In: Anatomy and Physiology
Write the word or phrase that best completes each statement or answers the question.I
f solute A is actively transported across the basolateral membrane into the epithelial cell and then passively crosses the apical membrane, then is A (reabsorbed / secreted) across this epithelium.
Epithelial cells have apical and basolateral surfaces. The apical surface is the surface that faces the lumen. The basolateral surface is attached to the basement membrane in the organ. Basement membranes connect the epithelial cells the inner connective tissue of the organ.
When the solute moves across the basement membrane, there is active transport against the concentration gradient. Thus, the solute moves from the connective tissue and basement membrane into the epithelial cells. Passive transport will move the solute from the epithelial cell cytoplasm to the lumen via the apical surface. Thus, the solute will be secreted into the lumen. Hence, this transport will lead to secretion of the solute.
Reabsorption is when the solute moves first across the apical surface and then moves through the basolateral membrane. This transport is seen for glucose transport from intestine to blood. The glucose is produced by carbohydrate digestion in intestinal lumen and enters blood circulation.
Right choice: secreted.