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)
