Muscle

Question 1

The two types of muscle tissue that are striated

Answer 1

skeletal and cardiac

Question 2

How many muscle fibers compose a fascicle

Answer 2

ten to one hundred

Question 3

What connective tissue covering surrounds each fascicle ( name and type)

Answer 3

perimysium-dense irregular

Question 4

What connective tissue covering surrounds each sk mus fiber (name and type)

Answer 4

endomysium- loose areolar

Question 5

What connective tissue covering surrounds an entire sk muscle (name and type)

Answer 5

epimysium/fascia- dense irregular

Question 6

holds muscles with similar function together in compartments

Answer 6

deep fascia

Question 7

define aponeurosis

Answer 7

a very broad tendon

Question 8

thin filament is composed of these three proteins

Answer 8

globular (G) actin, tropomyosin and troponin

Question 9

thin filaments attach to this structure whose ends define the sarcomere

Answer 9

Z disc/line

Question 10

the Z disc lies in what band

Answer 10

the light-colored I band (thin filaments)

Question 11

what band is comprised of thick AND thin filaments

Answer 11

the dark-colored A band

Question 12

what 2 elements comprise the H zone

Answer 12

the M line and ONLY thick filaments

Question 13

what protein extends from the Z disc to the M line

Answer 13

the elastic Tintin protein (also attaches to the thick filaments)

Question 14

what two structures maintain the organization of the thick filaments

Answer 14

the M line and tintin protein

Question 15

structure that moves with the thin filament when it slides

Answer 15

Z disc

Question 16

The three types of muscle protein

Answer 16

contractile (myosin, actin), regulatory proteins (troponin and tropomyosin), structural proteins (tintin, dystrophin, myomesin)

Question 17

which are there more of (in all muscle types): thin or thick filaments

Answer 17

thin (all muscle types have nearly twice as many. difference in number of thick and thin greatest in sm mus. sk mus: hexagonal arrangement)

Question 18

which of the filaments “slides” in the sliding filament theory

Answer 18

thin

Question 19

In what direction will the sacromere contract

Answer 19

toward the center of the muscle

Question 20

Myosin has binding sites for what 2 molecules

Answer 20

G- actin and ATP

Question 21

Ca in the sarcoplasm binds where

Answer 21

on troponin

Question 22

Globular heads of myosin are also called

Answer 22

cross-bridges

Question 23

How many heavy and light chain polypeptides make up myosin

Answer 23

2 heavy chains (head and tail), 4 light chains (head only)

Question 24

What is necessary for relaxed muscle state detachment of myosin from actin?

Answer 24

ATP binding breaks actin-myosin bond

Question 25

when a protein loses affinity for a substrate due to substrate binding at another site (as occurs in myosin)

Answer 25

allosteric regulation

Question 26

the state of ATP during the power stroke phase of the cross-bridge cycle:

Answer 26

During this time the ADP and inorganic phosphate detach from the myosin head.

Question 27

the event that occurs when hydrolysis of ATP occurs resulting in ADP and inorganic phosphate:

Answer 27

the myosin head recocks

Question 28

The three subunits of troponin are

Answer 28

troponin C (calcium), troponin T (tropomyosin) and troponin I (inhibitory/actin-binding).

Question 29

Process in which action potentials cause the release of calcium, formation of cross-bridges and sliding of thin over thick filaments

Answer 29

excitation-contraction coupling

Question 30

the single T tubule in contact with sarcoplasmic reticulum on both sides is termed

Answer 30

triad

Question 31

how does the T-tubule signal the sarcoplasmic reticulum to release Ca

Answer 31

by the "foot proteins" connecting dihydroxypyridine receptor + ryanodine receptor; a modified voltage-gated Ca channel

Question 32

How is Ca returned to the SR

Answer 32

after a certain time, all Ca is re-taken up by Calcium ATPase

Question 33

sk muscles are innervated by...

Answer 33

alpha motor neurons of ventral gray matter

Question 34

Define the term motor unit

Answer 34

a somatic motor neuron and ALL the muscle fibers it innervates

Question 35

receptors located on the motor end plate and are classified as

Answer 35

nicitinic acetyl choline

Question 36

infolded region of the sarcolemma that contains the acetylcholine receptors

Answer 36

motor end plate

Question 37

the force exerted on the muscle by an object, including the weight of an extremity

Answer 37

load

Question 38

A muscle contraction in which tension is generated but no movement occurs

Answer 38

isometric

Question 39

contraction in which tension is generated AND movement occurs (eccentric or concentric contraction)

Answer 39

isotonic

Question 40

response of a single muscle fiber to a single action potential

Answer 40

twitch

Question 41

The three phases of a twitch contraction

Answer 41

latent (cross-bridges form), contraction, relaxation

Question 42

what type smooth mus has stretch-induced excitation and more gap junctions

Answer 42

single unit

Question 43

hollow organs (uterus, GI, bladder) and SMALL vessels are what type of sm mus

Answer 43

single unit

Question 44

what are examples of multiunit sm mus

Answer 44

arrector pili, airways, large arteries, ciliary body and muscles of the eye

Question 45

thin filaments of sm mus consist of

Answer 45

tropomyosin and actin (no troponin)

Question 46

attached to the thin filament and act in similar manner to the Z disc in skeletal muscle

Answer 46

dense bodies

Question 47

sources for Ca in the sm muscle

Answer 47

SR, caveolae

Question 48

the binding of calcium to calmodulin activates this enzyme

Answer 48

myosin light chain kinase

Question 49

why is the shortening velocity slower in sm mus compared with sk mus

Answer 49

deceased rate of kinase and ATPase activity