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Biol 235 Human Anatomy and Physiology > Chapter 15 The Autonomic Nervous System > Flashcards

Chapter 15 The Autonomic Nervous System Flashcards

1
Q

What are the two main parts of the nervous system?

A

Somatic nervous system (SNS) and autonomic nervous system (ANS)

The SNS controls skeletal muscles, while the ANS regulates cardiac muscle, smooth muscle, and glands.

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2
Q

What type of control does the somatic nervous system usually operate under?

A

Voluntary control

Involves motor areas of the cerebral cortex activating somatic motor neurons.

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3
Q

What is the primary function of the autonomic nervous system?

A

Regulates cardiac muscle, smooth muscle, and glands

These tissues are often referred to as visceral effectors.

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4
Q

What is the role of preganglionic neurons in the autonomic nervous system?

A

Convey nerve impulses from the CNS to autonomic ganglia

Preganglionic neurons have their cell bodies in the CNS.

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5
Q

What neurotransmitter is released by all somatic motor neurons?

A

Acetylcholine (ACh)

Autonomic motor neurons can release ACh or norepinephrine (NE).

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6
Q

Fill in the blank: The sympathetic nervous system promotes the ______ response.

A

[fight-or-flight]

Prepares the body for emergency situations.

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7
Q

How many motor neurons are involved in most autonomic pathways?

A

Two motor neurons

Preganglionic and postganglionic neurons form the pathway.

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8
Q

What are the two divisions of the autonomic nervous system?

A

Sympathetic nervous system and parasympathetic nervous system

The enteric nervous system is also considered a third division.

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9
Q

True or False: The autonomic nervous system operates under conscious control.

A

False

The ANS usually operates without conscious control.

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10
Q

What are the anatomical components of the sympathetic ganglia?

A

Sympathetic trunk ganglia and prevertebral ganglia

These ganglia are sites of synapses between sympathetic preganglionic and postganglionic neurons.

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11
Q

What type of axon do postganglionic neurons in the autonomic nervous system typically have?

A

Unmyelinated type C fibers

These fibers terminate in visceral effectors.

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12
Q

What is the primary function of the parasympathetic nervous system?

A

Enhances rest-and-digest activities

Conserves and restores body energy.

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13
Q

What is the difference in sensory input between the somatic and autonomic nervous systems?

A

Somatic senses are consciously perceived; autonomic sensory input is usually not

Intense activation of interoceptors may produce conscious sensations.

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14
Q

What is the term for the collection of neuronal cell bodies in the peripheral nervous system?

A

Ganglion

Autonomic ganglia are specifically involved in the ANS.

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15
Q

Fill in the blank: The parasympathetic division is also known as the ______ division.

A

[craniosacral]

Preganglionic neurons are located in the brainstem and sacral spinal cord.

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16
Q

What type of fibers do sympathetic preganglionic neurons have?

A

Myelinated type B fibers

These fibers extend to autonomic ganglia.

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17
Q

What is divergence in the context of sympathetic preganglionic fibers?

A

A single preganglionic fiber synapsing with multiple postganglionic neurons

This explains widespread sympathetic responses.

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18
Q

What are interoceptors?

A

Sensory receptors located in blood vessels, visceral organs, and muscles

They monitor conditions in the internal environment.

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19
Q

What neurotransmitters are released by chromaffin cells in the adrenal medulla?

A

Epinephrine and norepinephrine (NE)

Chromaffin cells function like sympathetic postganglionic neurons.

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20
Q

What type of control can be learned over autonomic functions through practices like yoga?

A

Limited conscious control

Techniques such as biofeedback may enhance this ability.

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21
Q

What is the primary role of the hypothalamus in relation to the ANS?

A

Regulates ANS reflexes

The hypothalamus plays a critical role in homeostasis.

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22
Q

What is the function of chromaffin cells in the adrenal medullae?

A

Functionally like sympathetic postganglionic neurons, they release hormones into the blood.

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23
Q

What is the divergence pattern in sympathetic preganglionic fibers?

A

A single sympathetic preganglionic fiber can synapse with 20 or more postganglionic neurons.

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24
Q

How do parasympathetic responses differ from sympathetic responses?

A

Parasympathetic responses are localized to a single visceral effector.

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25
What are autonomic plexuses?
Tangled networks of sympathetic and parasympathetic axons that include sympathetic ganglia.
26
Name two major autonomic plexuses in the thorax.
* Cardiac plexus * Pulmonary plexus
27
What is the largest autonomic plexus and what does it surround?
The celiac plexus surrounds the celiac trunk.
28
What structures do the sympathetic trunk ganglia consist of?
* 3 cervical ganglia * 11 or 12 thoracic ganglia * 4 or 5 lumbar ganglia * 4 or 5 sacral ganglia * 1 coccygeal ganglion
29
What is the role of white rami in the sympathetic division?
They contain myelinated axons that connect the anterior ramus of the spinal nerve with the ganglia of the sympathetic trunk.
30
What is the function of gray rami communicantes?
They connect the ganglia of the sympathetic trunk to spinal nerves with unmyelinated axons.
31
True or False: Only thoracic and lumbar nerves have white communicating rami.
True
32
What do sympathetic nerves innervate in the thoracic cavity?
* Heart * Lungs * Other thoracic viscera
33
What are splanchnic nerves?
Nerves formed by sympathetic preganglionic axons that extend to outlying prevertebral ganglia.
34
What do chromaffin cells of the suprarenal medullae release?
* 80% epinephrine * 20% norepinephrine * Trace amount of dopamine
35
Where are the cell bodies of parasympathetic preganglionic neurons located?
In the brainstem and in the lateral gray matter of the second through fourth sacral segments.
36
What cranial nerves are involved in the cranial parasympathetic outflow?
* Oculomotor (III) * Facial (VII) * Glossopharyngeal (IX) * Vagus (X)
37
What is the main neurotransmitter released by cholinergic neurons?
Acetylcholine (ACh)
38
Fill in the blank: Cholinergic neurons include all sympathetic and parasympathetic _______ neurons.
preganglionic
39
Name the two types of cholinergic receptors.
* Nicotinic receptors * Muscarinic receptors
40
What type of receptors are present in the plasma membranes of all effectors innervated by parasympathetic postganglionic axons?
Muscarinic receptors
41
What ganglia are associated with the facial nerve and where are they located?
* Pterygopalatine ganglia, located lateral to the sphenopalatine foramen.
42
What is the significance of the vagus nerve in the parasympathetic division?
Carries nearly 80% of the total craniosacral outflow.
43
What structures do pelvic splanchnic nerves innervate?
* Colon * Ureters * Urinary bladder * Reproductive organs
44
What is nicotine?
A natural substance in tobacco leaves that is not normally present in nonsmokers.
45
What type of receptors are present in all effectors innervated by parasympathetic postganglionic axons?
Muscarinic receptors.
46
What mimics the actions of ACh by binding to muscarinic receptors?
Muscarine.
47
What is the effect of ACh on nicotinic receptors?
Causes depolarization and excitation of the postsynaptic cell.
48
What is the effect of ACh on muscarinic receptors?
Can cause either depolarization (excitation) or hyperpolarization (inhibition).
49
What enzyme quickly inactivates ACh?
Acetylcholinesterase (AChE).
50
What neurotransmitter is released by adrenergic neurons?
Norepinephrine (NE).
51
What are the two main types of adrenergic receptors?
Alpha (α) receptors and beta (β) receptors.
52
What is the function of β3 receptors?
Cause thermogenesis (heat production) in brown adipose tissue.
53
What is an agonist?
A substance that binds to and activates a receptor, mimicking the effect of a natural neurotransmitter or hormone.
54
What is an antagonist?
A substance that binds to and blocks a receptor, preventing a natural neurotransmitter or hormone from exerting its effect.
55
What is autonomic tone?
The balance between sympathetic and parasympathetic activity regulated by the hypothalamus.
56
What physiological responses are associated with sympathetic division activation?
Fight-or-flight response.
57
What acronym helps remember parasympathetic responses?
SLUDD (salivation, lacrimation, urination, digestion, defecation).
58
Fill in the blank: The sympathetic division increases heart rate, while the parasympathetic division _______.
decreases heart rate.
59
What type of neurotransmitter do most postganglionic neurons in the sympathetic division release?
Norepinephrine (NE).
60
What is the main function of α1 adrenergic receptors?
Excitation → contraction, causing vasoconstriction, dilation of pupil, and closing of sphincters.
61
What occurs during the fight-or-flight response?
Pupils dilate, heart rate increases, airways dilate, blood flow to non-essential organs decreases.
62
True or False: The effects of sympathetic stimulation are shorter lasting than those of parasympathetic stimulation.
False.
63
What happens to blood vessels during sympathetic activation?
Blood vessels to skeletal muscles, cardiac muscle, liver, and adipose tissue dilate.
64
What is the primary neurotransmitter released by parasympathetic postganglionic neurons?
Acetylcholine (ACh).
65
What are the physiological effects of the parasympathetic division?
Rest & digest activities.
66
What happens in the pancreas during sympathetic stimulation?
Inhibits secretion of digestive enzymes & insulin; promotes secretion of glucagon.
67
What are the locations of preganglionic neuron cell bodies for the sympathetic division?
Lateral gray horns of spinal cord segments T1–L2.
68
What is the effect of β2 adrenergic receptor activation in the lungs?
Relaxation → airway dilation.
69
What is the effect of muscarinic receptors on the stomach and intestines?
Increased motility & tone; sphincter relaxation.
70
What is the effect of α2 adrenergic receptors on pancreatic beta cells?
Decreased insulin secretion.
71
Fill in the blank: The sympathetic division is associated with _______ responses during stress.
fight-or-flight.
72
What happens to the gallbladder during parasympathetic stimulation?
Contraction → bile release into the small intestine.
73
What is the effect of α1 receptors on motility and tone?
Increased motility & tone; sphincter relaxation
74
What happens in the spleen when stimulated by α1 receptors?
Contraction & discharge of stored blood into general circulation
75
How do α1 receptors affect the ureter?
Increases motility
76
What is the effect of α1 receptors on male sex organs?
Smooth muscle contraction of ductus deferens, prostate, & seminal glands resulting in ejaculation
77
What is the effect of β2 receptors on the clitoris and penis?
Vasodilation; clitoris & penis erection
78
What effect do α1 receptors have on arrector muscles of the hair?
Contraction → hair erection causing goose bumps
79
What is the effect of α1 receptors on salivary gland arterioles?
Vasoconstriction, decreases secretion of saliva
80
What is the result of β2 receptor stimulation in salivary glands?
Vasodilation, increases saliva secretion
81
How do α1 receptors affect gastric gland arterioles?
Vasoconstriction, inhibits secretion
82
What is the effect of α1 receptors on intestinal gland arterioles?
Vasoconstriction, inhibits secretion
83
What happens to coronary arterioles with β2 receptor activation?
Relaxation → vasodilation
84
What is the effect of α1 receptors on skin and mucosal arterioles?
Contraction → vasoconstriction
85
What is the effect of α1 receptors on skeletal muscle arterioles?
Contraction → vasoconstriction; relaxation → vasodilation
86
What effect do α1 receptors have on brain arterioles?
Slight contraction → vasoconstriction
87
What is the effect of α1 receptors on kidney arterioles?
Blood vessel constriction → decreased urine volume
88
What are autonomic (visceral) reflexes?
Responses that occur when nerve impulses pass through an autonomic reflex arc
89
What are the components of an autonomic reflex arc?
* Sensory receptor * Sensory neuron * Integrating center * Motor neurons * Effector
90
What is the major control and integration center of the ANS?
Hypothalamus
91
What types of sensory input does the hypothalamus receive?
* Visceral functions * Olfaction * Gustation * Temperature changes * Osmolarity * Blood substance levels
92
What is the difference in control between the somatic nervous system and the ANS?
Somatic nervous system operates under conscious control; ANS usually operates without conscious control
93
What are the two major divisions of the ANS?
* Sympathetic * Parasympathetic
94
What is the role of preganglionic neurons in autonomic motor pathways?
First of the two motor neurons; synapses in an autonomic ganglion
95
Where are the cell bodies of sympathetic preganglionic neurons located?
Lateral gray horns of the 12 thoracic and the first two or three lumbar segments of the spinal cord
96
What neurotransmitter is released by cholinergic neurons?
Acetylcholine
97
What are the two types of cholinergic receptors?
* Nicotinic receptors * Muscarinic receptors
98
What do adrenergic neurons release?
Norepinephrine
99
What are the two main types of adrenergic receptors?
* Alpha receptors * Beta receptors
100
What is an agonist in the context of neurotransmitter activity?
A substance that binds to and activates a receptor, mimicking the effect of a natural neurotransmitter
101
What is the role of the sympathetic division of the ANS?
Favors body functions that can support vigorous physical activity and rapid production of ATP
102
How do the effects of sympathetic stimulation compare to parasympathetic stimulation?
Sympathetic effects are longer lasting and more widespread
103
What is the function of an autonomic reflex?
Adjusts the activities of smooth muscle, cardiac muscle, and glands
104
What is the role of the integrating center in an autonomic reflex arc?
Relays signals from sensory neurons to motor neurons

Biol 235 Human Anatomy and Physiology (5 decks)

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