Question 1

Which of the following statements best explains how tetanus can be generated in a skeletal muscle,given the all-or-none nature of action potentials?

Accepted Answer

A) During a single action potential in a skeletal muscle, there is not enough time for all of the calcium in the sarcoplasmic reticulum to diffuse into the cytosol and bind to troponin 
B) Skeletal muscle has no absolute refractory period 
C) Skeletal muscle has a much longer absolute refractory period than does a motor neuron 
D) During a single action potential in a skeletal muscle, there is not enough time for maximal tension to develop before the Ca-ATPase begins sequestering calcium ions 
E) Both during a single action potential in a skeletal muscle, there is not enough time for all of the calcium in the sarcoplasmic reticulum to diffuse into the cytosol and bind to troponin and skeletal muscle has a much longer absolute refractory period than does a motor neuron are correct 
A) During a single action potential in a skeletal muscle, there is not enough time for all of the calcium in the sarcoplasmic reticulum to diffuse into the cytosol and bind to troponin 
B) Skeletal muscle has no absolute refractory period 
C) Skeletal muscle has a much longer absolute refractory period than does a motor neuron 
D) During a single action potential in a skeletal muscle, there is not enough time for maximal tension to develop before the Ca-ATPase begins sequestering calcium ions 
E) Both during a single action potential in a skeletal muscle, there is not enough time for all of the calcium in the sarcoplasmic reticulum to diffuse into the cytosol and bind to troponin and skeletal muscle has a much longer absolute refractory period than does a motor neuron are correct D

Question 2

When a muscle has been contracting for an extended period of time (more than a few minutes),the primary source of ATP is

Accepted Answer

A) Transfer of energy and phosphate from creatine phosphate to ADP 
B) Glycolysis 
C) Oxidative phosphorylation 
D) Breakdown of myosin 
E) None of the choices are correct 
A) Transfer of energy and phosphate from creatine phosphate to ADP 
B) Glycolysis 
C) Oxidative phosphorylation 
D) Breakdown of myosin 
E) None of the choices are correct C

Question 3

John is a sprinter who specializes in quick and powerful bursts of speed followed by periods of rest.Jim is a marathon runner who specializes in long,steady runs.Compared to Jim,John is likely to have

Accepted Answer

A) Legs with a larger diameter 
B) Legs with a smaller diameter 
C) Hypertrophy of type I muscle fibers 
D) Legs with a larger diameter and hypertrophy of type I muscle fibers 
E) Legs with a smaller diameter and hypertrophy of type I muscle fibers 
A) Legs with a larger diameter 
B) Legs with a smaller diameter 
C) Hypertrophy of type I muscle fibers 
D) Legs with a larger diameter and hypertrophy of type I muscle fibers 
E) Legs with a smaller diameter and hypertrophy of type I muscle fibers A

Question 4

The force-generating sites in a myofibril are the Z lines.

Accepted Answer

A) True 
 B)False

Question 5

In smooth-muscle cells that can produce action potentials,cell membrane depolarization opens voltage-sensitive sodium channels.

Accepted Answer

A) True 
 B)False

Question 6

Few mitochondria is typical of which type of skeletal-muscle fibers?

Accepted Answer

A) Type I 
B) Type II 
A) Type I 
B) Type II

Question 7

During an isometric contraction of a skeletal muscle,

Accepted Answer

A) The I bands shorten and the A bands stay the same length 
B) The thick and thin filaments slide past each other 
C) Sarcomere length does not change 
D) Both the I bands shorten and the A bands stay the same length and the thick and thin filaments slide past each other take place 
E) None of the choices happen 
A) The I bands shorten and the A bands stay the same length 
B) The thick and thin filaments slide past each other 
C) Sarcomere length does not change 
D) Both the I bands shorten and the A bands stay the same length and the thick and thin filaments slide past each other take place 
E) None of the choices happen

Question 8

The difference in color between white muscle and red muscle is accounted for by the greater abundance of glycogen in white muscle.

Accepted Answer

A) True 
 B)False

Question 9

Myasthenia gravis is an autoimmune disease - that is,a disease in which one's immune system gradually attacks a part of one's own body,in this case the receptors for acetylcholine at the neuromuscular junction.Which of the following drugs might be useful in treating this disease?

Accepted Answer

A) A drug that inhibits acetylcholinesterase 
B) A drug that inhibits release of acetylcholine 
C) Curare 
D) Atropine (a muscarinic antagonist) 
E) All of the choices are correct 
A) A drug that inhibits acetylcholinesterase 
B) A drug that inhibits release of acetylcholine 
C) Curare 
D) Atropine (a muscarinic antagonist) 
E) All of the choices are correct

Question 10

The conclusion of cardiac muscle contraction is marked by which of the following

Accepted Answer

A) Concentration of calcium ions in the cytosol is greatly reduced by active transport; Ca 2+-ATPase pumps 
B) Concentration of calcium ions in the cytosol is greatly reduced by active transport; Ca 2+/Na+ cotransporters in sarcoplasmic reticulum and sarcolemma 
C) The release of actin protein degrading enzymes 
D) The release of myosin degrading enzymes 
E) Both concentration of calcium ions in the cytosol is greatly reduced by active transport; Ca 2+-ATPase pumps and concentration of calcium ions in the cytosol is greatly reduced by active transport; Ca 2+/Na+ cotransporters in sarcoplasmic reticulum and sarcolemma are correct 
A) Concentration of calcium ions in the cytosol is greatly reduced by active transport; Ca 2+-ATPase pumps 
B) Concentration of calcium ions in the cytosol is greatly reduced by active transport; Ca 2+/Na+ cotransporters in sarcoplasmic reticulum and sarcolemma 
C) The release of actin protein degrading enzymes 
D) The release of myosin degrading enzymes 
E) Both concentration of calcium ions in the cytosol is greatly reduced by active transport; Ca 2+-ATPase pumps and concentration of calcium ions in the cytosol is greatly reduced by active transport; Ca 2+/Na+ cotransporters in sarcoplasmic reticulum and sarcolemma are correct

Question 11

The shortening velocity of a skeletal muscle fiber increases with decreasing load because the rate at which the cross-bridge cycle can occur increases with decreasing load.

Accepted Answer

A) True 
 B)False

Question 12

In general,activating a slow-oxidative motor unit in a muscle will generate more tension than activating a fast-glycolytic motor unit.

Accepted Answer

A) True 
 B)False

Question 13

L-type calcium channels in cardiac muscle cells

Accepted Answer

A) Are essentially present and the same in both skeletal and cardiac muscle 
B) Are directly related to making them fatigue resistant 
C) Are responsible for preventing tetanic contractions in them 
D) Cause the absolute refractory period to be very short lived 
E) Provide the mechanism necessary for producing contractions of varying intensity or force 
A) Are essentially present and the same in both skeletal and cardiac muscle 
B) Are directly related to making them fatigue resistant 
C) Are responsible for preventing tetanic contractions in them 
D) Cause the absolute refractory period to be very short lived 
E) Provide the mechanism necessary for producing contractions of varying intensity or force

Question 14

During skeletal-muscle contraction,the I band and H zone shorten but the A band stays the same.

Accepted Answer

A) True 
 B)False

Question 15

Abundant mitochondria is typical of which type of skeletal-muscle fibers?

Accepted Answer

A) Type I 
B) Type II 
A) Type I 
B) Type II

Question 16

Which of the following statements regarding myosin in skeletal muscle is/are true?

Accepted Answer

A) Myosin heads contain two functional sites, one for actin and one for tropomyosin 
B) Myosin is an ATPase 
C) The rate of ATP hydrolysis by myosin is the same in all types of skeletal muscle 
D) Both myosin heads contain two functional sites, one for actin and one for tropomyosin and myosin is an ATPase are true 
E) All of the choices are true 
A) Myosin heads contain two functional sites, one for actin and one for tropomyosin 
B) Myosin is an ATPase 
C) The rate of ATP hydrolysis by myosin is the same in all types of skeletal muscle 
D) Both myosin heads contain two functional sites, one for actin and one for tropomyosin and myosin is an ATPase are true 
E) All of the choices are true

Question 17

The larger the diameter of a skeletal-muscle fiber,the greater the tension it can generate.

Accepted Answer

A) True 
 B)False

Question 18

The term "twitch" refers to the mechanical response of a muscle fiber during one cross-bridge cycle.

Accepted Answer

A) True 
 B)False

Question 19

Recruited first is typical of which type of skeletal-muscle fibers?

Accepted Answer

A) Type I 
B) Type II 
A) Type I 
B) Type II

Question 20

Muscles used for delicate,finely controlled movements have smaller motor units than more coarsely controlled muscles.

Accepted Answer

A) True 
 B)False

Which of the following statements best explains how tetanus can be generated in a skeletal muscle,given the all-or-none nature of action potentials?

When a muscle has been contracting for an extended period of time (more than a few minutes),the primary source of ATP is

John is a sprinter who specializes in quick and powerful bursts of speed followed by periods of rest.Jim is a marathon runner who specializes in long,steady runs.Compared to Jim,John is likely to have

The force-generating sites in a myofibril are the Z lines.

In smooth-muscle cells that can produce action potentials,cell membrane depolarization opens voltage-sensitive sodium channels.

Few mitochondria is typical of which type of skeletal-muscle fibers?

During an isometric contraction of a skeletal muscle,

The difference in color between white muscle and red muscle is accounted for by the greater abundance of glycogen in white muscle.

Myasthenia gravis is an autoimmune disease - that is,a disease in which one's immune system gradually attacks a part of one's own body,in this case the receptors for acetylcholine at the neuromuscular junction.Which of the following drugs might be useful in treating this disease?

The conclusion of cardiac muscle contraction is marked by which of the following

The shortening velocity of a skeletal muscle fiber increases with decreasing load because the rate at which the cross-bridge cycle can occur increases with decreasing load.

In general,activating a slow-oxidative motor unit in a muscle will generate more tension than activating a fast-glycolytic motor unit.

L-type calcium channels in cardiac muscle cells

During skeletal-muscle contraction,the I band and H zone shorten but the A band stays the same.

Abundant mitochondria is typical of which type of skeletal-muscle fibers?

Which of the following statements regarding myosin in skeletal muscle is/are true?

The larger the diameter of a skeletal-muscle fiber,the greater the tension it can generate.

The term "twitch" refers to the mechanical response of a muscle fiber during one cross-bridge cycle.

Recruited first is typical of which type of skeletal-muscle fibers?

Muscles used for delicate,finely controlled movements have smaller motor units than more coarsely controlled muscles.

Homeostasis: a Framework for Human Physiology

Chemical Composition of the Body

Cellular Structure, Proteins, and Metabolism

Movement of Molecules Across Cell Membranes

Control of Cells by Chemical Messengers

Neuronal Signaling and the Structure of the Nervous System

Sensory Physiology

Consciousness, the Brain, and Behavior

Control of Body Movement

The Endocrine System

Cardiovascular Physiology

Respiratory Physiology

The Kidneys and Regulation of Water and Inorganic Ions

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Regulation of Organic Metabolism and Energy Balance

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Exam 9: Muscle

Which of the following statements best explains how tetanus can be generated in a skeletal muscle,given the all-or-none nature of action potentials?

When a muscle has been contracting for an extended period of time (more than a few minutes),the primary source of ATP is

John is a sprinter who specializes in quick and powerful bursts of speed followed by periods of rest.Jim is a marathon runner who specializes in long,steady runs.Compared to Jim,John is likely to have

The force-generating sites in a myofibril are the Z lines.

In smooth-muscle cells that can produce action potentials,cell membrane depolarization opens voltage-sensitive sodium channels.

Few mitochondria is typical of which type of skeletal-muscle fibers?

During an isometric contraction of a skeletal muscle,

The difference in color between white muscle and red muscle is accounted for by the greater abundance of glycogen in white muscle.

Myasthenia gravis is an autoimmune disease - that is,a disease in which one's immune system gradually attacks a part of one's own body,in this case the receptors for acetylcholine at the neuromuscular junction.Which of the following drugs might be useful in treating this disease?

The conclusion of cardiac muscle contraction is marked by which of the following

The shortening velocity of a skeletal muscle fiber increases with decreasing load because the rate at which the cross-bridge cycle can occur increases with decreasing load.

In general,activating a slow-oxidative motor unit in a muscle will generate more tension than activating a fast-glycolytic motor unit.

L-type calcium channels in cardiac muscle cells

During skeletal-muscle contraction,the I band and H zone shorten but the A band stays the same.

Abundant mitochondria is typical of which type of skeletal-muscle fibers?

Which of the following statements regarding myosin in skeletal muscle is/are true?

The larger the diameter of a skeletal-muscle fiber,the greater the tension it can generate.

The term "twitch" refers to the mechanical response of a muscle fiber during one cross-bridge cycle.

Recruited first is typical of which type of skeletal-muscle fibers?

Muscles used for delicate,finely controlled movements have smaller motor units than more coarsely controlled muscles.

Homeostasis: a Framework for Human Physiology

Chemical Composition of the Body

Cellular Structure, Proteins, and Metabolism

Movement of Molecules Across Cell Membranes

Control of Cells by Chemical Messengers

Neuronal Signaling and the Structure of the Nervous System

Sensory Physiology

Consciousness, the Brain, and Behavior

Control of Body Movement

The Endocrine System

Cardiovascular Physiology

Respiratory Physiology

The Kidneys and Regulation of Water and Inorganic Ions

The Digestion and Absorption of Food

Regulation of Organic Metabolism and Energy Balance

Reproduction

The Immune System

Medical Physiology: Integration Using Clinical Cases

Filters