Question 1

During contraction, asynchronous cycling of crossbridges

Accepted Answer

A)  prevents tetany 
B)  prevents thick filaments from slipping backwards 
C)  prevents thin filaments from slipping backwards 
D)  utilizes less ATP 
E)  none of these 
A)  prevents tetany 
B)  prevents thick filaments from slipping backwards 
C)  prevents thin filaments from slipping backwards 
D)  utilizes less ATP 
E)  none of these

Question 2

Which of the following is involved in muscle relaxation?

Accepted Answer

A)  Acetylcholinesterase destroys acetylcholine to allow the muscle membrane to return to resting potential. 
B)  Ca2+ is actively taken up by the lateral sacs of the sarcoplasmic reticulum when there is no longer a local action potential. 
C)  The cross bridges pull the filaments back to their original resting positions. 
D)  Acetylcholinesterase destroys acetylcholine to allow the muscle membrane to return to resting potential, and Ca2+ is actively taken up by the lateral sacs of the sarcoplasmic reticulum when there is no longer a local action potential. 
E)  All of these. 
A)  Acetylcholinesterase destroys acetylcholine to allow the muscle membrane to return to resting potential. 
B)  Ca2+ is actively taken up by the lateral sacs of the sarcoplasmic reticulum when there is no longer a local action potential. 
C)  The cross bridges pull the filaments back to their original resting positions. 
D)  Acetylcholinesterase destroys acetylcholine to allow the muscle membrane to return to resting potential, and Ca2+ is actively taken up by the lateral sacs of the sarcoplasmic reticulum when there is no longer a local action potential. 
E)  All of these.

Question 3

Enlargement of muscle due to weight lifting is primarily a result of

Accepted Answer

A)  hypertrophy 
B)  hyperplasia 
C)  increased production of actin and myosin 
D)  increases in the number of cells 
E)  hypertrophy and increased production of actin and myosin 
A)  hypertrophy 
B)  hyperplasia 
C)  increased production of actin and myosin 
D)  increases in the number of cells 
E)  hypertrophy and increased production of actin and myosin

Question 4

Fast-glycolytic (type IIx) muscle fibers

Accepted Answer

A)  have high myosin-ATPase activity 
B)  can carry out oxidative phosphorylation 
C)  fatigue rapidly 
D)  contain myoglobin 
E)  all of these 
A)  have high myosin-ATPase activity 
B)  can carry out oxidative phosphorylation 
C)  fatigue rapidly 
D)  contain myoglobin 
E)  all of these

Question 5

Repaying the oxygen deficit after strenuous exercise involves

Accepted Answer

A)  formation of lactate in the muscle cells 
B)  replenishing stores of creatine phosphate 
C)  replenishing stores of glycogen 
D)  replenishing stores of creatine phosphate and glycogen 
E)  all of these 
A)  formation of lactate in the muscle cells 
B)  replenishing stores of creatine phosphate 
C)  replenishing stores of glycogen 
D)  replenishing stores of creatine phosphate and glycogen 
E)  all of these

Question 6

The functional unit of skeletal muscle is the myofibril.

Accepted Answer

The answer of The functional unit of skeletal muscle is...

Question 7

Actin

Accepted Answer

A)  has ATPase activity 
B)  is spherical 
C)  forms a helical chain that forms the main structural component of the thin filaments 
D)  is spherical and forms a helical chain that forms the main structural component of the thin filaments 
E)  all of these 
A)  has ATPase activity 
B)  is spherical 
C)  forms a helical chain that forms the main structural component of the thin filaments 
D)  is spherical and forms a helical chain that forms the main structural component of the thin filaments 
E)  all of these

Question 8

Complete each of the following statments.
The contractile response of a muscle fiber to a single action potential is called a(n) ____________________.

Accepted Answer

The answer of Complete each of the following statments.
The contractile...

Question 9

Stretch reflexes are important

Accepted Answer

A)  for maintaining balance and posture 
B)  for providing afferent information coordinating complex muscle activity 
C)  for determining the level of tone 
D)  for maintaining balance and posture, and for providing afferent information coordinating complex muscle activity 
E)  for providing afferent information coordinating complex muscle activity and for determining the level of tone 
A)  for maintaining balance and posture 
B)  for providing afferent information coordinating complex muscle activity 
C)  for determining the level of tone 
D)  for maintaining balance and posture, and for providing afferent information coordinating complex muscle activity 
E)  for providing afferent information coordinating complex muscle activity and for determining the level of tone

Question 10

Intrafusal muscle fibers

Accepted Answer

A)  are supplied by alpha motor neurons 
B)  are found within muscle spindles 
C)  contain sensory nerve endings that are activated by stretch 
D)  are supplied by alpha motor neurons and contain sensory nerve endings that are activated by stretch 
E)  are found within muscle spindles and contain sensory nerve endings that are activated by stretch 
A)  are supplied by alpha motor neurons 
B)  are found within muscle spindles 
C)  contain sensory nerve endings that are activated by stretch 
D)  are supplied by alpha motor neurons and contain sensory nerve endings that are activated by stretch 
E)  are found within muscle spindles and contain sensory nerve endings that are activated by stretch

Question 11

The work performed by a muscle is the force it develops divided by distance.

Accepted Answer

A) True 
 B)False

Question 12

The T tubules

Accepted Answer

A)  store Ca2+ 
B)  provide a means of rapidly transmitting ACh to the central portions of the muscle fiber 
C)  provide attachment sites for ACh 
D)  provide a means of rapidly transmitting ACh to the central portions of the muscle fiber and provide attachment sites for ACh 
E)  none of these 
A)  store Ca2+ 
B)  provide a means of rapidly transmitting ACh to the central portions of the muscle fiber 
C)  provide attachment sites for ACh 
D)  provide a means of rapidly transmitting ACh to the central portions of the muscle fiber and provide attachment sites for ACh 
E)  none of these

Question 13

The stretch receptors in the central portion of the muscle spindle can be activated by

Accepted Answer

A)  passive stretch of the whole muscle, including stretch of the muscle spindle 
B)  contraction of the end portions of the muscle spindle 
C)  gamma motor neuron stimulation of the muscle spindle 
D)  all of these 
E)  none of these 
A)  passive stretch of the whole muscle, including stretch of the muscle spindle 
B)  contraction of the end portions of the muscle spindle 
C)  gamma motor neuron stimulation of the muscle spindle 
D)  all of these 
E)  none of these

Question 14

In order for relaxation to occur, ACh must be removed from the muscle cell's receptors.

Accepted Answer

A) True 
 B)False

Question 15

Anaerobic exercise is endurance-type exercise.

Accepted Answer

A) True 
 B)False

Question 16

During an isotonic contraction:

Accepted Answer

A)  Filaments do not shorten in the muscle. 
B)  Movement does not occur inside the muscle. 
C)  The muscle does not change length. 
D)  The muscle's tension does not overcome a load. 
E)  The muscle's tension remains constant. 
A)  Filaments do not shorten in the muscle. 
B)  Movement does not occur inside the muscle. 
C)  The muscle does not change length. 
D)  The muscle's tension does not overcome a load. 
E)  The muscle's tension remains constant.

Question 17

Cross bridge interaction between actin and myosin in skeletal muscle is directly blocked by

Accepted Answer

A)  acetylcholine 
B)  triads 
C)  Z lines 
D)  calcium 
E)  tropomyosin 
A)  acetylcholine 
B)  triads 
C)  Z lines 
D)  calcium 
E)  tropomyosin

Question 18

Oxidative phosphorylation occurs within the mitochondria of muscle cells.

Accepted Answer

A) True 
 B)False

Question 19

Single-unit smooth muscle and cardiac muscle are both self-excitable.

Accepted Answer

A) True 
 B)False

Question 20

Whole muscle tension depends on all of the following except

Accepted Answer

A)  number of muscle fibers contracting 
B)  tension produced by each contracting fiber 
C)  extent of motor-unit recruitment 
D)  frequency of stimulation 
E)  the proportion of each motor unit used at any given time 
A)  number of muscle fibers contracting 
B)  tension produced by each contracting fiber 
C)  extent of motor-unit recruitment 
D)  frequency of stimulation 
E)  the proportion of each motor unit used at any given time

Exam 8: A--Muscle Physiology

During contraction, asynchronous cycling of crossbridges

Which of the following is involved in muscle relaxation?

Enlargement of muscle due to weight lifting is primarily a result of

Fast-glycolytic (type IIx) muscle fibers

Repaying the oxygen deficit after strenuous exercise involves

The functional unit of skeletal muscle is the myofibril.

Actin

Complete each of the following statments. The contractile response of a muscle fiber to a single action potential is called a(n) ____________________.

Stretch reflexes are important

Intrafusal muscle fibers

The work performed by a muscle is the force it develops divided by distance.

The T tubules

The stretch receptors in the central portion of the muscle spindle can be activated by

In order for relaxation to occur, ACh must be removed from the muscle cell's receptors.

Anaerobic exercise is endurance-type exercise.

During an isotonic contraction:

Cross bridge interaction between actin and myosin in skeletal muscle is directly blocked by

Oxidative phosphorylation occurs within the mitochondria of muscle cells.

Single-unit smooth muscle and cardiac muscle are both self-excitable.

Whole muscle tension depends on all of the following except

Introduction to Physiology and Homeostasis

Cell Physiology

The Plasma Membrane and Membrane Potential

Principles of Neural and Hormonal Communication

A--The Central Nervous System

B--The Central Nervous System

A--The Peripheral Nervous System: Afferent Division; Special Senses

B--The Peripheral Nervous System: Afferent Division; Special Senses

The Peripheral Nervous System: Efferent Division

B--Muscle Physiology

A--Cardiac Physiology

B--Cardiac Physiology

The Blood Vessels and Blood Pressure

The Blood

Body Defenses

A--The Respiratory System

B--The Respiratory System

A--The Urinary System

B--The Urinary System

A--Fluid and Acid-Base Balance

B--Fluid and Acid-Base Balance

A--The Digestive System

B--The Digestive System

Energy Balance and Temperature Regulation

A--Principles of Endocrinology: the Central Endocrine Glands

B--Principles of Endocrinology: the Central Endocrine Glands

A--The Peripheral Endocrine Glands

B--The Peripheral Endocrine Glands

A--The Reproductive System

B--The Reproductive System

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