Large animal digestive tract AHS1 Flashcards
What are the 4 main parts of the ruminant stomach?
Rumen
Reticulum
Omasum
Abomasum
How is the ruminant stomach different in young animals?
The abomasum is a lot larger because milk digestion happens there
Which is the most cranial part of the stomach?
The reticulum
What is the reticulum associated with?
Right up against the diaphragm and the oesophagus
What part of the ruminant stomach is mostly on the left side of the body?
The rumen
What parts of the ruminant stomach are mostly on the right hand side?
The omasum (midline) and the abomasum
What part of the stomach is the easiest to displace?
The abomasum
What are the different parts of the rumen called?
The dorsal sac
The blind sac (caudoventral)
The ventral sac
What is the rumens principal function?
Bacterial fermentation
What divides the rumen into its different parts?
External grooves with corresponding internal folds and pillars
What are the 3 main grooves on the rumen called?
Left longitudinal groove
Right longitudinal groove
Rumenoreticular groove/fold
What is important about the Rumenoreticular fold?
It acts as a dam and is a good landmark for the reticulum when foreign bodies get stuck in it
What does the internal surface of the rumen look like?
It has ruminal papillae which are more dense in the ventral part of the rumen where there is liquid instead of gas
What does the internal surface of the reticulum look like?
It has a honeycomb/net like appearance
Where is the omasum located?
Between the rumen and the liver
What does the internal surface of the omasum look like?
It has crescentic laminae - looks like a book/chocolate orange
What is the main function of the omasum?
Water absorption
What is the main function of the abomasum?
Chemical digestion - true stomach
Where is the abomasum located?
Mainly to the right of the rumen apart from part of the fundus
What does the internal surface of the abomasum look like?
Ruggae - wiggles and folds on the inside
What is the structure in young ruminants that allows milk to go straight into the abomasum?
The Rumenoreticular groove
Also known as the gastric groove
What is the gastric groove?
Two spirally twisted lips of on the wall of the reticulum and the lesser curvature of the omasum
How does the gastric groove work?
When the vagus nerve is stimulated the lips curl round and form a tube into the abomasum bypassing the rumen and the reticulum
How is the vagal reflex associated with the gastric groove stimulated?
Feeding on milk
What iis the main artery supplying blood to the stomach?
The coeliac artery
What are the arteries (that come off the coeliac artery) that follow the lesser curvature of the abomasum?
The left and right gastric arteries
What are the arteries (that come off the coeliac artery) that follow the greater curvature of the abomasum?
The gastroepiploic arteries
What are found in the longitudinal grooves of the rumen?
The left and right ruminal arteries
What is the main venous drainage of the ruminal stomach?
The veins mirror the arteries and drain via the splenic vein into the hepatic portal vein
What is the main parasympathetic innervation of the rumen?
The dorsal vagus nerve
What is the main parasympathetic innervation of the reticulum, omasum and abomasum?
The ventral vagus nerve
What is the main sympathetic innervation of the ruminal stomach?
The nerves come from the coeliac (coeliacomesenteric) plexus and take a similar route to the arteries
Where does the greater omentum attach to the ruminal stomach?
Along the right longitudinal groove and then left longitudinal groove of the rumen
Over the reticulum
Around the greater curvature of the abomasum
Down the duodenum
Where does the lesser omentum attach to the ruminal stomach?
Along the greater curvature of the omasum (because it is closely associated with the liver)
Along the lesser curvature of the abomasum
Where is the omental bursa?
Between the two layers of the greater omentum and goes from the ventral surface of the rumen to the duodenum on the dorsal surface
Where is the caecum found in a ruminant?
On the right side and projects caudally in the right pelvic inlet
What does the ascending colon look like in ruminants?
Varies between species but usually coiled in a spiral
Where is the jejunum found in the ruminant?
Hangs like a frill under the colon
What is the attachment between the ilium and the caecum called?
The ileocecal fold
What are the two main surgical incisions?
Paralumbar incision Paracostal incision (more ventral)
Where is the paralumbar fossa located?
The indent between the tuber sacrale and the tuber ischii and the costal arc
What is a dermatome?
The area of skin which each spinal nerve innervates
They are names after the spinal nerves
What kind of anaesthesia technique is used on cows?
Paravertebral anaesthesia - regional anaesthesia technique
How does paravertebral anaesthesia work?
The needle is injected near the transverse process
Some is injected into the dorsal ramus
The needle then goes through the intertransverse ligament
The rest is then injected into the ventral ramus
