Final Exam GI Physiology: Motility of Ruminant GI Tract

Question 1

What is RGR?

Answer 1

Reticular Groove Reflex- the formation of a groove from the esophagus to the abomasum

Question 2

Since RGR is a reflex, what is the stimuli?

Answer 2

Sight and smell
Suckling
Na+ and Cu+ salts
Vagal stimulation
ADH secretion

Question 3

How long does it take to complete the ruminoreticular cycle?

Answer 3

5-12 seconds

Question 4

What are the 5 steps in the ruminoreticular cycle?

Answer 4

1. Primary reticular depolarization and contraction
2. Partial reticular relaxation
3. Secondary reticular depolarization and contraction
4. Primary RUMINAL depolarization and contraction
5. Secondary RUMINAL depolarization and contraction

Question 5

Ingesta are separated by density because of the ruminoreticular cycle. What is the most dorsal ingesta? What is kept afloat?

Answer 5

Gas is most dorsal

Solid forage is kept afloat

Question 6

What are the 4 distinct phases of Rumination?

Answer 6

1. Regurgitation
2. Remastication
3. Reinsalivation
4. Reswallowing

Question 7

Reinsalivation is achieved through secretions by what gland?

Answer 7

The Parotid Gland

Question 8

The Parotid Gland produces _________ HCO3- and _______ PO4-2 during reinsalivation.

Answer 8

INCREASED HCO3-

DECREASED (PO4)2-

Question 9

Eructation is a vagovagal reflex. What does it accomplish?

Answer 9

Pushes gas from rumen into esophagus and promotes reverse peristalsis

Question 10

Extrinsic control of ruminant GI tract motility is controlled by the _______.

Answer 10

Vagus nerve

Question 11

Intrinsic control of ruminant GI tract motility is at the level of the ________ ________.

Answer 11

Myenteric plexus