Question 1

Norepinephrine-releasing fibers are called cholinergic fibers.

Accepted Answer

Norepinephrine-releasing fibers are called adrenergic fibers, while cholinergic fibers release the neurotransmitter acetylcholine.

Question 2

The rami communicantes are associated only with the sympathetic division of the ANS.

Accepted Answer

This statement is true. The rami communicantes are the small nerve branches that connect the spinal nerves with the sympathetic ganglia. They are only found in the sympathetic division of the autonomic nervous system.

Question 3

Acetylcholine is released by all somatic motor neurons, all preganglionic neurons of the ANS and by the postganglionic parasympathetic nerve fibers.

Accepted Answer

Acetylcholine is indeed released by all somatic motor neurons and all preganglionic neurons of the ANS. It is also the primary neurotransmitter released by postganglionic parasympathetic nerve fibers. However, it is not released by all postganglionic sympathetic nerve fibers. Some postganglionic sympathetic fibers release norepinephrine instead.

Question 4

Some sympathetic preganglionic fibers stimulate the adrenal medulla to release norepinephrine and epinephrine into the blood, producing a "surge of adrenaline."

Accepted Answer

This statement is true. The sympathetic nervous system can stimulate the adrenal medulla to release norepinephrine and epinephrine into the bloodstream, causing a physiological response commonly known as a "fight or flight" response. This surge of adrenaline can increase heart rate, blood pressure, and respiratory rate, among other effects.

Question 5

The facial (VII), glossopharyngeal (IX), and vagus (X) nerves contain postganglionic fibers of the parasympathetic nervous system.

Accepted Answer

The facial (VII), glossopharyngeal (IX), and vagus (X) nerves contain preganglionic fibers of the parasympathetic nervous system, not postganglionic fibers.

Question 6

The gray rami communicantes consist of myelinated postganglionic fibers.

Accepted Answer

The gray rami communicantes consist of unmyelinated postganglionic fibers that connect the sympathetic ganglia to spinal nerves.

Question 7

The ANS stimulates smooth muscles, skeletal muscles and glands, whereas the somatic nervous system innervates skeletal muscles only.

Accepted Answer

The somatic nervous system only innervates skeletal muscles, while the autonomic nervous system (ANS) regulates involuntary activities such as smooth muscle contraction, cardiac muscle contraction, gland secretion, and more.

Question 8

Somatic and visceral reflex arcs are similar, but visceral reflex arcs lack afferent fibers (visceral sensory neurons).

Accepted Answer

Somatic and visceral reflex arcs differ in several ways, but one significant difference is that visceral reflex arcs do involve afferent fibers. Visceral sensory neurons are responsible for detecting chemical, mechanical, and thermal changes in the viscera (internal organs), and they transmit this information to autonomic motor neurons in the reflex arc. The lack of conscious perception of visceral sensations is due to the fact that the afferent fibers synapse in the spinal cord or brainstem rather than in areas of the cerebral cortex that are involved in conscious awareness.

Question 9

The parasympathetic division innervates more organs than the sympathetic division.

Accepted Answer

The sympathetic and parasympathetic divisions of the autonomic nervous system both innervate many of the same organs but in different ways to maintain homeostasis. There isn't a clear distinction in the number of organs each innervates, as their primary function is to have opposing effects on the organs they target rather than to innervate a different set of organs.

Question 10

The craniosacral division is another name for the parasympathetic division.

Accepted Answer

The craniosacral division refers to the parasympathetic division, which has its preganglionic neurons originating in the cranial nerves (III, VII, IX, X) and the sacral region of the spinal cord (S2-S4).

Question 11

The sympathetic and parasympathetic divisions of the ANS have the same effect on most body organ systems.

Accepted Answer

The sympathetic and parasympathetic divisions of the ANS have opposite effects on most body organ systems. The sympathetic division generally prepares the body for "fight or flight" responses, while the parasympathetic division promotes "rest and digest" activities.

Question 12

Autonomic ganglia are sights of synapse and information transmission from preganglionic to postganglionic neurons.

Accepted Answer

Autonomic ganglia play a crucial role in the transmission of information from preganglionic to postganglionic neurons. They are responsible for receiving signals from the central nervous system and relaying them to the appropriate organs or tissues.

Question 13

The celiac ganglion is primarily associated with the sympathetic division.

Accepted Answer

The celiac ganglion, located in the abdomen, is a part of the sympathetic nervous system and plays a crucial role in regulating abdominal organs such as the stomach, liver, pancreas, and intestines. It receives sympathetic fibers from the thoracic and upper lumbar regions of the spinal cord.

Question 14

All visceral organs receive dual innervation from both the sympathetic and parasympathetic divisions of the
ANS.

Accepted Answer

Not all visceral organs receive dual innervation. Some, like the adrenal medulla and sweat glands, primarily receive sympathetic innervation.

Question 15

Thermoregulatory responses to increased heat are mediated by the parasympathetic nervous division.

Accepted Answer

Thermoregulatory responses to increased heat are actually mediated by the sympathetic nervous division. The sympathetic nervous system activates sweat glands, dilates blood vessels in the skin, and increases heart rate to release excess heat and maintain body temperature. The parasympathetic nervous system, on the other hand, is involved in rest and digestion functions.

Question 16

Most disorders of the autonomic nervous system reflect abnormalities of smooth muscle control.

Accepted Answer

Smooth muscle is a type of muscle that is regulated by the autonomic nervous system, and many disorders of the autonomic nervous system are characterized by abnormal smooth muscle control, such as in conditions like irritable bowel syndrome, gastroparesis, and orthostatic hypotension.

Question 17

The adrenal medulla is considered by some to be a "misplaced" sympathetic ganglion since embryologically, they arise from the same tissue.

Accepted Answer

The adrenal medulla and sympathetic ganglia both arise from the neural crest during embryonic development. Therefore, some consider the adrenal medulla to be a "misplaced" sympathetic ganglion as it shares many similarities with sympathetic ganglia, including the release of catecholamines (epinephrine and norepinephrine) in response to stress or stimulation of the sympathetic nervous system.

Question 18

The autonomic nervous system may cause activation or inhibition, depending on the division that is active and the target that is affected.

Accepted Answer

This is correct, as the sympathetic division typically causes activation while the parasympathetic division typically causes inhibition. However, there may be exceptions and some targets may not respond as expected.

Question 19

Autonomic ganglia are motor ganglia, containing the cell bodies of motor neurons.

Accepted Answer

Autonomic ganglia are collections of cell bodies of motor neurons that function in the automatic nervous system (ANS) to control involuntary smooth muscles, cardiac muscles, and glands.

Question 20

The effect of beta-blocker drugs (block beta-receptors) is to increase blood pressure.

Accepted Answer

The effect of beta-blocker drugs is to decrease blood pressure by blocking the action of adrenaline and reducing the force of heart contractions.

Quiz 14: The Autonomic Nervous System