digestion and absorbtion Flashcards

1
Q

6 basic functions of GI

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

2 main structures involved in digestion

A
  1. luminal tract (tube from top to bottom)

2. accessory organs - teeth, pancreas, liver stc

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3
Q

3 main roles of stomach

A
  1. break down food mechanically
  2. secrete acid/enzymes
  3. kill bacteria
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4
Q

role of SI

A

digestion and absorbtion

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5
Q

how is SI surface are increaed

A

microvillae

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6
Q

4 sources of luminal enzymes and what they are

A
  1. salivary glands - amylase, lipase
  2. stomach - pepsin, lipase
  3. pancreas - anylase, trypsin, lipase
  4. SI - enterokinase, dissacharidase, pepsidase
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7
Q

what happens to proteins in stomach

A

broken into polypeptides by gastirc acid and pepsin

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8
Q

what happens to proteins in SI

A

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

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9
Q

what removes AAs from polypeps

A

carboxypolypesdiases

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10
Q

how does AA enter system

A

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

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11
Q

what happens to AA in cell

A

broken into smaller AAs so can enter the blood

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12
Q

what happens to fat ins stomach and mouth

A

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

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13
Q

what happens to fat in SI

A

bile salts emulsify

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14
Q

what is eumlsification

A

bile salts align to make fat hydrophillic

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15
Q

what happens to fat with bile salts

A

along with lipase, broken down further into micelle

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16
Q

why are micelles important

A

allow it to cross H2O layer before brush border of cell

17
Q

what happens to fats within cell (2)

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

2. apoproteins attached in golgi to make chilomicron

18
Q

why is apoprotein important

A

allows CM to leave cell

19
Q

what can cause intraluminal malabsorbtion (3)

A
  1. lipase defic - pancreatitis
  2. impaired micelle formation - no bile salts - liver probs
  3. pH probs - H excess via gastroma, HCO3 via CF
20
Q

2 problem occuring with mucosa

A
  1. impaired uptake - celiacs, fistula

2. impaired CM formation - abetalipoprotenemia

21
Q

what happens to starch in mouth

A

amylase breaks it down into maltose

22
Q

what happens to starch in stomach

A

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

23
Q

what happens to starch in SI

A

pancreatic amylase (stronger) breaks it down to maltose

24
Q

what happens to maltose in SI

A

disaccaridases at brush border break disacs into monosacs

25
how does glucose get in
Na/glucose pump pulls it in + also solvent drag
26
how does fructose get in
via facilated diffusiton
27
what happens to fructose in cell
some turned into glucose
28
where is bile salts resabsorbed
illeum
29
where is B12 absorbed
activated in duod, but absorbed in illeum