Lecture 3.1: Filtration and Reabsorption

Question 1

What is the Function of a Nephron? What processes does it carry out?

Answer 1

Regulate plasma composition via:
• Filtration (forms glomerular filtrate)
• Reabsorption (movement from tubular fluid to blood)
• Secretion (movement from blood to tubular fluid)
• Absorption/Secretion – occurs via tubular cells (transcellular route) or between
cells (prarcellular route)

Question 2

Transcellular vs Paracellular Route

Answer 2

• Transcellular movement occurs via tubular cells and is highly dependent on
secondary active transport
• Paracellular route is between cells and is dependent on concentration/
electrical gradients

Question 3

What percentage of cardiac output do the kidneys recieve?

Answer 3

20%

Question 4

What is Renal Blood Flow (RBF) Auto-Regulation?

Answer 4

A vital homeostatic mechanism that protects the kidney from elevations in arterial pressure that would be transmitted to the glomerular capillaries and cause injury

Question 5

What is the Myogenic Hypothesis?

Answer 5

• If perfusion pressure increases, afferent arterioles are stretched
• Responds by contracting smooth muscle
• If perfusion pressure drops, afferent arteriole responds by relaxing smooth
muscle

Question 6

What is the Tubuloglomerular/Metabolic Hypothesis?