chapter 10 flashcards

Question 1

major functions of muscle tissue

Answer 1

movement, temp, posture

Question 2

contractability

Answer 2

ability to contract and pull proteins together, respond to a stimulus in order to contract

Question 3

excitability

Answer 3

the ability of muscle fibers to generate electrical impulses in response to stimuli

Question 4

conductivity

Answer 4

respond to electrical signal , continue to travel

Question 5

distensibility

Answer 5

able to stretch without being damaged

Question 6

elasticity

Answer 6

able to return to normal position after being stretched

Question 7

sliding filament theory

Answer 7

thin filaments slide towards the center of each sarcomere

Question 8

resting membrane potential

Answer 8

90 mV, muscle cell potential

Question 9

polarized membrane potential

Answer 9

difference in electrical charge across cell membrane

Question 10

ion channels

Answer 10

ions cannot diffuse through lipid component of plasma membrane , rely on specific protein channels

Question 11

leak channels

Answer 11

always open , continuously allow ions to flow down concentration gradients between cytosol and ecf

Question 12

gated channels

Answer 12

closed at rest, open in response to specific stimulus

Question 13

electrochemical gradient

Answer 13

diffusion of ion across plasma membrane is determined by both concentration gradient and electrical gradient

Question 14

concentration gradient

Answer 14

diffusion of an ion from high to low concentration, move out

Question 15

electrical gradient

Answer 15

movement of ion away from a like charge and towards opposite charge, move in

Question 16

generating a resting potential

Answer 16

electrical gradient favoriting diffusion out , potassium out sodium in

Question 17

action potentials

Answer 17

brief changes in membrane potential of cell from resting negative value to positive value then back to resting negative , generated by opening and closing of gated sodium and potassium channels in plasma membrane in response to stimulus

Question 18

resting stage

Answer 18

before stimulus arrives the membrane is resting membrane potential and gated na and k are closed

Question 19

depolarization stage

Answer 19

response to stimulus , na and k channels open and sodium enters cell making membrane less negative

Question 20

repolarization stage

Answer 20

sodium channels close while k channels open and k leaves the cell making membrane potential more negative inside positive and outside negative

Question 21

propagation

Answer 21

action potential able to move entire length of cell membrane

Question 22

neuromuscular junction

Answer 22

connection between a motor nerve and a muscle fiber that allows electrical impulses to convert into muscled contractions

Question 23

motor neuron

Answer 23

send motor message, to do, message

Question 24

synapse

Answer 24

where single motor neuron communicates with many muscle fibers

Question 25

axon terminal

Answer 25

bulb, end of motor neuron

Question 26

synaptic cleft

Answer 26

space between neuron and muscle cell

Question 27

motor end plate

Answer 27

region of muscle cell directly under axon

Question 28

excitation phase

Answer 28

1. Action potential arrives at the axon terminal and triggers calcium channels in axon terminal to open 2. Calcium ions move into the axon terminal and trigger exocytosis of synaptic vesicles. 3. Synaptic vesicles release ACh into synaptic cleft 4. ACh binds to receptors on the motor end plate 5. Sodium ion channels open and sodium ions enter the muscle fiber 6. Sodium entry depolarizes the sarcolemma creating an end-plate potential

Question 29

excitation contraction coupling

Answer 29

1. End-plate potential stimulates an action potential 2. Action potential is propagated down the T-tubules 3. T-tubule depolarization leads to the opening of calcium ion channels in the sarcoplasmic reticulum and calcium ions enter the cytosol 4. Calcium ions bind to troponin 5. Tropomyosin moves and the active sites on actin are exposed

Question 30

contraction phase (crossbridge)

Answer 30

1. ATP hydrolysis “cock” the myosin head 2. Myosin head binds to actin 3. Power stroke occurs when the phosphate detaches from the myosin head and myosin pulls actin toward the center of the sarcomere (m line) 4. ATP breaks the attachment of myosin to actin

Question 31

muscle relaxation

Answer 31

1. Acetylcholinesterase degrades the remaining ACh and the repolarization occurs 2. The sarcolemma returns to its resting membrane potential and calcium ion channels in SR close 3. Calcium ions are pumped back into the SR 4. Troponin shifts and pulls tropomyosin back into position to block active sites of actin and the muscle relaxes 5. Relaxation is a passive process

Question 32

creatine phosphate

Answer 32

muscle fibers, easily can donate phosphate ion

Question 33

anaerobic catabolism

Answer 33

glucose breaks down absorb into muscle , 2 pyruvate molecules and 2 atp, no oxygen needed

Question 34

aeorbic catabolism

Answer 34

reactions that require oxygen

Question 35

muscle twitch

Answer 35

smallest muscle contraction

Question 36

latent period

Answer 36

time for action potential to propagate across sarcolemma

Question 37

contraction period

Answer 37

repeated crossbridge cycles generate tension

Question 38

relaxation period

Answer 38

calcium ions levels reduced in cytosol by SR pumps :tension diminishes

Question 39

refractory period

Answer 39

between the start of latent period and into start of contraction period where the muscle fibers cannot respond to another stimulus

Question 40

wave summation

Answer 40

repeated stimulation of muscle fiber

Question 41

unfused (incomplete) tetanus

Answer 41

pause in between twitch, tension is low

Question 42

fused (complete)tetanus

Answer 42

brain sends message so fast allowing fast contraction

Question 43

type 1 fiber, slow twitch

Answer 43

-small diameter, slow-twitch fibers; contract slowly, produce less force for longer period of time -Rely on oxidative catabolism; large numbers of mitochondria and myoglobin molecules, well-developed blood supply; “dark muscle” -Predominate in postural muscles; sustain contractions for long durations

Question 44

type 2 fibers, fast twitch

Answer 44

-large diameter, fast twitch fibers, fatigue quickly -High myosin ATPase activity; rely mainly on glycolytic catabolism for ATP production -Fewer mitochondria, lower levels of myoglobin, less extensive blood supply; “white muscle”

Question 45

motor units

Answer 45

a single motor neuron and all fibers it innervates , signals for movement

Question 46

recruitment

Answer 46

- initiation of contraction activates a small number of motor units as greater force is needed more motor units are activated

Question 47

muscle tone

Answer 47

-when a muscle is at rest still has a degree of tension due to background level of motor unit activity, ready to respond to movement

Question 48

hypotonia

Answer 48

low muscle tone

Question 49

hypertonia

Answer 49

abnormally high muscle tone

Question 50

isotonic

Answer 50

causes muscle to change in length

Question 51

concentric

Answer 51

muscle tension exceed resistance , muscle able to shorten

Question 52

eccentric

Answer 52

to lengthen

Question 53

isometric

Answer 53

-muscle stays the same length but still create peak tension

Question 54

physical training

Answer 54

repeated use and how it changes the structure

Question 55

endurance training

Answer 55

looking at more repetition, long lasting performance (mitochondria), only works with oxygen type 1 fibers

Question 56

resistance training

Answer 56

fewer repetition, working without oxygen, have to have enough glucose, type 2 fibers

Question 57

disuse

Answer 57

decreased myofibrils, decreased muscle diameter, use it or lose it, can developed atrophy if not used

Question 58

muscle fatigue

Answer 58

-no energy to do more Depletion of key metabolites (CP, glycogen, glucose) -Decreased availability of oxygen -Environmental conditions

Question 59

similarities between smooth vs skeletal

Answer 59

need calcium, action and myosin

Question 60

differences between smooth vs skeletal

Answer 60

-no striations, arranged in unique way and make own crossbridge , -involuntary, no sarcoplasmic reticulum, no t tubules

Question 61

simialrites between cardiac vs skeletal

Answer 61

striations, sarcomeres, calcium actin myosin arranged the same, t tubules, sarcoplasmic reticulum

Question 62

differences between cardiac vs. skeletal

Answer 62

involuntary, short cells, one nucleus, intercalated discs, autorhythmic