What is the mechanism for HCO3- reabsorption in the proximal tubule? HCO3- acts

Question

What is the mechanism for HCO3- reabsorption in the proximal tubule?

HCO3- acts as a buffer for H+, combining to make H2CO3 which is then pumped from the lumen through the Type A intercalated cells into the ECF.

CO2 diffuses into proximal tubule cells. Carbonic anhydrase converts CO2 and water to H+ and HCO3- then NHE pumps the H+ into the lumen of the collecting duct and the Na+- HCO3-- symports moves HCO3- into the ECF.

CO2 diffuses through both the apical and the basolateral membranes of the proximal tubule cells to the ECF, where CA converts CO2 and H2O into H+ and HCO3-.

Select all that are TRUE for pluripotent hematopoietic stem cells: (select all that apply)

they are found primarily in the bone marrow.

another name for them is uncommitted stem cells

they eventually differentiate in to lymphocytes

they eventually differentiate in to megakaryocytes

they eventually differentiate in to erythrocytes.

Explanation / Answer

CO2 diffuses into proximal tubule cells. Carbonic anhydrase converts CO2 and water to H+ and HCO3- then NHE pumps the H+ into the lumen of the collecting duct and the Na+- HCO3-- symports moves HCO3- into the ECF.

HCO3- is reabsorbed from proximal convoluted tubules (PCT). This was given only in the option 2.

2. pluripotent hematopoietic stem cells

there is no such term pluripotent hematopoietic stem cells. pluripotent stem cells are uncommitted, i.e, they can give rise to any type of cells, and are present in umbilical cord. whereas, hematopoietic stem cells give rise to all types of cells and they are present in bone marrow.

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