The Autonomic Nervous System Flashcards

(53 cards)

1
Q

The ANS is a subdivision of the

A

PNS
controls autonomic visceral functions
works with rapidity

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2
Q

Three Divisions of the ANS:

A
  • sympathetic
  • parasympathetic
  • enteric
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3
Q

PNS:

A

insert flowchart

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4
Q

Which division of the autonomic nervous system maximises the use of metabolic resources?

A

sympathetic division

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5
Q

Basic Map of ANS:

A

bilateral, paravertebral sympathetic trunk allows sympathetic region of spinal cord to affect other areas because sympathetic axons can enter sympathetic trunk and ascend or descend to synapse at sympathetic ganglia

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6
Q

Axons do not pass directly to the effector organs; they form

A

disynaptic pathway

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7
Q

What is the exception to axons not passing directly to effector organs?

A

sympathetic supply to the adrenal medulla

functional benefit = momentarily faster to initiate fight or flight pathway by monosynaptic pathway to trigger chromaffin cells to release adr and noradr

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8
Q

General Autonomic Activity: Sympathetic:

A

insert diagram

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9
Q

Within autonomic sympathetic ganglia what is the main preganglionic neurotransmitter and its receptor?

A

ach
nicotinic receptors
ionotropic ligand -> results in depolarisation

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10
Q

Within autonomic sympathetic ganglia, what is the main postganglionic neurotransmitter and its receptor?

A

noradrenaline
adrenergic receptors
metabotropic GPCR (slow)

alpha 1 = blood vessels, antagonist for
hypertension

beta 1 = blood vessels/heart, antagonist for
hypertension

beta 2 = lungs/bronchi, agonist for asthma

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11
Q

Exception to autonomic postganglionic sympathetic neurons releasing noradrenaline?

A

Sweat glands use ach

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12
Q

The adrenal medulla is monosynaptic.

What is the main neurotransmitter used here?
Receptor?
Effect? -

A
  • ach
  • nicotinic receptors on chromaffin cells within
    the adrenal medulla
  • causes release of adr/Nadr into circulation
  • direct activation of sympathetic effector organs
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13
Q

What is the main neurotransmitter in autonomic preganglionic parasympathetic neurons?

A
  • ach
  • metabotropic GPCR (slow)
  • muscarinic receptors
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14
Q

Sympathetic Trunk/Chain:

A

insert diagrams

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15
Q

Sympathetic Trunk/Chain:

A

interconnected paravertebral gangli close to vertebral bodies, extending from cervical to sacral lvels

preganglionic fibers enter sympathetic trunk through white rami communicantes

from T1-L2 spinal nerves only

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16
Q

Sympathetic Trunk: Preganglionic Fibers:

A

on entering the trunk, preganglionic fibers will either:

- synapse in ganglion (on same level or 
  travel to another level)
- pass through ganglion forming splanchnic 
  nerves to synapse in prevertebral ganglia 
  to innervate internal organs
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17
Q

Sympathetic Trunk: Post-ganglionic fibers:

A

Either:
- travel to periphery via grey rami
communicans back into spinal nerves
- travel to viscera via medial
branches/plexus; from prevertebral
ganglia, postganglionic fibers forming
plexus around viscera

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18
Q

Journey of Spinal Nerve into and out of sympathetic trunk:

A
  • sympathetic axon sitting in lateral horn of
    spinal cord
  • exits spinal cord via the ventral horn
  • becomes ventral ganglionic root
  • leaves the ventral root / r and merges with the
    dorsal root to become the spinal nerve
  • sympathetic axon of spinal nerve can leave
    spinal nerve via the White Rami
    communicantes
  • now in sympathetic trunk
  • can now either synapse with post ganglionic
    neuron at same level or ascend and synapse
    with post ganglionic neuron at higher level,
    or descend and synapse with post ganglionic
    neuron at lower level
  • if synapsed at same level now post-
    ganglionic and is unmyelinated grey matter
  • leaves via grey rami communicantes back
    into spinal nerve
  • will either go to dorsal or ventral primary
    ramos, split off again and eventually get to
    target organs

ORRRR instead of synapsing in sympathetic trunk, will pass through becoming a splanchnic nerve and synapse in the pre-vertebral ganglia located close to target organs

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19
Q

Cervical Sympathetic Ganglia supply the (3):

A
  • heart
  • upper limbs
  • heart
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20
Q

Name the Cervical Sympathetic Ganglia:

A
  • superior (largest)
  • middle (smallest)
  • inferior (intermediate size)
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21
Q

Cervical Sympathetic Post-Ganglionic Fibers:

A
  • exit via the grey rami communicantes to
    spinal nerves
  • piggyback along the common carotid artery
    and existing vasculature to the heart
  • which then form an internal carotid plexus
  • and an external carotid plexus
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22
Q

The Cervical Post-ganglionic fibers in the internal carotid plexus results in

A
  • eye: dilation of pupil, raising of eye lid
  • lacrimal gland: inhibits secretions

want to see more and cry less during fight and flight

23
Q

The Cervical Post-ganglionic fibers in the external carotid plexus results in

A
  • inhibition of submandibular and parotid
    gland secretions

conserve unnecessary energy

24
Q

Cervical Sympathetic Ganglia:

A

insert diagram

25
Label carotid plexi:
insert diagram
26
Thoracic Sympathetic Ganglia supply the
thorax, heart, lungs and abdominal viscera
27
Thoracic Sympathetic Ganglia: Post Gangliionic Fibers:
- exit via the grey rami communicantes to spinal nerves - medially branches toward heart and lungs - form two sympathetic plexi - cardiac plexus - pulmonary plexus
28
Lumbar Sympathetic Ganglia supply
the abdominal viscera and lower limbs
29
Lumbar Sympathetic Post Ganglionic Fibers:
- exit via the grey rami communicantes to spinal nerves
30
Lumbar Sympathetic Pre-ganglionic fibers exit via
- lumbar splanchnic nerves to the abdomen - synapse in prevertebral ganglia - innervate the abdominal viscera including the large intestine
31
Sacral Sympathetic Ganglia supply
the pelvis and lower limb
32
Sacral Sympathetic Post Ganglionic Fibers exit via
- grey rami communicantes to spinal nerves supplying lower limbs - sacral splanchnic nerves to pelvic organs - inferior hypogastric pelvic organs
33
Parasympathetic pregagnlionic neurons are found
- within the brainstem - within S2-S4 spinal nerves
34
Parasympathetic ganglia are all located
close to target organs
35
Parasympathetic Ganglia:
insert diagrams
36
Parasympathetic ganglia lenght:
preganglionic fibers are longer
37
Within which cranial nerves do parasympathetic nerves arise?
- CN III = occulomotor nerve = edinger- westphal nucleus - CN VII = facial nerve = superior salivatory nucleus - CN IX = glossopharyngeal nerve = inferior salivatory nucleus - CN X = vagus nerve = nucleus ambiguous, dorsal motor nucleus
38
Cranial Parasympathetic:
insert diagram
39
How do cranial parasympathetic preganglionic axons reach ganglia?
by passing through cranial nerves
40
Where does the preganglionic occulomotor branches synapse?
ciliary ganglion
41
Parasympathetic innervation of the occulomotor nerve (post-ganglionic branch) results in
pupil contriction = sphincter pupillae
42
Where do the preganglionic branches of the facial nerve synapse?
the pterygopalatine ganglion which are involved in lacrimation the submandibular gland = saliva
43
Parasympathetic innervation of the facial nerve (post-ganglionic branch) results in
stimulation of the lacrimal gland stimulation of submandibular gland in watery saliva
44
Where does the preganglionic branches of the glossopharyngeal nerve synapse?
otic ganglion
45
Parasympathetic innervation of post-ganglionic branches of the glossopharyngeal nerve results in
stimulation of the parotid gland (watery saliva)
46
Vagus nerve post-ganglionic synapses
multiple lungs, heart, abdominal organs
47
Sacral Parasympathetic:
- S2,3,4 - from sacral spinal cord - preganglionic fibers exit via pelvic splanchnic nerves to pelvic organs - synapse near target organs - pelvic plexus - inferior hypogastric plexus
48
Sacral Parasympathetic:
insert diagram
49
Sacral Parasympathetic Innervation results in:
- urination: contraction of bladder wall, inhibition/relaxation of bladder sphincter - defecation: relaxation/inhibition of rectal sphincter - sexual function: vasodilation in erectile tissues
50
The Enteric Nervous System: Two Plexi:
- myenteric plexus = muscle layer = motility/contraction - submucosal = glandular secretions/blood flow
51
The enteric nervous system is truly autonomous hence can function after all central connections are severed. What is this called?
intrinsic control mechanism
52
Enteric Nervous System:
insert diagram
53
white and grey rami communicantes are
connections between the spinal nerve and sympathetic trunk