digestion and absorbtion

Question 1

6 basic functions of GI

Answer 1

1. movement
2. secretion of digestive juices
3. digestion
4. absorption
5. circulation - of blood through system
6. control of processes

Question 2

2 main structures involved in digestion

Answer 2

1. luminal tract (tube from top to bottom)

2. accessory organs - teeth, pancreas, liver stc

Question 3

3 main roles of stomach

Answer 3

1. break down food mechanically
2. secrete acid/enzymes
3. kill bacteria

Question 4

role of SI

Answer 4

digestion and absorbtion

Question 5

how is SI surface are increaed

Answer 5

microvillae

Question 6

4 sources of luminal enzymes and what they are

Answer 6

1. salivary glands - amylase, lipase
2. stomach - pepsin, lipase
3. pancreas - anylase, trypsin, lipase
4. SI - enterokinase, dissacharidase, pepsidase

Question 7

what happens to proteins in stomach

Answer 7

broken into polypeptides by gastirc acid and pepsin

Question 8

what happens to proteins in SI

Answer 8

polypeps broken into smaller polypeps using panc. enzymes (trypsin, chymotripsin)

Question 9

what removes AAs from polypeps

Answer 9

carboxypolypesdiases

Question 10

how does AA enter system

Answer 10

brush border pulls in di, tri AAs and and these are transported into cell via Na co-transporter

Question 11

what happens to AA in cell

Answer 11

broken into smaller AAs so can enter the blood

Question 12

what happens to fat ins stomach and mouth

Answer 12

breakup of 10% of TGs into MG and FFAs by acid resistant lipase

Question 13

what happens to fat in SI

Answer 13

bile salts emulsify

Question 14

what is eumlsification

Answer 14

bile salts align to make fat hydrophillic

Question 15

what happens to fat with bile salts

Answer 15

along with lipase, broken down further into micelle

Question 16

why are micelles important

Answer 16

allow it to cross H2O layer before brush border of cell

Question 17

what happens to fats within cell (2)

Answer 17

1. MG and FFA reesterify into TG in ER of cell

2. apoproteins attached in golgi to make chilomicron

Question 18

why is apoprotein important

Answer 18

allows CM to leave cell

Question 19

what can cause intraluminal malabsorbtion (3)

Answer 19

1. lipase defic - pancreatitis
2. impaired micelle formation - no bile salts - liver probs
3. pH probs - H excess via gastroma, HCO3 via CF

Question 20

2 problem occuring with mucosa

Answer 20

1. impaired uptake - celiacs, fistula

2. impaired CM formation - abetalipoprotenemia

Question 21

what happens to starch in mouth

Answer 21

amylase breaks it down into maltose

Question 22

what happens to starch in stomach

Answer 22

salivary amylase continues to break into maltose, HCl only allows 35%

Question 23

what happens to starch in SI

Answer 23

pancreatic amylase (stronger) breaks it down to maltose

Question 24

what happens to maltose in SI

Answer 24

disaccaridases at brush border break disacs into monosacs

Question 25

how does glucose get in

Answer 25

Na/glucose pump pulls it in + also solvent drag

Question 26

how does fructose get in

Answer 26

via facilated diffusiton

Question 27

what happens to fructose in cell

Answer 27

some turned into glucose

Question 28

where is bile salts resabsorbed

Answer 28

illeum

Question 29

where is B12 absorbed

Answer 29

activated in duod, but absorbed in illeum