Biology

Question 1

The minimum stimulus needed to cause muscle contraction is called

the threshold.

the latent period.

twitch.

recruitment.

innervation.

Question 2

Release of acetylcholine at a neuromuscular junction

decreases the release of Ca2+ from the sarcoplasmic reticulum.

increases permeability of the sarcolemma to Na+.

decreases the positive charge on the sarcolemma.

lowers the threshold of the muscle fiber.

overrides the inhibitory effect of acetylcholinesterase.

Question 3

One somatic motor neuron is stimulated by how many muscle fibers?

0

1

2

3

4

Question 4

To stimulate muscle contraction, acetylcholine is released from the ___________ into the synaptic cleft.

synaptic knob

junctional folds

sarcoplasmic reticulum

sarcolemma

terminal cisterna

Question 5

Opening of sodium gates typically leads to

repolarization of the plasma membrane.

hyperpolarization of the plasma membrane.

depolarization of the plasma membrane.

drifting of plasma membrane voltage toward a more negative value.

plasma membrane voltage returning to the resting membrane potential.

Question 6

The process of bringing more motor units into use during a muscle contraction is called

wave summation.

recruitment.

treppe.

incomplete tetanus.

complete tetanus.

Question 7

A reason that muscle twitches become progressively stronger in treppe is

Ca2+ accumulates in the sarcoplasm faster than the sarcoplasmic reticulum can reabsorb it.

ATP is regenerated faster than it is consumed.

myosin heads show faster and faster power strokes.

more and more acetytlcholine is released with each stimulus.

as the muscle warms up, aerobic respiration is accelerated.

Question 8

If one nerve stimulus arrives at a muscle fiber so soon that the fiber has only partially relaxed from the previous twitch, the most likely result will be

fatigue.

treppe.

incomplete tetanus.

complete tetanus.

flaccid paralysis.

Question 9

Aerobic respiration produces approximately _____ more ATPs per glucose molecule than glycolysis does.

12

24

36

48

100

Question 10

The term for shortening of a muscle while maintaining constant tension is

treppe.

tetanus.

isokinetic contraction.

isometric contraction.

isotonic contraction.

Question 11

An isometric contraction does not change muscle length.

True

False

Question 12

Which of the following is true concerning isotonic eccentric contraction?

The muscle shortens but tension remains constant.

The muscle lengthens but tension remains constant.

The muscle tenses and shortens.

The muscle tenses but length remains unchanged.

The muscle lengthens and tension declines.

Question 13

Which muscle(s) can contract without the need for nervous stimulation?

skeletal muscle

smooth muscle

cardiac muscle

smooth and cardiac muscle

skeletal, smooth and cardiac muscle

Question 14

Which of the following is very important for muscle to continue contraction during anaerobic respiration?

cholinesterase inhibitors

protease

myokinase

acetylcholinesterase

acid phosphatase

Question 15

Athletes who train at high altitudes increase their red blood cell count and thus increase their oxygen supply during exercise. Increased oxygen supply results in

increased glycolysis.

increased use of myokinase.

longer aerobic respiration.

longer anaerobic fermentation.

reduced ATP consumption.

Question 16

Use the image to name descibe what is happing in the electromyograpy /var/folders/9s/5k_n9ntx3sg2tkk2k98jfw200000gn/T/com.microsoft.Word/WebArchiveCopyPasteTempFiles/preview

Rapid shortening and relaxation a muscle fiber produces a quick jerk called

[ Choose ] Treppe Twitch Incomplete Tetanus Complete Tetanus Fatigue

Gradual, step-like increase of tensions separated by 1 sec

[ Choose ] Treppe Twitch Incomplete Tetanus Complete Tetanus Fatigue

Twitches that fuse with each other with no relaxation period

[ Choose ] Treppe Twitch Incomplete Tetanus Complete Tetanus Fatigue

Occurs when the metabolic components needed for muscle contraction are exhausted

[ Choose ] Treppe Twitch Incomplete Tetanus Complete Tetanus Fatigue

Question 17

Creatine kinase

donates one of its phosphate groups to ADP.

phosphorylates and activates certain enzymes in the sarcoplasm.

acts as a second messenger in muscle fibers.

catalyzes the transfer of phosphate from CP to ADP.

functions as a substitute for ATP during anaerobic fermentation.

Question 18

Which of the following best describes the resting membrane potential (RMP)?

The intracellular environment is negatively charged.

The intracellular environment has more positively charged sodium.

The extracellular environment is negatively charged.

It has a voltage of about +75 mV.

It depends on the muscle fiber absorbing potassium ions from the ECF.

Question 19

Oligodendrocytes serve the same purpose in the CNS that satellite cells do in the PNS.

True

False

Question 20

Most of the myelin sheath is composed of

lipids.

carbohydrates.

glycoproteins.

proteins.

polysaccharides.

Question 21

___ form myelin in the spinal cord.

Schwann cells

Astrocytes

Satellite cells

Oligodendrocytes

Microglia

Question 22

/var/folders/9s/5k_n9ntx3sg2tkk2k98jfw200000gn/T/com.microsoft.Word/WebArchiveCopyPasteTempFiles/preview This image shows a representative neuron. What does “5” represent?

synaptic knobs

Schwann cells

trigger zone

node of Ranvier

axon collateral

Question 23

/var/folders/9s/5k_n9ntx3sg2tkk2k98jfw200000gn/T/com.microsoft.Word/WebArchiveCopyPasteTempFiles/preview This image shows a representative neuron. What does “1” represent?

synaptic knobs

axons

Dendrites

interneurons

Please Match the cell type with the function. You may

Neuroglial cell that is related to immune tissue and phagocytizes dead nervous tissue

[ Choose ] Schwann cells Oligodendrocytes Fibrous Astrocytes Protoplasmic Astrocytes Ependymal cells Microglia

Forms the myelin sheath around most PNS axons

[ Choose ] Schwann cells Oligodendrocytes Fibrous Astrocytes Protoplasmic Astrocytes Ependymal cells Microglia

Line cavities of brain and spinal cord and secretes CSF

[ Choose ] Schwann cells Oligodendrocytes Fibrous Astrocytes Protoplasmic Astrocytes Ependymal cells Microglia

Star-like cells that form the blood brain-barrier

[ Choose ] Schwann cells Oligodendrocytes Fibrous Astrocytes Protoplasmic Astrocytes Ependymal cells Microglia

Forms the myelin sheath around most CNS axons

[ Choose ] Schwann cells Oligodendrocytes Fibrous Astrocytes Protoplasmic Astrocytes Ependymal cells Microglia

Star-like cell that forms a supportive framework in CNS and can form form scar tissue after injury

[ Choose ] Schwann cells Oligodendrocytes Fibrous Astrocytes Protoplasmic Astrocytes Ependymal cells Microglia

Spaces between these cells on an axon are called nodes of Ranvir

[ Choose ] Schwann cells Oligodendrocytes Fibrous Astrocytes Protoplasmic Astrocytes Ependymal cells Microglia

Aid in regeneration of damaged nerve fibers in the PNS

[ Choose ] Schwann cells Oligodendrocytes Fibrous Astrocytes Protoplasmic Astrocytes Ependymal cells Microglia

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