lecture 3- pancreas and liver

Question 1

Pancreas location

Answer 1

elongated gland lying below and behind stomach,

Question 2

Pancreas info

Answer 2

mixed gland (contains both exocrine and endocrine tissue), acinar and duct cells predominant, isolated islands of endocrine cells

Question 3

Pancreas secretions

Answer 3

endocrine and exocrine tissues. endocrine cells release glucagon and insulin to control blood sugar

Question 4

exocrine secretions

Answer 4

releases 1-2L of pancreatic juices per day

Question 5

Duct cells

Answer 5

sodium bicarbonate rich

Question 6

Pancreatic enzymes (acinar cells)

Answer 6

Proteolytic enzymes, Pancreatic Amylase, Pancreatic Lipase

Question 7

Proteolytic enzymes

Answer 7

Protein digestion

Question 8

Pancreatic Amylase

Answer 8

Carb digestion

Question 9

Pancreatic Lipase

Answer 9

Fat digestion

Question 10

3 major pancreatic proteases

Answer 10

trypsinogen, chymotrypsinogen, procarboxypeptidase

Question 11

protective mechanisms of pancreas

Answer 11

enzymes stored and released in inactive form, trypsinogen is activated to trypsin by enterokinase in duodenum, pancreas produces trypsin inhibitor, duodenum secretes mucus from epithelium wall

Question 12

Pancreatic amylase

Answer 12

hydrolyses polysaccharides into disaccharide (maltose). Ir can be secreted in active form as secretory cells do not contain polysaccharides

Question 13

Pancreatic lipase

Answer 13

hydrolyses TAG into monoglycerides and free fatty acids. Secreted in active form as TAG not structural component of pancreatic cells.

Question 14

Steatorrhoea

Answer 14

excess fat in faeces

Question 15

Alkaline Solution

Answer 15

is the largest component of pancreatic juice, neutralises chyme, duct cells

Question 16

Pancreatic exocrine secretion is regulated by

Answer 16

hormones

Question 17

Acidic chyme in duodenal lumen activates releases what from the duodenal mucosa?

Answer 17

Secretin which is carried by blood and ends in pancreatic duct cells and neutralises

Question 18

fats and protein products in duodenal lumen releases what from the duodenal mucosa?

Answer 18

CCK which is carried by blood to pancreatic acinar cells and digests

Question 19

Liver function

Answer 19

secretion of bile salts (digestive role)

Question 20

Hepatocytes receive blood from 2 sources

Answer 20

arterial blood from aorta and venous blood from digestive tract

Question 21

Bile consits of:

Answer 21

bile salts, cholesterol, lecithin (phospholipid), bilirubin (waste product from old red blood cells), aqueous alkaline fluid

Question 22

Gallbladder

Answer 22

storage of bile between meals

Question 23

what are gallstones (choleliths)?

Answer 23

crystalline bodies that have precipitated from components of bile

Question 24

How do bile salts facilitate fat digestion and absorption?

Answer 24

Emulsification (digestion- detergent action) and Micelles (absorption of fat)

Question 25

Micelles

Answer 25

cholesterol is dissolved in michelles core, amount that is carried depends on amount of bile salts and lecithin. If cholesterol secretion is out of proportion microcrystals form.

Question 26

Treatment of cholesterol gallstones involves-

Answer 26

ingestion of bile salts> increase bile salt pool> dissolve cholesterol

Question 27

regulation of bile secretion- chemical

Answer 27

bile salts stimulate their own secretion when returned to the liver during meal digestion

Question 28

regulation of bile secretion- hormonal

Answer 28

secretin stimulates an aqueous NaHCO3 bile secretion to neutralise chyme

Question 29

regulation of bile secretion- vagal

Answer 29

stimulation of liver to increase bile flow during cephalic phase plays a minor role

Question 30

During digestion

Answer 30

fats and proteins products in the duodenum stimulate the release of CCK. CCK stimulates contraction of the gallbladder and relaxation of the sphincter of Oddi, releasing bile into the duodenum, fat digestion/absorption

Question 31

Bilirubin

Answer 31

2nd major component of bile- a waste product excreted in bile. derived from degradation of the heme (iron-containing) part of the haemoglobin in red blood cells

Question 32

Bilirubin facts

Answer 32

is a yellow pigment, makes bile yellow, in the intestines it is modified by bacterial enzymes to make feaces brown, makes urine yellow. patients with jaundice have a yellow colour (eyes)

Question 33

Hepatitis

Answer 33

inflammatory disease of the liver, multiples causes- viral, obesity, toxic agents, prolonged inflammation associated with alcoholism leads to cirrhosis and eventually leads to liver failure

Question 34

The pancreatic duct cells secrete aqueous alkaline solution in response to what main stimulus in the duodenum?

Answer 34

acid

Question 35

Autocatalysis is a process whereby the active digestive enzyme in the lumen converts the inactive proenzyme to the active form. Which enzymes undergo this process?

Answer 35

trysinogen and pepsinogen

Question 36

The liver is an accessory digestive organ and the largest metabolic organ in the body. What is its primary digestive role?

Answer 36

secretion of bile salts

Question 37

Between meals, bile secreted by the liver hits the closed Sphincter of Oddi and gets diverted back up the common bile duct to the gallbladder. What happens when it gets there?

Answer 37

stored until the next meal and concentrated by actively removing salt

Question 38

Micelles are vital for absorption of the end products of fat digestion, monoglycerides and FFA. In the hydrophobic core of the micelles you will also find:

Answer 38

cholesterol, lipid soluble portion of bile salts, lecithin and vitamins

Question 39

Exocrine cells

Answer 39

mucous, chief cells, parietal cells

Question 40

Endocrine cells

Answer 40

ECI cells, G cells, D cells

Question 41

Mucous (product, stimuli, function)

Answer 41

Alkaline mucous. Mechanical stimulation by contents. Protects against mechanical pepsin and acid injury

Question 42

Chief cells (product, stimuli, function)

Answer 42

Pepsinogen gastric lipase. Acetylcholine (Ach), gastrin. Protein digestion (when activated) Fat digestion (small amount)

Question 43

Parietal cells (product, stimuli, function)

Answer 43

Hydrochloric acid (HCI) and intrinsic factor. Ach and gastrin histamine. Activates pepsinogen, breaks down CT, denatures proteins, kills microorganisms, facilitates absorption of Vit B12

Question 44

ECI (product, stimuli, function)

Answer 44

Histamine. Ach, gastrin. Stimulates parietal cells

Question 45

G cells (product, stimuli, function)

Answer 45

Gastrin. Protein products Ach. stimulates chief and ECI cells

Question 46

D cells (product, stimuli, function)

Answer 46

Somatostatin. Acid. Inhibits parietal, G and ECI cells