The Distal Convoluted Tubule & Collecting Duct Transport

unit 4 week 13 lesson 5

what does the distal convoluted tubule reabsorb

na, cl, k and ca

how is ca reabsorption increased

• if the hormone parathyroid hormone (PTH) is signalling to these tubule cells

principal cells in collecting duct

• principal cells are majority of epithelial cells found in the collecting duct

• they are responsive to a variety of hormones and will change how much of a substance can be reabsorbed from the filtrate

• the collecting duct is made up of a mix of epithelial cells composed of principal and two types of intercalated cells;

• type a and b

• intercalated cells are responsive to changes in plasma pH

• principal cells are responsive to hormones that regulate water and sodium balance

collecting duct channels

• aquaporin 2 on luminal responds to hormones (adh)

• aquaporin 3 or 4 on baso

• sodium channel on luminal, sodium moves from lumen to cell, responsive to hormone, aldosterone

• potassium channel on luminal, k moves from cell to lumen, responds to aldosterone

• atpase, 3 na out, 2 k in, responds to aldosterone