Epithelial transport if glucose

Question 1

Describe a overview of epithelial tissue

Answer 1

cells are either in single layer or multiple layers

cells are connected to a BM

They are under constant repair due to breakdown or injury

form the boundaries of organs and boundaries of skin to external environment

Question 2

Describe the tight junctions structure and location

Answer 2

found between intracellular space of epithelial cells

contains membrane proteins that encircle cell and connect to the adjacent epithelial cell

Question 3

What is the function of the tight juction

Answer 3

acts as a shield to prevent substances from travelling between cell space

divides the epithelial cell into two distinct domains. which are the basolateral and apical surface.

Question 4

Describe paracellular transport

Answer 4

transport through the tight junction

increase in electrical resistance= increase in tight junctions

Also referred to as leaky epithelium

Question 5

Describe Transcellular transport and give example

Answer 5

can be active or passive transport

occurs with the diffusion across the ion channel

Example:
Absorption: lumen to blood
Secretion: blood to lumen

Question 6

state the rules with Transcellular transport

Answer 6

1. entry and exit point (absorption: lumen apical/ secretion: blood basolateral)
2. electrochemical gradient: active or passive
3. electroneutrality: will the diffusion of an ion cause a counter action of another ion
4. Osmosis: will this cause a concentration gradient therefore will water follow.

Question 7

Describe the first 1-3 steps involved in glucose uptake within the intestine

Answer 7

1. Tight junctions that separate the apical and basallateral domain
2. Na pump (basal) that creates a conc gradient (2K in)
3. sodium glucose supporter that uses the conc gradient to allow glucose in above the conc gradient

Question 8

Describe the first 4-6 steps involved in glucose uptake within the intestine

Answer 8

4. Faciliated glucose transporter (GLut) allows glucose to diffuse aross the basolateral domain via passive diffusion
5. Na that was taken up via glucose exits via the Na pump
6. With the increase of Na and glucose within the epithelium CI and H20 diffuse across the tight junctions

Question 9

Describe Glucose and galactose malabsorption within the intestine

Answer 9

mutation of the glucose symporter= inability to uptake glucose= increase in osmolarity= increase of H20 within the intestine

Results in watery chime diarrheas’

Question 10

Describe the treatment of Glucose malabsorption

Answer 10

replace glucose with frutose (different carbohydrate group)
Frutose has a facilitated symporter (GLUT5)

fructose exits across the basolateral membrane via GLUT2

Question 11

Describe glucose malfunction within the kidneys

Answer 11

In the kidney glucose in the plasma is reabsorbed otherwise itll be within the urine

Question 12

Describe glucose uptake and diabetes situation

Answer 12

insulin activity is at a deficit and blood sugar is too high

Glucose symporter can not absorb glucose fast enough= appearance in urine