Functioning of the ANS

Question 1

State the NT released and the type of receptor found at each synapse in the ANS
What is the exception to this?

Answer 1

Sympathetic
- in ganglion = ACh, nicotinic receptor
- at tissue = NA, adrenergic receptor
Parasympathetic
- in ganglion = ACh, nicotinic receptor
- at tissue = ACh, muscarinic receptor 
Exception
- In sweat glands, ACh at target

Question 2

What does the SNS do?

Answer 2

• fight, flight, fright
• increase HR and BP
• decrease gut motility
• dilate pupils
• make long sighted

Question 3

What does the PNS do?

Answer 3

• rest and digest
• energy conservation
• digestion
• emptying
• penis ‘erection’
• pupils constrict
• make short sighted

Question 4

Sympathetic innervation in different blood vessels has different effects. Explain this.

Answer 4

Two types of adrengergic receptors, alpha and beta
Alpha cause vasocontriction, Beta cause vasodilation
In blood vessels of skeletal muscle and the heart, there are beta receptors, so SNS will cause vasodilation
In the head and reproductive system there are alpha receptors so SNS will cause vasoconstriction

Question 5

Explain salivary control in the head and neck

Answer 5

Both SNS and PNS cause saliva secretion
However:
SNS will cause vasoconstriction so decrease saliva production, small amount of saliva
PNS will cause vasodilation so increase saliva production, large amount of saliva

Question 6

Give 2 examples of interaction of the autonomic and somatic

Answer 6

Focusing the eyes on a near object
- ANS - pupils and lens
- Somatic  - eye movements
Response to cold
- ANS - vasoconstriction in skin
- Somatic  - shivering