Striated Muscle

Question 1

what are all the functions of muscle (7)?

Answer 1

1) . produce movement,
2) . help maintain posture,
3) . power respiration,
4) . produce body heat,
5) . communicate w/other organs,
6) . constrict organs and blood vessels,
7) . produce cardiac contraction

Question 2

4 properties of muscle

Answer 2

contractility
excitability
extensiblity
elasticity

Question 3

what are functional syncytium?

Answer 3

intercalated disks and gap junctions in striated cardiac muscle

Question 4

what are the components of a sarcomere?

Answer 4

I-band
A-Band
H-band
Z-discs
M-line

Question 5

what is the I-band?

Answer 5

thin filaments

actin

Question 6

what is in the A-band?

Answer 6

thick filaments

myosin

Question 7

What is the H-band?

Answer 7

located within A band
Contain only thick filaments
changes width w/muscle contraction

Question 8

What are the Z-discs?

Answer 8

form the boundaries of the sarcomere

Question 9

what occurs in a sarcomere during a concentric contraction?

Answer 9

Z-disk move closer together
Width of H-band diminishes
A-band width stays same
thin filaments slide toward H-zone/M-line

Question 10

how does Ca 2+ assist in muscle contraction?

Answer 10

binds to troponin, moves it, reveals binding site of tropomyosin

Question 11

how many nuclei does skeletal muscle have?

Answer 11

multiple

Question 12

how many nuclei does cardiac muscle have?

Answer 12

one

Question 13

what is the primary purpose of muscle?

Answer 13

to produce force

Question 14

where does force production occur in muscle?

Answer 14

sarcomeres, it is transmitted along the muscle to tendons

Question 15

what is the fundamental unit of muscle?

Answer 15

sarcomere

Question 16

What are the connective tissue layers within muscle?

Answer 16

1) . epimysium
2) . perimysium
3) . endomysium

Question 17

where is epimysuium?

Answer 17

around the whole muscle

Question 18

where is perimysium located?

Answer 18

around fascilces

Question 19

where is endomysium located?

Answer 19

around each muscle cell/fiber

Question 20

what allows for the transmission of force through the whole muscle?

Answer 20

connective tissue matrix

Question 21

T/F: connective tissue repairs very slowly and can impact movement and limit functionability

Answer 21

True

Question 22

what is the sarcolemma?

Answer 22

plasma membrane of the muscle cell

Question 23

what are satellite cells?

Answer 23

peripheral cells within individual muscle cells, help with tissue repair in skeletal muscle

Question 24

which filament moves as the sarcomere contracts?

Answer 24

actin/thin filaments

Question 25

during maximal contraction what is no longer visible in the sarcomere?

Answer 25

H zone

Question 26

what forms the boundaries of the sarcomere?

Answer 26

Z discs

Question 27

T/F: following muscle damage, actin can be measured in the blood?

Answer 27

True

Question 28

what on the muscle cell senses the voltage change from an axon terminal?

Answer 28

DHP receptor

Question 29

how does the AP reach the SR?

Answer 29

travels down the T-tubule and stimulate the DHP recepotr

Question 30

how does a muscle relaxer inhibit contraction?

Answer 30

limits release of Ca+ form SR or inhibits ACh from binding to motor end plates

Question 31

define motor unit

Answer 31

a motor neuron and all muscle fibers that it innervates

Question 32

T/F: muscle fibers innervated by the same motor unit can be different muscle fiber types

Answer 32

FALSE

Question 33

what happens as more motor units are recruited?

Answer 33

a stronger contraction is generated

Question 34

how would you expect to see in motor units organized within muscles designed for strength?

Answer 34

large number of muscle fibers per motor unit

Question 35

what would you expect to see in motor units organized within muscle designed for fine motor skills?

Answer 35

small number of fibers per motor unit

Question 36

what is the order of recruitment with motor units?

Answer 36

small motor units are recruited before larger motor units

Question 37

how could you tell if someone has more sarcomeres compared to another person?

Answer 37

size of muscles, larger muscles means more sarcomeres

Question 38

what causes muscle fatigue?

Answer 38

decreased ATP and increased ADP

Question 39

what is tetanus?

Answer 39

muscle contracts and remain contracted

Question 40

give an exampole of tetany

Answer 40

a charley horse, lock jaw

Question 41

what is required to get a tetany?

Answer 41

a summation

Question 42

what is a summation?

Answer 42

a high frequency of stimuli

Question 43

what is the length tension relationship?

Answer 43

the distance between actin and mysin determines how much tension/force can be produced.

Question 44

define pennation

Answer 44

refers to the orientation of how the muscle fiber run relative to the whole muscle

Question 45

what is pennation angle in reference to?

Answer 45

the location of the tendon

Question 46

what does a high degree of pennation allow for?

Answer 46

more muscle fibers to be packed in the same volume, results in more force production

Question 47

expected length and pennation angle in muscles that generate velocity

Answer 47

long fiber length, small pennation angles

Question 48

expected length and pennation angle in muscles that generate force

Answer 48

short fiber length, larger pennation angle

Question 49

individuals with a spinal cord injury would develop what type of muscle fiber type?

Answer 49

fast twitch (type 2a) because they are unable to exercise and will therefore fatigue quicker

Question 50

as we age, what happens to the number of satellite cells?

Answer 50

decreases

Question 51

satellite cell # with age, implications for PT

Answer 51

less satellite cells in older patients mean slower healing time

Question 52

what is fibrosis?

Answer 52

scar tissue, will result in decreased ROM

Question 53

how is force transmitted from the sarcomere to the tendon?

Answer 53

via connective tissue

Question 54

how many thin filaments surround each thick filament?

Answer 54

6

Question 55

how many thick filaments surround each thin filament?

Answer 55

3

Question 56

what is the myotendinous junction?

Answer 56

where the muscle connects to the tendon, is a weak point within the muscle but can be hypertrophied w/resistance training

Question 57

what is the purpose of the costamere?

Answer 57

connects the z line of the sarcomere to sarcolemma of a myofiber which helps transmit force

Question 58

what limits action between actin and mysin?

Answer 58

the troponin complex