Week 3: Digestion and absorption

Question 1

What does the gastrointestinal system secrete?

Answer 1

Water
Acids
Buffers
Enzymes

Question 2

What type of processes cause digestion?

Answer 2

Mechanical and chemical

Question 3

Where does 95% of absorption take place?

Answer 3

Small intestine

Question 4

What do we defecate?

Answer 4

Indigestible substances
Cells
Digested materials not absorbed

Question 5

Is the pancreas an endocrine or exocrine organ?

Answer 5

It is both

Question 6

What does endocrine mean?

Answer 6

Glands that sescrete hormones or other products directly into the blood

Question 7

What does exocrine mean?

Answer 7

Glands which secrete their products through ducts opening on to an epithelium rather than directly into the blood

Question 8

What is HCO3- necessary for?

Answer 8

Digestive enzyme activity
Micelle formation
Protecting doudenal muscosa

Question 9

What stimulates the production of HCO3-?

Answer 9

Secretin

Question 10

How much HCO3- is secreted everyday?

Answer 10

1.5 L per day

Question 11

What stimulates enzyme secretion?

Answer 11

CCK

Question 12

When is CCK releases?

Answer 12

When fat and protein are in the duodenum

Question 13

What do acinar cells secrete?

Answer 13

An enzyme rich Cl- solution

Question 14

What are the two types of complex carbohydrates?

Answer 14

Starch (plant)

Glycogen (meat)

Question 15

Where and how does most carbohydrate digestion occur?

Answer 15

The small intestine by the action of pancreatic alpha-amylase

Question 16

Where are glucose, galactose and fructose directly transported to from the portal vein?

Answer 16

The liver

Question 17

What are fructose and galactose converted into?

Answer 17

Glucose derivatives

Question 18

How does glucose enter organs?

Answer 18

Facilitated transport

Question 19

Where is insulin released?

Answer 19

Pancreas

Question 20

What regulates glucose levels in skeletal muscle and adipose tissue?

Answer 20

Insulin

Question 21

Where does protein digestion begin?

Answer 21

In the stomach

Question 22

What % of protein is digested in the stomach?

Answer 22

15%

Question 23

What is in the stomach that breaks down protein?

Answer 23

Pepsin

Question 24

What actively halts pepsin?

Answer 24

Alkaline pancreatic secretions

Question 25

Where is the majority of protein digested?

Answer 25

Small intestine

Question 26

What enzymes digest protein in the small intestine?

Answer 26

Pancreatic

Question 27

What are the two major classes of enzymes that break down protein?

Answer 27

Endopeptidases | Exopeptidases

Question 28

What do endopeptidases enzymes do?

Answer 28

Cleave interior peptide bonds

Question 29

What do exopeptide enzymes do?

Answer 29

Cleave external peptide bonds

Question 30

When are the enzymes in the pancreas activated and why?

Answer 30

When they are outside the pancreas to prevent digestion of pancreatic proteins

Question 31

What activates the enzymes released by the pancreas?

Answer 31

Trypsin

Question 32

What are di- and tri-peptides further borken down into?

Answer 32

Amino acids

Question 33

What breaks di- tri-peptides down?

Answer 33

Intracellular peptidases of enterocyte

Question 34

How are amino acids absorbed?

Answer 34

Diffusion and sodium dependent transport

Question 35

What are the functions of the liver?

Answer 35

Bile production Metabolism Detoxification of the blood

Question 36

When is bile produced?

Answer 36

It is continuously produced

Question 37

What happens to bile between meals?

Answer 37

It is stored in the gall bladder and concentrated

Question 38

What is the function of bile?

Answer 38

``` Excretion of: Bile pigments Cholesterol Steroids Heavy metals Drugs ```

Question 39

When does the gall bladder contract to eject bile into duodenum?

Answer 39

Following a meal

Question 40

What stimulates the contraction of the gall bladder?

Answer 40

Secretin and CCK

Question 41

What % of bile salts are reabsorbed and recycled?

Answer 41

90%

Question 42

What are lipids emulsified by?

Answer 42

Bile

Question 43

What does lipases break triglycerides into?

Answer 43

Fatty acids and monoglycerides

Question 44

What are fatty acids and monoglycerides packaged into?

Answer 44

Micelles that are absorbed by microvilli

Question 45

What are fatty acids and monoglycerides converted back into?

Answer 45

Triglycerides

Question 46

What do the triglycerides aggregate with?

Answer 46

Cholesterol, proteins and phospholipids

Question 47

When triglycerides aggregate with cholesterol, proteins and phospholipids what do they form?

Answer 47

Chylomicrons

Question 48

Where do chylomicrons move?

Answer 48

Into a lymph capillary , which transports them to the rest of the body

Question 49

Where are vitamins absorbed?

Answer 49

In the small intestine

Question 50

How much water is absorbed each day?

Answer 50

8 litres

Question 51

How much water each day is secreted into the GI tract?

Answer 51

6 litres

Question 52

What % of water is absorbed into the small intestine?

Answer 52

90%

Question 53

What % of water is absorbed into the large intestine?

Answer 53

10%