CH 15 Flashcards

1
Q

autonomic

A

“self-governed” and fully independent.

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2
Q

Autonomic nervous system (ANS)

A

a motor nervous system that controls smooth, cardiac muscle, and glands.

-A.K.A visceral motor system.

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3
Q

Primary organs of the ANS

A

viscera of thoracic and abdominal cavities.

Some structures of the body wall.

  • cutaneous blood vessels.
  • sweat glands.
  • piloerector muscles.
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4
Q

ANS (cont.)

A

carries out actions INVOLUNTARILY: without our conscious intent or awareness.

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5
Q

Denervation hypersensitivity

A

exaggerated response of cardiac and smooth muscle if autonomic nerves are severed.
-spinal cord injuries

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6
Q

Visceral reflexes

A

unconscious, automatic

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7
Q

example of homeostatic negative feedback loop

A

high blood pressure detected by arterial stretch receptors (1), afferent neuron (2) carries signal to CNS, efferent (3) signals travel to the heart, then (4) heart slows reducing blood pressure.

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8
Q

example of homeostatic negative feedback loop

A

high blood pressure detected by arterial stretch receptors (1), afferent neuron (2) carries signal to CNS, efferent (3) signals travel to the heart, then (4) heart slows reducing blood pressure.

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9
Q

Sympathetic divison

A

prepares body for physical activity: exercise, trauma, arousal, competition, anger or fear.

  • increases heart rate, BP, airflow, blood glucose levels, etc.
  • reduces blood flow to skin and digestive tract.
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10
Q

Parasympathetic division

A

clams many body functions reducing energy expenditure and assists in bodily maintenance (rest and digest)

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11
Q

Parasympathetic tone

A
  • maintains smooth muscle tone in intestines.

- hold resting heart rate down to about 70 to 80 beats per minute.

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12
Q

Sympathetic tone

A

keeps most blood vessels partially constricted and maintains blood pressure.

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13
Q

(Autonomic output pathways) control nucleus in the ______ and other brainstem regions.

A

hypothalamus

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14
Q

Autonomic pathway

A
  • signal must travel across 2 NEURONS to get to target organ.
  • must cross a synapse where these two neurons meet in an autonomic ganglion.
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15
Q

Presynaptic neuron

A

the first neuron has a some in the brainstem or spinal cord. (type B)

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16
Q

____ with a _________ whose axone extends the rest of the way to the target cell. (type C)

A

Synapses ; postganglionic neuron

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17
Q

Sympathetic division

A
  • also called thoracolumbar division.

- relatively short preganglionic and long postganglionic fibers.

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18
Q

Preganglionic neurosomas

A

in lateral horns and nearby regions of the grey matter of spinal cord.

  • fibers exit spinal corby way of spinal nerves T1 to L2.
  • lead to nearby sympathetic chain of ganglia (paravertebral ganglia)
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19
Q

each paravertebral ganglion is connected to a spinal nerve by two branches:

A

communicating rami

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20
Q

Preganglionic fibers

A

small myelinated fibers that travel from spinal nerve to the ganglion by way of the white communicating ramus. (myelinated)

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21
Q

Postganglionic fibers

A

leave the ganglion by way of the gray communicating ramus (unmyelinated).
-forms a bridge back to the spinal nerve.

extend the rest of the way to the target organ.

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22
Q

nerve fibers leave the sympathetic chain by___, ___, and _____.

A

spinal, sympathetic, splanchnic nerves.

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23
Q

spinal nerve route

A
  • some postganglionic fibers exit a ganglion by way of the grey ramus.
  • return to the spinal nerve and travel the rest of the way to the target organ.
  • most sweat glands, piloerector muscles, and blood vessels of the skin and skeletal muscles.
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24
Q

sympathetic nerve route

A
  • other nerves weaver by way of sympathetic nerves that extend to heart, lungs, esophagus, and thoracic.
  • these nerves form carotid plexus around each carotid artsy of the neck.
  • issue fibers from there to the effectors in the head. (sweat, salivary, nasal glands, piloerector muscles, blood vessels, dilator of iris) (superior cervical)
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25
Q

some fibers of superior and middle cervical ganglia form _____ to the heart. (sympathetic division)

A

cardiac nerves

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26
Q

Splanchnic nerve route

A

some fibers that arise from spinal nerves T5 to T12 pass through the sympathetic ganglia without synapsing.

  • continue on as the splanchnic nerves.
  • lead to second set of ganglia: collateral ganglia and synapse there.
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27
Q

Collateral ganglia contribute to a network called the ________

A

abdominal aortic plexus

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28
Q

abdominal aortic plexus

3 major collateral ganglia:

A

wraps around abdominal aorta

  • celiac: heart, lungs, liver, gall bladder.
  • superior mesenteric: small intestine, proximal colon.
  • inferior mesenteric: kidneys, urinary bladder, reproductive organs, distal colon, rectum.
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29
Q

Solar plexus

A

collective name for the celiac and superior mesenteric ganglia.
-nerves radiate from ganglia like ray of the sun.

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30
Q

Adrenal glands

A

paired on superior poles of the kidneys.

-each is two glands with different functions:
adrenal cortex
adrenal medulla

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31
Q

Adrenal cortex

A

(outer layer)

secretes steroid hormones

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32
Q

Adrenal medulla

A

(inner core)
-essentially a sympathetic ganglion.
secretes a mixture of hormones into blood stream.
-catecholamines–85% epinephrine (adrenaline) and 15% norepinephrine (noradrenaline)
-also function as neurotransmitters

33
Q

parasympathetic division

A

pathways of long preganglionic fibers

  • fibers in cranial nerves III, VII, IX, and X.
  • fibers arising from sacral spinal cord.
34
Q

terminal ganglia

A

in or near target organs

-long preganglionic, short postganlionic fibers.

35
Q

Neuronal divergence (PD)

A

less than sympathetic division.

36
Q

Oculomotor nerve

A

(III) narrows pupil and focuses lens.

37
Q

Facial nerve

A

(VII) tear, nasal, and salivary glands.

38
Q

Glossopharyngeal nerve

A

(IX) parotid salivary gland

39
Q

Vagus nerve

A

(X) (90%)

  • viscera as far as proximal half of colon.
  • cardiac, pulmonary, and esophageal plexus.
40
Q

Enteric nervous system

A

the nervous system of the digestive tract.

  • does not arise from the brainstem or spinal cord.
  • does not innervate smooth muscle and glands.
  • 100 million neurons found in digestive tract.
  • no components in CNS
  • has its own reflex arcs (stretch receptors)
  • regulates motility of esophagus, stomach, and intestines and secretion.
  • normal digestive func. requires sympathetic and parasympathetic systems.
41
Q

Hirschsprung disease

A

hereditary defect causing absence of enteric nervous system.

  • no innervation in sigmoid colon and rectum.
  • constricts permanently and will now passage of feces.
  • feces becomes impacted.
42
Q

Megacolon

A

massive dilation of bowel accompanied by abdominal dissension and chronic constipation.

  • may be colonic gangrene, perforation of bowel, and peritonitis.
  • usually evident in newborns who fail to have their first bowel movement.
43
Q

How can different autonomic neurons have different effects constricting some vessels but dilating others?

A
  • Sympathetic and parasympathetic fibers secrete different neurotransmitters.
  • Target cells respond to the same neurotransmitter differently depending upon the type of receptor they have for it.
44
Q

All autonomic fibers secrete either _____ or ________.

A

acetylcholine

norepinephrine

45
Q

acetylcholine (ACh) is secreted by all preganglionic neurons both divisions and the postganglionic parasympathetic neurons called ________.

A

Cholinergic fibers

46
Q

NEis secreted by nearly __________.
called__________.
receptors for it called _________.

A

all sympathetic postganglionic neurons.

adrenergic fibers

adrenergic receptors

47
Q

alpha-adrenergic receptors

A

two subclasses use different second messengers (a1 & a2)

48
Q

Beta-adrenergic receptors

A

two subclasses with different effects, but both act through cAMP as a second messenger (B1 & B2)

49
Q

A1

A

smooth muscle contraction (blood vessels to skin, GI tract, kidneys) contraction of uterus, arrector pili, internal urethral sphincter.

50
Q

A2

A

beta cells of pancreas, GI sphincters.

51
Q

B1

A

increase HR, increase renin in kidneys.

52
Q

B2

A

vasodilation to heart, skeletal muscle, liver, bronchodilation.

53
Q

B3

A

adipose tissue

54
Q

Autonomic effects are often an _____ result other effect on blood vessels.

A

indirect

55
Q

Vasodilation

A

increased blood flow; increased secretion.

56
Q

Vasoconstriction

A

decreased blood flow; decreased secretion.

57
Q

Sympathetic effects tend to last ____ than parasympathetic effects.

A

longer

  • ACh released by parasympathetics is broken down quickly at synapse.
  • NE by sympathetics is reabsorbed by nerve, diffuses to adjacent tissues, and much passes into blood stream.
58
Q

Sympathetic fibers

A

also secrete endothelial cells, substance P, neuropeptide Y, somatostatin, Neurotensin.

59
Q

Parasympathetic fibers

A

stimulate endothelial cells to release gas, nitric oxide, which cause vasodilation by inhibiting smooth muscle tone

-function is crucial to penile erection— means of action of viagra.

60
Q

Dual innervation

A

most viscera receive nerve fibers from both parasympathetic and sympathetic division.

2 types:
antagonistic effect
cooperative effect

-both do not normally innervate an organ equally (digestion, heart rate)

61
Q

Antagonistic effect

A

oppose each other

  • exerted through dual innervation of same effector cells
  • heart rate decreases (parasympathetic )
  • heart rate increases (sympathetic)
  • Exerted because each division innervates different cells.
  • pupillary dilator muscle (sympathetic) dilates pupil.
  • constrictor pupillae (parasympathetic) constrict pupil.
62
Q

Cooperative effects

A

two division act on different effectors to produce a unified overall effect.

  • parasympathetics increases salivary serous cell secretion.
  • sympathetics increase salivary mucous cell secretion.
63
Q

some effectors receive only sympathetic fibers.

examples:

A

adrenal medulla, arrector pili muscles, sweat glands and many blood vessels.

ex’s: regulation of blood pressure and routes of blood flow.

64
Q

vasomotor tone

A

a baseline firing frequency of sympathetics.

  • keeps vessels in state of partial constriction.
  • can shift blood flow from one organ to another as needed.

sympathetic divisions acting alone can exert opposite effects on the target organ through control of blood

  • during stress
  • blood vessels to muscles and heart dilate.
  • blood vessels to skin constrict.
65
Q

vasoconstriction

A

increase in firing frequency

66
Q

vasodilation

A

decrease in firing frequency

67
Q

blood vessels to skin _____ to minimize bleeding if injury occurs during stress or exercise.

A

vasoconstrict

68
Q

Cerebral cortex (in ANS)

A

has an influence: anger, fear, anxiety

  • powerful emotional influence the ANS because of the connections between out limbic system, and the hypothalamus.
  • phobia
  • biofeedback
69
Q

Hypothalamus (in ANS)

A

major visceral motor control center

-nuclei for primitive functions: hunger, thirst, sex.

70
Q

Midbrain, pons, and medulla oblongata contain:

in ANS

A

nuclei for cardiac and vasomotor control, salivation, swallowing, sweating, bladder control, and pupillary changes.

71
Q

Spinal cord reflexes

A
  • defecation and micturition reflexes are integrated in spinal cord.
  • we control these functions because of our control over skeletal muscle sphincters; if the spinal cord is damaged, the smooth muscle of bowel and bladder is controlled by autonomic reflexes built into the spinal cord (baroreceptors)
72
Q

Neuropharmacology

A

study the effects of drugs on the nervous system

73
Q

Sympathomimetics

A

enhance sympathetic activity

  • stimulate receptors or increase norepinephrine release.
  • cold medicines that dilate the bronchioles or constrict nasal blood vessels (sudafed, a1, b2 blocker)
74
Q

Sympatholytics

A

suppress sympathetic activity

  • block receptors or inhibit norepinephrine release.
  • Beta blockers reduce high BP interfering with effects of epinephrine/norepinephrine on heart and blood vessels.
75
Q

Parasympathomimetics

A

enhance activity

76
Q

parasympatholytics

A

suppress activity

77
Q

Many drugs also act on neurotransmitters in ____

ex:

A

CNS

prozac blocks reuptake of serotonin to prolong its mood-elevating effect

78
Q

Caffeine competes with ______ (the presence of which causes sleepiness) by binding to its receptors.

A

adenosine