3.5 - Midgut and Hindgut

Duodenum, jejunum, ileum, cecum, ascending colon, and part of the transverse colon

What organs are considered Midgut

cranial mesenteric artery

main blood supply of the midgut (not taking into account branches)

cranial mesenteric ganglia

Sympathetic innervation of the midgut

vagus nerve

parasympathetic innervation of the midgut

remaining transverse colon, descending colon, and rectum

What organs are considered hindgut

Caudal mesenteric artery

main blood supply of the hindgut (not taking into account branches)

caudal mesenteric ganglia

sympathetic innervation of the hindgut

pelvic splanchnic nerves

parasympathetic innervation of the hindgut

True

T/F - both the jejunum and the ileum have arcades of arteries and vasa recta along their length, but they begin to look different the closer you get to the ileum

common bile duct and pancreatic duct

What are the 2 ducts that drain into the duodenum

major duodenal pailla

What sphincter controls the common bile duct and the pancreatic duct's release into the duodenum?

Jejunal, cranial pancreaticoduodenal, ileocolic, and middle colic

What are the 5 main branches off of the cranial mesenteric artery

distal duodenum and jejunum

What do the jejunal arteries supply

Right pancreatic lobe and middle duodenum

What does the caudal pancreaticoduodenal supply

Ascending colon

what does the ileocolic supply

Cecal and right colic

What are the 2 branches off the ileocolic artery

cecum

What does the cecal branch of the ileocolic artery supply

curve between ascending and transverse colon

What does the right colic branch of the ileocolic artery supply

First main part of the transverse colon

What does the middle colic supply

Brunner's glands

Glands found in the duodenum that secrete a specialized mucous to protect the duodenum from the highly acidic chyme delivered from the stomach

plica circulares

Folds of the duodenum that aren't distensible but are covered with intestinal villi to increase surface area for absorption

Simple columnar cells with goblet cells and microvilli

What is the makeup of the intestinal villi epithelium

Enterocytes

specialized absorptive cells in the villi of the small intestine

Tall microvilli, tight junctions, and many lateral infoldings

What are the main histological characteristics of enterocytes

False

T/F - the tight junctions between the enterocytes in the intestinal villi never allow passage of water or electrolytes

Glycocalyx

A mix of glycoproteins and mucous secreted near the apical membrane of intestinal villi that trap molecules

Fenestrated capillaries and lacteals

What is the capillary and lymphatic network found in the lamina propria of the small intestines

Transport proteins and carbohydrates

Function of the fenestrated capillary network found in the lamina propria of the small intestines

Transport fats

Function of the lacteal in the lamina propria of the small intestine

GALT

Gut associated lymphoid tissue composed of aggregated nodules of lymphoid tissue that provides host defense

Ileum

Where is GALT the most abdundant

No specific function

What is the function of the cecum in carnivorans

No

In carnivorans, does the cecum and the ileum have a direct connection

Ascending colon

What organ does the cecum have direct connection with in carnivorans

cecocolic orifice

opening between cecum and ascending colon

Cranial rectal and left colic

2 main branches off of the caudal mesenteric artery that supplies the hindgut

distal descending colon and cranial part of rectum

What does the cranial rectal artery supply

part of the transverse colon and the descending colon

What does the left colic artery supply

Middle colic artery

What anastomoses with the left colic artery at the splenic flexure

Absorption of water, vitamins, and electrolytes

Main function of the large intestine

Secrete mucous to help passage of feces

There is a lack of villi and digestive glands in the large intestine, but why is there an abundance of goblet cells still present

Straight and regular invaginations of the intestinal glands

What can be a histological clue that you have moved from the small to large intestine in regards to the appearance of their epithelium

Absorption isn't as important

Why is there only a small amount of short microvilli in the large intestine

Simple columnar

Epithelium type of the large intestine

No

Are there lymphatic capillaries (lacteals) found in LP of the large intestine

contract intestinal glands and compacts feces

Function of the muscularis mucose in the large intestine

Haustrae

Bubble-like compartmentalizations of the colon formed by the muscularis externa

Tenia coli

bands of smooth muscle along most of the length of the colon, more apparent in large animals

Smooth and skeletal muscle

What muscle is present in the rectum to facilitate defecation

Yes

Are mucous glands still present in the rectum

Cisterna chyli

What is the lymphatic drainage site for the foregut nodes

Thoracic duct

Largest lymphatic vessel in the body

Jejunal nodes

Which lymph nodes of the foregut are large in dogs

after the organs they drain

What are the lymph nodes of the foregut named after