The large intestine

Question 1

What are the functions and sections of the large intestine

Answer 1

functions: storage of feces, defication, absorbtion (Na+ and H2O)
Sections:
cecum
colon (acending, hepatic flexure, transverse, splatic flexure, decending colon, sigmoid colon)

Question 2

What is the cecum

Answer 2

Blind ended pouch at the start fo the large intestine
fed from ileum by ileocecal valve
Contains the vermiform appendix - storage of gut bacteria -> can become appendicitise when inflamed

Question 3

What are four core changes to the large intestinal wall

Answer 3

Teniae coli = 3 bands of longitudinal muscle rather than a ring to create stronger contractions
Omental appendicies = sacs of fat
Haustra = pouches in the wall - seperated by semilunar folds
Mucosa = no villi but intestinal glands -> mucus secretion in gland, Na+ and H2O abosption near surface

Question 4

What is the anatomy of the rectum

Answer 4

After sigmoid colon - rectum -> anal canal -> anus
epithelium changes to strattified squamus at anal columns

Question 5

What are our defication reflexes

Answer 5

Short reflex: local contractions of the rectum pushing feces to anal canal
Long reflex: signal sent to the spinal cord which relays to the rest of the intestine to push feces to rectum
reflexes lead to internal anal sphincter relaxation

Question 6

What are the anal sphincters

Answer 6

Internal anal sphincter = smooth muscle relaxed by short and long reflex
External anal sphicter = skeletal muscle enables control of defication

Question 7

What is the function, location and blood supply of the liver

Answer 7

Functions - metabolic processes, detoxing blood, producing bile
Located - URH of abdomnopelvic cavity connected via lesser omentum

Blood supply - 25% of total blood supply
- 1/3 oxy blood from hepatic artery
- 2/3 deoxy nutriant rich blood from the hepatic portal vein

hepatic portal vein, hepatic artyer, bile duct all travel in the lesser omentum

Question 8

What is the structure of the liver

Answer 8

The liver is broken into hexagonal lobules - lobules made from lines of hepatocytes
Hepatocytes produce bile
At the middle of a lobule = central vein
at the corners of the lobules = hepatic portal triad (bile duct + branch of hepatic portal vein and hepatic artery)
Between hepatocytes = liver sinusoid and bile canulliculi

Bile canuliculi drain to bile duct in triad
liver sinusoid drains to central vein

Question 9

Where does the liver central vein drain to

Answer 9

Central vein drains to hepatic vein -> inferior vena cava

Question 10

What is the anatomy and function of the gallbladder

Answer 10

Hollow organ below the liver connected via the cyctic duct
- bile duct connects to pancreatic duct at the hepatopancreatic ampulla
Stores and concentrates bile until required
gallstones form when overconcentration happens

liver draining storage: common hepatic duct -> cycteic duck
Use: GB -> cyctic duct -> common bile duct