Autonomic Nervous System

Question 1

Autonomic ganglia

Answer 1

PNS:
Terminal ganglia
Located close to or within the wall of target tissue

SNS:
Two types ganglia: paravertebral (sympathetic trunk) and preverterbral
Paravertebral base skull to coccyx
Pre vertebral lie ant to vertebral column next to major arteries (coeliac, sup mesenteric and inf mesenteric ganglia)
White rami communicantes connect SNS pre ganglionic fibers to paravertebral fibers

Question 2

Post ganglionic fibers

Answer 2

PNS:
Short
Cell bodies within autonomic ganglia

SNS:
Post ganglionic long
Cell bodies within autonomic ganglia

Grey rami communicantes connect SNS ganglia to spinal nerves

Question 3

Neurotransmitters:

Pre/post ganglionic PNS/SNS

Answer 3

All PNS/SNS pre ganglionic cholinergic (release AcH)

PNS post ganglionic cholinergic

Only SNS cholinergic sweat glands

SNS adrenergic (Norad)

Adrenal medulla SNS post ganglionic fibres - adrenaline 80%, norad 20%

Question 4

Receptors

Answer 4

Receptors within all autonomic ganglia and on the adrenal medulla are nicotinic ACh (nAChR)

Effector organ innervated by PNS muscarinic ACh (mAChR)

Effector organ innervated by SNS adrenergic receptors (alpha or beta)

mAChR also on sweat glands

Question 5

Which organs are not under dual control

Answer 5

SNS:

Sweat glands
Arrector pili muscles
Adipose cells kidney
Most blood vessels

PNS:

Lacrimal glands

Question 6

Tell me about pre-ganglionic fibers

Answer 6

Myelinated type B:

PNS:

Cell bodies lie in nuclei of cranial nerves III, VII, IX and X
Lateral grey horns of 2nd- 4th sacral segment
Long- form craniosacral outflow tract

SNS:

Cell bodies in lateral grey horns of 1-12 thoracic and 1-3 lumbar segments
Short
Form thoraco-lumbar outflow tract