L37: Autonomics of the Abdomen

Question 1

Lymphatic Drainage + Innervation of the FOREGUT?

Answer 1

CELIAC TRUNK - Sympathetic: Celiac ganglion - Parasympathetic: Vagus (X) .. cranial nerve 10

Question 2

Lymphatic Drainage + Innervation of the MIDGUT?

Answer 2

CRANIAL MESENTERIC ARTERY - Symp: Cranial Mesenterig g. - Para: Vagus (X)

Question 3

Lymphatic Drainage + Innervation of the HINDGUT?

Answer 3

CAUDAL MESENTERIC ARTERY - Symp: Caudal Mesenteric g. - Para: Pelvic Splanchnic nn.

Question 4

Autonomic Nervous System has 2 neuron divisons called:

Answer 4

• Sympathetic outflow- long postganglionic axon
• Parasympathetic outflow- very short postganglionic axon (often present in wall of organ being innervated)

Question 5

What is the KEY DIFFERENCE* between the 2 neuron system?

Answer 5

NO PARASYMPATHETIC INNERVATION TO THE BODY WALL

Question 6

Sympathetic vs Parasympathetic effects in the abdomen?

Answer 6

Sympathetic: Decreased activity of GI tract = slow(er) inhibition of digestion and slows rate of absorp

Parasympathetic: Increased activity of GI tract = increase motility and secretion, and absorption

Question 7

What does the enteric nervous system regulate?

Answer 7

GI tract as a separate component of the ANS, acting as a local reflex response

Question 8

The digestive tract has as many neurons as the _______

Answer 8

Spinal cord

Question 9

Sympathetic and parasympathetic nerve fibers modulate the ____

Answer 9

ENS

Question 10

_____ and ____ plexi regulate bowel musculature and are located btwn ____ and ____ smooth muscle layers of the GI tract

Answer 10

Myenteric and submucosal plexi;

Located btwn inner circular and outer logitudinal

Question 11

Enteric nervous system: Waves of contraction and relaxation in the bowel are due to? (2)

Answer 11

• Mechanoreceptors monitoring stretch
• Enteric nervous system responding in a reflexive manner

Question 12

ENS is INHIBITED by _____ and EXCITED by ___?

Answer 12

Inhibited by sympathetic nerve fibers

Excited by parasympathetic nerve fibers

Question 13

Parasympathetic nerve fibers are innervated by (2)?

Answer 13

Vagus nerve (CN X) and splanchic nerves (anatomically responsible for delivering axons to abdomen) from sacral spinal cord

Question 14

What is distension during peristalsis of colon?

Answer 14

Sensory neuron synpases on excitatory motorneurons proximal to the bolus and contracts muscle fibers

Question 15

What is relaxation during peristalsis of colon?

Answer 15

Sensory neuron synpases on inhibitory interneurons distal to the bolus and allows muscle fibers to relax

Question 16

What structures do the Foregut, midgut, and hindgut nerves innervate?***

Answer 16

Foregut –> stomach, duodenum, pancreas, liver, spleen, gallbladder

Midgut–> duodenum, jejunum, ileum, cecum, part of colon

Hindgut –> part of colon, rectum, anal canal

Question 17

Splanchnic Nerves Deliver Preganglioncs:

• Foregut Sympathetic Eg, Midgut Sympathetic Eg. Fore-midgut parasympathetic Eg.

Answer 17

Question 18

Abdominopelvic Autonomic Plexus in Carnivorans: what do they do?

Greater Splanchnic nn, Celiac ganglia, Lumbar splanchnic nn, Cranial mesenteric ganglion, Cadual mesenteric ganglion

Answer 18

Question 19

Carnial mesenteric ganglia/plexus innervates what organ?

Answer 19

Liver- hepatic artery

Question 20

Lesions of vagal supple in bovines; vagus regulated functions (6)?

Answer 20

1. Ruminoreticular contraction
2. Omasal cycle
3. Eructation
4. Rumination
5. Reflex closure of reticular groove
6. Abomasal motility and secretion

Question 21

What is vagotomy?

Answer 21

Stops ruminoreticular activity, recovers eventually (1 vagus artery)

Question 22

What is fatal omasal paralysis*?

Answer 22

Lesions to both vagal trunks, ruminoreticulum distends and backs up

Question 23

Potential causes of fatal omasal paralysis or vagotomy?

Answer 23

Lesions, foreign bodies, volvulus (nails)