Question 1

Skeletal muscle fibers are formed during embryonic development by the fusion of many smaller cells.

Accepted Answer

A) True 
 B)False

Question 2

All cross bridges within a sarcomere stroke in unison when pulling the actin filaments.

Accepted Answer

A) True 
 B)False

Question 3

Increasing the number of recruited motor units in a muscle increases its force or strength of contraction.

Accepted Answer

A) True 
 B)False

Question 4

Skeletal muscle fibers

Accepted Answer

A)  have T tubules within their sarcomeres 
B)  have Z lines extending down the middle of the I bands 
C)  contain gap junctions 
D)  all of these 
E)  have T tubules within their sarcomeres, and Z lines extending down the middle of the I bands 
A)  have T tubules within their sarcomeres 
B)  have Z lines extending down the middle of the I bands 
C)  contain gap junctions 
D)  all of these 
E)  have T tubules within their sarcomeres, and Z lines extending down the middle of the I bands

Question 5

Which of the following statements about the different types of muscle fibers is incorrect?

Accepted Answer

A)  The higher the ATPase activity, the faster the speed of contraction. 
B)  Muscles that have high glycolytic capacity and large glycogen stores are more resistant to fatigue. 
C)  Muscles with high ATP-synthesizing ability are more resistant to fatigue. 
D)  Oxidative types of muscle fibers contain myoglobin. 
E)  Muscle fibers containing large amounts of myoglobin have a dark red color in comparison to the paler fibers, which have little myoglobin. 
A)  The higher the ATPase activity, the faster the speed of contraction. 
B)  Muscles that have high glycolytic capacity and large glycogen stores are more resistant to fatigue. 
C)  Muscles with high ATP-synthesizing ability are more resistant to fatigue. 
D)  Oxidative types of muscle fibers contain myoglobin. 
E)  Muscle fibers containing large amounts of myoglobin have a dark red color in comparison to the paler fibers, which have little myoglobin.

Question 6

Complete each of the following statments.
The major source of calcium in smooth muscle is from the ____________________.

Accepted Answer

extracellu

Question 7

Pacemaker activity

Accepted Answer

A)  refers to spontaneous depolarizations of the membrane resulting from shifts in passive ionic fluxes accompanying automatic changes in channel permeability 
B)  refers to spontaneous depolarizations of the membrane due to cyclical changes in Na+-K+ pump activity 
C)  is characteristic of single-unit smooth muscle but not found in any other muscle type 
D)  refers to spontaneous depolarizations of the membrane resulting from shifts in passive ionic fluxes accompanying automatic changes in channel permeability, and is characteristic of single-unit smooth muscle but not found in any other muscle type 
E)  refers to spontaneous depolarizations of the membrane due to cyclical changes in Na+-K+ pump activity, and is characteristic of single-unit smooth muscle but not found in any other muscle type 
A)  refers to spontaneous depolarizations of the membrane resulting from shifts in passive ionic fluxes accompanying automatic changes in channel permeability 
B)  refers to spontaneous depolarizations of the membrane due to cyclical changes in Na+-K+ pump activity 
C)  is characteristic of single-unit smooth muscle but not found in any other muscle type 
D)  refers to spontaneous depolarizations of the membrane resulting from shifts in passive ionic fluxes accompanying automatic changes in channel permeability, and is characteristic of single-unit smooth muscle but not found in any other muscle type 
E)  refers to spontaneous depolarizations of the membrane due to cyclical changes in Na+-K+ pump activity, and is characteristic of single-unit smooth muscle but not found in any other muscle type

Question 8

The region between two Z lines is a

Accepted Answer

A)  muscle fiber 
B)  myofibril 
C)  myofilament 
D)  sarcomere 
E)  sarcoplasmic reticulum 
A)  muscle fiber 
B)  myofibril 
C)  myofilament 
D)  sarcomere 
E)  sarcoplasmic reticulum

Question 9

Muscle cells are the only cell types that contain intracellular contractile proteins.

Accepted Answer

A) True 
 B)False

Question 10

During an isometric contraction, the muscle

Accepted Answer

A)  maintains a constant tension 
B)  shortens 
C)  moves a body part 
D)  maintains a constant length 
E)  tension is greater than the load 
A)  maintains a constant tension 
B)  shortens 
C)  moves a body part 
D)  maintains a constant length 
E)  tension is greater than the load

Question 11

Which is not characteristic of cross bridges?

Accepted Answer

A)  They are a component of thin filaments. 
B)  They are comprised of myosin. 
C)  They have an actin binding site. 
D)  They have an ATPase binding site. 
E)  They provide power stroking. 
A)  They are a component of thin filaments. 
B)  They are comprised of myosin. 
C)  They have an actin binding site. 
D)  They have an ATPase binding site. 
E)  They provide power stroking.

Question 12

During muscle contraction, the A band becomes shorter.

Accepted Answer

A) True 
 B)False

Question 13

Complete each of the following statments.
If a muscle cell is excited adequately, ____________________ is released from the sarcoplasmic reticulum.

Accepted Answer

The answer of Complete each of the following statments.
If a...

Question 14

Summation events result from increasing amounts of cytoplasmic calcium levels.

Accepted Answer

A) True 
 B)False

Question 15

Binding of ____ to myosin permits the cross-bridge to ____.

Accepted Answer

A)  ATP; bind with actin 
B)  ATP; detach from actin 
C)  calcium; bind with actin 
D)  calcium; detach from actin 
E)  none of these 
A)  ATP; bind with actin 
B)  ATP; detach from actin 
C)  calcium; bind with actin 
D)  calcium; detach from actin 
E)  none of these

Question 16

Complete each of the following statments.
In a state of ____________________, a muscle cannot maintain any kind of tension.

Accepted Answer

The answer of Complete each of the following statments.
In a...

Question 17

During excitation-contraction coupling,

Accepted Answer

A)  The action potential travels down the T tubules. 
B)  Ca2+ is released from the sarcoplasmic reticulum. 
C)  Ca2+ is taken up by the sarcoplasmic reticulum. 
D)  The action potential travels down the T tubules, and Ca2+ is released from the sarcoplasmic reticulum. 
E)  The action potential travels down the T tubules, and Ca2+ is taken up by the sarcoplasmic reticulum. 
A)  The action potential travels down the T tubules. 
B)  Ca2+ is released from the sarcoplasmic reticulum. 
C)  Ca2+ is taken up by the sarcoplasmic reticulum. 
D)  The action potential travels down the T tubules, and Ca2+ is released from the sarcoplasmic reticulum. 
E)  The action potential travels down the T tubules, and Ca2+ is taken up by the sarcoplasmic reticulum.

Question 18

A function of tropomyosin is to

Accepted Answer

A)  bind Ca2+ 
B)  form attachments with myosin cross bridges 
C)  prevent myosin cross bridges from attaching to the thin filaments 
D)  act as an ATPase 
E)  none of these 
A)  bind Ca2+ 
B)  form attachments with myosin cross bridges 
C)  prevent myosin cross bridges from attaching to the thin filaments 
D)  act as an ATPase 
E)  none of these

Question 19

Muscles that have a fine degree of control have small motor units.

Accepted Answer

A) True 
 B)False

Question 20

Myosin is considered to be a regulatory protein because it plays an important role in the regulation of muscle contraction.

Accepted Answer

A) True 
 B)False

Exam 8: A--Muscle Physiology

Skeletal muscle fibers are formed during embryonic development by the fusion of many smaller cells.

All cross bridges within a sarcomere stroke in unison when pulling the actin filaments.

Increasing the number of recruited motor units in a muscle increases its force or strength of contraction.

Skeletal muscle fibers

Which of the following statements about the different types of muscle fibers is incorrect?

Complete each of the following statments. The major source of calcium in smooth muscle is from the ____________________.

Pacemaker activity

The region between two Z lines is a

Muscle cells are the only cell types that contain intracellular contractile proteins.

During an isometric contraction, the muscle

Which is not characteristic of cross bridges?

During muscle contraction, the A band becomes shorter.

Complete each of the following statments. If a muscle cell is excited adequately, ____________________ is released from the sarcoplasmic reticulum.

Summation events result from increasing amounts of cytoplasmic calcium levels.

Binding of ____ to myosin permits the cross-bridge to ____.

Complete each of the following statments. In a state of ____________________, a muscle cannot maintain any kind of tension.

During excitation-contraction coupling,

A function of tropomyosin is to

Muscles that have a fine degree of control have small motor units.

Myosin is considered to be a regulatory protein because it plays an important role in the regulation of muscle contraction.

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

Binding of to myosin permits the cross-bridge to .