(LEC 22) Vertebrate Excretory System- Kidneys

Nitrogenous Waste

The waste products that result from the metabolism of nitrogen-containing molecules, removed by vertebrates through various forms.

Ammonia Excretion

The process by which sunfish excrete ammonia through their gills.

Uric Acid

A form of nitrogenous waste excreted by spotted turtles and herring gulls.

Nephron

The functional unit of the kidney that performs filtration, reabsorption, and secretion.

Glomerulus

A dense ball of capillaries where filtration occurs in the kidney.

Filtrate

The liquid formed when blood is filtered in the nephron, containing water, ions, and nutrients.

Tubular Reabsorption

The process in which cells lining the renal tubule reabsorb ions, nutrients, and water back into the bloodstream.

Countercurrent Multiplier

A mechanism in the Loop of Henle that creates a concentration gradient for water reabsorption.

Proximal Convoluted Tubule

The part of the nephron that reabsorbs about 75% of the fluid entering the nephron.

Vasa Recta

The peritubular capillaries that quickly remove water reabsorbed via osmosis in the kidneys.

Bowman’s Capsule

The part of the nephron that collects filtrate from the glomerulus.

Tubular Secretion

The process of actively secreting additional substances into the renal tubule for removal.

Epitheleal Podocytes

Cells of Bowman’s capsule that help form filtration slits for liquid to enter from capillary lumen.

Concentration of Urine

Urine is typically four times more concentrated than blood due to reabsorption processes.

Glomerular Filtration Rate

The rate at which blood is filtered by the glomeruli, approximately 180 liters per day.