Excretory Systems & Salt and Water Balance

Vocabulary flashcards for excretory systems and salt/water balance in animals.

Osmoregulation

Management of the body's water content and solute concentration.

Osmosis

Movement of water through a semipermeable membrane from regions of high to low water concentration.

Transport Epithelium

Layer of cells used to move specific solutes in particular directions.

Kidney

An organ special in the maintenance of fluid composition and produces hormones.

Ammonia (NH3)

A nitrogenous waste product of protein and nucleic acid hydrolysis, very toxic and soluble in water.

Urea

A less toxic nitrogenous waste product made in the liver by combining ammonia and carbon dioxide.

Uric Acid

A relatively non-toxic and insoluble nitrogenous waste product secreted as a semisolid paste.

Proteinuria

The presence of protein in the urine, often associated with hypertension, kidney failure, pregnancy, or diabetes.

Hematuria

The presence of red blood cells in the urine, may be due to menstruation or urinary tract infection.

Pyuria

The presence of white blood cells (pus) in the urine, often indicative of a urinary tract infection.

Hemoglobinuria

The presence of hemoglobin in the urine, can occur with high-degree burns or transfusion reactions.

Ketonuria

The presence of ketones in the urine, often seen in starvation.

Metanephridia

Excretory system of flatworms consisting of dead-end tubes capped within a ball that draws water and solutes from interstitial fluid into tubules.

Nephridiopores

Openings through which urine exits the body from tubules in metanephridia.

Nephridium

Excretory organs that remove wastes found in many organisms, including flatworms; similar to nephrons in kidneys.

Nephrostome

Ciliated funnel-like opening through which body fluids are filtered in nephridia.

Malpighian Tubules

Organs in insects that remove nitrogenous wastes and function in osmoregulation, opening into the digestive system.

Renal Cortex

The outer layer of the kidney, responsible for filtering blood.

Renal Medulla

The middle layer of the kidney, responsible for regulating urine concentration.

Renal Hilum

Region in the medial aspect of the kidney where blood vessels, nerves, and lymphatic vessels enter and exit.

Renal Sinus

Empty cavity within the kidney.

Nephron

Tiny blood filtering units of the human urinary system that forms urine from filtrate.

Cortical Nephron

85% of nephrons, primarily located in the cortex.

Juxtamedullary Nephron

15% of nephrons, have very long loops of Henle.

Glomerulus

Ball of about 50 intertwined capillaries where filtration takes place in the renal corpuscle.

Bowman's Capsule

Also known as the Glomerular Capsule, surrounds the glomerulus and collects filtrate.

Podocytes

Modified special squamous cells in the visceral layer of Bowman's capsule, with primary foot processes.

Slit Pore/Filtration Slit

Slits/openings found in secondary pedicels that extend off primary processes, allows filtrate to selectively pass.

Proximal Convoluted Tubule (PCT)

Part of the renal tubule system with simple cuboidal epithelium and apical microvilli; reabsorbs sodium, chloride, bicarbonate, and glucose.

Loop of Henle

The 3rd part of the renal tubule containing 4 segments; ascending thin/thick and descending thin/thick.

Distal Convoluted Tubule (DCT)

Simple cubodial epithelium composed of principle cells; possesses receptors for ADH and aldosterone.

Collecting Duct

The final part of the nephron; contains principal cells and intercalated cells.

Filtration

Blood pressure forces filtrate out of glomerulus capsule and into Bowman's space.

Tubular Reabsorption

Water and solutes move across tubular epithelium into interstitial fluid and then into peritubular capillaries.

Tubular Secretion

Peritubular capillaries release extra amounts of hydrogen, potassium, uric acid, and products of hemoglobin into interstitial fluid then across tubular epithelium into filtrate.