Question 1

Which of the following best describes the difference between the somatic motor division and the autonomic division of the efferent nervous system?

Accepted Answer

The somatic motor division controls skeletal muscle and is mostly voluntary, while the autonomic division controls smooth muscle, cardiac muscle, glands, and some adipose tissue and is mostly involuntary.

Question 2

Which neurotransmitter is released by both sympathetic and parasympathetic preganglionic neurons onto nicotinic cholinergic receptors?

Accepted Answer

Acetylcholine

Question 3

A patient is experiencing increased heart rate and dilated pupils. Which branch of the autonomic nervous system is most active?

Accepted Answer

Sympathetic branch

Question 4

Which of the following is TRUE regarding antagonistic control in the autonomic nervous system?

Accepted Answer

Most internal organs are under antagonistic control, where one branch is excitatory and the other is inhibitory.

Question 5

Which neurotransmitter is primarily released by postganglionic sympathetic neurons at the neuroeffector junction?

Accepted Answer

Norepinephrine

Question 6

The adrenal medulla is considered a modified sympathetic ganglion because:

Accepted Answer

Its chromaffin cells act as postganglionic neurons that secrete epinephrine into the blood.

Question 7

Which of the following correctly matches the receptor type with its response to neurotransmitters in the autonomic nervous system?

Accepted Answer

$$\$$alpha_1$$-adrenergic receptors cause muscle contraction or secretion when activated by norepinephrine.

Question 8

A drug blocks muscarinic cholinergic receptors. Which physiological effect would most likely be observed?

Accepted Answer

Reduced parasympathetic responses such as decreased gland secretion and slowed heart rate

Question 9

Which anatomical feature distinguishes the origin of sympathetic and parasympathetic branches?

Accepted Answer

Sympathetic neurons originate in the thoracic and lumbar regions of the spinal cord, while parasympathetic neurons originate in the brain stem and sacral spinal cord.

Question 10

Which of the following best describes the structure of autonomic pathways?

Accepted Answer

They consist of two neurons in series: a preganglionic neuron and a postganglionic neuron, with a synapse in an autonomic ganglion.

Question 11

Which nerve contains about 75% of all parasympathetic fibers and is responsible for carrying sensory information from internal organs to the brain?

Accepted Answer

Vagus nerve

Question 12

A patient is given a drug that acts as a $$\$$beta_1$$-adrenergic receptor antagonist. What effect would you expect on the heart?

Accepted Answer

Decreased heart rate and force of contraction

Question 13

Which of the following statements about the somatic motor pathway is correct?

Accepted Answer

It consists of a single, myelinated neuron originating in the CNS and is always excitatory to skeletal muscle fibers.

Question 14

Which enzyme is found in the synaptic cleft of the neuromuscular junction and is responsible for breaking down acetylcholine?

Accepted Answer

Acetylcholinesterase

Question 15

Which of the following is a property of nicotinic acetylcholine receptors at the neuromuscular junction?

Accepted Answer

They are chemically-gated channels with two binding sites for acetylcholine and are always excitatory.

Question 16

Which of the following scenarios best illustrates cooperative control in the autonomic nervous system?

Accepted Answer

Sympathetic and parasympathetic branches work on different tissues to achieve a common physiological goal.

Question 17

Which of the following is TRUE regarding neuroeffector junctions in the autonomic nervous system?

Accepted Answer

They are the synapse between a postganglionic autonomic neuron and its target cell, often involving varicosities.

Question 18

Which of the following is an exception to dual antagonistic control in the autonomic nervous system?

Accepted Answer

Sweat glands, which receive only sympathetic innervation and are under tonic control.

Question 19

A patient with damage to the hypothalamus may have difficulty maintaining homeostasis because:

Accepted Answer

The hypothalamus acts as a homeostatic control center, integrating sensory information and coordinating autonomic, endocrine, and behavioral responses.

Autonomic and Somatic Motor Control: Study Notes for Human Physiology (BIO224)

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