Osmolarity and Tonicity in Kidney Function

These flashcards cover essential vocabulary related to osmolarity, tonicity, kidney anatomy, and physiological processes in urine formation and regulation.

Osmolarity

The number of particles in a solution measured in osmol/L.

Tonicity

The ability of a solution to affect the volume of a cell by causing water movement.

Diffusion

The process through which atoms or molecules intermingle due to random thermal motion.

Net Diffusion

Directional movement of particles from an area of higher concentration to an area of lower concentration.

Isosmotic

Two solutions have an equal number of solute particles per unit volume.

Hyperosmotic

A solution that has a higher osmotic pressure than another solution.

Hyposmotic

A solution that has a lower osmotic pressure than another solution.

Glomerular filtration rate (GFR)

The amount of filtrate formed in both kidneys every minute; average is about 125 ml/min.

Reabsorption

The process of moving molecules or fluid from the filtrate back into the blood.

Secretion

The process of moving selected molecules from the blood into the filtrate.

Renin-Angiotensin-Aldosterone system

A hormone system that regulates blood pressure and fluid balance.

Aquaporin

A water channel protein inserted into cell membranes to facilitate water reabsorption.

ADH (Anti-diuretic hormone)

Hormone that regulates water reabsorption in the kidneys.

Loop of Henle

A section of the nephron that creates a concentration gradient in the renal medulla.

Erythropoietin

A hormone produced by the kidneys that stimulates red blood cell production.

Renal corpuscle

The filtration unit of the nephron, consisting of the glomerulus and Bowman’s capsule.

Proximal tubular reabsorption

The first step in the nephron where a significant amount of filtrate is reabsorbed back into the blood.

Filtrate

The fluid that is filtered from the blood at the glomerulus into the nephron.

Extracellular fluid volume

The total volume of fluid outside of cells, regulated by the kidneys.