SNAB biology

Olive_18

Does anyone know what causes water to be drawn out of the epithelial cells ?

(edited 5 years ago)

Could it be osmosis?

I guess. Does that mean the excess water detected by the epithelial cells is actually in the cells aswell then?

Original post by Daisy87!

Could it be osmosis?

Reply 3

Daisy87!

I would think there’s a water imbalance between the epithelial cells and the outside. If the concentration of water inside the cells is greater than externally then it will be drawn out via osmosis so there is somewhat an equilibrium

Reply 4

Olive_18

Awesome thanks :smile:

Original post by Daisy87!

Reply 5

Daisy87!

No worries :smile:

it’s probably something along those lines

Reply 6

LightningLorenzo

I think you might be talking about the change in mucus viscosity to do with the CFTR channel and sodium channel, so for water out of the epithelial cells the Cl ions are pumped into them across the basal membrane which is at the bottom of the cell, then at the top where the mucus is the CFTR channel is open and Cl ions diffuse out. This causes an electrical gradient to be set up due to the negative charge of the Cl ions so positive Na ions diffuse into the mucus. This difference in salt water concentration causes water to be drawn out of the cells by osmosis.

I've opened up a thread for SNAB 2019 students on potential questions that could come up and how we'd answer them, feel free to share any of your ideas in it if you want https://www.thestudentroom.co.uk/showthread.php?t=5953314&p=83285400#post83285400