Autonomic nervous system Flashcards Preview

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Flashcards in Autonomic nervous system Deck (44)
1

Map of ANS in body

Parasympathetic
- Brainstem
- S2-S4

Sympathetic
- T1-L2

2

Axons of ANS

Always synapse at ganglia [di-synaptic pathway]
- EXCEPT sympathetic supply to adrenal medulla

3

General parasympathetic neuronal pathway

Cranial nerve nuclei/ Grey matter spinal cord----[myelinated preganglionic axon]---->

Cranial/ spinal nerve----> Parasympathetic ganglion------[unmyelinated postganglionic axon]--->

Effector organ

4

General sympathetic neuronal pathway

Grey matter spinal cord---[myelinated preganglionic axon, spinal nerve]----->

Sympathetic ganglion{synapse}-----[unmyelinated postganglionic axon]----->

Effector organ.

5

Neurotransmission in ANS pathways
- Ganglia
- Postganglion, sympathetic neurones
- Adrenal medulla

In ganglia
- Ach is NT released
- Bind on nicotinic receptors on postganglionic neurones [fast]

Post-ganglionic sympathetic neurones:
- Noradrenaline released [XC in sweatglands, Ach used]
- Binds to adrenergic receptors [slow]

Adrenal medulla:
- Ach released
- Binds to nicotinic receptors on chromaffin cells
- Causes release of adrenaline/noradrenaline into the blood= activation of sympathetic effector organs

6

Alpha-1 adrenergic receptors

G-protein coupled receptor
- Responds to Noradrenaline

Found on blood vessel smooth muscle

7

Beta-1 adrenergic receptors

Found in the heart

G-protein coupled receptor
- Responds to Noradrenaline

8

Beta-2 adrenergic receptors

Found on bronchial smooth muscle cells.

G-protein coupled receptor
- Responds to Noradrenaline

9

Prazosin

Anti-hypertensive ----> Alpha-adrenergic antagonist

10

Atenolol

Anti-hypertensive----> Beta-adrenergic antagonist

11

Salbutamol

Short acting, beta-2 agonist
- Treatment for asthma

12

Neurotransmission
- Postganglionic parasympathetic neurones

Ach is released
- Binds to muscarinic receptors on effector organs [slow]

13

Atropine

Muscarinic antagonist

Treatment for:
- Bradycardia
- Dilate pupils
- Reduction of glandular secretions

14

White rami communicans

Section of preganglionic fibre that enters the sympathetic trunk
- T1-L2

15

Sympathetic trunk

Interconnected paravertebral ganglia from cervical to sacral levels.

16

Preganglionic fibres entering sympathetic trunk

Either:

1. Synapse in paravertebral ganglion

or
2. Pass through paravertebral ganglio n without synapsing ---> form splanchnic nerve and synapse at prevertebral ganglion

17

Route of post-ganglionic fibres from sympathetic trunk

To the periphery:
- Back into spinal nerves via grey rami communicans

To the viscera
- Via medial branches/ plexus

18

Route of post-ganglionic fibres from pre-vertebral ganglia

Postganglionic fibres from sympathetic trunk from plexus around viscera.

19

Cervical sympathetic trunk

3 ganglia
- Superior
- Middle
- Inferior

Satellite- Inferior + T1 ganglia

20

Sympathetic supply to the upper limbs

Post-ganglionic fibres of the cervical ganglia
- Exit via grey rami communicans
- Enters spinal nerves

21

Cervical Sympathetic supply to the heart

Post-ganglionic fibres of cervical sympathetic ganglion
- Travels down common carotid artery to the heart
- Contributes to cardiac plexus

22

Cervical Sympathetic supply to the head

Postganglionic fibres of the superior cervical ganglion
- Travels up the internal ----> Internal carotid plexus
- To eye
- To lacrimal gland



- Travels up external carotid artery----> External carotid plexus
- To submandibular and parotid glands

23

Pterygopalatine ganglion

Parasympathetic ganglion
- Branch of facial nerve [petrosal nerve] synapses here

- Postganglionic fibres contribute to internal carotid plexus [lacrimal gland and nose mucosa]

24

Horner's syndrome

Combination of symptoms caused by disruption to sympathetic supply to the head

Any pathway between the hypothalamus to preganglionic neurones is affected
- Descending autonomic pathways [e.g MS]

Symptoms:
- Pupil constriction [miosis]
- Drooping eyelid [ptosis]
- Skin [anhydrosis]

25

Thoracic splanchnic nerves

Preganglionic fibres from thoracic sympathetic nerves.

Three nerves:
Greater
Lesser
Least

Pierces the diaphragm and synapses in pre-vertebral ganglia:
- Celiac
- Superior mesenteric
- Aorticorenal

Post ganglion fibres from pre-vertebral plexus around viscera.

26

Celiac ganglion

Pre-vertebral ganglion where thoracic splanchnic nerve synapses

- Supplies stomach + duodenum.

27

Superior mesenteric ganglion

Pre-vertebral ganglion.
- Thoracic splanchnic nerves synapses here.

Supplies small intestines

28

Aorticorenal ganglion

Pre-vertebral ganglion
- Location of synapse for thoracic splanchnic nerves

Supplies kidney innervation.

29

Thoracic sympathetic trunk ganglia

12 in total.

Post-ganglionic fibres:
- Grey rami communicans ---> spinal nerves

- Medial branches ---> heart and lungs [cardiac and pulmonary plexus]

30

Lumbar sympathetic trunk
- How many
- Postganglionic exit
- Preganglionic exit

4 ganglia

Postganglionic exit:
- Grey communicans to spinal nerves

Preganglionic exit:
- Lumbar splanchnic nerves---> synapse in pre-vertebral ganglia in pelvis
- Inferior mesenteric ganglion

31

Inferior mesenteric ganglion

Pre-vertebral ganglion
- Lumbar splanchnic nerves [preganglionic fibres] synapse here

Supplies large intestine

32

Sacral sympathetic trunk ganglia
- How many?
- Post-ganglionic exit

4 ganglia in total

Post-ganglionic exit:
- Grey rami communicans to spinal nerves [supplying lower lim]

- Sacral splanchnic nerves to pelvis organs.

33

Parasympathetic preganglionic neurones

Located in:
- Brainstem [become cranial nerves]
- Grey matter spinal cord [S2-4]---> pelvic splanchnic

34

Location of preganglionic neuronal cell bodies

Cranial nerve nuclei

35

CN 3 nucleus

Edinger-Westphal nucleus

36

CN 7 nucleus

Superior-salivatory nucleus

37

CN 9 nucleus

Inferior salivatory nucleus

38

Vagus nerve nucleus

Nucleus ambiguous

Dorsal motor nucleus

39

Ciliary ganglion

Parasympathetic ganglion
- Oculomotor nerve synapses here
- Innervates sphincter pupillae [pupil constriction]

40

Submandibular ganglion

Parasympathetic ganglion
- CN VII synapses here
- Innervates submandibular gland
= watery saliva

41

Otic ganglion

Parasympathetic ganglion
- Glossopharyngeal nerve synapses here.
- Innervate parotid gland= watery saliva

42

Sacral parasympathetic innervation
- Preganglionic exit
- Innervation

Preganglionic fibres exits via pelvic splanchnic nerves

Innervates pelvic organs
- Forms pelvic plexus
- Preganglionic fibres synapse directly onto target organs

43

Sacral parasympathetic function
- Bladder
- Rectum
- Sexual function

Bladder= urination
- Contracts bladder wall
- Inhibits sphincter

Rectum= defecation
- Inhibits sphincter

Sexual function = vasodilation of erectile tissue

44

Enteric nervous system plexi

Auerbach/ Myenteric plexus = smooth muscle contraction regulation

Meissner's/ Submucosal plexus = regulation of glandular secretions