L34: Mid-Hindgut

Question 1

What is specialized about the GI system of CANINES?

Answer 1

‘Simple’- roughly 4x body length

Question 2

What is specialized about the GI system of EQUINES? (3)

Answer 2

• Hindgut specialist- very roughly 12x body length - Elaborated cecum for fermentation - Sacculated colon

Question 3

What is specialized about the GI system of BOVINES? (3)

Answer 3

• Foregut specialists- very roughly 20x body length - Elaborated stomach for fermentation - Elongated ascending colon

Question 4

What are the three parts of the SI (midgut)?*

Answer 4

Duodenum, Jejunum, Ileum

Question 5

What is the function of SI? (3)

Answer 5

1. Secretion of intestinal juices 2. Complete basic conversion of food into small absorbable molecules 3. Absorption

Question 6

What is absorption of SI aided by? (4)

Answer 6

Aided by: - Length or SI - Internal SA - Vascularized villi (AA, simple sugars) - Lacteals (FA and glycerol)

Question 7

Mesenteric vessels and innervation travel within the mesentery to sustain ___ and _____

Answer 7

Jejunum and Ileum

Question 8

Part of jejunum that is closer to duodenum is considered?

Answer 8

Proximal

Question 9

Circular folds, aka ____, are permanent features that _______!*

Answer 9

Plicae circulares- increase SA

Question 10

Less SA at part of ____ and rather smooth at first part of ____

Answer 10

Ileum, colon

Question 11

Long straight arteries in the jejunum are called

Answer 11

Vasa recta

Question 12

Peyer’s patches are located ___?

Answer 12

Located toward end of ileum

Question 13

General characteristics between Jejunum and Ileum: wall, diameter, vasa recta, arcades, mesenteric fat, plicae circulares, peyer patches (lymphoid)

Answer 13

Question 14

Functions of comparative LI? (3)

Answer 14

• Lubricate feces (by goblet cells) for passage
• Colon absorbs water, vits, electrolytes
• Ctrl diameter of fecal mass

Question 15

In the carnivorans, there are no significant functions of the ileocolic junction and cecum, however, it is unsualy because these two structures ______

Answer 15

Have no direct connection

Question 16

The cecum communites with the ascending colon through _______ to __________.

Answer 16

Cecocolic orifice adjacent to the ileal orifice

Question 17

Up to ___% of horse’s energy needs are met by microbial fermentation products, mainly as VFA; the clon reabsorbs ____% of water assocaited with fermentation.

Answer 17

75%, 90-95%

Question 18

Equine large intestine is made up of what three things?

Answer 18

1. Ascending Colon (LV, RV, LD, RD)
2. Transverse Colon
3. Descending Colon

Question 19

Development of equine cecum- what occurs?

Answer 19

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

Question 20

On the equine ventral abdominal view, there are key features called ___?

Answer 20

Haustra (sacculations) and tenia coli (long muscle stripes..not found in carnivorans)

Question 21

What is defecation? (process)

Answer 21

• Fecal mass passes through coon by peristalsis, antiperistalsis, rhythmic segmentation and mass movement
• Stretches rectal wall stimulates voluntary straining, causes anal sphincter to relax

Question 22

What are compostion of feces?

Answer 22

• Water, fiber, bacteria, mucus, dead & living bacteria, contents of anal sacs, sloughed intestinal cells, stercobilin* BILE REMNANTS (pigment)

Question 23

What is intestinal volvulus?

Answer 23

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

Question 24

Arterial Supply to Mid and Hindgut- 2 main arteries, supplies what?*

Answer 24

1. Cranial Mesenteric Artery

(Supplies MIDGUT)

2. Caudal Mesenteric Artery

(Supplies HINDGUT)

Question 25

What does cranial Mesenteric artery

Answer 25

SI, ascending colon (right), transverse colon (middle)

Question 26

Ileocolic artery supplies blood to?

Answer 26

Portions of ascending colon and cecum

Question 27

Caudal mesenteric artery branches?

Answer 27

Left colic artery, cranial rectal (rectum)

Question 28

Critical anastomosis at middle and left colic?

Answer 28

Middle Colic- Cranial MA

Left Colic- Caudal MA

Where there is a junction/ sharing

Question 29

Similar anastomosis between right colic and ileocolic in horses; look for?

Answer 29

Gastrophilus Larvae (nematode from gastric infections)

Question 30

Venous Drainage of Midgut and Hindgut Derivatives: (pic)

Answer 30

Question 31

All lymph in this picture drain to ____*

Answer 31

Cisterna Chyli, a large reservoir in the dorsal part of abdominal wall*

Question 32

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)***!!!!

Answer 32

Portal vein;

Caudal vena cava;

Hepatic Vein

Question 33

**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!!**

Answer 33

Liver

Hepatic vein