Ch. 16 Flashcards

1
Q

The autonomic nervous system (ANS) maintains homeostasis of the body by regulating many involuntary activities including…

A

Heart rate, breathing rate, body temp, digestive processes and urinary functions

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2
Q

The somatic motor system regulates activites of the skeletal muscle and the ANS regulates the activity of all other effectors such as..

A

Smooth muscle, cardiac muscle and glands

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3
Q

The ANS is divided into what 3 divisions?

A

Sympathetic division

Parasympathetic division

Enteric nervous system

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4
Q

The enteric nervous system consists of

A

nervous tissue of the digestive tract

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5
Q

Sympathetic divison is often referred to as _______ because____________?

A

Fight or flight

bc it has more influence on effectors inder conditions of increased physical activity or stress

Maximum expendure of energy / best use possible

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6
Q

The parasympathetic division is often referred to as________ because _____________?

A

Rest and digest divison

Has more influence under conditons of rest

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7
Q

Motor neurons that innervate skeletal muscles are called Somatic motor neurons. Motor neurons that innervate smooth muscle, cardiac muscle and glands are called

A

autonomic motor neurons and are part of ANS

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8
Q

The ANS has 2 neurons in a series extending between CSN and the innervated organs, What are the 2 neurons called?

A

Preganglionic neuron and Postganglionic neuron

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9
Q

The preganglionic neuron cell body is located where?

A

In the CNS within either brainstem or lateral gray horn and axons extend to autonomic ganglion outside of the CNS

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10
Q

The postganglion neuron synapses with preganglion neuron where?

A

Autonomic ganglia where the postganglion neuroncell bodies are located the axons exend to teh effector organs and synapse with their target tissues

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11
Q

The postganglion neuron synapses with preganglion neuron where?

A

Autonomic ganglia where the postganglion neuroncell bodies are located the axons exend to teh effector organs and synapse with their target tissues

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12
Q

The axons of all somatic motor neurons are myelinated. What are the axons of ANS?

A

Preganglion nuerons are myelinated

Postganglion neurons are unmyelinated

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13
Q

Many movements of somaic nervous system are volunatary, ANS is?

A

Involuntarily controlled

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14
Q

The effect on somaic motor neurons on skeletal muscles are always excitatory, the effect on autonomic motor neurons is?

A

Either excitatiry or inhibitory

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15
Q

The major neurotransmitter in somatic motor system is acetylcholine (ACH) the major neurotransmitter in ANS is?

A

ACH
Epinephrine (E)
Norepinephrine (NE)

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16
Q

Somatic always uses ACH what does the autonomic system use?

A

Preganglionic neuron uses ACH

Postganglionic neuron uses either ACH or norephinephrine

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17
Q

Sympathetic divison
Aka Thoracolumnar divison

Where are cell bodies located and why is it called Thoracolumnar divison?

A

Cell bodies of sympathetic preganglion neurons are in the lateral horns of spinal cord gray matter between T1 and L2

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18
Q

What are the 2 types of sympathic ganglia?

A

Sympathetic chain ganglia and collateral ganglia

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19
Q

Sympathetic chain ganlgia

Aka Paravertebral ganglia

A

Located along left and right sides of vertebral column. Connected to each other forming a chain

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20
Q

As a result of fusion during fetal development there are usually how many pairs of ganglia …

A

3 pair’s of cervical ganglia
11 pairs of thoracic ganglia
4 pairs of lumbar ganglia
4 pairs of sacral ganglia

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21
Q

Collateral ganglia

Aka prevertebral ganglia

A

unpairs ganglia located in abdominopelivc cavity.

*Anterior to vertebral column

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22
Q

What are the 4 potential pathways of axons that exit the sympathetic chain ganglion?

A
  1. Spinal nerves
  2. Sympathetic nerves
  3. Splanchnic
  4. Innervation to the adrenal gland
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23
Q

What is the pathway of axons that exit sympathetic chain ganglia to spinal nerves?

A
  1. Exit lateral gray horn and out ventral root through white ramus communicans
  2. Synpase with postganglionic neuron in sympathic chain ganglion

*They can synapse at same leve or inferiorly or superiorly

  1. Axons of postganglion neurons pass through the gray ramus communicans and reenter a spinal nerve
  2. Project through spinal nerve to skin and blood vessels of skeletal muscles
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24
Q

What is the pathway of axons that exit sympathetic chain ganglia to Sympathetic nerves?

A
  1. Exit lateral gray horn and out ventral root through white ramus communicans
  2. Synpase with postganglionic neuron in sympathic chain ganglion

*They can synapse at same leve or inferiorly or superiorly

  1. Postganglionic axons leaving the sympathetic chain ganglion form sympathetic nerves, which supply organs in thoracic cavity, such as heart
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25
Q

What is the pathway of axons that exit sympathetic chain ganglia to Splanchnic nerves?

A
  1. Exit lateral gray horn and out ventral root through white ramus communicans, enter sympathetic chain ganglia and, without synapsing exit at same or different level to form splanchnic nerves.
  2. They enter the collateral ganglion where they synpase with postganglionic neurons
  3. Then extend o the effectors of abdominopelvic cavity
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26
Q

Splanchnic nerves are composed of __________sympathetic nerves are composed of __________

A

Preganglionic axons
Postganglionic axons

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27
Q

What is the pathway of axons that exit sympathetic chain ganglia to innervation of adrenal gland?

A

The innervation of adrenal gland is through a splanchnic nerve.

  1. Exit lateral gray horn and out ventral root through white ramus communicans pass through sympathetic chain ganglion and collateral ganglion
  2. Synpase with cells in the medulla of adrenal gland
  3. Cause release of either epinephrine or norepinephrine which circulate in blood and affect all tissues having receptors to which they can bind.

*General response is to prepare an individual for physical activity

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28
Q

Adrenal medulla

A

inner portion of the adrenal gland and consists of specialized cells dervied from neural crest cells during embryonic development

*Neural crest cells are the same cells that give rise to the postganglionic cells of ANS

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29
Q

Adrenal medullary cells are

A

Round and have no axons or dendrites and are divided into 2 groups

80% secrete epinephrine aka adrenaline
20% secrete norepinehrin aka noradrenaline

30
Q

Parasympathetic division
aka craniosacral division

A

Cell bodies are located in either within cranial nerve nuclei in brainstem or within lateral parts of gray matter in sacral region of spinal cord from S2-S4

31
Q

Axons from the parasympathetic preganglionic neurons from the brain are cranial nerves?

A

III, VII, IX, X

32
Q

The axons associated with the sacral region are?

A

Pelvic splanchnic nerves

33
Q

The axons of parasympathetic preganglionic neurons course through cranial nerves or pelvic splanchnic nerves to

A

termianl gangla where they synapse with postganglionic neurons then to the effectors

*The terminal ganglia are either near or embedded within the walls of the organs innervated by parasympathetic organs

34
Q

Autonomic nerve plexuses

A

complex interconnected neural networks formed by neurons of the sympathetic and parasympathetic diviisons

Axons of sensory neurons also contribute

Autonomic nerve plexuses are typically named according to the organs they supply or blood vessels along which they are found

35
Q

What are the major ways sympathetic postganglion axons reach effectors?

A
  1. Spinal nerves
  2. Head and neck nerve plexuses
  3. Thoracic nerve plexuses
  4. Abdominopelvic nerve plexuses
36
Q

Cardiac plexus

A

Regulating the heart

37
Q

Pulmonary plexus

A

regulating the lungs

38
Q

What are the 4 abdominopelvic nerve plexus?

A

Celiac plesus - innervates diaphram, stomach, spleen, liver, gallbladder, adrenal glands, kidneys, testes and ovaries

Superior mesenteric plexus - innervates pancreas, small intestine, ascending colon and transverse colon

Inferior mesenteric plexus - innervates transverse colon to the rectum

Superior and inferior hypogastric plexus innervates descending colon to recum, urinary bladder and reproductive organs in pelvis

39
Q

The major means by which parasympathetic postganglionic axons reach effectors are?

A

Cranial nerves innervating head and neck
The vagus nerve and thoracic nerve plexus
Abdominal nerve plexus
Pelvic splanchnic nerves and pelvic nerve plexus

40
Q

What are the 3 pairs of cranial nerves that have parasympathetic preganglionic axons that extend to terminal ganglia in the head and postganglionic neurons innervate the nearby structures?

A
  1. Oculomotor nerve through ciliary ganglion, innervates ciliary muscles and iris of eye
  2. Facial nerve through pterygopalatine ganglion innervates lacrimal gland the mucosal glands of nasal cavity and palate. Facial nerve through the submandibular ganglion, also innervates the submandibular and sublingual salivary glands
  3. Glossopharyngeal nerve, through otic ganglion, innervates the parotid salivary gland
41
Q

Where are the sensory neurons in autonomic nerve plexuses located?

A

Cell bodies aare found in dorsal root ganglia of spinal nerves and in the cranial nerve sensory ganglia

42
Q

The enteric nervous system consists of nerve plexuses with the?

A

Wall of digestive tract

43
Q

The enteric nervous system plexuses have contributions from what 3 sources?

A
  1. Sensory neurons that connect digestive tract to CNS
  2. ANS motor neurons that connect the CNS to the digestive tract
  3. Enteric neurons, which are confined to the enteric plexuses
44
Q

What are the 3 major types of enteric neurons

A
  1. Enteric sensory neurons - detect changes in chemical composition of the contents of digestive tract or dectect stretch of digestive tract
  2. Enteric motor neurons - stimulate or inhibit smooth muscle contraction and gland secretion
  3. Enteric interneurons - connect enteric sensory and motor neurons to each other
45
Q

Dual innervation

A

The ANS innervates most organs by both sympathetic and parasympathetic neurons

Examples of both: Gastrointestincal tract, heart, urinary bladder, and reproductive tract

46
Q

What are the typical responses produced by the sympathetic division during excersice ?

A
  1. Increased heart rate and force of contraction increase blood pressure and movement of blood
  2. Vasodialation of blood vessels in skeletal and cardiac muscle - O2 and nutrients are used and waste products are produced
  3. Vasocontriction occurs in blood vessels of tissues not involved in excersice
  4. Dilation of air passageways
  5. Increased breakdown of stored energy sources (glycogen to glucose)
  6. Body temp increases generating heat
  7. Activities of non essential organs decrease. Ex. digesting food decreases
47
Q

Increased activity of parasympathetic division during rest includes?

A
  1. Regulates digestion by stimulating secretion of glands, promoting mixing of food and moving through digestive tract
  2. Controls defecation and urination
  3. Lowers heart rate and lowers blood pressure
  4. Contricts air passageways
48
Q

Sympathetic and parasympathetic neurons secrete one of 2 neurotransmitters?

A

Acetylcholine or norepineohrine

49
Q

If a neuron secretes acetlychloine it is called?

A

Cholinergic neuron

*All preganglionic neurons of the sympathetic and parasympathetic divisions are cholinergic

*All postganglionic neurons of the parasympathetic divisons are also cholinergic

*A few postganglionic neurons that innervate thermoregulatory swea glands are cholinergic

50
Q

If a neuron secretes norepinephrine it is called?

A

adrenergic neuron

*Most all postganglionic neurons fo the sympathetic division are adrenergic

51
Q

What are the substances other than regular neurotransmitters that have been extracted from ANS neurons?

A

Nitric oxide, fatty acids, monoamines

52
Q

Agonist

A

bind to specific receptors and activate them

53
Q

Antagonists

A

bind to specific receptors and prevent them from being activated

54
Q

Cholinergic receptors are classified as?

A
  1. Nicotinic receptors
  2. Muscarinic receptors
55
Q

Adrenergic receptors

A

to which norepinephrine or epinephrine binds.

Located in plasma membrane of effectors innervated by sympathetic division

56
Q

Adrenergic receptors are subdivided into what 2 categories?

A

Alpha (a) receptors
Beta (b) receptors

57
Q

Adrenergic receptors can be stimulated in what 2 ways?

A
  1. By the nervous system
  2. by epinephrine and norepinephrine released from adrenal gland
58
Q

Auonomic reflexes involve

A

Adjustments to cardiac muscle, smooth muscle, and glandular tissues in response to stimuli

Involved sensory receptors, interneurons, motor neurons and effector cells

59
Q

Barorecptors

A

(stretch receptors) in the walls of large arteries near heart detect changes in blood pressure

60
Q

The hypothalamus is in overall control of ANS. for the most part, Stimulation of the posterior hypothalamus produces _________ where stimulation of the anterior hypothalamus produces __________ responses

A

Sympthetic responses
Parasymapthetic responses

61
Q

Local reflex of enteric nervous system

A

does not involve CNS but produces an involuntary unconscious, stereotypical response to a stimulus

62
Q

Hirschsprung disease

A

caused by ineffective parasympathetic stimulation of the colon

63
Q

Visceral effectors do not need _____ to function

A

ANS - only to adjust activity to chaning needs

64
Q

Autonomic tone

A

normal background rate of activity that represents a balance of the 2 systems according to the bodys changing needs

65
Q

Parasympathetic tone

A

Maintains smooth muscle tone in intestines and holds resting HR down to 70-80BPM

66
Q

Sympathetic tone

A

Keeps most BV partially constricted to maintain BP. Excites the heart but inhibits digestive and urinary functions (Parasympathetic is opposite)

67
Q

What is the big parasympathetic nerve/reflex?

A

Vagus nerve - lowers heart rate

68
Q

What is the sympathetic reflex/nerve?

A

Cardiac accelerator - increases heart rate

69
Q

What are examples of parasympthatetic nerves?

A

Things that have to do with
Gastric and intestinal
Defecation/urination
Swallowing
Coughing
baroreceptor

70
Q

What are examples of sympthatetic nerves?

A

Cardioacceleratory
Vasomotor