Autonomic Nervous System

Question 1

What are the sensory components of the autonomic nervous system?

Answer 1

Receptors –> Baroreceptors

Viscera - not consciously perceived

Question 2

What are the properties of the motor components of the ANS?

Answer 2

Effectors innervated —> viscera, smooth muscle/cardiac muscle

Somatic NS innervates Skeletal muscle

Question 3

What is the anatomical difference between the ANS and CNS?

Answer 3

ANS is made up of a pre and post ganglionic neurone.

SNS has 1 neurone from CNS to skeletal muscle

Question 4

What are the divisions of the ANS?

Answer 4

Sympathetic nervous system

Parasympathetic nervous system

Question 5

How many neurones innervate viscera in the efferent pathway?

Answer 5

2 neurones
1 sympathetic
1 parasympathetic

Question 6

Where are the preganglionic neurone cell bodies found?

Answer 6

in the CNS

Question 7

Where are the postganglionic neurone cell bodies found?

Answer 7

In a ganglion

Question 8

What neurotransmitter is released at the synapse between the pre and post ganglionic neurone?

Answer 8

ACh

Question 9

What neurotransmitter is released via the sympathetic post ganglionic neurone? what is the exception to this?

Answer 9

Noradrenaline

Exception is sweat glands which are stimulated by their post ganglionic sympathetic neurone releasing ACh.

Question 10

What neurotransmitter is released via the parasympathetic post ganglionic neurone?

Answer 10

ACh

Question 11

What is the different in relationships between the SNS and the ANS?

Answer 11

SNS - One neurone to one muscle fibre (discrete relationship)

ANS - One postganglionic neurone cell branches to innervate many different effector cells (diffuse relationship)

Question 12

What is the adrenal medulla?

Answer 12

Neuroendocrine organ - releasing adrenaline and noradrenaline in circulation.

Acts as a post ganglionic sympathetic neurones after being innervated by pre ganglionic sympathetic neurones releasing ACh.

Question 13

What is the functional implication of the diffuse relationship in the ANS?

Answer 13

allow for single activation via ganglion branching by the varicosity to allow widespread control of the effector

Question 14

What is the importance of adrenaline/noradrenaline release by neuroendocrine cells?

Answer 14

Allows for some receptors located away from nerve endings (such as in blood vessels/bronchioles) to be activated by adrenaline/NA circulating in the blood.

Question 15

What are the functions of the ANS?

Answer 15

Homeostasis

Vision

Reproduction

Question 16

What are the functions of the Sympathetic NS?

Answer 16

Used for alert and active function

Also defence response - fright/fight/flight

Question 17

What are the functions of the Parasympathetic NS?

Answer 17

Used for rest and digest

Energy conservations, digestion, emptying

Question 18

How does the ANS work for most organs?

Answer 18

Duel innervations - both sympathetic and parasympathetic (antagonistic responses)

Question 19

What examples are there for antagonistic responses of the ANS?

Answer 19

Heart - Increase HR (symp) Decrease HR (p.symp)

GIT - Decrease motility (symp) Increase motility (p.symp)

Pupil - Dilation (symp) Constriction (p.symp)

Question 20

What effectors of the ANS are not stimulated in an antagonistic way?

Answer 20

Endocrine glands (eg. sweat)
Still duel innervation but not antagonistic

Question 21

What effectors of the ANS receive single innervation?

Answer 21

Sweat glands - Sympathetic only

Most blood vessels - Smooth muscle is sympathetic only

Question 22

How does vasomotor tone work?

Answer 22

In most blood vessels

Increase Sympathetic activity - Vasoconstriction

Decrease Sympathetic activity - Vasodilation

Question 23

Which blood vessels receive duel innervation?

Answer 23

Blood vessels of the head and reproductive organs

Sympathetic - Vasoconstriction

Parasympathetic - Vasodilation

Question 24

How is blood vessel diameter regulated?

Answer 24

All vessels:
Increase sympathetic activity releases NA at postganglionic neurones to innervate alpha receptors and cause vasoconstriction

Specific vessels:
Increase sympathetic activity stimulates adrenal medulla to release NA into circulation which will activate non-innervated beta receptors and cause vasodilation

Balancing act between them both will determine blood vessel diameter.

Question 25

Give an example of where the sympathetic and parasympathetic nervous systems are working together

Answer 25

Male sex organs

parasympathetic - erection
Sympathetic - Ejaculation

Question 26

Give and example where the somatic and autonomic NS can integrate together

Answer 26

Focusing on near by objects:
SNS - eye movements
ANS - Pupil lens adjustments

Response to the cold:
SNS - shivering
ANS - vasoconstriction in the skin.