The student asks the professor why water and electrolytes are transported in both directions through tight junctions and intercellular spaces rather than across cell membranes. What response by the professor is best?
A)The intercellular hydrostatic pressure is inadequate to push the water and electrolytes across the cell membranes.
B)A balance of cations and ions among the electrolytes on each side of the cell membranes cannot be maintained.
C)The epithelial cell membranes are formed of lipids that are hydrophobic and therefore repel water.
D)Receptors on those cell membranes are occupied with a diffusion of amino acids and monosaccharides.

Question

Quizplus · Accepted Answer

The epithelial cell membranes of the small intestine are formed of lipids and are hydrophobic or tend to repel water. Therefore, water and electrolytes are transported in both directions-toward the capillary blood or toward the intestinal lumen-through the tight junctions and intercellular spaces rather than across cell membranes.

The Student Asks the Professor Why Water and Electrolytes Are