Introduction to Epithelia and Epithelial Transport flashcards

Question 1

Transport epithelia

Answer 1

Form single layer of cells and function to move solutes (and water) across cell membranes and from one compartment to another

Question 2

Polarity of epithelia

Answer 2

2 distinct sides 1. Apical side (facing the tissue lumen) 2. Basolateral side (facing the intercellular solution and bloodstream

Question 3

Paracellular transport

Answer 3

Movement of water and solutes through tight junctions between epithelial cells

Question 4

Transcellular transport

Answer 4

Movement through the epithelial cells

Question 5

Basolateral membrane

Answer 5

Faces the intercellular solution and bloodstream. Has a high density of Na+/K+ pump molecules maintaining large transmembrane gradient to be used for secondary active transport.

Question 6

Charges moving across membranes

Answer 6

Must be balanced. If moving positive charges then must either move negative charges in the same direction or move positive charges in the opposite direction

Question 7

Do transport of solutes across epithelia increase when action potentials occur?

Answer 7

No; there are no action potentials in epithelia

Question 8

How to solve a problem looking for final intracellular volume?

Answer 8

1. First determine direction of water flow 2. Find osmolarity (mOsm/L) outside cell (multiply by # of ions) 3. Find amount of solute outside cell by multiplying osmolarity by volume outside 4. Find amount of solute inside cells by multiplying osmolarity by volume inside 5. Add together outside and inside solutes and volumes 6. Divide total solute by total volume to get final osmolarity inside and outside 7. Use: New osmolarity times X L = Old osmolarity times Initial L