Chapter 9- Muscles and Muscle Tissue
What are the types of muscle tissue
skeletal, smooth, cardiac
Which type of muscle tissue are attached to bone and skin, are striated, voluntary, contract rapidly, and require nervous system stimulation?
What type of muscle tissue is only in the heart, striated, can contract without nervous system stimulation, and is involuntary?
What type of muscle tissue is also called visceral, is not striated, can contract without nervous system stimulation, is involuntary, and found in the walls of hollow organs?
What type of muscle tissue is multinucleated?
What special characteristic of muscle tissue is the ability to receive and respond to stimuli?
What special characteristic of muscle tissue is the ability to shorten forcibly when stimulated?
What special characteristic of muscle tissue is the ability to be stretched?
What special characteristic of muscle tissue is the ability to recoil to resting length?
What are the important functions of muscle?
movement of fluid or bones; maintain posture and body position; stabilizing joints; heat generation
What are the additional functions of muscles?
protect organs; form valves; control pupil size; causes goosebumps
Each muscle is served by what?
one artery, one nerve, and one or more veins
What is the most external part of skeletal muscle - a dense, irregular connective tissue that surrounds the entire muscle?
What is the fibrous connective tissue that surrounds fascicles (groups of muscle fibers) in skeletal muscle?
What is the fine areolar connective tissue surrounding each individual muscle fiber/cell?
Skeletal muscle attaches in at least what two places?
origin and insertion
What type of attachment in skeletal muscle occurs when the epimysium is fused to the periosteum of bone or the perichondrium of cartilage?
What type of attachment in skeletal muscle occurs when connective tissue wrappings extend beyond the muscle as rope-like tendon or sheetlike aponeurosis?
What is the plasma membrane of a skeletal muscle fiber/cell called?
What is the cytoplasm called in a skeletal muscle fiber?
What are the modified structures called in a skeletal muscle fiber?
myofibrils, sarcoplasmic reticulum, and T tubules
In skeletal muscle, what is the lighter region in the middle of the dark A band, where filaments do not overlap?
In skeletal muscle, what is the line of protein myomesin that bisects the H zone?
In skeletal muscle, what is the coin shaped sheet of proteins on the midline of the light I band that anchors thin filaments and connects myofibrils to one another?
Z disc (line)
Which filaments run the entire length of the A band?
Which filaments run the length of the I band and partway into the A band?
What is the region between two successive Z discs called?
What is the smallest contractile unit (functional unit) of muscle fiber?
What are the thin filaments called that extend across the I band and partway into A band, and are anchored to Z discs?
What are the thick filaments called that extend the length of the A band and connect at the M line?
Myosin heads contain 2 smaller, light polypeptide chains that act as ______ _______ during contraction.
What are the regulatory proteins that bind to actin?
tropomyosin and troponin
What links thin filaments to proteins of the sarcolemma; and are mutated in someone with muscular distrophy?
What functions in regulation of intracellular calcium levels, stores and releases calcium to allow muscles to contract?
What are continuations of the sarcolemma, increase the muscle fiber's surface area, penetrate the cell's interior at each A band-I band junction, and associate with paired terminal cisterns to form triads that encircle each sarcomere?
In the triad, what conducts impulses deep into the muscle fiber?
During contraction, thin filaments slide past thick filaments, and actin and myosin overlap more. This is called?
sliding filament model of contraction
What occurs when myosin heads bind to actin?
What forms and breaks several times, ratcheting thin filaments towards the center of the sarcomere?
What must happen for skeletal muscle to contract?
activation (must generate action potential in the sarcolemma) and excitation-contraction coupling (action potential is propagated along the sarcolemma and calcium levels rise briefly)
What does the sarcoplasmic reticulum release to bind to troponin?
What happens when calcium/potassium enter/leave the cell?
It becomes depolarized
When calcium binds to troponin, what is exposed?
myosin-binding sites on actin
What binds to actin, causing contraction to begin?
Action potential travels along what, causing the sarcoplasmic reticulum to release calcium?