Test 3

Question 1

What is visceral muscle

Answer 1

also called smooth muscle
- found in the walls of hollow organs and is involuntary
- pushes fluids around by contracting
Ex; stomach, airways, blood vessels

Question 2

what is skeletal muscle

Answer 2

long, multi-nucleated parallel cells
- most voluntarily
- creates movement by pulling bones
ex: deltoid, Biceps brachii

Question 3

What is cardiac muscle

Answer 3

One nucleus per cell, striated with intercalated discs
- involuntary keeps the blood pumping
- only found in the heart
Ex: heart

Question 4

describe the microscopic anatomy of skeletal muscle

Answer 4

Sarcomere - Contractile unit of muscle fibers
- thick and thin filament

Question 5

describe the events that happen in the neuromuscular junction

Answer 5

The synaptic connection between the terminal end of a motor nerve and the muscle
- tells the muscle to contract

Question 6

what is resting potential

Answer 6

The in-balance of electrical change that happens between the nerve cells and their surrounds

Question 7

what is depolarization

Answer 7

NA ions go in which causes a rise

Question 8

what is action potential

Answer 8

The high point of the contraction

Question 9

what is repolarization

Answer 9

K ions go out which slowly brings down the reaction

Question 10

What are the three connective tissue sheaths

Answer 10

Epimysium, perimysium and endomysium

Question 11

what is the epimysium

Answer 11

dense irregular connective tissue that surrounds the entire muscle

Question 12

what is the perimysium

Answer 12

fibrous connective tissue that surrounds fascicles

Question 13

what is the endomysium

Answer 13

fine areolar connective tissue that surrounds each muscle fiber

Question 14

what is the sarcolemma

Answer 14

the muscle fiber plasma membrane

Question 15

what is the sarcoplasm

Answer 15

muscle fiber cytoplasm

Question 16

what is a myofibril

Answer 16

a densely packed rodlike element found in the muscle
smallest section in muscle fibers

Question 17

what is the a band

Answer 17

dark region found in myofibrils

Question 18

what is the H zone

Answer 18

a lighter region in the middle of the A band

Question 19

what is the M line

Answer 19

line of proteins that bisects the H zone vertically

Question 20

what is the I band

Answer 20

the lighter regions

Question 21

what is the Z disc (line)

Answer 21

sheet of proteins on midline of light I band

Question 22

actin is

Answer 22

thin filaments

Question 23

myosin is

Answer 23

thick filaments

Question 24

what is the muscle twitch

Answer 24

the contraction and relaxation of the muscle

Question 25

List the 4 steps for muscle contraction

Answer 25

Neuromuscular junction
muscle fiber exitation
excitation- contraction coupling
cross bridge cycle

Question 26

list the 4 main parts of the neuromuscular junction

Answer 26

1. motor neuron fires an AP down the axon
2. motor neuron releases ACh into synaptic cleft
3. ACh binds receptors to sarcolemma \
4. ACh binding causes end plate potential (EPP)

Question 27

what happens during muscle fiber excitation

Answer 27

Local depolarization (EPP) triggers an AP in adjacent sarcolemma

Question 28

what are the three steps in Excitation-contraction coupling

Answer 28

1. AP in sarcolemma travels down the T-tube
2. Sarcoplasmic reticulum releases CA2
3. Ca2 binds troponin which shifts tropomyosin to show myosin-binding sites on actin

Question 29

what happens in the cross bridge cycle

Answer 29

contraction occurs via cross bridge cycle

Question 30

What are the 4 steps of the cross bridge cycle

Answer 30

1. Myosin and actin attach
2. myosin pulls actin towards M-line
3. Cross bridge detachment : ATP attaches to myosin which causes detachment
4. ATP cocks myosin into high energy state