Question 1

During the power stroke, all the cross bridges on myosin do not stroke in unison when pulling the actin filaments.

Accepted Answer

A) True 
 B)False

Question 2

More tension is developed during twitch summation than during a single twitch because the duration of elevated cytosolic Ca2+ concentration increases during summation, thus increasing the availability of cross-bridge binding sites.

Accepted Answer

A) True 
 B)False

Question 3

Which of these factors is characteristic of cardiac muscle tissue?

Accepted Answer

A) well-developed sarcoplasmic reticulum 
B) fast myosin ATPase activity 
C)  neurogenically initiated contraction 
D)  presence of gap junctions 
A) well-developed sarcoplasmic reticulum 
B) fast myosin ATPase activity 
C)  neurogenically initiated contraction 
D)  presence of gap junctions

Question 4

Match the types of muscles, labelled a. through g., with the properties in question. (Options may be used more than once or not at all.)
a.skeletal muscle only
b.single-unit smooth muscle only
c.cardiac muscle only
d.skeletal muscle and cardiac muscle
e.skeletal muscle and single-unit smooth muscle
f.single-unit smooth muscle and cardiac muscle
g.skeletal, single-unit smooth, and cardiac muscles
-considered to be involuntary

Accepted Answer

The answer of Match the types of muscles, labelled a....

Question 5

Which of the following is the first step in excitation-contraction coupling?

Accepted Answer

A) Exposed actin sites bind with myosin cross bridges. 
B) Troponin binds calcium. 
C)  Calcium is released from the sarcoplasmic reticulum. 
D)  Sodium channels open in the fibre's membrane. 
A) Exposed actin sites bind with myosin cross bridges. 
B) Troponin binds calcium. 
C)  Calcium is released from the sarcoplasmic reticulum. 
D)  Sodium channels open in the fibre's membrane.

Question 6

Which of the following provides the energy for cross-bridge cycling during muscle contraction?

Accepted Answer

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

Question 7

Which of these statements correctly describes actin?

Accepted Answer

A) It is spherical. 
B) It contains a globular head that forms the cross bridges between the thick and thin filaments. 
C)  It is referred to as a regulatory protein. 
D)  It is inhibited by Ca2+. 
A) It is spherical. 
B) It contains a globular head that forms the cross bridges between the thick and thin filaments. 
C)  It is referred to as a regulatory protein. 
D)  It is inhibited by Ca2+.

Question 8

Atrophy can develop in a muscle by either denervation or disuse.

Accepted Answer

A) True 
 B)False

Question 9

According to the sliding filament mechanism of muscle contraction, the muscle fibres of one motor unit slide in closer together between the muscle fibres of adjacent motor units.

Accepted Answer

A) True 
 B)False

Question 10

Which of the following applies during an isotonic contraction of a muscle in the arm?

Accepted Answer

A) The muscle does NOT contract. 
B) The muscle does NOT change length. 
C)  The tension in the muscle does NOT overcome a load. 
D)  The tension in the muscle remains constant. 
A) The muscle does NOT contract. 
B) The muscle does NOT change length. 
C)  The tension in the muscle does NOT overcome a load. 
D)  The tension in the muscle remains constant.

Question 11

Acetylcholinesterase removes ACh from receptors.

Accepted Answer

A) True 
 B)False

Question 12

Which of these events happens when an action potential reaches the presynaptic terminal of the motor neuron?

Accepted Answer

A) Calcium is released inside the muscle fibre. 
B) Acetylcholine is released into the synaptic cleft. 
C)  Acetylcholinesterase is released into the synaptic cleft. 
D)  Physical contact between the motor neuron and the muscle fibre occurs. 
A) Calcium is released inside the muscle fibre. 
B) Acetylcholine is released into the synaptic cleft. 
C)  Acetylcholinesterase is released into the synaptic cleft. 
D)  Physical contact between the motor neuron and the muscle fibre occurs.

Question 13

What happens when a muscle atrophies?

Accepted Answer

A) The muscle fibres split lengthwise. 
B) The muscle decreases in mass and becomes weaker. 
C)  The muscle fibres increase in diameter. 
D)  The muscle fibres undergo mitotic cell division. 
A) The muscle fibres split lengthwise. 
B) The muscle decreases in mass and becomes weaker. 
C)  The muscle fibres increase in diameter. 
D)  The muscle fibres undergo mitotic cell division.

Question 14

The metabolic capability of a muscle fibre can affect the degree of tension it can develop.

Accepted Answer

A) True 
 B)False

Question 15

The three types of muscle tissue are ____________________, ____________________, and ____________________.

Accepted Answer

cardiac; s

Question 16

Tropomyosin covers the cross-bridge binding sites on the thick filaments when a sarcomere is not contracting.

Accepted Answer

A) True 
 B)False

Question 17

What happens during coactivation?

Accepted Answer

A) All the muscle fibres in a skeletal muscle are activated simultaneously. 
B) The gamma motor-neuron and alpha motor-neuron systems to a skeletal muscle are activated simultaneously. 
C)  All the cross bridges within a single skeletal muscle are activated simultaneously. 
D)  The primary (annulospiral) and secondary (flower-spray) endings within a muscle spindle are activated simultaneously. 
A) All the muscle fibres in a skeletal muscle are activated simultaneously. 
B) The gamma motor-neuron and alpha motor-neuron systems to a skeletal muscle are activated simultaneously. 
C)  All the cross bridges within a single skeletal muscle are activated simultaneously. 
D)  The primary (annulospiral) and secondary (flower-spray) endings within a muscle spindle are activated simultaneously.

Question 18

Thick filaments are made up of the protein ____________________, whereas thin filaments are composed of the three proteins ____________________, ____________________, and ____________________.

Accepted Answer

myosin
actin; tropom

Question 19

The only energy source that can be used directly by the contractile machinery of a muscle fibre is ____________________.

Accepted Answer

The answer of The only energy source that can be...

Question 20

Which of the following events is NOT involved in the relaxation of muscle?

Accepted Answer

A) Acetylcholine is destroyed by acetylcholinesterase. 
B) There is no longer a local action potential. 
C)  The T tubules actively take up the Ca2+ that was released. 
D)  The actin and myosin molecules are no longer bound together. 
A) Acetylcholine is destroyed by acetylcholinesterase. 
B) There is no longer a local action potential. 
C)  The T tubules actively take up the Ca2+ that was released. 
D)  The actin and myosin molecules are no longer bound together.

During the power stroke, all the cross bridges on myosin do not stroke in unison when pulling the actin filaments.

More tension is developed during twitch summation than during a single twitch because the duration of elevated cytosolic Ca²⁺ concentration increases during summation, thus increasing the availability of cross-bridge binding sites.

Which of these factors is characteristic of cardiac muscle tissue?

Which of the following is the first step in excitation-contraction coupling?

Which of the following provides the energy for cross-bridge cycling during muscle contraction?

Which of these statements correctly describes actin?

Atrophy can develop in a muscle by either denervation or disuse.

According to the sliding filament mechanism of muscle contraction, the muscle fibres of one motor unit slide in closer together between the muscle fibres of adjacent motor units.

Which of the following applies during an isotonic contraction of a muscle in the arm?

Acetylcholinesterase removes ACh from receptors.

Which of these events happens when an action potential reaches the presynaptic terminal of the motor neuron?

What happens when a muscle atrophies?

The metabolic capability of a muscle fibre can affect the degree of tension it can develop.

The three types of muscle tissue are , , and .

Tropomyosin covers the cross-bridge binding sites on the thick filaments when a sarcomere is not contracting.

What happens during coactivation?

Thick filaments are made up of the protein , whereas thin filaments are composed of the three proteins , , and .

The only energy source that can be used directly by the contractile machinery of a muscle fibre is ____________________.

Which of the following events is NOT involved in the relaxation of muscle?

Introduction to Physiology and Homeostasis

Cell Physiology

The Plasma Membrane and Membrane Potential

Principles of Neural and Hormonal Communication

The Central Nervous System

The Peripheral Nervous System: Efferent Division

Muscle Physiology

Cardiac Physiology

The Blood Vessels and Blood Pressure

The Blood

Body Defenses

The Respiratory System

The Urinary System

Fluid and Acidbase Balance

The Digestive System

Energy Balance and Temperature Regulation

Filters

Exam 6: The Peripheral Nervous System: Afferent Division; Special Senses

During the power stroke, all the cross bridges on myosin do not stroke in unison when pulling the actin filaments.

More tension is developed during twitch summation than during a single twitch because the duration of elevated cytosolic Ca2+ concentration increases during summation, thus increasing the availability of cross-bridge binding sites.

Which of these factors is characteristic of cardiac muscle tissue?

Which of the following is the first step in excitation-contraction coupling?

Which of the following provides the energy for cross-bridge cycling during muscle contraction?

Which of these statements correctly describes actin?

Atrophy can develop in a muscle by either denervation or disuse.

According to the sliding filament mechanism of muscle contraction, the muscle fibres of one motor unit slide in closer together between the muscle fibres of adjacent motor units.

Which of the following applies during an isotonic contraction of a muscle in the arm?

Acetylcholinesterase removes ACh from receptors.

Which of these events happens when an action potential reaches the presynaptic terminal of the motor neuron?

What happens when a muscle atrophies?

The metabolic capability of a muscle fibre can affect the degree of tension it can develop.

The three types of muscle tissue are ____________________, ____________________, and ____________________.

Tropomyosin covers the cross-bridge binding sites on the thick filaments when a sarcomere is not contracting.

What happens during coactivation?

Thick filaments are made up of the protein ____________________, whereas thin filaments are composed of the three proteins ____________________, ____________________, and ____________________.

The only energy source that can be used directly by the contractile machinery of a muscle fibre is ____________________.

Which of the following events is NOT involved in the relaxation of muscle?

Introduction to Physiology and Homeostasis

Cell Physiology

The Plasma Membrane and Membrane Potential

Principles of Neural and Hormonal Communication

The Central Nervous System

The Peripheral Nervous System: Efferent Division

Muscle Physiology

Cardiac Physiology

The Blood Vessels and Blood Pressure

The Blood

Body Defenses

The Respiratory System

The Urinary System

Fluid and Acidbase Balance

The Digestive System

Energy Balance and Temperature Regulation

Filters

More tension is developed during twitch summation than during a single twitch because the duration of elevated cytosolic Ca²⁺ concentration increases during summation, thus increasing the availability of cross-bridge binding sites.

The three types of muscle tissue are , , and .

Thick filaments are made up of the protein , whereas thin filaments are composed of the three proteins , , and .