Question 1

During contraction of skeletal muscle fibers, the

Accepted Answer

A)  Contractile proteins contract. 
B)  Thin filaments slide inward toward the A band's center as a result of cycles of cross-bridge binding and bending. 
C)  Thick and thin filaments become tightly coiled, thus shortening the sarcomere. 
D)  I bands slide in between the A bands. 
E)  Lateral sacs of the sarcoplasmic reticulum shrink, pulling the Z lines closer together. 
A)  Contractile proteins contract. 
B)  Thin filaments slide inward toward the A band's center as a result of cycles of cross-bridge binding and bending. 
C)  Thick and thin filaments become tightly coiled, thus shortening the sarcomere. 
D)  I bands slide in between the A bands. 
E)  Lateral sacs of the sarcoplasmic reticulum shrink, pulling the Z lines closer together.

Question 2

Fast-glycolytic muscle fibers do not require as much oxygen use as slow-oxidative fibers.

Accepted Answer

A) True 
 B)False

Question 3

Of the steps in excitation-contraction below, which occurs before the others?

Accepted Answer

A)  Exposed actin sites bind with myosin cross bridges. 
B)  Sodium channels open in the fiber's membrane. 
C)  Calcium is released from the sarcoplasmic reticulum. 
D)  Troponin binds calcium. 
E)  Attachment of ATP allows for cross bridge detachment. 
A)  Exposed actin sites bind with myosin cross bridges. 
B)  Sodium channels open in the fiber's membrane. 
C)  Calcium is released from the sarcoplasmic reticulum. 
D)  Troponin binds calcium. 
E)  Attachment of ATP allows for cross bridge detachment.

Question 4

Tetanus occurs when a muscle fiber is stimulated so rapidly that it is not allowed to relax between stimulations, resulting in a smooth, sustained contraction.

Accepted Answer

A) True 
 B)False

Question 5

A skeletal muscle produces motion by pulling the origin toward its insertion.

Accepted Answer

A) True 
 B)False

Question 6

Myoglobin

Accepted Answer

A)  can store small amounts of O2 
B)  increases the rate of O2 transfer from the blood into muscle fibers 
C)  is abundant in fast-glycolytic fibers 
D)  can store small amounts of O2 and increases the rate of O2 transfer from the blood into muscle fibers 
E)  all of these 
A)  can store small amounts of O2 
B)  increases the rate of O2 transfer from the blood into muscle fibers 
C)  is abundant in fast-glycolytic fibers 
D)  can store small amounts of O2 and increases the rate of O2 transfer from the blood into muscle fibers 
E)  all of these

Question 7

Myosin

Accepted Answer

A)  is found in the A band 
B)  is found in the I band 
C)  is in the thin filaments 
D)  contracts during muscle contraction because it is one of the contractile proteins 
E)  none of these 
A)  is found in the A band 
B)  is found in the I band 
C)  is in the thin filaments 
D)  contracts during muscle contraction because it is one of the contractile proteins 
E)  none of these

Question 8

Which of the following muscle types are myogenic?

Accepted Answer

A)  cardiac muscle 
B)  single-unit smooth muscle 
C)  multi-unit smooth muscle 
D)  cardiac muscle and single-unit smooth muscle 
E)  single-unit smooth muscle and multi-unit smooth muscle 
A)  cardiac muscle 
B)  single-unit smooth muscle 
C)  multi-unit smooth muscle 
D)  cardiac muscle and single-unit smooth muscle 
E)  single-unit smooth muscle and multi-unit smooth muscle

Question 9

Slow-oxidative muscle fibers would be found in high density in the leg muscles of Olympic sprinters.

Accepted Answer

A) True 
 B)False

Question 10

Thick filaments in skeletal muscle are composed of

Accepted Answer

A)  actin 
B)  troponin and tropomyosin 
C)  myosin 
D)  actin, troponin, and tropomyosin 
E)  all of these 
A)  actin 
B)  troponin and tropomyosin 
C)  myosin 
D)  actin, troponin, and tropomyosin 
E)  all of these

Question 11

Central fatigue of a muscle directly results from the accumulation of lactic acid in the muscle.

Accepted Answer

A) True 
 B)False

Question 12

Fatigue is the failure of a muscle fiber to maintain ____ as a result of previous contractile activity.

Accepted Answer

A)  excitability 
B)  muscle mass 
C)  tension 
D)  sarcomere number 
E)  mitochondria 
A)  excitability 
B)  muscle mass 
C)  tension 
D)  sarcomere number 
E)  mitochondria

Question 13

Complete each of the following statments.
In smooth muscle, Ca2+ binds with the protein ____________________, which is structurally similar to troponin.

Accepted Answer

Question 14

Fast-oxidative (type IIa) fibers

Accepted Answer

A)  contain very few mitochondria 
B)  can be converted into fast-glycolytic fibers by regular resistance activities 
C)  are most abundant in muscles specialized for maintaining low-intensity contractions for long periods of time without fatigue 
D)  can be converted into fast-glycolytic fibers by regular resistance activities and are most abundant in muscles specialized for maintaining low-intensity contractions for long periods of time without fatigue 
E)  all of these 
A)  contain very few mitochondria 
B)  can be converted into fast-glycolytic fibers by regular resistance activities 
C)  are most abundant in muscles specialized for maintaining low-intensity contractions for long periods of time without fatigue 
D)  can be converted into fast-glycolytic fibers by regular resistance activities and are most abundant in muscles specialized for maintaining low-intensity contractions for long periods of time without fatigue 
E)  all of these

Question 15

Which of the following is not involved in the relaxation of muscle?

Accepted Answer

A)  synthesis of ACh by acetylcholinesterase 
B)  initiation of action potentials 
C)  the troponin-tropomyosin complex slipping back into its blocking position 
D)  detachment of actin from tropomyosin 
E)  T tubules actively absorbing Ca2+ 
A)  synthesis of ACh by acetylcholinesterase 
B)  initiation of action potentials 
C)  the troponin-tropomyosin complex slipping back into its blocking position 
D)  detachment of actin from tropomyosin 
E)  T tubules actively absorbing Ca2+

Question 16

Select the correct statement about the summation of simple twitches.

Accepted Answer

A)  They can occur because of the long duration of the action potential in a muscle fiber. 
B)  They reduce the tension in a muscle. 
C)  They result from the slow stimulation of a muscle fiber. 
D)  The effect is unrelated to the refractory periods of action potentials. 
E)  The twitches resulting from separate action potentials add together. 
A)  They can occur because of the long duration of the action potential in a muscle fiber. 
B)  They reduce the tension in a muscle. 
C)  They result from the slow stimulation of a muscle fiber. 
D)  The effect is unrelated to the refractory periods of action potentials. 
E)  The twitches resulting from separate action potentials add together.

Question 17

Complete each of the following statments.
The additional oxygen that must be taken into the body after strenuous exercise in order to return the tissues to pre-exercise conditions is called the ____________________.

Accepted Answer

excess pos

Question 18

Complete each of the following statments.
The ____________________ component is the noncontractile tissue part of a muscle.

Accepted Answer

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

Question 19

Gradation of muscle contraction can be accomplished by stimulating variable portions of each muscle fiber.

Accepted Answer

A) True 
 B)False

Question 20

During a cross-bridge cycle in skeletal muscle, the

Accepted Answer

A)  Cross bridge is energized when it hydrolyzes ATP. 
B)  Myosin cross bridge must bind with an ATPase before the cross bridge will experience a power stroke. 
C)  Ca2+ causes the troponin-tropomyosin complex to move off the actin-binding sites on myosin. 
D)  ADP binds to the cross bridge at the end of the power stroke. 
E)  Cross bridge is energized when it hydrolyzes ATP, and myosin cross bridge must bind with an ATPase before the cross bridge will experience a power stroke. 
A)  Cross bridge is energized when it hydrolyzes ATP. 
B)  Myosin cross bridge must bind with an ATPase before the cross bridge will experience a power stroke. 
C)  Ca2+ causes the troponin-tropomyosin complex to move off the actin-binding sites on myosin. 
D)  ADP binds to the cross bridge at the end of the power stroke. 
E)  Cross bridge is energized when it hydrolyzes ATP, and myosin cross bridge must bind with an ATPase before the cross bridge will experience a power stroke.

Exam 8: A--Muscle Physiology

During contraction of skeletal muscle fibers, the

Fast-glycolytic muscle fibers do not require as much oxygen use as slow-oxidative fibers.

Of the steps in excitation-contraction below, which occurs before the others?

Tetanus occurs when a muscle fiber is stimulated so rapidly that it is not allowed to relax between stimulations, resulting in a smooth, sustained contraction.

A skeletal muscle produces motion by pulling the origin toward its insertion.

Myoglobin

Myosin

Which of the following muscle types are myogenic?

Slow-oxidative muscle fibers would be found in high density in the leg muscles of Olympic sprinters.

Thick filaments in skeletal muscle are composed of

Central fatigue of a muscle directly results from the accumulation of lactic acid in the muscle.

Fatigue is the failure of a muscle fiber to maintain ____ as a result of previous contractile activity.

Complete each of the following statments. In smooth muscle, Ca2+ binds with the protein ____________________, which is structurally similar to troponin.

Fast-oxidative (type IIa) fibers

Which of the following is not involved in the relaxation of muscle?

Select the correct statement about the summation of simple twitches.

Complete each of the following statments. The additional oxygen that must be taken into the body after strenuous exercise in order to return the tissues to pre-exercise conditions is called the ____________________.

Complete each of the following statments. The ____________________ component is the noncontractile tissue part of a muscle.

Gradation of muscle contraction can be accomplished by stimulating variable portions of each muscle fiber.

During a cross-bridge cycle in skeletal muscle, the

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

Filters

Complete each of the following statments. In smooth muscle, Ca²⁺ binds with the protein ____________________, which is structurally similar to troponin.