Anatomy and Physiology

How does latroxin, the venom of the black widow spider, cause muscle spasms and rigidity?

How does latroxin, the venom of the black widow spider, cause muscle spasms and rigidity?

How does latroxin, the venom of the black widow spider, cause muscle spasms and rigidity?
A) It stimulates acetylcholine release from autonomic preganglionic neurons.
B) It inhibits the degradation of acetylcholine at all synapses.
C)

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Which of the following statements is true of communication across the neuromuscular junction?

Which of the following statements is true of communication across the neuromuscular junction?

Which of the following statements is true of communication across the neuromuscular junction?
A) The end-plate potential is always of sufficient magnitude to depolarize the muscle cell to threshold to initiate an action potential.
B) Acetyl

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The opening of a cation channel that allows both Na+ and K+ to move through will cause the membrane

The opening of a cation channel that allows both Na+ and K+ to move through will cause the membrane

The opening of a cation channel that allows both Na+ and K+ to move through will cause the membrane to ________ because of the ________.
A) depolarize : greater Na+ electrochemical gradient as compared with K+
B) not change : same electroch

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What is the graded change in membrane potential that occurs at the motor end plate of skeletal muscl

What is the graded change in membrane potential that occurs at the motor end plate of skeletal muscl

What is the graded change in membrane potential that occurs at the motor end plate of skeletal muscle called?
A) muscarinic potential
B) adrenergic potential
C) action potential
D) inhibitory postsynaptic potential
E) end-pla

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In the model for quiet breathing, expiration is induced by

In the model for quiet breathing, expiration is induced by

In the model for quiet breathing, expiration is induced by
A) activation of inspiratory neurons in the dorsal respiratory center.
B) activation of expiratory neurons in the ventral respiratory center.
C) activation of expiratory neuron

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Which of the following is located between the invaginations of the motor end plate of a neuromuscula

Which of the following is located between the invaginations of the motor end plate of a neuromuscula

Which of the following is located between the invaginations of the motor end plate of a neuromuscular junction?
A) β2 receptors
B) acetylcholinesterase
C) muscarinic receptors
D) β3 receptors
E) nicotinic receptors

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The ________ is the respiratory center that appears to facilitate the transition between inspiration

The ________ is the respiratory center that appears to facilitate the transition between inspiration

The ________ is the respiratory center that appears to facilitate the transition between inspiration and expiration.
A) medullary respiratory group
B) ventral respiratory group
C) central pattern generator
D) pontine respiratory g

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Where on skeletal muscle is the highest density of nicotinic receptors?

Where on skeletal muscle is the highest density of nicotinic receptors?

Where on skeletal muscle is the highest density of nicotinic receptors?
A) motor unit
B) terminal bouton
C) dendrites
D) axon hillock
E) motor end plate

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During active breathing, bursts of action potentials are observed to occur

During active breathing, bursts of action potentials are observed to occur

During active breathing, bursts of action potentials are observed to occur
A) asynchronously in the inspiratory and expiratory motor neurons.
B) simultaneously in the inspiratory and expiratory motor neurons.
C) synchronously in the i

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What is the neurotransmitter released from motor neurons?

What is the neurotransmitter released from motor neurons?

What is the neurotransmitter released from motor neurons?
A) dopamine
B) norepinephrine
C) acetylcholine
D) epinephrine
E) GABA

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Which of the following nerves has activity during quiet inspiration?

Which of the following nerves has activity during quiet inspiration?

Which of the following nerves has activity during quiet inspiration?
A) phrenic nerve only
B) internal intercostal nerve only
C) external intercostal nerve only
D) both the phrenic nerve and internal intercostal nerves
E) bot

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With respect to their innervation, individual skeletal muscle fibers (cells) are innervated by

With respect to their innervation, individual skeletal muscle fibers (cells) are innervated by

With respect to their innervation, individual skeletal muscle fibers (cells) are innervated by
A) a single motor neuron.
B) multiple motor neurons.
C) a single motor neuron and autonomic neuron.
D) multiple motor neurons and auto

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During quiet breathing, a person's breathing cycle consists of

During quiet breathing, a person's breathing cycle consists of

During quiet breathing, a person's breathing cycle consists of
A) contraction and relaxation of inspiratory and expiratory muscles.
B) contraction of inspiratory muscles.
C) contraction of inspiratory muscles and relaxation of ex

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The somatic nervous system is often referred to as the ________ system.

The somatic nervous system is often referred to as the ________ system.

The somatic nervous system is often referred to as the ________ system.
A) craniosacral
B) unconscious
C) neuromuscular
D) involuntary
E) voluntary

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The hydrogen ions released by the dissociation of carbonic acid are buffered by their

The hydrogen ions released by the dissociation of carbonic acid are buffered by their

The hydrogen ions released by the dissociation of carbonic acid are buffered by their
A) transport out of the erythrocyte as a sodium ion moves in.
B) binding to hemoglobin.
C) transport into the erythrocyte as sodium ions move out.

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The somatic nervous system regulates the activity of

The somatic nervous system regulates the activity of

The somatic nervous system regulates the activity of
A) the cardiovascular system.
B) the kidneys.
C) endocrine organs.
D) skeletal muscle.
E) many organs.

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Within an erythrocyte, the conversion of CO2 to bicarbonate is prevented from reaching equilibrium b

Within an erythrocyte, the conversion of CO2 to bicarbonate is prevented from reaching equilibrium b

Within an erythrocyte, the conversion of CO2 to bicarbonate is prevented from reaching equilibrium by the
A) temperature of the body.
B) presence of hydrogen ions.
C) efflux of bicarbonate from the erythrocyte via the chloride shift.

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Students who suffer from test anxiety often have some of the following symptoms: the need for freque

Students who suffer from test anxiety often have some of the following symptoms: the need for freque

Students who suffer from test anxiety often have some of the following symptoms: the need for frequent urination, dilated pupils, and a dry mouth. What branch of the autonomic nervous system would cause these symptoms?
A) voluntary
B) sympa

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Scopolamine is a muscarinic antagonist that acts by blocking muscarinic acetylcholine receptors. Alt

Scopolamine is a muscarinic antagonist that acts by blocking muscarinic acetylcholine receptors. Alt

Scopolamine is a muscarinic antagonist that acts by blocking muscarinic acetylcholine receptors. Although it is not clear how scopolamine prevents nausea and vomiting due to motion sickness, which statement below best describes the mechanism of actio

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The presence of bicarbonate ions in the blood has an important direct effect, aside from the transpo

The presence of bicarbonate ions in the blood has an important direct effect, aside from the transpo

The presence of bicarbonate ions in the blood has an important direct effect, aside from the transport of CO2, that involves
A) altering the affinity of hemoglobin for oxygen.
B) stimulating the proliferation of alveolar epithelial cells.

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Where are most of the autonomic nervous system control centers located?

Where are most of the autonomic nervous system control centers located?

Where are most of the autonomic nervous system control centers located?
A) limbic system
B) spinal cord
C) brainstem
D) frontal lobe
E) thalamus

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Which statement best describes how people die of carbon monoxide poisoning?

Which statement best describes how people die of carbon monoxide poisoning?

Which statement best describes how people die of carbon monoxide poisoning?
A) Carbon monoxide is toxic because it readily picks up oxygen to produce carbon dioxide, causing acidosis and eventual death.
B) Carbon monoxide causes decompressi

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What is the primary mechanism of carbon dioxide transport in blood?

What is the primary mechanism of carbon dioxide transport in blood?

What is the primary mechanism of carbon dioxide transport in blood?
A) bound to hemoglobin
B) dissolved in the red blood cells
C) as bicarbonate dissolved in the plasma
D) dissolved in the plasma
E) as bicarbonate dissolved i

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What area of the brain initiates the fight-or-flight response by producing widespread activation of

What area of the brain initiates the fight-or-flight response by producing widespread activation of

What area of the brain initiates the fight-or-flight response by producing widespread activation of the sympathetic nervous system?
A) hypothalamus
B) amygdala
C) brainstem
D) limbic system
E) cerebellum

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Where in blood does the conversion of CO2 to bicarbonate occur?

Where in blood does the conversion of CO2 to bicarbonate occur?

Where in blood does the conversion of CO2 to bicarbonate occur?
A) erythrocytes
B) capillary endothelial cells
C) platelets
D) leukocytes
E) plasma

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People who have done a lot of endurance training can have a resting heart rate of 50 beats per minut

People who have done a lot of endurance training can have a resting heart rate of 50 beats per minut

People who have done a lot of endurance training can have a resting heart rate of 50 beats per minute compared to the normal resting heart rate of 70-80 beats per minute. This decreased heart rate in trained individuals is the partly result of
A

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Which of the following statements about 2,3-BPG is FALSE?

Which of the following statements about 2,3-BPG is FALSE?

Which of the following statements about 2,3-BPG is FALSE?
A) 2,3-BPG is an intermediate of glycolysis.
B) 2,3-BPG is produced by red blood cells.
C) 2,3-BPG produces a rightward shift in the hemoglobin-oxygen dissociation curve.
D

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One of the adaptations that occur to muscles due to exercise is that contractions become stronger an

One of the adaptations that occur to muscles due to exercise is that contractions become stronger an

One of the adaptations that occur to muscles due to exercise is that contractions become stronger and steadier over time even with no change in muscle mass. Which statement below best explains why muscle contractions may become stronger?
A) 

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The carbamino effect describes a change in the conformation of hemoglobin that is induced by a(n)A)

The carbamino effect describes a change in the conformation of hemoglobin that is induced by a(n)A)

The carbamino effect describes a change in the conformation of hemoglobin that is induced by a(n)
A) decrease in pH.
B) increase in pH.
C) increase in temperature.
D) increase in CO2.
E) decrease in temperature.

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In what class of autonomic neuron and within what organelle is the enzyme monoamine oxidase located?

In what class of autonomic neuron and within what organelle is the enzyme monoamine oxidase located?

In what class of autonomic neuron and within what organelle is the enzyme monoamine oxidase located?
A) smooth ER of parasympathetic postganglionic neurons
B) mitochondria of sympathetic postganglionic neurons
C) synaptic vesicles of s

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Which statement best describes the Bohr effect?

Which statement best describes the Bohr effect?

Which statement best describes the Bohr effect?
A) The Bohr effect refers to a decrease in pH which decreases the affinity of hemoglobin for oxygen.
B) The Bohr effect speeds up metabolism and therefore increases the temperature in the body

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What enzyme degrades the neurotransmitter released from varicosities of parasympathetic postganglion

What enzyme degrades the neurotransmitter released from varicosities of parasympathetic postganglion

What enzyme degrades the neurotransmitter released from varicosities of parasympathetic postganglionic neurons?
A) catechol-O-methyltransferase only
B) catechol-O-methyltransferase and monoamine oxidase
C) monoamine oxidase only
D

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Which statement best describes why oxygen is unloaded in tissue that is highly active?

Which statement best describes why oxygen is unloaded in tissue that is highly active?

Which statement best describes why oxygen is unloaded in tissue that is highly active?
A) As temperature increases, the Bohr effect causes hemoglobin to release oxygen.
B) As temperature increases, the carbamino effect causes hemoglobin to

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The presence of ________ within varicosities initiates the release of neurotransmitter.

The presence of ________ within varicosities initiates the release of neurotransmitter.

The presence of ________ within varicosities initiates the release of neurotransmitter.
A) voltage-gated Ca2+ channels
B) voltage-gated Na+ channels
C) voltage-gated K+ channels
D) mechanically-gated Na+ channels
E) mechanica

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In the pulmonary arteries, the partial pressure of oxygen is approximately ________, and hemoglobin

In the pulmonary arteries, the partial pressure of oxygen is approximately ________, and hemoglobin

In the pulmonary arteries, the partial pressure of oxygen is approximately ________, and hemoglobin is approximately ________ saturated with oxygen.
A) 100 mm Hg : 98%
B) 80 mm Hg : 90%
C) 60 mm Hg : 80%
D) 25 mm Hg : 50%
E)

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What are swellings of postganglionic autonomic axons from which neurotransmitters are released calle

What are swellings of postganglionic autonomic axons from which neurotransmitters are released calle

What are swellings of postganglionic autonomic axons from which neurotransmitters are released called?
A) parasympathetic chains
B) neuromuscular junctions
C) sympathetic trunks
D) ganglia
E) varicosities

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In the systemic arteries, the partial pressure of oxygen is approximately ________, and hemoglobin i

In the systemic arteries, the partial pressure of oxygen is approximately ________, and hemoglobin i

In the systemic arteries, the partial pressure of oxygen is approximately ________, and hemoglobin is approximately ________ saturated with oxygen.
A) 100 mm Hg : 98%
B) 40 mm Hg : 75%
C) 60 mm Hg : 50%
D) 100 mm Hg : 75%
E)

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Actions at which class of adrenergic receptor generally have inhibitory effects?

Actions at which class of adrenergic receptor generally have inhibitory effects?

Actions at which class of adrenergic receptor generally have inhibitory effects?
A) β1
B) α1
C) α1 and β1
D) β2
E) nicotinic

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Propranolol is a non-selective β adrenergic receptor antagonist. It would be appropriate for a docto

Propranolol is a non-selective β adrenergic receptor antagonist. It would be appropriate for a docto

Propranolol is a non-selective β adrenergic receptor antagonist. It would be appropriate for a doctor to prescribe propranolol to treat
A) hypertension.
B) asthma.
C) myasthenia gravis.
D) low blood pressure.
E) peptic ulcer

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Which of the following increases oxygen unloading from hemoglobin?

Which of the following increases oxygen unloading from hemoglobin?

Which of the following increases oxygen unloading from hemoglobin?
A) decreased temperature
B) increased oxygen levels in the tissue
C) increased carbon dioxide in the tissue
D) increased blood pH
E) decreased metabolism

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