According to the guard hypothesis, R gene products “guard” cellular proteins, which are called guardees or decoys

TLS Online TPP Program

#Id: 2575

#Unit 7. System Physiology – Animal

Transport of water and solutes from the interstitial fluid into the peritubular capillaries occurs by ultrafiltration.

TLS Online TPP Program

#Id: 2576

#Unit 7. System Physiology – Animal

Glucose reabsorption is a two-step process: 

Na+-glucose cotransport across the luminal membrane 

Facilitated glucose transport across the peritubular membrane

TLS Online TPP Program

#Id: 2577

#Unit 7. System Physiology – Animal

Proximal tubular reabsorption

Reabsorbs 67% of the filtered Na+

Reabsorbs 67% of the filtered water

Reabsorbs 100% of the filtered glucose & amino acids 

Reabsorbs 85% of the filtered HCO3−

Reabsorbs most of the filtered phosphate, lactate, and citrate

TLS Online TPP Program

#Id: 2578

#Unit 7. System Physiology – Animal

Isosmotic reabsorption is a hallmark of proximal tubular function: Solute and water reabsorption are coupled and are proportional to each other.

TLS Online TPP Program

#Id: 2579

#Unit 7. System Physiology – Animal

The proximal tubule is the site of glomerulotubular balance, a mechanism for coupling reabsorption to the GFR.

TLS Online TPP Program

#Id: 2580

#Unit 7. System Physiology – Animal

Proximal tubule epithelial cells are highly metabolic and have large numbers of mitochondria to support

powerful active transport processes.