GI 9 - The Intestines Flashcards

1
Q

Name the cells in the intestines which secrete antibacterial enzymes ie Lyzozymes + Defensins:

A

Paneth cells

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

Approx. how many microvilli are present on each enterocyte?

A

~ 3000 per cell

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

What is the approx. total surface area of the GI tract? How much of this is the small intestine?

A

~ 30 m^2

Small intestines = ~ 20 m^2

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

How does the small intestine have such massive surface area?

A
  • Folds of Kerckring
  • Villi + Crypts of Lieberkuhn
  • Microvilli
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where are plicae circulares found?

A

Small intestine

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

What type of epithelial cells are found in the intestines?

A

Simple columnar epithelia

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

Name the 2 types of starch that we can digest, the enzymes required for digestion, and the products of digestion:

A

Amylose -> Glucose + Maltose via Amylase

Amylopectin -> alpha-dextrins via Isomaltase

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

Which monosaccharides are transported by SGLT1 into the enterocyte from the GI lumen?

A

Glucose

Galactose

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

Which monosaccharides are transported by GLUT5 into the enterocyte from the GI lumen?

A

Fructose

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

How do monosaccharides move across the basolateral membrane of the enterocyte?

A

GLUT2

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

Which transporters are present on the apical membrane of the enterocyte for carbohydrate absorption?

A

SGLT1

GLUT5

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

Which enzymes to break down carbohydrates are present on the brush-border?

A
  • Maltase
  • Isomaltase
  • Amylase
  • Lactase
  • Sucrase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which enzymes to break down proteins are present on the brush-border?

A
  • Trypsin
  • Chemotrypsin
  • Elastase
  • Carboxypeptidase A + B
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which transporters can move amino acids and peptides into the enterocyte, from the GI lumen?

A

Na+-AA symporter

PEPT1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What causes micelles to fall apart, allowing the absorption of fats into the enterocytes?

A

Acidic brush-border (formed by Na+/H+ exchanger)

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

What are the components of a chylomicron?

A
  • Triacylglycerides
  • Cholesterol
  • Phospholipids
  • ApoB-48 (protein)
17
Q

Where are chylomicrons formed, and what is their function?

A

Enterocytes

Transport dietary lipid from intestines to Liver + Adipose cells

18
Q

Which electrolyte must be present for the absorption of glucose, water and other electrolytes?

A

Na+ - forms concentration/osmotic gradient

19
Q

What is the blood supply to the small intestines?

A

Superior mesenteric artery

20
Q

What is the function of the proximal half of the large intestine?

A

Absorption of minerals + H2O

21
Q

What is the function of the distal half of the large intestine?

A

Storage and mucous secretion

22
Q

What is the blood supply of the ascending colon, and proximal transverse colon?

A

SMA:

  • Ileocolic
  • Right colic
  • Middle colic
23
Q

What is the blood supply to the distal transverse colon, and descending colon?

A

IMA:

  • Left colic
  • Sigmoid arteries
24
Q

What structures are present at the Caecum?

A
  • Ileocaecal valve

- Appendix

25
Q

The superior rectal artery is the continuation of which artery?

A

IMA - becomes sup. rectal when passes into pelvis

26
Q

What is the taenia coli?

A

3 narrow bands of longitudinal muscle running the length of the large intestine
- except in rectum, anal canal and appendix

27
Q

At what point does the colon stimulate the urge to defecate?

A

When rectum ~ 25% full

28
Q

Is the internal anal sphincter controlled by the parasympathetic or sympathetic nervous system?

A

Parasympathetic