Distal Convoluted Tubule & Collecting Duct Function

This set of flashcards covers key concepts regarding the functions of the distal convoluted tubule and collecting duct in the nephron, focusing on ion and water reabsorption, hormonal regulation, and related physiological mechanisms.

What is the primary function of the distal convoluted tubule (DCT)?

The DCT is primarily involved in the reabsorption of sodium and other ions.

What hormone regulates sodium reabsorption in the DCT?

Aldosterone regulates sodium reabsorption in the DCT.

How do sodium ions move across the epithelial cells of the DCT?

Sodium moves into the cells via epithelial sodium channels (ENaCs) and is pumped out by sodium-potassium ATPases.

What happens to water when sodium is reabsorbed in the DCT?

Water follows sodium by osmosis into the blood vascular compartment, which can increase blood pressure.

What drug blocks sodium channels in the DCT to treat hypertension?

Amiloride blocks sodium channels in the DCT.

What hormone is released by the posterior pituitary to regulate water reabsorption in the collecting duct?

Vasopressin (or antidiuretic hormone, ADH) is released to regulate water reabsorption.

How do principal cells in the collecting duct contribute to urine concentration?

Principal cells allow water reabsorption through aquaporin channels controlled by vasopressin.

What is the role of the vasa recta in the kidneys?

The vasa recta maintains the corticomedullary gradient essential for urine concentration.

What is hypovolemic shock, and how is it related to kidney function?

Hypovolemic shock is a condition of low blood volume that triggers the renin-angiotensin system to maintain blood pressure.

What effect does the renin-angiotensin system have on blood vessels?

It causes constriction of blood vessels, which increases blood pressure.

How does the concentration of ions in the vasa recta compare to the interstitial space?

The concentration of ions in the vasa recta equilibrates with the interstitial space along the corticomedullary gradient.

What are the two cell types present in the collecting duct and their functions?

Principal cells reabsorb water, while intercalated cells regulate hydrogen ion secretion for pH control.

What happens to vasopressin levels in a well-hydrated individual?

In a well-hydrated state, vasopressin release decreases, resulting in less water reabsorption.

Why can certain individuals develop kidney stones, according to the lecture?

Some individuals lack specific molecules that prevent kidney stone formation, influenced by diet and genetic factors.