Anatomy and physiology ch. 7 The muscular system

Question 0

epimysium

Answer 0

connective tissue sheath that contains the muscle groups

Question 1

skeletal muscle

Answer 1

also known as striated muscle,

it has 4 major characteristics: contractility, excitability, extensibility, and elasticity

Question 2

muscle fasciculi

Answer 2

various muscle bundles inside of the epimysium

Question 3

perimysium

Answer 3

connective tissue that binds muscle fibers together to make a muscle fasciculi

Question 4

muscle fibers

Answer 4

muscle cells

Question 5

endomysium

Answer 5

surrounds individual muscle fibers inside of the muscle fasciculi

Question 6

sarcolemma

Answer 6

the cell membrane of the muscle fiber

Question 7

transverse tubules

Answer 7

also known as T tubules, these go from the surface of the muscle cell and past the sarcolemma (cell membrane)

Question 8

sarcoplasmic reticulum

Answer 8

the T tubules go into this, and this is the place where there is a high concentration of CA2+, which is needed for muscle contraction.

Question 9

sarcoplasm

Answer 9

the cytoplasm of the muscle cell

Question 10

myofibrils

Answer 10

threadlike structures that extend from one end of the fiber to the other. composed of 2 parts, the actin myofilaments, and myosin. these function together to make the muscle contract.

Question 11

sarcomeres

Answer 11

one unit of contracting cells, located between z disks. the smallest unit that can contract by itself.

Question 12

actin myofilaments

Answer 12

also known as thin filaments, these are made up of 3 parts. Actin, Troponin, and Tropomyosin

Question 13

actin

Answer 13

the part that the myosin heads connect to

Question 14

troponin

Answer 14

these have binding sites for CA2+

Question 15

tropomyosin

Answer 15

these block the myosin myofilaments (thick filaments) from joining to the actin molecules. they are moved by CA2+ (found in troponin)

Question 16

myosin myofilaments

Answer 16

also known as thick filaments, they look like gold clubs, and the head of these attach to the actin when the tropomyosin is moved out of the way.

Question 17

z disk

Answer 17

the ends of a sarcomere, these are protein fibers that separate sarcomeres by providing an attachment for the actin.

Question 18

I band

Answer 18

consists of only actin myofilaments, has a z disk usually in the middle of it

Question 19

A band

Answer 19

the area between I disks that looks dark that contains both actin myofilaments and myosin myofilaments. the center of this is the H zone and the M line, which are light

Question 20

H zone

Answer 20

the center of the A band which only contains myosin myofilaments (this is the part that gives so the muscle can contract)

Question 21

M line

Answer 21

where the myosin myofilaments are anchored to. this is the center of the sarcomere

Question 22

resting membrane potential

Answer 22

the charge difference across a cell membrane

Question 23

motor neuron

Answer 23

nerve cells that stimulate muscles to contract. they generate action potentials that travel to skeletal muscle fibers

Question 24

neuromuscular junction

Answer 24

the synapse between a motor neuron and the muscle cell it is stimulating

Question 25

motor unit

Answer 25

refers to the neuron and the skeletal muscle fiber that it controls as a whole

Question 26

presynaptic terminal

Answer 26

an enlarged axon terminal

Question 27

synaptic cleft

Answer 27

the space between the presynaptic terminal and the postsynaptic membrane

Question 28

postsynaptic membrane

Answer 28

the muscle fiber membrane that receives the signal

Question 29

synaptic vesicles

Answer 29

vesicles that contain acetylcholine which move from the presynaptic terminal to the postsynaptic membrane

Question 30

resting membrane potential

Answer 30

when the inside of the cell membrane has a more negative charge than the outside of the cell

Question 31

depolarization

Answer 31

when the NA+ moves inside of the cell making the inside of the cell positive compared to the outside of the cell

Question 32

repolarization

Answer 32

going from the positive back to the resting membrane potential

Question 33

hyperpolarization

Answer 33

makes a cell membrane more negative than it was at the resting membrane potential

Question 34

sliding filament model

Answer 34

1. action potential goes to open CA2+ channels in presynaptic terminals
2. CA2+ causes release of ACh into synaptic cleft
3. Ach binds to receptor sites on postsynaptic membrane, and open NA+ channels, and NA+ rushes in
4. NA+ causes the T tubules and the sarcolemma to release their stored CA2+
5. CA2+ goes to troponin
6. the attachment causes tropomyosin to move out the way of the actin
7. myosin attaches to actin (cross-bridge)
8. P is released and the myosin heads bend
9. the bending make actin slide over the myosin (power stroke)
10. acetylcholinesterase breaks down ACh, NA+ channels close, causing the muscle to stop contracting.

Question 35

threshhold

Answer 35

weakest stimulus needed to produce a response

Question 36

twitch

Answer 36

rapid contraction and relaxation of a muscle

Question 37

tetanus

Answer 37

when the frequency of stimulation is so fast that no relaxation occurs

Question 38

Isometric

Answer 38

the amount of tension in the muscle increases (weight increases)

Question 39

isotonic

Answer 39

the amount of repititions increase

Question 40

tone

Answer 40

constant amount of tension of a long period of time

Question 41

slow twitch fibers

Answer 41

contract slowly
uses aerobic respiration
dark meat

Question 42

fast twitch fibers

Answer 42

contract quickly
uses energy from glycogen
white meat

Question 43

origin

Answer 43

non movable end of a muscle

Question 44

insertion

Answer 44

movable end of a muscle

Question 45

belly

Answer 45

the middle of a muscle

Question 46

prime mover

Answer 46

the muscle that is responsible for the majority of the movement i.e the bicep for flexion of the arm

Question 47

synergist

Answer 47

muscles that work together

Question 48

antagonist

Answer 48

muscle that opposes another muscle i.e. the tricep to the bicep

Question 49

naming skeletal muscle

Answer 49

1. location
2. origin/ insertion
3. size
4. shape
5. function

Question 50

lag phase (of muscle contraction)

Answer 50

the lag between the stimulus and actual contraction

Question 51

contraction phase (of muscle contraction)

Answer 51

time during which the muscle contracts

Question 52

relaxation phase (of muscle contraction)

Answer 52

time during which the muscle relaxes.

Question 53

summation

Answer 53

increasing the force of the contraction by rapidly stimulating the muscle. this is caused by dumping more calcium in the myofibrils than is actively transported out to the Sarcoplasmic reticulum

Question 54

recruitment

Answer 54

more contraction can occur because more motor units are stimulated to contract.

Question 55

aerobic respiration

Answer 55

uses O2 and breaks down glucose to make ATP, CO2, and H2O. this occurs in the mitochondria.

Question 56

anaerobic respiration

Answer 56

does not use O2, instead it uses glucose to make ATP and Lactic acid. this process uses only glucose.

Question 57

creatine phosphate

Answer 57

the muscle cells stored energy that can be used fast to make atp

Question 58

muscular fatigue

Answer 58

occurs when the muscle uses ATP faster than it produces it, and lactic acid builds up faster than it is removed

Question 59

physiological contracture

Answer 59

when a muscle cannot contract or relax because there is too little ATP to bind to myosin myofilaments

Question 60

psychological fatigue

Answer 60

involves the central nervous system. the muscles can still contract, but the person thinks they cannot keep going.