Physiology 4 - Muscles

Front 1

What are the two muscle contractile proteins?

Back 1

Actin - thin
Myosin - thick

Front 2

What are the regulatory proteins of muscle?

Back 2

troponin
tropomyosin

Front 3

What are the giant accessory proteins of muscle?

Back 3

nebulin
titin

Front 4

What are the smallest units of muscle?

Back 4

myofibrils (actin and myosin)

Front 5

What component of a muscle fiber has voltage gated channels and is excitable?

Back 5

sarcolemma

Front 6

What component of a muscle fiber wraps around each myofibril, has t-tubules and allows AP's to reach the interior of the cell?

Back 6

sarcoplasmic reticulum

Front 7

What component of a muscle fiber directs the release of Ca2+.

Back 7

terminal cisternae

Front 8

What is a t-tubule and its terminal cisternae called?

Back 8

triad

Front 9

A myosin head is also called a ____.

Back 9

crossbridge

Front 10

The SR releases Ca2+ which binds to ____ in muscle contraction.

Back 10

troponin

Front 11

At rest what covers the binding site on the actin?

Back 11

tropomyosin

Front 12

What accessory protein allows the thick filaments to stretch and return to their original length?

Back 12

titin

Front 13

What accessory protein helps stabilize the thin filaments?

Back 13

nebulin

Front 14

z line to z line is defined as a ____.

Back 14

Sarcomere

Front 15

What must be present for crossbridge cycling to occur?

Back 15

ATP
Ca2+

Front 16

A motor neuron innervates ____ muscle fiber(s), while a muscle fiber is innervated by ____ motor neuron(s).

Back 16

several
one

Front 17

Where does a motor neuron meet the muscle fiber, and what is the gap called?

Back 17

neuromuscular junction
neuromuscular cleft

Front 18

Is a motor end plate part of the motor neuron or muscle fiber?

Back 18

muscle fiber
sarcolemma formed around a motor neuron

Front 19

A motor neuron releases ____ which binds to a ____ receptor, which causes an ____ and ____ of the muscle fiber.

Back 19

ACh
Nicotinic ACh
end-plate potential
depolarization

Front 20

What is a single contraction-relaxation cycle called?

Back 20

twitch

Front 21

What happens when Ca2+ levels fall and begin to be pumped back into the SR? What is used to pump it back into the SR?

Back 21

Ca2+ unbinds from troponin and tropomyosin slides back to cover the actin binding site causeing muscle relaxation
Ca2+ - ATPase

Front 22

What would happen if the Ca2+ - ATPase did not function correctly?

Back 22

Since it is what pumps Ca2+ back into the SR, Ca2+ would remain outside the SR and the muscle would not be able to relax

Front 23

What is muscle's quick energy storage compound?

Back 23

Creatine phosphate

Front 24

Creatine phosphate + ADP ---> ?
What direction does this reaction go during activity?

Back 24

creatine + ATP
to the right

Front 25

What do muscles use in the first few seconds of moderate aerobic activity?

Back 25

stored gycogen to make glucose

Front 26

During anaerobic metabolism, what does glucose form?

Back 26

lactate
only 2 ATP per molecule

Front 27

What is the up and downside of anaerobic metabolism?

Back 27

fast
not sustainable

Front 28

What is the main source of energy after 30 minutes of activity?

Back 28

fatty acids

Front 29

How does muscle get energy after its own glycogen stores are depleted?

Back 29

from glucose and fatty acids via the bloodstream

Front 30

Short bursts of exercise use ____ metabolism.

Back 30

anaerobic

Front 31

Long durations of exercise use ____ metabolism.

Back 31

aerobic

Front 32

For a muscle to move a load, the ____ must be greater than the ____.

Back 32

muscle tension
load

Front 33

Force exerted on an object by a muscle is called ____.

Back 33

tension

Front 34

Force exerted on muscle by an object is the ____.

Back 34

load

Front 35

What is it called when a muscle moves a load and shortens.

Back 35

isotonic contraction

Front 36

What is it called when a muscle has tension but does not shorten or change in length?

Back 36

isometric contraction

Front 37

Why is there a time lag between muscle AP and the start of muscle tension? What is this time lag called?

Back 37

because it takes time for the Ca2+ to bind to troponin and start crossbridge cycling
latent period

Front 38

The number of crossbridges made with actin is affected by ____, ____, and ____.

Back 38

frequency of stimulation
fiber diameter (muscle size)
fiber length

Front 39

The increase in frequency of APs causes what? Which is called what?

Back 39

increase in muscle tension
summation

Front 40

Twitches can be summated until a maximum tension is reached called ____.

Back 40

tetanus

Front 41

In unfused tetanus, stimulus are ____ to allow muscle to relax slightly between stimuli.

Back 41

apart

Front 42

In fused tetanus muscles are ____ to relax and reach a steady tension.

Back 42

not allowed

Front 43

Muscle fatigue and a loss of tension is more likely in ____ tetanus.

Back 43

fused

Front 44

WHat is it called when the nervous system activates extra fibers when more force is needed?

Back 44

muscle recruitment

Front 45

What can affect actin/myosin overlap?

Back 45

changes in fiber length

Front 46

What are the three groups of muscle fibers based on speed of contraction and resistance to fatigue?

Back 46

slow-twitch oxidative
fast-twitch oxidative
fast-twitch glycolytic

Front 47

Fast mysoin ATPase that hydrolyzes ATP quickly is ____ dependent?

Back 47

genetically

Front 48

Which muscle fiber is type I

Back 48

slow oxidative

Front 49

Which muscle fiber is type IIa

Back 49

fast oxidative

Front 50

Which muscle fiber is type IIb

Back 50

fast glycolytic

Front 51

Which muscle fiber types change if a person switches from mostly weightlifting to mostly running?

Back 51

fast glycolytic to fast oxidative

Front 52

_____ fibers are white.

Back 52

glycolitic

Front 53

_____ fibers are red.

Back 53

oxidative

Front 54

_____ fibers are larger in diameter.

Back 54

glycolitic

Front 55

_____ fibers are smaller in diameter.

Back 55

oxidative

Front 56

_____ fibers have few mitochondria.

Back 56

glycolitic

Front 57

_____ fibers have many mitochondria.

Back 57

oxidative

Front 58

_____ fibers have few capillaries.

Back 58

glycolitic

Front 59

_____ fibers have many capillaries.

Back 59

oxidative

Front 60

_____ fibers produce 2 ATP per glucose.

Back 60

glycolitic

Front 61

_____ fibers produce 36 ATP per glucose.

Back 61

oxidative

Front 62

_____ fibers are recruited last.

Back 62

glycolitic

Front 63

_____ fibers are recruited first.

Back 63

oxidative

Front 64

_____ fibers contain myoglobin.

Back 64

oxidative

Front 65

_____ fibers are resistant to fatigue

Back 65

oxidative

Front 66

_____ fibers fatigue quickly.

Back 66

glycolitic

Front 67

Smooth muscle is controlled by the ___.

Back 67

ANS

Front 68

Skeletal muscle is controlled by the ____.

Back 68

Somatic nervous system

Front 69

Smooth muscle has no troponin, but has ____ instead.

Back 69

calmodulin

Front 70

Smooth muscle has a ____ developed SR.

Back 70

less

Front 71

Smooth muscle can be dual innervated by which two systems

Back 71

sympathetic and parasympathetic

Front 72

T-tubules are not found in ____ muscle.

Back 72

smooth

Front 73

____ smooth muscle is found in places where fine control is needed.

Back 73

multi-unit

Front 74

What is the most common smooth muscle type?

Back 74

single unit smooth muscle

Front 75

What are myosin light chains?

Back 75

small regulatory protein chains in the myosin head of smooth muscle

Front 76

In smooth muscle, ATPase activity of the myosin is ____ and the contraction of the twitch is ____.

Back 76

slower
longer

Front 77

In single unit smooth muscle, cells are coupled by ____, which causes what?

Back 77

gap junctions
causes the tissue to behave like one unit