Autonomic Nervous System 1

Question 1

What is the other name for autonomic NS

Answer 1

The Visceral motor nervous system

Question 2

What are the subsections of the autonomic NS

Answer 2

Parasympathetic NS and the Sympathetic NS

Question 3

What do the somatic and visceral/autonomic NS supply?

Answer 3

Somatic - skeletal muscle

Autonomic - Smooth muscle, glands, cardiac muscle, adipocytes

Question 4

In the autonomic NS what does the two neuron system consist of?

Answer 4

Pre-ganglionic fibres that originate from the CNS and Post-ganglionic fibres that originate from autonomic ganglia

Question 5

Of the sympathetic NS where do the pre/post ganglionic fibres originate from?

Answer 5

Pre-ganglionic - Thoracolumbar (short pre-ganglionic)

Post-ganglionic - Paravertebral chain or prevertebral ganglia (long post-ganglionic)

Question 6

Of the parasympathetic NS where do the pre/post ganglionic fibres originate from?

Answer 6

Pre-ganglionic - craniosacral (long pre-ganglionic fibres)

Post-ganglionic - In or near the target organ (short post-ganglionic)

Question 7

What are the target organs of the parasympathetic nervous system?

Answer 7

• Eyes
• Lacrimal Gland
• Salivary glands
• Hear, lungs and upper GI (supplies by vagus n)
• Lower GI, bladder and genitalia.

Question 8

What are the target organs of the Sympathetic NS?

Answer 8

• Structures in head and neck such as blood vessels, salivary glands etc
• Heart and lungs
• Adrenal medulla
• Liver, GI, bladder and genitalia
• Blood vessels and sweat glands

Question 9

When pre-ganglionic sympathetic neurons enter the paravertebral ganglion/chain, what are the four options it can do?

Answer 9

1. Enter the paravertebral chain and ascend in the chain to synapse at a ganglion higher up
2. Pre-ganglionic fibres enter the chain and synapses in a ganglion at the same level then passes out with the spinal cord at that level
3. Enters paravertebral chain and descends to synapse at a ganglion at a lower level
4. Pre-ganglionic fibre doesn’t synapse in paravertebral chain but heads out as a splanchnic nerve and synapses in a prevertebral ganglion and then supplies contents of abdomen.

Question 10

Try draw the autonomic motor reflex

Answer 10

Add image after writing notes

Question 11

Explain why you can get referred pain

Answer 11

Visceral sensory neurons synapse at the same spinal segment that gives rise to sensory information for other areas. So damage to the heart can cause pain in the shoulder.

Question 12

What are the PSNS and SNS effects on the heart

Answer 12

PSNS - Decreases heart rate

SNS - Increases heart rate and force of contraction

Question 13

What are the PSNS and SNS effects on the digestive tract

Answer 13

PSNS - Increases motility and secretion

SNS - Decreases motility and secretion

Question 14

What are the PSNS and SNS effects on the lungs

Answer 14

PSNS - Bronchoconstriction

SNS - Bronchodilation

Question 15

What are the PSNS and SNS effects on the urinary bladder

Answer 15

PSNS - Release of urine (contraction of detrusor muscles and relaxation of internal sphincter muscle)
SNS - urine retention (relaxation of detrusor muscles and contraction of internal sphincter)

Question 16

What are the PSNS and SNS effects on the pupil of the eye

Answer 16

PSNS - constriction

SNS - dilation

Question 17

What are the PSNS and SNS effects on the male sexual organ

Answer 17

PSNS - Erection

SNS - Ejaculation

Question 18

What are the PSNS and SNS effects on the blood vessels

Answer 18

PSNS - No effect except for the blood vessels needed to generate an erection
SNS - constriction

Question 19

What are the PSNS and SNS effects on the salivary glands

Answer 19

Both - increased secretion

Question 20

What are the PSNS and SNS effects on the sweat glands

Answer 20

PSNS - no effect

SNS - increased secretion

Question 21

What are the PSNS and SNS effects on the liver

Answer 21

PSNS - no effect

SNS - Glycogenolysis and Gluconeogensis

Question 22

What are the PSNS and SNS effects on the pilomotor

Answer 22

PSNS - no effect

SNS - Piloerection

Question 23

Describe an autonomic nervous system effect where both PSNS and SNS are causing innervation at the same target

Answer 23

The eye;
Sympatheric NS innervates the pupillary dilator muscles causing mydriasis
Parasympathetic NS innervates pupillary constrictor muscles causing Miosis

Question 24

What are some rules of the PSNS and SNS

Answer 24

They may oppose or compliment, they rarely have the same effect and some tissues are only innervated by one. Generalise PSNS as rest and digest while SNS is fight or flight

Question 25

where do pre-ganglionic sympathetic fibres synapse on the adrenal gland? and what does this release?

Answer 25

They synapse on chromaffin cells which release adrenaline and noradrenaline

Question 26

All pre-ganglionic neurons of the PSNS and SNS release what?

Answer 26

Acetylcholine which binds to nicotinic receptors.

Question 27

All postganglionic PSNS neurons release what?

Answer 27

ACh that binds to muscarinic

Question 28

What do most postganglionic sympathetic neurons release? what do the others release?

Answer 28

Most release noradrenaline. Some release Ach (sweat glands)