Muscles 2 and 3

Question 1

A motor unit consists of

Answer 1

a motor neuron and the muscle fiber it innervates

Question 2

What are the two ways you can increase the force of a muscle

Answer 2

recruit more motor units or increase the frequency

Question 3

At the neuromuscular junction once the action potential reaches the synaptic terminal, the synaptic terminal ______, and voltage gated ____ channels are opened. Then, the neurotransmitter _____ is released into the synaptic cleft via _____. Then the transmitter binds to the ______receptors on the postsynaptic membrane. This causes channels to open, allowing ____ to pass through, which depolarizes the cell membrane

Answer 3

depolarizes

calcium

acetylcholine

exocytosis

nicotonic

sodium

Question 4

watch this

https://www.youtube.com/watch?v=LlgaziPCFU0

Answer 4

do it

Question 5

watch this starting 5 mins to 9 mins

https://www.youtube.com/watch?v=Ktv-CaOt6UQ

Answer 5

do itttt

Question 6

which bands get shorter with a contraction and which ones stay the same?

Answer 6

shorter: I band and H zone
same: A band

Question 7

Eciation contraction coupling consists of: action potential travelling down the _______, _____is released into the sarcoplasm (muscle cell cytoplasm), ____ binds to troponin, leaving the binding sites exposed which allows for _____ to bind to ______, and ____ is required for them to detach from one another

Answer 7

T tubules

calcium

calcium

myosin

actin

ATP

Question 8

to terminate the muscle contraction, the enzyme known as ______ turns acetylcholine back into ____ and _____, which causes ____ to move back from T tubule back into terminal cisternae, and ____ to return to resting position

Answer 8

acetylcholinesterase

choline and acetate

calcium

myosin

Question 9

What is the relationship between force/load and velocity of a muscle contraction

Answer 9

inverse: when the load is high, velocity is low. When force is low, velocity is high

Question 10

For muscle training, you can either do ____ training or ____ training, but you can’t do both.

Answer 10

endurance

strength

Question 11

What is the difference between isometric contractions and isotinc contractions?

Answer 11

isotronic: the length is changing, but the load is staying relativley the same. think a bicep curl at the gym
isometric: no change in the size (no shortening or lengthening), think of you holding a glass and it fills with water. your muscles are still working, but they are not changing legnth. Instead, the load is increasing

Question 12

What are te two kinds of isotonic contractions?

Answer 12

concentric: shortening
eccentric: lengthening

Question 13

What are the pahses of a muscle twitch?

Answer 13

latent, contraction, relaxation

Question 14

What is wave summation? Incomplete tetanus? Tetnus?

Answer 14

It is when there is a stimulation to contract while the muscle is still contrcting, so more calcium is entering the sarcoplasm while the first contraction is still happening. This causes summation where the next contractions are stronger than the first. The tension will continue to rise with each action potential until it reaches a peak point (which is called incomplete tetanus). Tetanus happens if the stimulus frequency is too high and doesnt give the muscle cell enough relaxation time (relaxation phase dissapears compeltely)

Question 15

What are the two anerobic ways to produce ATP? what kind of muscles use these methods?

What is the aerobic way to produce ATP? what kind of muscle uses this method?

Answer 15

creatine phosphate getting converted to creatine via direct phosphorylation creates ATP, enough for 10-15 seconds (type 2b)

glycolysis (break down of glucose) also produced ATP, enough for 2 mins(type 2a)

oxidative metabolism (electron transport chain) produces enough AT{ prolonged periods, (type 1, endurance)

Question 16

When does myogenesis occur?

Answer 16

during embryonic and fetal development

Question 17

What happens when there is poor nutrition during primary and secondary myogenesis?

What about in the muscle fiber hypertrophy phase?

Answer 17

there is a loss of fibers and muscle mass and this is not reversible

there is a loss of cross sectional area of the muscles cells and this is reversible

Question 18

What is the role of satellite cells?

Answer 18

they are stem cells in the muscle and can aid in muscle repair but research is still unsure how much they are able to contribute to the regrowth

Question 19

Why do muscle cells have tons of neucli?

Answer 19

because to form a mature muscle cell, many cells come together to fuse into one cell

Question 20

Trye or false: an animal is born with all of its muscle cells already grown (if normal)

Answer 20

true

Question 21

True or false: after birth an animal can regrow some muscle cells if some become damaged

Answer 21

false

Question 22

what are the two ways muscle can grow?

Answer 22

hypertrophy (increase in the individual size of each cell)

hyperplasia (splitting, divison, increase in number of cells)

Question 23

increaseing the length of a sarcomere has what affect on force, velocity, and shortening capacity?

Answer 23

force: no change
velocity: increases/doubles

shortening capacity: doubled

Question 24

hyperplasia (having more sarcromeres in paralell) has what affect on force, velocity, and shortening capacity?

Answer 24

force: doubled
velocity: no change

shortening capacity: no change

Question 25

hyperplasia, splitting and increasing the number of muscle fibers/cells, happens mostly in ______

Answer 25

fetal development

Question 26

what is a muscle spasm?

Answer 26

involuntary contractions of muscles, often painful

Question 27

what is a muscle cramp?

Answer 27

sustained spasms that can last a few seconds to 15 minutes or longer

Question 28

What is muscle strain? WHat causes it? Where does it often occur?

Answer 28

tearing of he muscle

overexertion or stretching beyond its range

musculotendinous junctions because everything is coming to a common point

Question 29

there are two kinds of muscle atrophy what are they?

Answer 29

neurogenic and myogenic

Question 30

what is neurogenic atrophy? what is an example?

Answer 30

when dennervation occurs and protein degredation then occurs, decreasing muscle mass

ex. sweeny in horses is dennervation of the suprascapular nerve which then causes supra and infraspnatous to atrophy

Question 31

what is myogenic atrophy?

Answer 31

due to malnutrition or weight loss secondary to other diseases, or an excess in corticosteroids like cortisol. results in ONLY the atrophy of type 2 fibers (fast)

Question 32

muscle necrosis/ rhabdomyolysis is associated with what clinical features?

Answer 32

muscle pain, contracture (shortening and hardneing of muscles), increased respiratory rate, sweating

Question 33

what causes muscle necrosis?

Answer 33

nutritional: vitamin ´ and selenium deficiency

infectious

immune

metabolic

Question 34

what is muscular dystrophy?

Answer 34

inherited progressive degernation of skeletal muscle. there is a deficinecy of dystrophin (protein which anchors sarcrolemma to actin of cytoskeleton), so every time the muscle contracts, small rips form in the cell membrane. this allows calcium to come in and bind with a protease and the proteases destroy and break down muscles