Lecture 32: ANS (Sympathetic Division)

Question 1

Describe the main differences that exist
between the somatic and autonomic nervous
systems.

Answer 1

• effectors:
  1. cardiac muscle, smooth muscle, glands 2. skeletal muscle
• control:
  1. involuntary 2. voluntary
• output:
  1. 2 efferent neurons exit CNS
  2. 1 efferent neuron exits CNS
• 1: ANS and 2: SNS

Question 2

Differentiate between the parasympathetic and
sympathetic nervous systems in terms of
anatomy and function.

Answer 2

• Parasympathetic
  1. Anatomy: nicotinic receptors –> muscarinic receptors, ciliary/pterygopalatine/submandibular/otic ganglion
  2. Function: “rest and digest”
• Sympathetic
  1. Anatomy: nicotinic receptors –> adrenergic receptors (sweat glands are muscarinic!, adrenal medulla is chromaffin cells!)
  2. Function: “fight or flight”

Question 3

Describe the neurotransmitters used and the

effects of the sympathetic nervous system.

Answer 3

• acetylcholine (ACh): released by preganglionic neurons and binds to postganglionic cell body to cause a release ACh or NE
• norepinephrine (NE): acts as neurotransmitter (release from nerve ending) or hormone depending (release from adrenal gland) to cause increase in metabolism and constriction of smooth muscle in arterioles and bladder