. this action is applied to a ____
3. This Lever moves on a fixed point called the ___
4. The action of the lever is apposed by a...

1. action
2. Lever (a bone)
3. Fulcrum (joint)
4. Force acting in the opposite direction


There are three classes of levers

1. First class
2. second class
3. third class


classes of levers
1. first class

1. The fulcrum (joint) lies between the applied force and the resistance force (opposed force)
tilting the head forward and backward


classes of levers
2. second class

2. The resistance is located between the applied force and the fulcrum (joint)
standing on your tip toes


classes of levers
3. third class

3. The force is applied between the resistance and fulcrum (joint)
flexing the lower arm


Levers and Pulleys: A Systems Design for Movement
1. sometimes, a tendon may...
2. this bony projection could be called...
3. example

1. loop around a bony projection
2. pulley
3. lateral malleolus and trochlea of the eye


Changes that occur in muscles as we age

1. Skeletal muscle fibers become smaller in diameter
2. There is a decrease in the number of myofibrils
3. Contain less glycogen reserves
4. Contain less myoglobin
5. There is a decrease in myosatellite cells
6. There is an increase in fibrous connective tissue


changes in muscles as we age
4. Contain less myoglobin results in(2)

1. decrease in strength and endurance
2. Muscles fatigue rapidly


changes occur in muscles as we age
6. There is an increase in fibrous connective tissue
A. Results in (2)

1. Results in fibrosis
2. The ability to recover from muscular injuries decreases