Chapter 8 1c Excitation

Question 1

What are the four stages of muscle physiology?

Answer 1

excitation
excitation-contraction coupling
contraction
relaxation

Question 2

What is the purpose of excitation in muscle contractions?

Answer 2

muscle is stimulated

Question 3

What is the coupling (E-C) period of muscle contraction?

Answer 3

a short period between the signal and when the muscle starts contracting

Question 4

What happens during the contraction phase of muscle contraction?

Answer 4

when the muscle shortens and contracts when the actin and myosin grab onto each other and pull

Question 5

Is a cell more negatively charged inside or outside the cell?

Answer 5

inside

Question 6

What is the resting membrane potential?

Answer 6

stored potential energy

Question 7

what does it mean for a cell to be isotonic?

Answer 7

it has the same concentration inside and outside

Question 8

what is a connection between two electrically excitable cells?

Answer 8

synapse

Question 9

what is the synapse called that occurs where a nerve fiber connects with its target muscle?

Answer 9

neuromuscular junction (NMJ)

nerve top blue arrow muscle bottom blue arrow

Question 10

Name the pink highlighted region

Answer 10

synaptic knob

Question 11

name the pink highlighted region

Answer 11

synaptic vessicle

Question 12

what does the synaptic vessicle carry?

Answer 12

a neurotransmitter called Acetylcholine

Question 13

what is the abbreviation for acetycholine?

Answer 13

ACh

Question 14

what is another name for the synaptic knob?

Answer 14

terminal

Question 15

what is ACh and what does it do?

Answer 15

neurotransmitter that stimulates muscle cells

Question 16

what part of the muscle cell is highlighted in pink?

Answer 16

sarcolemma

Question 17

what is the name for the region containing the sarcolemma where the muscle connects to the nerve?

Answer 17

motor end plate

Question 18

what are the pink highlighted regions on the motor end plate called?

Answer 18

junctional folds

Question 19

what is located along the junctional folds of the neuromuscular junction?

Answer 19

ACh receptors

Question 20

what is the pink highlighted region between the motor neuron and the muscle cell?

Answer 20

synaptic cleft

Question 21

What is the nerve impulse?

Answer 21

the quick flip in positive and negative charges

Question 22

What is another name for the nerve impulse?

Answer 22

action potential

Question 23

what is the process in the neuromuscular junction from nerve impulse to muscle action potential?

Answer 23

• action potential (nerve impulse) comes down the neuron
• calcium channels open due to the nerve voltage
• calcium goes down concentration gradient into the synaptic knob
• calcium triggers the synaptic vessicles to release ACh through exocytosis
• calcium enters synaptic cleft
• ACh binds to ACh receptors
• sodium comes in, which changes the charge from positive to negative, and that creates a muscle action potential
• muscle action potential spreads all throughout the muscle cell

Question 24

are the calcium channels voltage-gated in a neuromuscular junction event?

Answer 24

yes

Question 25

What is the resting membrane potential?

Answer 25

the negative potential energy inside of the cell before the nerve impulse hits

Question 26

what happens to the cell charge when the sodium channels open and what is it called?

Answer 26

we go from negative to positive
depolarization

Question 27

after the cell charge goes past zero and becomes positive, what happens?

Answer 27

sodium channels start to close and potassium channels open

Question 28

what is it called when the potassium exits the cell after the sodium creates a positive charge?

Answer 28

repolarization