Lecture 8 - Pancreas and liver

Question 1

Chyme

Answer 1

Low pH
Hypertonic
Partially digested food

Question 2

Brunner’s glands

Answer 2

Secrete alkaline mucous, protecting the cells lining the duodenum from acidic chyme

Question 3

Hypertonicity of chyme

Answer 3

Stomach is impermeable to water therefore chyme is hypertonic in stomach

Controlled release of chyme to prevent rapid water movement from the ECF and circulation to the chyme in the duodenum which would decrease blood pressure

Question 4

Pancreatic secretions

Answer 4

Pancreatic enzymes aqueous bicarbonate solution

Question 5

Liver secretions

Answer 5

Bicarbonate

Bile

Question 6

Stimuli for pancreatic secretions

Answer 6

Acetylcholine (vagus PS)
CCK
Secretin

Question 7

Secretin

Answer 7

Stimulated by acidity in the duodenum and jejunum

Stimulates pacreatic ductal epithelium to secrete aqueous bicarbonate solution

Question 8

Cholecystokinin

Answer 8

Stimulated by proteins and fatty acids entering the small intestines

Stimulates pancreatic acinar to release enzymes

Causes gall bladder to contract and sphincter of Oddi to relax

Question 9

Pancreatic exocrine function

Answer 9

90% exocrine - digestive enzymes

Question 10

Pancreatic structure

Answer 10

Head located in the ‘C’ shape of the duodenum where the common bile duct and pancreatic duct enter the duodenum at the sphincter of Oddi

Contains:
Acinar - release enzymes
- Ducts - release aq bicarbonate solution which neutralises acidic chyme

Endocrine function:
- Islets of Langerhan - insulin and glucagon released into blood stream

Question 11

Pancreatic enzymes

Answer 11

Amylase
Lipase
Proteases (inactive)

Question 12

Proteases

Answer 12

Trypsin
Chymotrypsin
Elastase
Carboxypeptidase

Question 13

Zymogen granules

Answer 13

Inactive proteases are stored in zymogen granules preventing the digestion of the pancreas

Question 14

Pancreatitis

Answer 14

In pancreatitis due to blockage, pH decreases which activates proteases and causes pancreatic digestion

Question 15

Ampulla of Vater

Answer 15

Where the common bile duct and pacreatic duct come together to enter the duodenum at the sphincter of Oddi

Question 16

Bile

Answer 16

Made in the liver
Stored and concentrated in the gall bladder
Released in the duodenum (250 - 1000 ml/day)

Question 17

What is bile made of?

Answer 17

Secreted by heaptocytes:

• Bile salts from bile acids
• Bile pigments

Alkaline solution - secreted by cells lining the bile ducts stimulated by secretin

Question 18

Role of bile

Answer 18

Emulsifyes fats, increasing SA so they are readily digested by lipases

Question 19

Liver components

Answer 19

Hepatocytes (80%)
Lots of RER and SER
Stacks of golgi apparatus 
Contains lots of glycogen 
Kupffer cells - macrophages in the liver

Question 20

Portal vein

Answer 20

All blood from gut drains into the liver via the PORTAL VIEN

Question 21

Sections of the liver

Answer 21

Left
Right
Caudate - near IVC
Quadrate - near gallbladder

Question 22

Connective tissue connecting the liver to the abdominal wall

Answer 22

Falciform ligament

Question 23

Liver lobule

Answer 23

Hexagonal
Central vein in middle
6 portal triads

Question 24

Portal triad

Answer 24

Bile duct
Portal vein
Hepatic artery

Question 25

Hepatic artery

Answer 25

Provides oxygenated blood to hepatocytes Blood flow opposite to bile flow

Question 26

Caniculi

Answer 26

Hepatocytes produce substances in bile and excreted into the caniculi to the bile duct

Question 27

Functional area of liver lobule

Answer 27

Acinus

Question 28

Acinus

Answer 28

Blood enters from the periphery of the lobule to the centre

Question 29

Zone 1

Answer 29

Closest to periphery | More prone to toxicity as first exposure

Question 30

Zone

Answer 30

Closest to the centre | More prone to ischaemia as furthest from the hepatic artery

Question 31

Bile salts

Answer 31

Conjugated bile acids More soluble at duodenal pH than bile acids

Question 32

Bile acids

Answer 32

Cholic acid Synthesised and conjugated to amino acids in liver to form bile salts

Question 33

What do bile salts do?

Answer 33

Amphipathic - Emulsification of dietary lipids into smaller units to increase surface area Create micelles to transport hydrophobic molecules (lipid digestion products) towards enterocytes of duodenum where the bile salt disperses.

Question 34

Lipid products of digestion

Answer 34

Cholesterol Free fatty acids Monoglycerides

Question 35

Bile salts at the enterocyte

Answer 35

Lipids diffuse into the enterocyte but bile salts do not Bile salts remain in gut and are reabsorbed by the terminal ileum therefore returned to liver via the portal vein . Liver recycles the bile salts

Question 36

Chylomicrons

Answer 36

Lipids are re-estified in the enterocyte into triglycerides in ER Packed with apoproteins and carried via chylomicrons (lipoprotein) where it is exocytosed from the cell. Carried in the lymph system via lacteals to the thoracic duct [chylomicrons too large to enter capillary]

Question 37

Steatorrhoea

Answer 37

Undigested fat in the faeces - pale - floating - foul smell Due to: inadequate secretion of bile salts/bile acids/pancreatic lipase