Exp 2: Skeletal Muscle Physiology Flashcards Preview

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Flashcards in Exp 2: Skeletal Muscle Physiology Deck (47)
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T-tubules

Part of sarcolemma that carries the action potential

1

Triad

T-tubule plus two terminal cisternae

2

Terminal cisternae

Part of sarcoplasmic reticulum that stores calcium

3

Sarcolemma

Plasma membrane of muscle cell

4

Cytosol (sarcoplasm)

Intracellular fluid around organelles

5

Sarcoplasmic reticulum

Endoplasmic reticulum in muscle cell

6

Synaptic vessicles in the motor neuron terminal end contain the neurotransmitter:

Acetylcholine

7

Opening of ligand-gated channels leads to ________ of the motor end plate.

Depolarization

8

Once the post-synaptic membrane depolarizes, an action potential is propagated along the _____ down into the interior of the cell via the ____.

sarcolemma; T-tubules

9

What molecule has a binding site for myosin head?

Actin

10

Which molecule covers the binding site?

tropomyosin

11

Which molecule has a binding site for calcium?

troponin

12

What molecule must bind to the myosin head in order for it to disconnect with actin?

ATP

13

A motor unit:

is composed of a neuron and all the muscle fibers it innervates.

14

Muscle tone refers to:

a state of sustained, partial contractions which is necessary to maintain posture

15

Muscle tone is the result of:

asynchronous firing of motor units.

16

The tension developed by a skeletal muscle can be increased by increasing the:

-number of motor units stimulated.
-stimulation to each motor unit.

17

Which of the following contract in an all or none fashion?

single muscle fiber

18

Match the three phase of a muscle twitch with their definitions.
A) Sarcomeres shorten
B) Sarcomeres return to resting length
C) Sarcomeres are at resting length

A) Contraction
B) Relaxation
C) Latent period

19

Under normal circumstances, at the level of single skeletal muscle fibers, there are:

all-or-none responses

20

True or False: The muscles of the eye need to make precise small motor movements. Therefore, you would find large motor units in the eye, while you would find small motor units in postural muscle such as the thigh.

False

21

Below is a list of the four phases of temporal summation. Put them in the correct order:

treppe
incomplete tetanus
complete tetanus
fatigue

treppe
incomplete tetanus
complete tetanus
fatigue

22

Activity 1: As the stimulus voltage was increased in this activity, which of the following occurred?

The muscle force generated increased.

23

Activity 1: Which of the following can trigger a muscle twitch?

release of acetylcholine and electrical stimulation

24

Activity 1: Which of the following describes the relaxation phase?

The sarcomeres are increasing in length, and the force generated decreases.

25

Activity 2: As the stimulus voltage increased, the resulting muscle tension _______.

increased to a point until it reached a plateau

26

Interpretation-Activity 2: In the lab, if a researcher finds that the threshold stimulus to induce an action potential in a muscle fiber's sarcolemma was 3.0 volts. Which of the following would result in muscle tension?

3.0 volts and 4.0 volts

27

Activity 2: Increasing the applied voltage in the simulation corresponds to which in vivo event?

Motor unit recruitment

28

Activity 2: Which of the following is occurring during the contraction phase?

Cross-bridge cycling is taking place.

29

Activity 3: Which of the following does NOT describe treppe?

An increase in stimulus intensity is required to see the effect.