Post Rumen Anatomy

Question 1

What are the main functions of the omasum?

Answer 1

1. Absorption of water (60%)
2. Absorption of VFAs
3. Controls digesta movement to abomasum (2 stage pump)

Question 2

What are laminae omasia and what is their purpose?

Answer 2

They are longitudinal muscular folds (leaves) in the omasum that are covered in hornlike papilli

Question 3

Structures of the abomasum

Answer 3

A. Cardiac region (secretes mucous)
B. Fundus (contains gastric glands)
C. Antrum
D. Pylorus (secretes mucous and some zymogens)
E. Pyloric sphincter (controls outflow)

Question 4

How is HCl secretion stimulated in the abomasum?

Answer 4

It is stimulated by VFA and contractions of the abomasum.

Question 5

Why does pH need to be decreased in the abomasum?

Answer 5

1. Denature proteins
2. Dissolves minerals b
3. Gastric digestion
4. Kill bacteria and pathogens

Question 6

What enzymes are secreted in the abomasum?

Answer 6

HCl - hydrolyzes proteins
Pepsinogen (becomes pepsin) - breakdown proteins
Lysozyme - lyse bacterial cell walls
Esterases/lipases - breakdown lipids

Question 7

How are the enzymes secreted in the abomasum?

Answer 7

Parietal cells in the gastric pits secrete enzymes which are activated by HCl

Question 8

How does the ruminant abomasum differ from the non-ruminant stomach and why?

Answer 8

Abomasum is thinner than a stomach.
Limited ability to digest starches and sugars (bc bacteria do it)

Question 9

What is a displaced abomasum? What causes it?

Answer 9

moves out of places, associated with calving
LDA- slips under the rumen to the left side
RDA - rides up to dislocate above the omasum

Question 10

Structures of the small intestine

Answer 10

Sigmoid loop
Duodenum
Jejunum (longest part)
Ileum
Ileocecal junction

Question 11

Structures of the large intestine

Answer 11

Ileocecal junction
Cecum (blind sac)
Spiral Colon
Descending Colon
Rectum

Question 12

Bile and pancreatic ducts enter what part of the small intestine?

Answer 12

It enters the duodenum after the sigmoid loop

Question 13

Is the pH higher in the duodenum or the ileum?

Answer 13

Ileum is more basic which his better for peptic activity

Question 14

What are villi?

Answer 14

Projections that increase surface area

Question 15

What are the functions of the small intestine?

Answer 15

1. Regulation of flow
2. Chemical and enzymatic digestion (pancreas, gallbladder, mucosal surface)
3. Absorption

Question 16

What are the functions of the large intestine?

Answer 16

1. Absorption (Mineral, VFAs, water, ammonia-N)
2. Fermentation (lower # of bacteria)

Question 17

Does the host secrete enzymes into the large intestine?

Answer 17

No enzymes or villi

Question 18

Under what conditions would fermentation in the cecum be important?

Answer 18

Increased rate of passage of forages and high grain diets