Question 1

The brief period of time between the beginning of the action potential in the muscle and the beginning of contraction is referred to as the

Accepted Answer

A)  refractory period. 
B)  latent period. 
C)  relaxation phase. 
D)  depolarization period. 
E)  repolarization period. 
A)  refractory period. 
B)  latent period. 
C)  relaxation phase. 
D)  depolarization period. 
E)  repolarization period.

Question 2

Match from the following list.
-The structures that serve as the attachment site for the thin filaments and mark the boundaries for one sarcomere.

Accepted Answer

A) A band 
B) I band 
C) Z disk 
D) H zone 
E) M line 
A) A band 
B) I band 
C) Z disk 
D) H zone 
E) M line

Question 3

Skeletal muscle cells are usually attached to bone by

Accepted Answer

A)  fascicles. 
B)  ligaments. 
C)  tendons. 
D)  flexors. 
A)  fascicles. 
B)  ligaments. 
C)  tendons. 
D)  flexors.

Question 4

Sketch a graph of the length-tension relationship in a contracting skeletal muscle,and explain its shape in terms of events in the sarcomere.

Accepted Answer

The answer of Sketch a graph of the length-tension relationship...

Question 5

Which of the following statements is NOT correct regarding the motor units and their activation?

Accepted Answer

A)  A motor unit in muscles of gross movement can have thousands of muscle cells. 
B)  All muscle fibers in a single motor unit are of the same fiber type. 
C)  A weak contractile stimulus activates fast-twitch motor units. 
D)  The metabolic capacity of muscle fibers within a motor unit can be altered. 
E)  At its peak intensity, a contractile stimulus will activate muscle fibers that are easily fatigued. 
A)  A motor unit in muscles of gross movement can have thousands of muscle cells. 
B)  All muscle fibers in a single motor unit are of the same fiber type. 
C)  A weak contractile stimulus activates fast-twitch motor units. 
D)  The metabolic capacity of muscle fibers within a motor unit can be altered. 
E)  At its peak intensity, a contractile stimulus will activate muscle fibers that are easily fatigued.

Question 6

Store-operated calcium channels open in response to ________.

Accepted Answer

depleted i

Question 7

Which fibers fatigue sooner?

Accepted Answer

A)  fast-twitch fibers 
B)  slow-twitch fibers 
A)  fast-twitch fibers 
B)  slow-twitch fibers

Question 8

Smooth muscle fibers can sustain a contraction without fatigue by allowing dephosphorylated myosin to remain attached to actin in what is called the ________.

Accepted Answer

The answer of Smooth muscle fibers can sustain a contraction...

Question 9

This protein is activated by the Ca2+-calmodulin complex to phosphorylate the myosin light chain protein.

Accepted Answer

A)  tropomyosin 
B)  myosin heavy chain 
C)  myosin light chain kinase 
D)  myosin light chain phosphatase 
A)  tropomyosin 
B)  myosin heavy chain 
C)  myosin light chain kinase 
D)  myosin light chain phosphatase

Question 10

In the lever system that characterizes the interaction between bones and muscle,the bones act as the ________ whereas the joints form the ________.

Accepted Answer

A)  lever, fulcrums 
B)  fulcrum, levers 
C)  lever, pulleys 
D)  fulcrum, pulleys 
A)  lever, fulcrums 
B)  fulcrum, levers 
C)  lever, pulleys 
D)  fulcrum, pulleys

Question 11

Groups of adjacent fibers bundled together into units are called ________.These bundles are surrounded by the proteins ________ and elastin as well as ________ that deliver nutrients to the muscle cells.

Accepted Answer

fascicles;

Question 12

Which of the following would cause the crossbridge to transition from a high force state to a low force state?

Accepted Answer

A)  increasing myosin ATPase activity 
B)  increasing intracellular calcium 
C)  decreasing intracellular calcium 
D)  energizing the myosin head 
E)  decreasing myosin ATPase activity 
A)  increasing myosin ATPase activity 
B)  increasing intracellular calcium 
C)  decreasing intracellular calcium 
D)  energizing the myosin head 
E)  decreasing myosin ATPase activity

Question 13

The nervous system avoids muscle fatigue during submaximal contraction by

Accepted Answer

A)  always recruiting slow-twitch motor units. 
B)  asynchronous recruitment. 
C)  synchronous recruitment. 
D)  always recruiting fast-twitch motor units. 
A)  always recruiting slow-twitch motor units. 
B)  asynchronous recruitment. 
C)  synchronous recruitment. 
D)  always recruiting fast-twitch motor units.

Question 14

A(n)________ contraction describes the opening of stretch-activated channels in smooth muscle cells in response to a distortion of the cell membrane that is commonly observed in ________.

Accepted Answer

myogenic,b

Question 15

The reductions in muscle force generation at lengths different from optimal are a result of a(n)________.

Accepted Answer

decrease i

Question 16

Compare and contrast the structural and functional differences between single-unit and multi-unit smooth muscle fibers,particularly in regard to their ability to vary their force of contraction.

Accepted Answer

Single-unit characteristics: all smooth

Question 17

The action potential traveling along the t-tubule is detected by the

Accepted Answer

A)  ryanodine receptor. 
B)  dihydropyridine (DHP) receptor (L-type calcium channel). 
C)  acetylcholine receptor. 
D)  Ca2+ ATPase. 
A)  ryanodine receptor. 
B)  dihydropyridine (DHP) receptor (L-type calcium channel). 
C)  acetylcholine receptor. 
D)  Ca2+ ATPase.

Question 18

A motor unit consists of

Accepted Answer

A)  one neuron and all the skeletal muscle fibers it controls. 
B)  one skeletal muscle fiber and all the neurons that control that fiber. 
C)  one skeletal muscle fiber and the neuron that controls that fiber. 
D)  one axon terminal branch and the myofibrils it controls. 
A)  one neuron and all the skeletal muscle fibers it controls. 
B)  one skeletal muscle fiber and all the neurons that control that fiber. 
C)  one skeletal muscle fiber and the neuron that controls that fiber. 
D)  one axon terminal branch and the myofibrils it controls.

Question 19

Fatigue that occurs in response to extended submaximal exertion is usually due to ________ whereas fatigue to a short duration of maximal exertion involves ________.

Accepted Answer

glycogen depletion,e

Question 20

Factors playing a role in fatigue can be classified into 2 categories.Define those two categories and provide an example of each.

Accepted Answer

Central fatigue,peripheral fatigue.Centr

Exam 12: Muscles

The brief period of time between the beginning of the action potential in the muscle and the beginning of contraction is referred to as the

Match from the following list. -The structures that serve as the attachment site for the thin filaments and mark the boundaries for one sarcomere.

Skeletal muscle cells are usually attached to bone by

Sketch a graph of the length-tension relationship in a contracting skeletal muscle,and explain its shape in terms of events in the sarcomere.

Which of the following statements is NOT correct regarding the motor units and their activation?

Store-operated calcium channels open in response to ________.

Which fibers fatigue sooner?

Smooth muscle fibers can sustain a contraction without fatigue by allowing dephosphorylated myosin to remain attached to actin in what is called the ________.

This protein is activated by the Ca2+-calmodulin complex to phosphorylate the myosin light chain protein.

In the lever system that characterizes the interaction between bones and muscle,the bones act as the ________ whereas the joints form the ________.

Groups of adjacent fibers bundled together into units are called ________.These bundles are surrounded by the proteins ________ and elastin as well as ________ that deliver nutrients to the muscle cells.

Which of the following would cause the crossbridge to transition from a high force state to a low force state?

The nervous system avoids muscle fatigue during submaximal contraction by

A(n)________ contraction describes the opening of stretch-activated channels in smooth muscle cells in response to a distortion of the cell membrane that is commonly observed in ________.

The reductions in muscle force generation at lengths different from optimal are a result of a(n)________.

Compare and contrast the structural and functional differences between single-unit and multi-unit smooth muscle fibers,particularly in regard to their ability to vary their force of contraction.

The action potential traveling along the t-tubule is detected by the

A motor unit consists of

Fatigue that occurs in response to extended submaximal exertion is usually due to ________ whereas fatigue to a short duration of maximal exertion involves ________.

Factors playing a role in fatigue can be classified into 2 categories.Define those two categories and provide an example of each.

Introduction to Physiology

Molecular Interactions

Compartmentation: Cells and Tissues

Energy and Cellular Metabolism

Membrane Dynamics

Communication, Integration, and Homeostasis

Introduction to the Endocrine System

Neurons: Cellular and Network Properties

The Central Nervous System

Sensory Physiology

Efferent Division: Autonomic and Somatic Motor Control

Integrative Physiology I: Control of Body Movement

Cardiovascular Physiology

Blood Flow and the Control of Blood Pressure

Blood

Mechanics of Breathing

Gas Exchange and Transport

The Kidneys

Integrative Physiology II: Fluid and Electrolyte Balance

The Digestive System

Metabolism and Energy Balance

Endocrine Control of Growth and Metabolism

The Immune System

Integrative Physiology III: Exercise

Reproduction and Development

Filters

This protein is activated by the Ca²⁺-calmodulin complex to phosphorylate the myosin light chain protein.

In the lever system that characterizes the interaction between bones and muscle,the bones act as the whereas the joints form the .

Groups of adjacent fibers bundled together into units are called .These bundles are surrounded by the proteins and elastin as well as that deliver nutrients to the muscle cells.

A(n) contraction describes the opening of stretch-activated channels in smooth muscle cells in response to a distortion of the cell membrane that is commonly observed in .

Fatigue that occurs in response to extended submaximal exertion is usually due to whereas fatigue to a short duration of maximal exertion involves .