Autonomic Nervous System

Question 1

Describe the differences in the sympathetic and parasympathetic nerve fibres

Answer 1

1. where they exit the CNS
2. length of pre & post ganglionic fibres
3. the neurotransmitters and receptors involved

Question 2

Where do most sympathetic nerve fibres originate?

Answer 2

lateral horn of the thoracic and lumbar regions of the spinal cord

Question 3

Where do most parasympathetic nerve fibres originate?

Answer 3

cranial and sacral areas of the CNS

Question 4

Describe the difference in length between the sympathetic and parasympathetic nerve fibres

Answer 4

sympathetic has short pre ganglionic and long post ganglionic fibres

parasympathetic has long pre ganglionic and short post ganglionic fibres

Question 5

How do the neurotransmitters differ between the sympathetic and parasympathetic system?

Answer 5

both pre-ganglionic fibres release acetylcholine

parasympathetic post-ganglionic fibres release acetylcholine
sympathetic post-ganglionic fibres release epinephrine or norepinephrine

Question 6

How do the receptors differ between the sympathetic and parasympathetic system?

Answer 6

parasympathetic system:
pre-ganglionic fibres use nicotinic receptors (cholinergic)
post-gangionic fibres use muscarinic receptors (cholinergic)

sympathetic system:
pre-ganglionic fibres use nicotinic receptors (cholinergic)
post-ganglionic fibres use a1, a2, b1, b2 receptors (adrenergic)

Question 7

Name the two cholinergic receptors

Answer 7

nicotinic and muscarinic

Question 8

Name the adrenergic receptors and describe where they can be found as well as their effect

Answer 8

alpha 1: excitation/constriction of arterioles to most sympathetic target tissues
alpha 2: inhibition/relaxation of digestive organs
beta 1: excitation/increase rate of heart
beta 2: inhibition/relaxation of smooth muscles of arterioles and bronchioles