12 - Function Of The DS

Question 1

What are the GI functions?

Answer 1

Ingest
Digest
Absorb
Defecate

Question 2

What does digestion include?

Answer 2

Mechanical breakdown

Chemical digestion

Question 3

What do extrinsic salivary glands secrete?

Answer 3

Serous, enzyme rich saliva in response to:

Ingested food which stimulates chemoreceptors and mechanoreceptors and to the thought of food

Question 4

In the stomach how much gastric fluid do the gastric glands secrete

Answer 4

400 - 800 cm3

Question 5

What is chime

Answer 5

Bolus + gastric fluid

Question 6

What do chief cells secrete?

Answer 6

Pepsinogen

Question 7

What do parietal cells secrete

Answer 7

HC1 and Lipases

Question 8

What does HC1 do

Answer 8

Hydrolyses pepsinogen to pepsin

Kills bacteria
Denatures proteins and softens fibrous tissues in food
Activates pepsin and renin
Renders calcium and iron salts suitable for absorption
Begins the hydrolysis of sucrose

Question 9

What does the pancreatic juice do

Answer 9

Neutralises almost all of the acid immediately as the chime enters the duodenum

Question 10

What does bile help do

Answer 10

Neutralise the stomach acid

Question 11

What are the two basic routes by which molecules will enter the blood?

Answer 11

Hepatic portal vein

Fats are transported up to the left subclavian vein

Question 12

Where are chylomicrons made?

Answer 12

In the ER of absorptive cells of mucosal villi cells

Question 13

What do chylomicrons do?

Answer 13

Transport dietary lipids from intestines, via lymphatic system and then bloodstream to aidipose, cardiac and muscle tissue

Question 14

What are triglycerides hydrolysed by

Answer 14

Lipoprotein lipase to free fatty acids and glycerol

Question 15

What is a lacteal

Answer 15

A lymphatic capillary that absorbs dietary fats in the villi of the small intestine

Question 16

What starts the hydrolysis of proteins in the stomach?

Answer 16

Pepsin

Question 17

Where is trypsin produced

Answer 17

In the pancreas

Question 18

What happens in the duodenum

Answer 18

It catalyses the hydrolysis of peptide bonds:

Proteins to peptides

Question 19

What is chymotrypsin

Answer 19

A pancreatic enzyme acting in the duodenum where it performs proeteolysis

Question 20

Amino acid molecules are absorbed into the bloodstream via … dependant amino acid transporters

Answer 20

Na+

Question 21

Amino acids and small peptides are absorbed where

Answer 21

Into the small intestine §

Question 22

What hydrolyses proteins to peptides

Answer 22

Trypsin and chymotrypsin

Question 23

What hydrolyse peptides to individual amino acids

Answer 23

Brush borders

Question 24

What is glucose absorbed by?

Answer 24

Epithelial cells using a protein carrier

Question 25

Where are electrolytes absorbed?

Answer 25

In the small intestine

Question 26

Where are vitamins K and B absorbed

Answer 26

Large Intestine

Question 27

Where are most dietary vitamins absorbed>

Answer 27

Small intestine

Question 28

What are the two types of nervous control of the GI tract?

Answer 28

Intrinsic control - activity of the nerve plexuses near the GI tract initiating short reflexes
Extrinsic controls - long reflexes arising within or outside the GI tract