GI Digestion and Absorption Flashcards Preview

Digestive, Endocrine, and Metabolic Systems > GI Digestion and Absorption > Flashcards

Flashcards in GI Digestion and Absorption Deck (30):
1

About ______ percent of proteins are digested by gastric pepsin.

15

2

Luminal peptidases and brush-border enzymes break down _______________.

proteins into dipeptides, tripeptides, and amino acids

3

Intracellular peptidases within enterocytes break down ____________. This prevents the need for basolateral polypeptide transporters.

dipeptides and tripeptides to amino acids

4

The major uptake route for amino acids is ______________.

sodium cotransport (from the Na/K ATP pump gradient)

5

Infants utilize ____________ to absorb proteins.

pinocytosis

6

Protons help ____________ get absorbed via cotransport.

dipeptides and tripeptides

7

The body can make all necessary lipids except _____________.

linoleic acid (omega-6 fatty acid) – which gets converted to arachidonic acid – and alpha-linoleic acid (omega-3 fatty acid)

8

What is steatorrhea?

Excessively greasy stool

9

The substance in lacteals is called ______________.

chyle

10

Most GI secretion occurs in the ___________, while most absorption occurs in the ____________.

stomach; jejunum

11

Potassium is absorbed ____________ in the jejunum and ______________ in the colon.

paracellularly; transcellularly

12

Vitamin D is first hydroxylated in the __________ and then again in the ______________.

liver; kidney

13

Iron can be absorbed as ___________.

Fe2+ or heme

14

Water absorption ___________ as you proceed from the small intestine to the large intestine.

decreases (because paracellular permeability decreases in the colon); in the distal colon, water absorption must be coupled to ion movement

15

Chloride channels are dependent on _____________.

cAMP

16

True or false: loperamide can treat cholera diarrhea.

False. Loperamide does not affect the diarrheal mechanism of cholera.

17

Maltose is __________.

a disaccharide of glucose

18

Elastase breaks down ______________.

neutral, aliphatic amino acids

19

True or false: fatty acids require co-transport to be absorbed.

False. They pass through the membrane.

20

What activates pepsinogen?

Low pH (1-3)

21

How are the pancreatic proteases terminated?

They digest themselves.

22

Cysteinuria is usually accompanied by __________.

loss of lysine, arginine, and ornithine (COAL); this results from loss of the Na-amino acid transporter, resulting in inability to absorb or excrete these molecules

23

Chylomicrons contain what three things?

Triglycerides, cholesterol, and phospholipids

24

Lipase and colipase form what?

Micelles that are passively absorbed

25

Water rapidly crosses the intestinal epithelium, so chyme ____________.

quickly becomes isotonic with the blood

26

By what receptors are proteins absorbed?

- Sodium cotransport
- Proton cotransport for di- and tripeptides
- Pinocytosis of peptides (only in infants)
- Sodium independent transport

27

What does lipase do?

It hydrolyzes triglycerides to free fatty acids.

28

Chylomicrons are synthesized in _________________.

intestinal epithelium

29

About _______ liters of fluid are secreted into the gut each day. All but about 100-200 mLs is reabsorbed.

9

30

In which part of the GI tract does sodium enter via ENaC?

The colon

Decks in Digestive, Endocrine, and Metabolic Systems Class (133):