Lecture 15 - Physiology of The Small Intestine and Accessory Organ 1

Question 1

Sphincter which secretions from pancreas, liver, gallbladder.

Answer 1

Sphincter of Oddi, pancreatic duct and bile ducts merge at this point.

Question 2

Exocrine cells in pancreas

Answer 2

Enzymatic, these break down all food types

Question 3

endocrine cells in pancreas

Answer 3

hormonal, release insulin, glucagon, somatostatin affecting carbohydrate metabolism

Question 4

Acinar cells in pancreas

Answer 4

secrete enzymes and fluids into duct systems which is stimulated by cholecystokinin (chemical) and Ach (hormonal)

Question 5

Duct cells in pancreas

Answer 5

Stimulated by secretin releasing secretions rich in bicarbonate

Question 6

Why are zymogens excreted from pancreas and not active enzymes?

Answer 6

because enzymes are very potent and could damage it

Question 7

What type of cell are most pancreatic cells?

Answer 7

exocrine (99%)

Question 8

Aqueous component of pancreatic secretions

Answer 8

rich in bicarbonate (pH=8) which neutralises acidic chyme when it enters duodenum, stimulated by secretin

Question 9

Enzymatic component (pancreatic secretions)

Answer 9

proteolytic enzymes (cleave peptides) are activated in duodenum by Enterokinase. Pancreatic amylase secreted in active form). Other enzymes (colipase, cholesterol esterase, phospholipase A2) activated by trypsin in duodenum

Question 10

What are proteolytic enzymes?

Answer 10

enzymes that cleave peptides, secreted as zymogen by pancreas, activated by Enterokinase in duodenum

Question 11

What happens when pancreatic enzymes attack the pancreas?

Answer 11

pancreatitis

Question 12

What can pancreatitis be caused by?

Answer 12

Gallstones, potentially blocking sphincter of Oddi. Or alcohol abuse.

Question 13

Treatment of pancreatitis

Answer 13

pain and infection management, electrolyte therapy and possibly surgery if chronic

Question 14

What are main functions of liver (not all 500)

Answer 14

processes digested food from intestine, manufactures bile, stores monosaccharides as glycogen, stores iron, Vits and other chems.
Breaks down glycogen, fat or protein to glucose
Metabolises drugs, breaks down poisons

Question 15

Structure of Liver

Answer 15

• Hepatic cells arranged in radial pattern around central vein make up lobules, which form lobes of liver (2 main lobes)
• Receives double blood supply (hepatic artery supplies with oxygenated blood (30%), portal vein supplies with de-oxygenated nutrient-rich blood (70%)
• The hepatic cells extract O2 and most nutrients, detoxify/store poisons and drugs, secrete products (except bile, secreted via bile duct) into hepatic vein.

Question 16

Hepatic cells (liver)

Answer 16

extract O2 and most nutrients, detoxify/store poisons and drugs, secretes products into hepatic vein (except bile, secreted via bile duct)

Question 17

Important cell type in liver

Answer 17

hepatic cells

Question 18

What is bile?

Answer 18

Bile- excretory product of liver metabolism, digestive secretion. Bile salts emulsify fats into small droplets so enzymes can access and efficiently break it down. Bile cholesterol, bile pigments (bilirubin) is what gives yellow/brown colour