6. GIT tract - ruminants Flashcards
what is the tracheal bifurcation?
the division of the trachea into the right and left main bronchi
what is the Oesophageal hiatus?
the opening in the diaphragm through which the oesophagus passes from the thoracic to abdominal cavity
what is the course of the oesophagus in the cervical region
- Begins at the pharynx
- Descends dorsal to trachea to the middle of the neck
- Midneck the oesophagus lies on the left dorsolateral aspect of the trachea
- Regaining a median position above the trachea before or shortly after entering the thorax
what is the course of the oesophagus in the thoracic region
- continuing beyond tracheal bifurcation, it Passes over the heart before penetrating the oesophageal hiatus of the diaphragm
- Capable of reversed peristalsis or antiperistalsis. This allows food to be easily regurgitated from the rumen and chewed properly
what are the primary locations for choke in ruminants?
- thoracic inlet
- hiatus of diaphragm
- cardia of the rumen
what type of stomach do ruminants have?
complex and composite
name the 4 compartments of the ruminant stomach
- rumen
- reticulum
- omasum
- abomasum
what compartments of the stomach are in the fore stomach (proventriculi)?
rumen, reticulum, omasum
describe the internal structure of the fore-stomach
- Non-glandular
- Lined with stratified squamous epithelium
- Process and digest feedstuff
- Papillae
is the abomasum glandular or non-glandular
glandular
what is the main function of the rumen?
fermentation
what are grooves?
thickened smooth muscle pillars on the inside of the rumen - formed my tunica mucosa
what do the coronary pillars do?
divide the caudal blind sacs
what do Cranial pillars do?
divides the dorsal and cranial sacs
what is the rumen divided into?
sacs
describe the rumen structure
- Grooves - thickened smooth muscle pillars inside the rumen
- Ruminal pillars: divide the dorsal and ventral ruminal sacs (Longitudinal groove/pillar)
- Coronary pillars: divide the caudal blind sacs
- Cranial pillar: divides the dorsal and cranial sacs
describe the papillae structure and function in the forestomach
- mucosal projections like pegs
- Increase surface area
- Absorption of VFA’s (volitile fatty acids)
the rumen and reticulum occupy which side of the abdominal cavity?
left
describe the location of the reticulum
- caudal to diaphragm, closely situated to the heart and liver
- medial to the 6th to 8th ribs on the left side with the cranial wall at the elbow
microanatomy of the rumen of the cow
- No muscularis mucosa
- Complete short papillae and part of long papillae
- Stratified squamous epithelium
microanatomy of the reticulum of the cow
Sides and crests of long folds have conical papillae with keratinised tips
- Lamina propria
- lamina muscularis
- tunica muscularis
what does the reticulum do?
serves as a pump that causes liquid to flow into and out of the rumen
microanatomy of the rumen of the cow
- Complete short papillae and part of long papillae
- There is no muscularis mucosa in this part of the stomach
- Stratified squamous epithelium
describe the location of the omasum
Lies in the lower part of the cranial abdomen between reticulum and cranial rumen to the left and the liver on the right
describe the function of the abomasum
Glandular, Secrete acids and digestive enzymes
describe the location of the abomasum
Fills the right cranially abdomen
lies largely on the abdominal floor at the midline/ just to the right side
describe the structure of the abomasum
divided into two limbs- fundus and body and pyloric portion
what is the Ruminoreticular compartment
functional unit of the rumen and reticulum
where is the ruminoreticular compartment
extends from the 7th rib up to the pelvis
occupy the entire left part of the abdominal cavity
Gastric groove structure
Two spiral muscular folds forms a passageway from the cardia to the abomasum
what does the gastric groove consist of
- reticular groove extending in the ruminoreticular compartment
- Omasal groove in the omasum
- Abomasal groove in the abomasum
what is the function of the gastric groove
Allowing ingested milk to bypass forestomach hence avoiding fermentation
With change of diet this bypass less used (weaning)
describe the greater and lesser omental connections to the omentum
- Attachment of the greater omentum begins dorsal to the esophagus
- Lesser omentum arises from the visceral surface of the liver
describe the omentum structure ruminants
Fatty and vascular
where is the greater omentum found
- extend ventrally and to the right of the rumen then attach to descending duodenum
- Right longitudinal groove of rumen
- Left longitudinal groove of rumen
- Greater curvature of the abomasum, and duodenum
describe the walls of the greater omentum
Superficial wall: arises from the left side of the rumen (left longitudinal groove)
Deep wall: arises from the right side of the rumen (right longitudinal groove)
name the different parts of the small intestine
Duodenum
Jejunum
Ileum
name the different parts of the large intestine in order
Caecum
Ascending colon:
proximal loop of colon (before spiral colon)
Spiral colon
distal loop of colon (after spiral colon)
Transverse colon
Descending colon
In the stomach blood supply, which artery forms three branches, providing the main flow of blood?
Celiac artery
name the 3 branches of the celiac artery
Splenic, Left gastric and hepatic a.
name the arteries that provide blood supply to the stomach
Right and left ruminal arteries
Right and left gastric arteries
Right and left gastroepiploic arteries
describe the right and left rumen arteries
- the right rumen artery comes from the splenic
- the left rumen artery comes from the left gastric
- they follow longitudinal grooves
describe the Right and left gastric arteries
- follow the lesser curvature of the abomasum
anasastomise/ connect freely externally
describe the Right and left gastroepiploic arteries
Right and left gastroepiploic arteries follow the greater curvature of the abomasum (originate from hepatic and left gastric arteries)
what after supplies the bulk of the intestines?
cranial mesenteric artery
the first part of the duodenum is supplied from which artery
the celiac artery
descending colon is supplied from which artery
the caudal mesenteric artery
which nerve provides sensory and motor pathways in the GIT
vagus
