GENERAL HISTOLOGY

Detailed explanation-1: -The major route for the transport of dietary glucose from intestinal lumen into enterocytes is the Na+/glucose cotransporter (SGLT1), although glucose transporter type 2 (GLUT2) may also play a role.

Detailed explanation-2: -Glucose enters the epithelial cells by a process catalyzed by the cotransporter SGLT-1. Intracellular cAMP activates the transepithelial transport by a mechanism possibly involving phosphorylation of SGLT-1. The glucose accumulated intracellularly can diffuse out of the cells by facilitated diffusion through GLUT2.

Detailed explanation-3: -Sodium-glucose cotransporter (SGLT) activity mediates apical sodium and glucose transport across cell membranes. Cotransport is driven by active sodium extrusion by the basolateral sodium/potassium-ATPase, thus facilitating glucose uptake against an intracellular up-hill gradient.

Detailed explanation-4: -The correct answer is option B. The sodium-glucose transporter (SGLT) is an integral transmembrane protein that is found in the cells that form the mucosa of the cell intestine. The sodium-glucose transporter is a cotransporter molecule, meaning it permits the passage of two different molecules at the same time.

Detailed explanation-5: -Epithelial transport requires that epithelial cells are polarized, that is, the proteins present in the apical (airway facing) and the basolateral (blood facing) membrane are not the same. This polarization can promote net flux of sodium from lumen to interstitium.