L34: Mid-Hindgut Flashcards
What is specialized about the GI system of CANINES?
‘Simple’- roughly 4x body length
What is specialized about the GI system of EQUINES? (3)
- Hindgut specialist- very roughly 12x body length - Elaborated cecum for fermentation - Sacculated colon
What is specialized about the GI system of BOVINES? (3)
- Foregut specialists- very roughly 20x body length - Elaborated stomach for fermentation - Elongated ascending colon
What are the three parts of the SI (midgut)?*
Duodenum, Jejunum, Ileum
What is the function of SI? (3)
- Secretion of intestinal juices 2. Complete basic conversion of food into small absorbable molecules 3. Absorption
What is absorption of SI aided by? (4)
Aided by: - Length or SI - Internal SA - Vascularized villi (AA, simple sugars) - Lacteals (FA and glycerol)
Mesenteric vessels and innervation travel within the mesentery to sustain ___ and _____
Jejunum and Ileum
Part of jejunum that is closer to duodenum is considered?
Proximal
Circular folds, aka ____, are permanent features that _______!*
Plicae circulares- increase SA
Less SA at part of ____ and rather smooth at first part of ____
Ileum, colon
Long straight arteries in the jejunum are called
Vasa recta
Peyer’s patches are located ___?
Located toward end of ileum
General characteristics between Jejunum and Ileum: wall, diameter, vasa recta, arcades, mesenteric fat, plicae circulares, peyer patches (lymphoid)
Functions of comparative LI? (3)
- Lubricate feces (by goblet cells) for passage
- Colon absorbs water, vits, electrolytes
- Ctrl diameter of fecal mass
In the carnivorans, there are no significant functions of the ileocolic junction and cecum, however, it is unsualy because these two structures ______
Have no direct connection
The cecum communites with the ascending colon through _______ to __________.
Cecocolic orifice adjacent to the ileal orifice
Up to ___% of horse’s energy needs are met by microbial fermentation products, mainly as VFA; the clon reabsorbs ____% of water assocaited with fermentation.
75%, 90-95%
Equine large intestine is made up of what three things?
- Ascending Colon (LV, RV, LD, RD)
- Transverse Colon
- Descending Colon
Development of equine cecum- what occurs?
Stippled part is homologous with cecum of other species
Non-stippled part is the annexed first part of colon
The cecocolic orifice is a constrictrion of the ascending colons
On the equine ventral abdominal view, there are key features called ___?
Haustra (sacculations) and tenia coli (long muscle stripes..not found in carnivorans)
What is defecation? (process)
- Fecal mass passes through coon by peristalsis, antiperistalsis, rhythmic segmentation and mass movement
- Stretches rectal wall stimulates voluntary straining, causes anal sphincter to relax
What are compostion of feces?
- Water, fiber, bacteria, mucus, dead & living bacteria, contents of anal sacs, sloughed intestinal cells, stercobilin* BILE REMNANTS (pigment)
What is intestinal volvulus?
Complete twisting of a loop of intestine around its mesenteric attachment site- this endangers blood supply which can lead to necrosis of affected bowel; there is also reddened poriton of colon indicative of strangulation
Arterial Supply to Mid and Hindgut- 2 main arteries, supplies what?*
- Cranial Mesenteric Artery
(Supplies MIDGUT)
- Caudal Mesenteric Artery
(Supplies HINDGUT)
What does cranial Mesenteric artery
SI, ascending colon (right), transverse colon (middle)
Ileocolic artery supplies blood to?
Portions of ascending colon and cecum
Caudal mesenteric artery branches?
Left colic artery, cranial rectal (rectum)
Critical anastomosis at middle and left colic?
Middle Colic- Cranial MA
Left Colic- Caudal MA
Where there is a junction/ sharing
Similar anastomosis between right colic and ileocolic in horses; look for?
Gastrophilus Larvae (nematode from gastric infections)
Venous Drainage of Midgut and Hindgut Derivatives: (pic)
All lymph in this picture drain to ____*
Cisterna Chyli, a large reservoir in the dorsal part of abdominal wall*
All venous drainage from any organ that had food that ran through it has to go to liver via _____ then blood drains from liver to ____ by ____ vein (back of liver open up CVC)***!!!!
Portal vein;
Caudal vena cava;
Hepatic Vein
**All venous draininge from any organ that had food that ran through it must first go to the ____ by the portal vein, then blood drains from liver to the caudal vena cava by the ____ vein- this is the predominant way the portal vena drainage connects to caval vena drainage!!**
Liver
Hepatic vein
