muscle and neurons

Question 1

80% of the lactic acid produced by skeletal muscle is converted to pyruvic acid by the ________.

Answer 1

kidneys

Question 2

A myofilament that runs throughout the core of a thick filament and anchors it to a Z disc is called a(n) ________.

Answer 2

elastic filament

Question 3

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

Answer 3

36

Question 4

Athletes who train at high altitudes increase their red blood cell count, which increases their oxygen supply during exercise. Increased oxygen supply results in ________.

Answer 4

longer aerobic respiration

Question 5

Cardiac muscle has very little capacity for regeneration because it lacks ________.

Answer 5

satellite cells

Question 6

During muscle contraction, a single myosin head consumes ATP at a rate of about ________ ATP per second.

Answer 6

5

Question 7

How many muscle fibers stimulate one somatic motor neuron?

Answer 7

0

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 ________.

Answer 8

incomplete tetanus

Question 9

If the potassium leak channels were suddenly blocked in a resting neuron, what would happen to its resting membrane potential?

Answer 9

It would become more positive.

Question 10

In order for muscle to continue contracting during anaerobic fermentation, which of the following is essential?

Answer 10

Myokinase

Question 11

In skeletal muscle, the term that describes the alternating light and dark bands is ________.

Answer 11

striations

Question 12

Loss of muscle mass from lack of activity is called ________.

Answer 12

atrophy

Question 13

Michael Jordan was arguably the best player in professional basketball history. Scientifically, one would expect him to have highly developed ________ fibers.

Answer 13

white

Question 14

Place the following events in synaptic transmission at a cholinergic synapse in order: A - A postsynaptic potential is produced; B - Voltage gated calcium channels open and calcium enters the cell; C - ACh is released and diffuses across the synaptic cleft; D - A nerve signal arrives at a synaptic knob; E - Ligand gated sodium channels open and sodium enters the cell.

Answer 14

D, B, C, E, A

Question 15

Shortening a muscle while it maintains constant tension is called ________.

Answer 15

an isotonic contraction

Question 16

Skeletal muscle is called ________, because it is usually subject to conscious control.

Answer 16

voluntary

Question 17

The absence or inhibition of acetylcholinesterase at a synapse would lead to ________.

Answer 17

tetanus

Question 18

The minimum stimulus needed to cause muscle contraction is called the ________.

Answer 18

threshold

Question 19

The process of engaging more motor units to increase the strength of a muscle contraction is called ________.

Answer 19

recruitment

Question 20

The protein that acts as a calcium receptor in skeletal muscle is ________.

Answer 20

troponin

Question 21

The sarcolemma of a resting muscle fiber is most permeable to ________.

Answer 21

potassium

Question 22

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

Answer 22

synaptic vesicles

Question 23

What happens when acetylcholine stimulates its receptors in the neuromuscular junction?

Answer 23

The permeability of the sarcolemma to Na+ increases

Question 24

When a skeletal muscle lengthens, its ________ helps resist excessive stretching and subsequent injury to the muscle.

Answer 24

collagen

Question 25

Where is dystrophin, the protein that is defective in muscular dystrophy, normally found?

Answer 25

Between the outermost myofilaments and the sarcolemma of a muscle fiber

Question 26

Where would you expect to find numerous gap junctions in muscular tissue?

Answer 26

The intercalated discs of cardiac muscle

Question 27

Which fibers are primarily responsible for producing lactic acid?

Answer 27

Type IIB fast glycolytic fibers

Question 28

Which muscle type depends solely on the sarcoplasmic reticulum as its calcium source?

Answer 28

skeletal muscle

Question 29

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

Answer 29

Smooth and cardiac muscle

Question 30

Which of the following contains overlapping thick and thin filaments?

Answer 30

a band

Question 31

Which of the following has the largest mitochondria?

Answer 31

cardiac muscle

Question 32

Which of the following is an accurate comparison of skeletal muscle to smooth muscle?

Answer 32

Smooth muscle contracts and relaxes more slowly.

Question 33

Which of the following is not a purpose of the excess postexercise oxygen consumption (EPOC) in muscle?

Answer 33

To neutralize carbon dioxide buildup

Question 34

Which of the following is predominately made up of myosin?

Answer 34

the thick filament

Question 35

Which of the following is true concerning isotonic eccentric contraction?

Answer 35

The muscle lengthens but tension remains constant.

Question 36

Which of the following is not a characteristic of a muscle cell?

Answer 36

plasticity

Question 37

Which of the following marks the boundaries of a sarcomere?

Answer 37

Z discs

Question 38

Which of the following would be caused by a contraction of smooth muscle?

Answer 38

goose bumps

Question 39

Which statement best describes the goal of medications used to treat myasthenia gravis?

Answer 39

To inhibit the function of cholinesterase

Question 40

Why is the contraction strength of smooth muscle relatively independent of its resting length?

Answer 40

It does not have sarcomeres