DHUBS 2 - WEEK 10 - EXAM

Question 1

What are the structures that the autonomic motor efferents act on?

Answer 1

Smooth and cardiac muscle.
- Gut muscles
- Arterial muscles
- Pupil muscles
- Heart muscles

Question 2

What are differences are there between the motor efferent of the somatic and
autonomic nervous system?

Answer 2

Somatic system is under voluntary control.
Autonomic is involuntary.

Somatic acts on skeletal muscle.
Autonomic acts on smooth and cardiac muscle.

Question 3

Which neurotransmitters are used in the sympathetic and parasympathetic nervous system? Which ones are used in the pre and post ganglionic fibers of the SNS?

Answer 3

Parasympathetic nervous system used acetylcholine.

Sympathetic nervous systems pre ganglionic fibres use acetylcholine and post ganglionic fibres use adrenaline.

Question 4

What are the two main plexus of the enteric nervous system and what are their functions?

Answer 4

Myenteric Plexus (Auerbach’s Plexus):
Located between the longitudinal and circular muscle layers, primarily controlling motility.

Submucosal Plexus (Meissner’s Plexus):
Located in the submucosa, regulating blood flow, secretions, and absorption.

Question 5

What are the actions of the parasympathetic nervous system?

Answer 5

Rest and repair” system (or “rest and digest”)
- Decrease heart rate

• Dilate the visceral blood vessels to increase blood perfusion to allow absorption of nutrients
• Inhibit SNS to dilate peripheral blood vessels (note peripheral blood vessels only have SNS innervation) – reduces blood pressure
• Constrict the pupils
• Increase digestion and repair functions
• Increase bladder contraction
• Increase immune system function
• Facilitates neuroplasticity (synaptic connections)

Question 6

What are the actions of the sympathetic nervous system?

Answer 6

Fight, flight or reproduce system

• Increase heart rate.
• Constrict the blood vessels to increase blood pressure and improve (short-term) tissue perfusion.
• Dilate the pupils to allow more light to the retina.
• Relax airway muscles to increase O2 intake
  Slow digestion and repair functions.
• Release sugar into the blood stream to allow for energy production.
• Cause sweating and piloerection.
• Reduces bladder contraction.
• Depresses immune system function.

Question 7

What sections of the spine do the SNS and PNS arise from?

Answer 7

SNS arise from the T1 - L2/3 levels of the spines

PNS arise from the S2 - 4 sacral segments.