Misc nerve systems: Enteric Nervous System, Swallowing Mechanism, Pudendal nerve

Question 1

Process during swallowing:

1. Relaxation of upper esophageal sphincter (UES)
2. Peristalsis in the esophagus
3. Relaxation of lower esophageal sphincter (LES)

Answer 1

1) Relaxation of upper esophageal sphincter (UES)

• when the tonic vagal drive is inhibited

Question 2

Process during swallowing:

1. Relaxation of upper esophageal sphincter (UES)
2. Peristalsis in the esophagus
3. Relaxation of lower esophageal sphincter (LES)

Answer 2

2) Peristalsis in the

• upper (skeletal muscle) portion of the esophagus
  
  • driven by the nucleus ambiguous of the Vagus nerve
• thoracic and abdominal portion
  
  • the esophagus is driven by the dorsal motor nucleus of the Vagus

Question 3

Process during swallowing:

1. Relaxation of upper esophageal sphincter (UES)
2. Peristalsis in the esophagus
3. Relaxation of lower esophageal sphincter (LES)

Answer 3

3) Relaxation of lower esophageal sphincter (LES)

• by nitrergic neurons in Aurbach’s plexus
  
  • driven by the dorsal motor nucleus of the Vagus nerve

Question 4

Enteric Nervous System:

Overview

Answer 4

Enteric Nervous System:

• The enteric nervous system within the walls of the gut form a highly complex and elaborate network, often referred to as the third division of the autonomic nervous system.
• It exerts a major influence over all activities in the gut.
• The enteric nervous system is estimated to possess as many neurons as are found in the entire spinal cord.
• The enteric system is divided into two layers: myenteric plexus (Auerbach’s) and submucosal (Meissner’s)

Question 5

Enteric Nervous System:

external layer

Answer 5

Enteric Nervous System:

• The external layer is the myenteric plexus (Auerbach’s)
  
  • controlling the muscularis externa

Question 6

Enteric Nervous System:

internal layer

Answer 6

Enteric Nervous System:

• The internal layer is the submucosal (Meissner’s)
  
  • controlling the glandular and immune components of the submucosal layers

Question 7

Pudendal Nerve:

S2-4 is the source of the perineal nerves

which provide motor innervation to the?

Answer 7

• Muscles:
  
  • Bulbocavernosus
  • Ischiocavernosus
  • Superficial and deep perineal
• Sphincters:
  
  • External urethral
  • Anal