Autonomic nervous system

Question 1

What is the efferent system?

Answer 1

Peripheral nerves that carry impulses from the CNS , which can be divided into somatic and autonomic nerves

Question 2

Autonomic nerve divisions

Answer 2

parasympathetic and sympathetic

Question 3

Autonomic nerve functions

Answer 3

involuntary control of body functions

Question 4

Sympathetic nervous system primary function

Answer 4

Stimulate body’s fight or flight or freeze response.

Question 5

Structure of neurons and origins

Answer 5

SHORTER Pre-ganglionic- thoracolumbar division of the spinal cord, mainly T1 to L2/L3. militated
post-ganglionic - LONGER extends throughout the body. Unmyelinated

Question 6

Structure of sympathetic ganglia

Answer 6

paravertebral chain ganglia that interconnect the neurones. Sympathetic ganglion cells typically in discrete ganglia with long post ganglionic fibres

Question 7

What is the preganglionic neurotransmitter in sympathetic nerves?

Answer 7

acetylcholine- nicotinic

Question 8

Sympathetic post ganglionic neurotransmitter

Answer 8

adrenaline

Question 9

What is the sympathetic outflow?

Answer 9

From thoracic and lumbar nerve divisions to all viscera and cardiac and smooth muscle and glands

Question 10

Viscera definition

Answer 10

all internal organs in the main cavities of the body

Question 11

Sympathetic nervous system association with adrenaline?

Answer 11

Preganglionic fibres synapse with the adrenal medulla, releasing acetylcholine which activates it to release adrenaline.

Question 12

Other roles of the sympathetic nervous system

Answer 12

vasoconstriction of blood vessels towards digestive tract, skin and kidneys- due to the activation of alpha-1 adrenergic receptors by norepinephrine released by post ganglionic neurones.

Question 13

Parasympathetic nervous system primary function

Answer 13

stimulate the body’s ‘rest and digest’ or ‘feed and breed’ activities

Question 14

Structure of parasympathetic neurons and origins

Answer 14

origin- 4 cranial nerves and
pelvic splanchnic nerve- S2-4

preganglionic neuron- long

postganglionic neuron short

Question 15

Why are the neurones these lengths?

Answer 15

The preganglionic neurons don’t synapse in the paravertebral ganglionic chain, instead synapse in intramural ganglia within the organs they innervate.

Thus the pre is very long and post is short.

Question 16

Structure of ganglia

Answer 16

synapse in intramural ganglia within the organs they innervate.

Four paired parasympathetic ganglia of the head and neck, including the otic and ciliary ganglia.

Question 17

Two neurotransmitters in parasympathetic nerves

Answer 17

Pre ganglionic nerve fibre- ACh nicotinic

Post ganglionic nerve fibre- ACh muscarinic

Question 18

4 different cranial nerves and function

Answer 18

Oculomotor nerve III- innervates the eye, controlling 4/6th of the ciliary
Facial nerve VII - innervates the ganglia supplying the tear and salivary glands- pterogopalatine ganglion
Glossopharyngeal nerve IX- supplies otic ganglion regulating the parotid salivary gland
vagus nerve X- supplies heart and lungs and alimentary system

Question 19

Vagus nerve ganglion location

Answer 19

C1

Question 20

pelvic splanchnic nerve function

Answer 20

Innervate pelvic viscera and urogenital tract

Question 21

Different sympathetic ganglia and the nerves that synapse

Answer 21

paravertebral midline ganglia- the heart, lungs

coeliac ganglia- great and small splanchnic - foregut

superior mesenteric ganglia- large intestine, adrenal gland, pancreas, liver and ducts - midgut

inferior mesenteric ganglia- kidney, bladder and sexual organs- pelvic organs

Question 22

What is Horner’s syndrome?

Answer 22

Caused by a lesion in the superior cervical ganglion which causes loss of sympathetic action, thus cause permanent constriction of pupil, drooping eyelid and a dry and flushed face.

Question 23

How can hyperhidrosis be managed?

Answer 23

Cut appropriate level of sympathetic nerve roots or use botulinum toxin.

Question 24

What is the adrenal medulla?

Answer 24

Part of the adrenal gland, located at the centre surrounded by the adrenal cortex. Consists of cells that’s secrete epinephrine and norepinephrine, in response to stimulation by sympathetic preganglionic neurons

Question 25

What are the adrenal medullary cells modified from?

Answer 25

Modified sympathetic postganglionic cells that have lose their axons and dendrites.

Question 26

Adrenal medullary cells location and function

Answer 26

Cells form clusters around capillaries where they release norepinephrine and epinephrine into the blood

Question 27

What is the enteric nervous system?

Answer 27

One of the main divisions of the autonomic nervous system, neither sympathetic nor parasympathetic. Mesh like system of neurons the govern the function of the gastrointestinal tract.

Question 28

Is the ENS independent, if not what innervates it?

Answer 28

Capable of operating independently of the brain and spinal cord however does rely on innervation from the autonomic nervous system via the vagus nerve and prevertebral ganglia.

Question 29

What are prevertebral ganglia?

Answer 29

Sympathetic ganglia that lie between the paravertebral ganglia and the target organ

Question 30

Types of neurons in the ENS

Answer 30

Sympathetic- parasympathetic- secretomotor-

Question 31

Secretomotor definition

Answer 31

Refers to the capacity of a nerve to induce a gland to secrete a substance

Question 32

2 plexi in the ENS + locations

Answer 32

Myenteric (Auerbach’s)- between inner and outer layers of muscular external

submucosal (Meissner’s) - in submucosa

Question 33

Different functions of the ENS

Answer 33

Peristalsis and the churning of the intestinal contents, secretion of enzymes, forming neurotransmitters, segmentation