Chapter 6 Basic Renal Processes for Sodium, Chloride, and Water (ADH and Na+ Handling)

Vocabulary flashcards covering key terms related to sodium, chloride, and water handling in the kidney, with emphasis on ADH and the collecting duct.

ADH (antidiuretic hormone)

Hormone that primarily increases water reabsorption in the collecting ducts by promoting insertion of aquaporin-2 channels; its direct effect on Na+ handling along the nephron is limited and not primarily in the collecting duct.

Collecting duct

Nephron segment where final water reabsorption occurs; activity is regulated by ADH and aldosterone, influencing urine concentration.

Aquaporin-2 (AQP2)

Water channel that is inserted into the apical membrane of collecting duct cells in response to ADH, increasing water reabsorption.

Sodium (Na+) handling along the tubule

Movement and regulation of Na+ reabsorption throughout nephron segments; largely controlled by aldosterone in the collecting duct, with ADH having indirect effects on overall volume/osmolality.

Aldosterone

Mineralocorticoid hormone that increases Na+ reabsorption (and K+ secretion) in the collecting duct via ENaC and Na+/K+-ATPase activity.

Proximal tubule

Nephron segment where the majority of Na+ and water reabsorption occurs, typically reabsorbing solutes and water in an iso-osmolar fashion.

Loop of Henle (thick ascending limb)

Segment that reabsorbs Na+, K+, and 2Cl− via NKCC transporter in the thick ascending limb, contributing to the medullary osmotic gradient.

Osmolality and urine concentration

Relationship between solute concentration and water reabsorption; ADH modulates water reabsorption to concentrate or dilute urine, thereby affecting tubular fluid osmolality.