ENS

Question 1

Afferent neurotransmission

Answer 1

Intrinsic primary afferents*
Extrinsic primary afferents*
Serotonin
Calcitonin gene related peptide
Substance P

Question 2

Common problems associated with issues with ENS

Answer 2

Inflammation
Ileus
Hypermotility
Hypersensitivity
Allodynia

Question 3

Longitudinal muscle

Answer 3

Thin muscle coat
Contraction shortens length, expands radius
Innervated/activated by excitatory MN
Few gap junctions
Ca++ release important

Question 4

Circular muscle

Answer 4

Thick muscle
Contraction increases length, decreases radius
Innervated by both inhibitory and excitatory MN
Activated by ICC and excitatory MN
Many gap junctions
Ca++ release important

Question 5

Migrating Motility Complex (MCC)

Answer 5

Phase 1: quiescence
Phase 2: longest phase
Phase 3: shorter, with more aggressive activity

*can be interrupted by food intake in some species (not ruminants)

Question 6

Alteration of motility

Answer 6

1. Physiologic (pain, distention, stress)
2. Pharmacologic
3. Pathologic (obstruction, inflammation, neurologic)

Question 7

Sensory receptors

Answer 7

1. Mechanoreceptors: size/distortion
2. Chemoreceptors: acid, AA, lipid, osmotic, etc.
3. Thermoreceptors