Muscle physiology and anatomy

Question 1

What does a muscle look like?

Answer 1

muscles look like bundles of bundles.

Question 2

What are fascicles?

Answer 2

These bundles that make up muscles structure

Question 3

what are fascicles made of?

Answer 3

muscle fibers

Question 4

what are muscle fibers made of?

Answer 4

muscle cells

Question 5

what are myofibrils in a muscle cell?

Answer 5

muscle cells have smaller bundles called myofibrils

Question 6

What is a myofilament?

Answer 6

the myofilaments are smaller tubules of the myofibrils

Question 7

There are two primary types of myofilaments

Answer 7

actin and myosin

Question 8

epimysium

Answer 8

wrapped around a muscle. Holds a bunch of fascicles inside of the muscle.

Question 9

Perimysium

Answer 9

each fascicle is wrapped up in a connective tissue called

Question 10

endomysium

Answer 10

wraps around muscle fiber and cell

Question 11

epimysium, perimysium, and endomysium

Answer 11

what are three major connective tissues that makes up the repeated bundles of the muscle structures in skeletal muscles.

Question 12

fascia

Answer 12

a thick layer of connective tissue that sometimes merges with epimysium, can sometimes be inflamed.

Question 13

sarcomeres

Answer 13

are the repeated units made up of actin and myosin found at the myofibril. They are the light and dark bands repeatedly wrapped and not wrapped around each other in a repeated pattern on the muscle fibers/muscle cell.

Question 14

Where does actin attached to at the sarcomeres

Answer 14

actin attaches to the end discs at the ends of these sacromeres. z disks attaches to actin.

Question 15

during muscle contractions, what changes?

Answer 15

These z disks attached to actin to slide over one another. it brings one z-disks closer to the other z-disk during muscle contraction. So the entire sarcomere shortens. the I band with only actin attached shortens as well. the H zone shortens too. A band does not change.

Question 16

The H zone

Answer 16

middle of the filament with an m line made up of myosin

Question 17

I band

Answer 17

where actin is at the end of sacromere

Question 18

A band

Answer 18

is from one end of the myosin all the way to the other end of myosin that meets up with actin.

Question 19

what do these myosin and actin do during muscle contraction?

Answer 19

they overlap between the two.

Question 20

What happens to myosin and actin when we lengthen and pull muscle?

Answer 20

actin and myosin band pulls further apart. slide one another and don’t overlap

Question 21

what happens to actin and myosin when contracted

Answer 21

they overlap more often repeated pattern

Question 22

How can muscles stretch beyond its resting point?

Answer 22

we need a muscle that works opposite of the other muscle to stretch.

Question 23

What is the process that enables actin and myosin to overlap together during muscle contraction?

Answer 23

myosin has golf shaped heads that grabs and pulls actin when actin is getting closer. ATP binds to the myosin head and extend it back to loaded position and grabs and pulls when it sees actin.

Question 24

What is the physiological process when muscles need to relax?

Answer 24

the actin is wrapped in troponin and tropomyosin

Question 25

What is tropomyosin?

Answer 25

a long protein that can wind all the way around actin and covers around active sides that myosin bind to disabling myosin from pulling actin.

Question 26

what is troponin?

Answer 26

a little lock mechanism and locks tropomyosin in one place and can unlock tropomyosin to contract.

Question 27

What is calcium role in relaxing muscles?

Answer 27

calcium floods into the myofibril, calcium binds to troponin, and this unlocks tropomyosin to move out of the way for myosin to see and bind to actin.

Question 28

Three major processes for producing ATP that aids in contractions

Answer 28

cellular respiration, glycolysis,

Question 29

cellular respiration

Answer 29

blood glucose and other things undergo cellular respiration; break down glucose and produce ATP, can happen in mitochondria, oxygen, co2, heat and causes ATP which ATP allows myosin to be reloaded

Question 30

glycolysis

Answer 30

take glucose snaps in half to produce ATP, these two broken glucoses break down into lactic acid, reusable energy that roams around muscles, a byproduct. Doesn't need oxygen. Is not energy efficient.

Question 31

What happens to the unspent ATP that is free roaming?

Answer 31

breaks down into creatine and makes a molecule called creatine phosphates can be converted back into ATP and is stored in the muscles. creatine phosphates are more long term than ATP that is consumed easily and fast.

Question 32

neuro-muscular junction

Answer 32

neurons send out electrical information where a neuron meets a muscle

Question 33

How does the neuron meet up with the skeleton muscles for contraction to be stimulated?

Answer 33

At the end of an axon of a neuron split into multiple neuron terminals that can touch a variety of different structures such as a skeleton muscle

Question 34

presynaptic terminal

Answer 34

the end of the neuron closer to skeleton muscles

Question 35

synaptic cleft

Answer 35

the space between the presynaptic terminal and the skeleton muscle or the post synaptic membrane

Question 36

How do we get this electrical information to cause stimulation to contract the fibers of the muscles?

Answer 36

the presynaptic terminal has small membrane bound vesicles compartment filled with neurotransmitters are tiny little messenger flies down the axon terminals and merge with plasma and dumped in the synaptic cleft on the surface of the post synaptic membrane where receptors receive the electrical signals to transmit across the muscle itself that activates calcium to flood into the muscle fibers to allow the key and lock mechanism to cause myosin to grab onto the actin and causes muscle contraction.

Question 37

acetylcholine

Answer 37

neurotransmitter at the presynaptic terminal and the post synaptic membrane

Question 38

sarcolemma

Answer 38

the surface of the muscle fiber like the plasma membrane of the muscle

Question 39

sarcoplasm

Answer 39

inside of the plasma membrane of the muscle fiber

Question 40

sarcoplasmic reticulum

Answer 40

weblike structure wrapped around the myofibril (housing the actin and myosin that slides passed each other). This sarcoplasmic reticulum is a modified endoplasmic reticulum where it stores calcium so when the muscle fiber gets stimulated, sarcoplasmic reticulum drops the calcium it stores into the myofibril.

Question 41

What happens when muscle relaxes at the chemical level when calcium is present and what is the role of the sarcoplasmic reticulum in this process of relaxing muscle?

Answer 41

the calcium is pumped back into the sarcoplasmic reticulum

Question 42

How can the electrical signals quickly get inside the muscle fibers and into the myofibrils?

Answer 42

T tubes, these transverse tubules allows the signals to go deep into the myofibrils away from the sarcolemma.

Question 43

how to measure muscle contraction?

Answer 43

unit- muscle twitch. smallest unite of muscles amount of muscle contraction.

Question 44

lag phase

Answer 44

the beginning of the phase, no contractions visibly seen. the time it takes for the initial stimulus for the muscle to contract. a couple of milliseconds for the electrical signals to pass from presynaptic terminal to cause acetylcholine to release bind to the receptors of the post synaptic surface membrane, triggers calcium to release.

Question 45

contraction phase

Answer 45

when calcium is release and binds to troponin to unlock tropomyosin for the myosin heads to load and grab and pull actin for contraction to occur, tension is visibly shown on muscle measurements.

Question 46

relaxation period

Answer 46

calcium is being pumped out and into the sarcoplasmic reticulum holdings and muscle contraction stops.

Question 47

all or non-principle

Answer 47

if a muscle is stimulated or hit a threshold to contract that muscle fiber that will contract as it can and when the stimuli stop the muscle will relax. (Light switch flip. ON/OFF)

Question 48

motor unit

Answer 48

one nerve or neuron that sends info to spread and touch muscle fibers and can contract in one unit.

Question 49

motor unit recruitment

Answer 49

When we take one motor unit and stimulate just those muscle fibers and if needed, we can recruit more motor units to contract more muscle fibers to make the contraction bigger

Question 50

How can we generate different strength in a muscle?

Answer 50

motor unit recruitment

Question 51

wave summation

Answer 51

we send information to muscles and cause it to contract. allow the muscle twitch and before it goes to relaxation period, we can send more muscle twitch behind each other to stack to cause higher tension

Question 52

myogram

Answer 52

wave muscle contractions graph

Question 53

tetanus

Answer 53

where we can measure the amount of or like the smoothness of the muscle contraction.

Question 54

complete tetanus

Answer 54

when a muscle is contracted at its highest point and the tension remains solid

Question 55

incomplete tetanus

Answer 55

when a muscle contracts while holding something and allow it to relax and it will start to shake

Question 56

isometric muscle contractions

Answer 56

where we put tension on a muscle without moving the bones attached to the muscles we put tension, plank push up position. ideally don't change length. push on accelerator on a car on steady speed

Question 57

isotonic muscle

Answer 57

put tension on muscle and the length of the muscle changes

Question 58

concentric muscl contractions

Answer 58

we put tension on a muscle, and it overcomes resistance and shortens. the upward phase of a bicep curl when we hold a dumbbell in our hand and put tension in the brachii and overcome the tension and contraction and muscle will shorten

Question 59

eccentric muscle contractions

Answer 59

we put tension in our muscle but allow the muscle to lengthen. start top of our bicep curl the finished position and slowly extend our muscle and allow the dumbbell to lower

Question 60

muscle hypertrophy process

Answer 60

muscle increases in size after it has been contracting and relaxing for period of time

Question 61

What happens to muscles that have undergone muscle hypertrophy.

Answer 61

inside of the muscle fibers stays the same, myofibril increases in diameter and amount, more nuclei helps build protein. better coordination, and motor units are effective and fast in being recruited.

Question 62

muscle atrophy

Answer 62

when you stop working out. in cast, cannot move. the state where a muscle decrease in size. the opposite effect as muscle hypertrophy. increase subcutaneous fats.

Question 63

slow twitch muscle fibers

Answer 63

genetics dictation. contract slowly. smaller. good blood supply. tons of mitochondria. fatigue resistance. Prolonged activity. produces not much force. like holding our neck. postural muscles. atp break down slow atp. slow twich muscles are good at cycling activities

Question 64

fast twitch muscle fibers

Answer 64

genetics dictation. respond to nervous stimulation. a little blood supply. fewer mitochondria. seconds of contractions. break down atp fast. single sustained explosive movement. like a jump.

Question 65

can we train fast or slow twitch muscle fibers?

Answer 65

yes.

Question 66

muscle fatigue

Answer 66

decrease in the ability for the muscle