Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physiology Test 3 > Digestion And Absorption > Flashcards

Digestion And Absorption Flashcards

1
Q

What does absorption of nutrients in small intestine depend on?

A

Intact Villous lining of small intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What isS on upper half of villi in small intestine?

A

Membrane-bound enzymes and site for absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does the bottom half of villous lining do?

A

Secrete buffers and mucus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the unstirred water layer?

A

Slowing of laminar flow by edges of lumen with mixture of mucus secreted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What substrate does salivary amylase work on? What is its products?

A

Isomaltose

Maltose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What substrates do pepsin’s work on? Products?

A

Works on proteins and polypeptides to make smaller peptide chains (oligopeptides)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What substrate does pancreatic amylase work on? Products?

A

Starches to make isomaltose and maltose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What substate does enterokinase work on? Products?

A

Typsinogen—> trypsin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What substrate do peptidases work on? Products?

A

Polypeptides to make smaller peptides down to Amino acid, di and tri peptides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What substrate does maltase work on? Product?

A

Maltose down to glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What substrate does isomaltase work on? Products

A

Isomaltose—> glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What substrate does lactase work on?products

A

Lactose—> glu and galactose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What substrate does sucrose work on? Products?

A

SUCROSE—-> Glucose and fructose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the BB enzymes located in small intestine?

A 
Enterokinase
Peptidases
Maltase 
Isomaltase
Lactase
Sucrose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where are di and tri peptides converted to amino acids?

A

Inside cytoplasm of enterocyte by peptidases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What type of carbohydrates can get into enterocyte?

A

Monosaccharides only!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Where does carbohydrate digestion begin?

A

Mouth with salivary alpha amylase Digests some carbohydrates to maltose/isomaltose (mainly maltose)
-stops digestion once food in stomach because of low pH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where does carbohydate digestion continue after mouth?

A

In duodenum, pancreatic alpha amylase secreted by pancreas
-continue to break down starches to maltose/isomaltose
In small intestine, brush border enzymes continue breakdown of maltose, isomaltose, sucrose, lactose to monosaccharides (glucose, fructose, galactose)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is absorbed via the SGLT-1 transporter on intestinal lumen?

A

Glucose, galactose absorbed via Glucose/Na cotransport, (also pulls in water)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is absorbed via GLUT 5 facilitated transport on intestinal lumen?

A

Fructose

21
Q

How are monosaccharides brought into capillaries from enterocytes?

A

Facilitated transport (GLUT -2)

22
Q

All glucose absorption inside small intestine is ____ ____

A

Insulin-independent

23
Q

Where does protein digestion begin?

A

Stomach with pepsinogen (secreted by chief cells)—> becomes pepsin by activation of HCl

24
Q

What are the pancreatic proteases?

A

Trypsinogen
Chymotrypsinogen
Procardoxypeptidase

Typsinogen is converted to trypsin by enterokinase (BB enzyme)

Then trypsin converts chymotrypsinogen—> chymotrypsin, procarboxypeptidase—> carboxypeptidase

These break down protein—> oligopeptides

25
Q

What do small intestine brush border enzymes do to proteins?

A

Break down oligopeptides into lots of Amino acids, di and tri peptides.

26
Q

What proteins can be absorbed into enterocyte?

A

Amino acid, di, tri peptides

27
Q

What proteins can go into capillary?

A

ONLY Amino acids.

Inside enterocyte, di and tri peptides are converted amino acids by peptidases in cytoplasm

28
Q

How are di/tri peptides brought into enterocyte?

A

Facilitated transport

29
Q

How are amino acids brought into enterocyte?

A

Facilitated transport as well as Na dependent transport

30
Q

What is trypsin inhibitor?

A

Enzyme produced by pancrease that prevents trypsin form becoming activated in pancreas and ducts and damaging tissue.

31
Q

Where does lipid digestion start?

A
  • Mouth with lingual lipase (by von ebner’s glands)
  • Begins hydrolysis of TG to diglycerides and FFA.

-This enzyme remains active in stomach

32
Q

What happens to digestion of lipids in stomach?

A

Gastric lipase secreted by chief cells

-hydrolyzes TG to diglycerides and FFA

33
Q

What happens to lipid digestion in small intestine?

A

Pancreatic lipase- hydrolyzes TG to monoglycerides and free fatty acids

BUT,
Needs help of colipase

Pro colipase secreted by duodenum and activated by trypsin to form colipase

34
Q

What is role of micelle?

A

“Taxiing” lipids through unstirred water layer

35
Q

What happens to lipids once inside enterocyte?

A

Enter smooth endoplasmic reticulum and re-esterified with FFA into TG, Phospholipids, and cholesterol esters

Form chylomicrons which exocytose from enterocyte and are absorbed into lymph

36
Q

How is bile absorbed in terminal ileum?

A

Conjugated bile- Via secondary active transport with Na (also brings in water)

Unconjugated bile enters enterocyte through diffusion

37
Q

How is Na absorbed in jejunum?

A

Na/K ATPase creates gradient needed for
-secondary active transport of Na into cell, either

-with sugars, amino acids.

  • Na/H antiport
  • NKCC-2 (Na-Cl-K cotransport)
38
Q

How is iron absorbed in intestine?

A

Iron always has to be bound inside blood (otherwise toxic)

  • Iron bound to protein can stay in cell (ferritin storage) or leave, and bind to transferrin in blood and go to liver for storage and bone marrow for use

Loose 3 mg iron everyday (from recycling enterocytes)

39
Q

What does VItamin D do at enterocytes?

A
  • Increase Ca channels at luminal wall
  • Increase calbindin
  • Increase Ca ATPase pump activity
40
Q

What does calcium bind to once inside enterocyte?

A

Calbindin (this binding is increased by vitamin D)

41
Q

What does binding of ca to calbindin allow?

A

Allows Ca gradient to continue, bringing more Ca into cell

42
Q

Once in enterocyte, how does Ca go to capillary?

A

Ca ATPase or Ca/Na antiport

43
Q

Once in blood, does calcium stay bound?

A

40% bound, 60% free

Not necessary to have everything bound in plasma but it is bound intracellularly

44
Q

In what ways do we protect vitamin B12 as it’s going through GI system?

A
  • In mouth, bound to TC-1 secreted by mouth. This protects B12 from pepsins in stomach
  • In stomach, binds to intrinsic factor (forms B12-IF-TC-1 compounds
  • TC-1 cleaved in small intestine by trypsin
  • Left with B12-IF combo in small intestine. (Which is dimerized)
  • This protects b12 from pancreatic lipases
  • Goes to terminal ileum to be absorbed
45
Q

How is b-12 absorbed at terminal ileum?

A
  • Specific receptors that recognize B12-IF dimer and goes to transporters where absorbed
  • Binds to TC-2 in enterocyte where it leaves, go to blood, goes to liver for storage or bone marrow for maturation of RBC
46
Q

What stimulates Na absorption in colon?

A

Aldosterone

47
Q

What happens if you eat a lot of fiber?

A

Less water will come out of chyme, softer stools

48
Q

What does the increase in fluid and pressure in lower intestine from diarrhea, cause?

A

Increased motility and reduced absorption

49
Q

What is the composition of feceS?

A

Water (75%)
SOlids (25%) - cellulose (variable), bacteria (30%), inorganic (15%), fat (5%)

Containers K AND HCO3

Physiology Test 3 (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions