Question 1

A motor unit refers to

Accepted Answer

A)  a single motor neuron plus all of the muscle fibers it innervates 
B)  a single muscle fiber plus all of the motor neurons that innervate it 
C)  all of the motor neurons supplying a single muscle 
D)  a pair of antagonistic muscles 
E)  a sheet of smooth muscle cells connected by gap junctions 
A)  a single motor neuron plus all of the muscle fibers it innervates 
B)  a single muscle fiber plus all of the motor neurons that innervate it 
C)  all of the motor neurons supplying a single muscle 
D)  a pair of antagonistic muscles 
E)  a sheet of smooth muscle cells connected by gap junctions

Question 2

The smallest unit of contraction within a skeletal muscle is a

Accepted Answer

A)  myofibril 
B)  muscle fiber 
C)  sarcomere 
D)  thin filament 
E)  thick filament 
A)  myofibril 
B)  muscle fiber 
C)  sarcomere 
D)  thin filament 
E)  thick filament

Question 3

Complete each of the following statments.
The gradation of whole-muscle tension depends on the number of ____________________ that are stimulated.

Accepted Answer

muscle fib

Question 4

Cardiac muscle tissue

Accepted Answer

A)  has well developed sarcoplasmic reticulum 
B)  has fast myosin ATPase activity 
C)  contracts only when stimulated neurogenically 
D)  has gap junctions 
E)  stores calcium in its T tubules 
A)  has well developed sarcoplasmic reticulum 
B)  has fast myosin ATPase activity 
C)  contracts only when stimulated neurogenically 
D)  has gap junctions 
E)  stores calcium in its T tubules

Question 5

Fast-oxidative muscle fibers have a high concentration of mitochondria.

Accepted Answer

A) True 
 B)False

Question 6

Single-unit smooth muscle has no innervation.

Accepted Answer

A) True 
 B)False

Question 7

Which molecules are involved with regulation of cross bridge attachment activity?

Accepted Answer

A)  calcium ions 
B)  troponin 
C)  myosin 
D)  calcium ions and troponin 
E)  all of these 
A)  calcium ions 
B)  troponin 
C)  myosin 
D)  calcium ions and troponin 
E)  all of these

Question 8

Actin

Accepted Answer

A)  does not perform a power stroke during muscle contraction 
B)  contains a globular head that forms the cross bridges between the thick and thin filaments 
C)  is not found within A bands 
D)  is inhibited by Ca2+ 
E)  none of these 
A)  does not perform a power stroke during muscle contraction 
B)  contains a globular head that forms the cross bridges between the thick and thin filaments 
C)  is not found within A bands 
D)  is inhibited by Ca2+ 
E)  none of these

Question 9

Complete each of the following statments.
The ____________________ stores calcium ions inside muscle cells.

Accepted Answer

sarcoplasm

Question 10

According to the sliding-filament mechanism, the

Accepted Answer

A)  A bands slide in closer between the I bands. 
B)  Thin filaments slide inward toward the center of the A band. 
C)  Z lines slide in between the T tubules. 
D)  Contractile proteins contract, thus shortening the sarcomere. 
E)  Filaments slide into the lateral sacs of the sarcoplasmic reticulum. 
A)  A bands slide in closer between the I bands. 
B)  Thin filaments slide inward toward the center of the A band. 
C)  Z lines slide in between the T tubules. 
D)  Contractile proteins contract, thus shortening the sarcomere. 
E)  Filaments slide into the lateral sacs of the sarcoplasmic reticulum.

Question 11

Which of the following does not directly influence motor neurons?

Accepted Answer

A)  primary motor cortex 
B)  cerebellum 
C)  brain stem 
D)  afferent neurons (through intervening interneurons) 
E)  none of these 
A)  primary motor cortex 
B)  cerebellum 
C)  brain stem 
D)  afferent neurons (through intervening interneurons) 
E)  none of these

Question 12

During muscle contraction, the

Accepted Answer

A)  Z lines move farther away from the thick filaments. 
B)  A band becomes narrower. 
C)  H zone becomes narrower or disappears. 
D)  I band remains unchanged. 
E)  Both H zone becomes narrower or disappears, and I band remains unchanged. 
A)  Z lines move farther away from the thick filaments. 
B)  A band becomes narrower. 
C)  H zone becomes narrower or disappears. 
D)  I band remains unchanged. 
E)  Both H zone becomes narrower or disappears, and I band remains unchanged.

Question 13

The energy for cross bridge cycling during muscle contraction is provided by:

Accepted Answer

A)  acetylcholine 
B)  Ca2+ 
C)  ATP 
D)  myosin 
E)  actin 
A)  acetylcholine 
B)  Ca2+ 
C)  ATP 
D)  myosin 
E)  actin

Question 14

Complete each of the following statments.
The immediate source for supplying additional ATP at the onset of exercise is ____________________.

Accepted Answer

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

Question 15

Complete each of the following statments.
The ____________________ is the extensor muscle found in the thigh that contracts during the patellar tendon reflex.

Accepted Answer

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

Question 16

In a muscle fiber undergoing maximal tetanic stimulation, the velocity of shortening ____ as the load ____.

Accepted Answer

A)  decreases; decreases 
B)  decreases; increases 
C)  increases; increases 
D)  remains constant; increases 
E)  remains constant; decreases 
A)  decreases; decreases 
B)  decreases; increases 
C)  increases; increases 
D)  remains constant; increases 
E)  remains constant; decreases

Question 17

Denervated muscle fibers become progressively smaller and their content of actin and myosin decreases.

Accepted Answer

A) True 
 B)False

Question 18

Picking up a book at a constant speed requires that

Accepted Answer

A)  muscle tension be equal to the book's weight 
B)  the muscle perform an eccentric contraction 
C)  the muscle perform an isometric contraction 
D)  the muscle perform a concentric contraction 
E)  muscle tension be equal to the book's weight and the muscle to perform a concentric contraction 
A)  muscle tension be equal to the book's weight 
B)  the muscle perform an eccentric contraction 
C)  the muscle perform an isometric contraction 
D)  the muscle perform a concentric contraction 
E)  muscle tension be equal to the book's weight and the muscle to perform a concentric contraction

Question 19

Thin and thick filaments overlap in the A band.

Accepted Answer

A) True 
 B)False

Question 20

When a muscle atrophies:

Accepted Answer

A)  The muscle fibers split lengthwise. 
B)  It decreases in mass and becomes weaker. 
C)  Its fibers increase in diameter. 
D)  Its fibers undergo mitotic cell division. 
E)  The muscle fibers dissolve and are replaced by fibrous scar tissue. 
A)  The muscle fibers split lengthwise. 
B)  It decreases in mass and becomes weaker. 
C)  Its fibers increase in diameter. 
D)  Its fibers undergo mitotic cell division. 
E)  The muscle fibers dissolve and are replaced by fibrous scar tissue.

Exam 8: A--Muscle Physiology

A motor unit refers to

The smallest unit of contraction within a skeletal muscle is a

Complete each of the following statments. The gradation of whole-muscle tension depends on the number of ____________________ that are stimulated.

Cardiac muscle tissue

Fast-oxidative muscle fibers have a high concentration of mitochondria.

Single-unit smooth muscle has no innervation.

Which molecules are involved with regulation of cross bridge attachment activity?

Actin

Complete each of the following statments. The ____________________ stores calcium ions inside muscle cells.

According to the sliding-filament mechanism, the

Which of the following does not directly influence motor neurons?

During muscle contraction, the

The energy for cross bridge cycling during muscle contraction is provided by:

Complete each of the following statments. The immediate source for supplying additional ATP at the onset of exercise is ____________________.

Complete each of the following statments. The ____________________ is the extensor muscle found in the thigh that contracts during the patellar tendon reflex.

In a muscle fiber undergoing maximal tetanic stimulation, the velocity of shortening ____ as the load ____.

Denervated muscle fibers become progressively smaller and their content of actin and myosin decreases.

Picking up a book at a constant speed requires that

Thin and thick filaments overlap in the A band.

When a muscle atrophies:

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

In a muscle fiber undergoing maximal tetanic stimulation, the velocity of shortening as the load .