Day 3

Question 1

What do motor neurons connect with?

Answer 1

They connect with skeletal muscles

Question 2

What do motor neurons tell the skeletal muscle to do?

Answer 2

They tell them to contract

Question 3

Both neurons and muscles are what?

Answer 3

Both are excitable cells

Question 4

Both neurons and muscles respond to stimuli by changing their what?

Answer 4

By changing their resting membrane potential

Question 5

What is an action potential?

Answer 5

It is a large change in a membrane potential that spreads rapidly over long distances with a cell

Question 6

What do motor neurons use as a neurotransmitter?

Answer 6

Acetylcholine (ACh)

Question 7

What does acetylcholine do for motor neurons?

Answer 7

It tells the skeletal muscle to contract

Question 8

Chemically gated ion channels are opened by what

Answer 8

They are open by chemical messengers

Question 9

What do chemically gated ion channels create?

Answer 9

They create small local changes in membrane potential

Question 10

What do voltage gated ion channels do?

Answer 10

They open or close and response to changes in the membrane potential

Question 11

The axon of each motor, neuron branches as it enters the what?

Answer 11

The muscle

Question 12

What does the axon form as it branches?

Answer 12

It forms a neuromuscular junction with a single muscle fiber

Question 13

The axon terminal and muscle fiber are separated by what?

Answer 13

The synaptic cleft

Question 14

What does the synaptic cleft separate?

Answer 14

The axon terminal and muscle fiber

Question 15

Synaptic vesicles with the axon terminal contains what

Answer 15

Acetylcholine

Question 16

The muscle fibers sarcolemma Has junctional folds with what?

Answer 16

ACh receptors

Question 17

Name the sequence of events leading to contraction

Answer 17

A motor neuron fires, an action potential down its axonThe motor neurons axon terminal releases ACh into the synaptic cleftACH binds receptors on the junctional folds of the sarcolemmaACH binding causes a local deep polarization called an end plate potentialThe local depolarization, triggers an action potential in the Adjacent sarcolemmaThe action potential in sarcolemma travels down T tubulesSarcoplasmic reticulum releases CA +2CA +2 binds to trombone which chefs trip said to uncover the finding sites on actinMyosin heads, bind actin, and contraction occurs via Crossbridge cycling

Question 18

What is excitation contraction coupling?

Answer 18

It is the sequence of events by which an action potential along the circle Lima leads to the sliding of myo filaments

Question 19

The action potential propagates along where

Answer 19

The Sarcolemma and down the T tubules

Question 20

The transition of the AP along the T tubules causes what?

Answer 20

It causes voltage sensitive to be proteins to change shape, opening CA +2 release channels in the SR

Question 21

In excitation contraction coupling, calcium ions flow into what?

Answer 21

Into the cytosol

Question 22

In excitation contraction coupling, Calcium ions bind what?

Answer 22

Troponin

Question 23

In excitation contraction coupling Calcium ions, remove what?

Answer 23

Removes the blocking action Of tropomyosin

Question 24

In excitation contraction coupling, Myosin binding sites on the thin filaments are exposed and ready for what?

Answer 24

Myosin binding

Question 25

In excitation contraction coupling, Myosin binding to Actin forms what and what begins?

Answer 25

Forms cross, bridges, and contraction begins

Question 26

What is the cross bridge cycling?

Answer 26

it is the series of events during which myosin heads pull thin filaments toward the center of the Sarcomere

Question 27

How does the cross bridge cycling begin?

Answer 27

Epic begins when the energized myosin head attaches to an actin microfilament forming a cross bridge

Question 28

In the cross bridge cycling ADP and PI released and then the myosin head does what?

Answer 28

The myosin head, pulls the actin filament toward the M line

Question 29

In cross bridge cycling ATP attaches to myosin weakening what?

Answer 29

Weakening the link between myosin and actin and causing the myosin head to detach.

Question 30

In cross bridge cycling, myosin hydrolyzes what?

Answer 30

ATP to ADP an PI

Question 31

In cross bridge cycling, Myosin hydrolyzes Returning the myosin head to it’s What?

Answer 31

To its pre-stroke high energy position

Question 32

The cross bridge cycling continues as long as what happens?

Answer 32

As long as ATP is available and CA +2 is bound to troponin

Question 33

What does a motor unit consist of?

Answer 33

It consists of one motor neuron and all the muscle fibers it innervates

Question 34

A muscle that exerts fine control have what type of motor unit?

Answer 34

A small motor unit

Question 35

Large weight-bearing muscles have what type of motor unit

Answer 35

A large motor unit

Question 36

A muscle twitch is the response of what?

Answer 36

It is the response of a muscle to a single stimulation

Question 37

A muscle twitch has three phases named them

Answer 37

The latent period, The period of contraction, and the period of relaxation

Question 38

Muscle contractions are graded in two ways describe them

Answer 38

An increase in the frequency of stimulation causes temporal summation, and the increase in strength of stimulation causes recruitment

Question 39

In graded muscle contractions, temporal submission occurs when what happens?

Answer 39

When a second contraction begins before the muscle has completely relaxed

Question 40

In the graded muscle contraction as the stimulation frequency increases what happens

Answer 40

The relaxation time between twitches becomes shorter, concentration of CA +2 in the cytosol rises, and wave summation becomes greater, progressing to unfused or incomplete tetanus

Question 41

In the graded muscle contraction, muscle tension increases until what happens?

Answer 41

Until it reaches maximal tension