Ruminant Abdomen

What is the primary structure visible on the left side of a ruminant's abdomen?

Rumen

What is the primary structure visible on the right side of a ruminant's abdomen?

Omasum

What is the function of the greater omentum in ruminants?

Supports and insulates abdominal organs

What is the supraomental recess and what does it do?

Space between the deep and superficial leaves of the greater omentum where the intestines and other abdominal organs can be located, acting as a sling

Where is the dorsal sac of the rumen located in relation to the omentum?

Not covered by omentum

What are the external features of the rumen?

The external features include the rumen pillars, grooves, and sacs, which aids its function in digestion and fermentation in ruminants.

What are the 5 muscular sacs of the rumen called?

Dorsal, ventral, cranial, caudodorsal and caudoventral sacs

What are the internal features of the rumen?

Pillars and muscular papillae

What type of epithelium lines the rumen?

Stratified squamous epithelium

Where is the reticulum located in relation to the diaphragm, rumen and heart?

Adjacent to diaphragm and heart and located cranially to the rumen.

What is the distinctive feature of the omasum's internal structure?

It has many folds called laminae

Between which ribs is the omasum typically located?

Ribs 8-11

What is the function of the gastric groove in unweaned ruminants?

Forms a closed tube for milk to pass directly from the oesophagus to the abomasum

What stimulates the gastric groove reflex?

ADH

How many compartments does a ruminant stomach have?

4

What is the primary function of the abomasum?

Acidic digestion, similar to a simple stomach

What artery supplies blood to the ruminant stomach?

Coeliac artery

What are the three main branches of the coeliac artery in ruminants?

Ruminal, splenic, hepatic

Where is the liver located in ruminants?

Right side of the abdomen and extends towards the diaphragm.

What are the four lobes of the ruminant liver?

Left, right, caudate, and quadrate

What is the shape of a cow's spleen?

Elongated

What is the shape of a sheep's spleen?

Oval

Where is the paralumbar fossa, and why is it important?

Depression behind the last rib, used for surgical entry into the abdomen

What is the function of the omasum?

Water and mineral absorption

How does the abomasum's epithelium differ from other stomach compartments?

Glandular epithelium for acid secretion and enzyme production

What is the spiral colon in ruminants?

Coiled portion of the large intestine that aids in water absorption and fermentation

What is the primary movement of ingesta in the rumen?

A figure of 8 flow pattern that mixes and moves food through the rumen for fermentation

What happens during rumination?

Partially chewed plant material enters the rumen and is broken down by microbes

What do microbes in the rumen break down?

Cellulose and other complex carbohydrates

What are the products of fermentation in the rumen?

VFAs, carbon dioxide, and methane

How does the reticulum assist in rumination?

Helps to regurgitate food back to the mouth for rechewing

What does the omasum do to digesta?

Absorbs water and nutrients, further grinding food.

Contractions of the omasum are….

biphasic

What happens in phase 1 of the omasum contractions?

Ingesta is squeezed into recesses between the laminae

The

what happens in phase 2 of the omasum contractions?

mass contraction of the omasum

What does the abomasum secrete?

HCl, and pepsin and mucous

What is the pH of the abomasum?

Where is the gallbladder located in ruminants?

On the visceral surface of the liver

What is the function of the reticulum?

Traps and regurgitates large food particles for rumination

How does the ruminant liver differ from that of carnivores?

Less distinct lobulation and relatively smaller size

What is the primary function of the rumen?

Fermentation of plant material by microorganisms

Where are the lymph nodes of the ruminant abdomen primarily located?

Along blood vessels and in mesenteries

What is the omental bursa?

The area enclosed by the greater omentum, contains the ventral sac of the rumen. 

What is the function of the omental bursa in ruminants?

It serves as a space for storing fat and allows for movement of the intestines

How does the position of the abomasum change during displacement?

Moves between the rumen and left body wall

What is the clinical significance of the rumen's left side location?

Site for rumen fluid sampling and trocharization in bloat