Question 1

Too much acetylcholinesterase causes

Accepted Answer

A)   continuous stimulation of the muscle fiber.
B)   rapid degradation of acetycholine.
C)   voltage-gated calcium ion channels opening in the presynaptic terminal.
D)   an increase in sodium uptake by the muscle fiber.
E)   exocytosis of synaptic vesicles.F) None of the above
G) C) and E)

Question 2

An action potential

Accepted Answer

A)   occurs when the local potential reaches threshold level.
B)   is not propagated.
C)   has no repolarization phase.
D)   is an example of negative feedback.
E)   can be of varying strengths depending on strength of the stimulus.F) A) and D)
G) B) and E)

Question 3

In which of the following situations does a resting membrane potential exist?

Accepted Answer

A)   a relaxed muscle fiber
B)   a conducting neuron
C)   a stimulated sensory receptor in the skin
D)   a contracting cardiac muscle cell
E)   the eye seeing an imageF) A) and D)
G) B) and E)

Question 4

Skeletal muscle develops from multinucleated cells called

Accepted Answer

A)   fascicles.
B)   myoblasts.
C)   myofibrils.
D)   myotomes.
E)   fasciculi.F) C) and D)
G) A) and D)

Question 5

After contraction has occurred, the calcium is

Accepted Answer

A)   destroyed by cholinesterase.
B)   chemically bound to the cross bridges.
C)   secreted by the Golgi apparatus to the outside of the cell.
D)   released from troponin.
E)   returned to the sarcolemma.F) D) and E)
G) B) and E)

Question 6

Arrange the following list of biochemical events in the correct sequence. (1)  An action potential is conducted deep into the muscle fiber by the T tubule.
(2)  Calcium ions bind to troponin.
(3)  The membranes of the sarcoplasmic reticulum become more permeable to calcium ions.
(4)  Calcium ions diffuse into the sarcoplasm around the myofibril.
(5)  The troponin-tropomyosin complex moves exposing active sites.

Accepted Answer

A)   1, 5, 2, 3, 4
B)   1, 3, 4, 2, 5
C)   1, 2, 3, 4, 5
D)   1, 3, 2, 5, 4
E)   1, 4, 3, 2, 5F) A) and B)
G) C) and D)

Question 7

Oxygen deficit represents

Accepted Answer

A)   the amount anaerobic metabolism must increase after exercise.
B)   the amount of oxygen converted to lactic acid during exercise.
C)   the amount of carbon dioxide that cells need to eliminate.
D)   conversion of pyruvic acid to lactic acid.
E)   the amount of oxygen that cells need to replenish ATP supplies after exercise.F) All of the above
G) A) and C)

Question 8

The capacity of a muscle cell to shorten forcefully is known as

Accepted Answer

A)   contractility.
B)   excitability.
C)   extensibility.
D)   elasticity.
E)   flexibility.F) None of the above
G) All of the above

Question 9

Concentric contractions occur when

Accepted Answer

A)   the muscle produces increasing tension as it shortens.
B)   the tension and length of the muscle remain constant during a contraction.
C)   tension in a muscle is maintained while the muscle increases in length.
D)   the muscle produces tension while the length of the muscle increases.
E)   isometric contractions occur.F) A) and E)
G) A) and C)

Question 10

Cardiac muscle cells are like skeletal muscle cells in that they both

Accepted Answer

A)   have striations.
B)   depolarize as a result of sodium and calcium influxes.
C)   possess intercalated disks.
D)   lack sarcomeres.
E)   are multinucleated.F) All of the above
G) A) and D)

Question 11

Curare blocks acetylcholine receptors at the motor end plate. This would result in

Accepted Answer

A)   increased stimulation of the muscle.
B)   more acetylcholinesterase production.
C)   lack of calcium uptake by the muscle fiber.
D)   inability of the muscle fiber to respond to nervous stimulation.
E)   sustained contraction of the muscle.F) B) and D)
G) A) and B)

Question 12

Shivering

Accepted Answer

A)   increases heat loss from the skin.
B)   is a response of the nervous system to a high fever.
C)   helps raise body temperature.
D)   causes vasoconstriction.
E)   occurs when body temperature is slightly elevated.F) C) and E)
G) A) and B)

Question 13

Hypertrophy of skeletal muscles from weight lifting is caused by an increase in the

Accepted Answer

A)   number of muscle fibers.
B)   size of muscle fibers.
C)   number of striations.
D)   number of nuclei within the muscle fibers.
E)   number of muscle cells.F) A) and C)
G) None of the above

Question 14

Which of the following statements concerning slow-twitch oxidative muscle fibers is false?

Accepted Answer

A)   They split ATP slowly.
B)   They have large deposits of myoglobin.
C)   They are well adapted to anaerobic activity.
D)   They have a well developed blood supply.
E)   They have low glycogen stores.F) A) and E)
G) C) and D)

Exam 9: Muscular System: Histology and Physiology

Cardiac muscle cells are like skeletal muscle cells in that they both

Correct Answer
verified

Concentric contractions occur when

Correct Answer
verified

Which of the following statements concerning slow-twitch oxidative muscle fibers is false?

Correct Answer
verified

Curare blocks acetylcholine receptors at the motor end plate. This would result in

Correct Answer
verified

Skeletal muscle develops from multinucleated cells called

Correct Answer
verified

The capacity of a muscle cell to shorten forcefully is known as

Correct Answer
verified

Oxygen deficit represents

Correct Answer
verified

Shivering

Correct Answer
verified

Correct Answer
verified

Hypertrophy of skeletal muscles from weight lifting is caused by an increase in the

Correct Answer
verified

Too much acetylcholinesterase causes

Correct Answer
verified

After contraction has occurred, the calcium is

Correct Answer
verified

In which of the following situations does a resting membrane potential exist?

Correct Answer
verified

An action potential

Correct Answer
verified

Exam 9: Muscular System: Histology and Physiology

Cardiac muscle cells are like skeletal muscle cells in that they both

Correct AnswerverifiedShow Answer

Concentric contractions occur when

Correct AnswerverifiedShow Answer

Which of the following statements concerning slow-twitch oxidative muscle fibers is false?

Correct AnswerverifiedShow Answer

Curare blocks acetylcholine receptors at the motor end plate. This would result in

Correct AnswerverifiedShow Answer

Skeletal muscle develops from multinucleated cells called

Correct AnswerverifiedShow Answer

The capacity of a muscle cell to shorten forcefully is known as

Correct AnswerverifiedShow Answer

Oxygen deficit represents

Correct AnswerverifiedShow Answer

Shivering

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Hypertrophy of skeletal muscles from weight lifting is caused by an increase in the

Correct AnswerverifiedShow Answer

Too much acetylcholinesterase causes

Correct AnswerverifiedShow Answer

After contraction has occurred, the calcium is

Correct AnswerverifiedShow Answer

In which of the following situations does a resting membrane potential exist?

Correct AnswerverifiedShow Answer

An action potential

Correct AnswerverifiedShow Answer

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