XII Biology-Excretory System

Flame cells are the specialized excretory cells found in the simplest freshwater invertebrates, including flatworms like tapeworms, to remove waste materials.

Nephrons are the functional units of the kidney. After filtration and processing, the final urine is collected and discharged into the collecting ducts, which then lead to the renal pelvis and ureter.

GFR stands for Glomerular Filtration Rate, which is the volume of fluid filtered from the renal glomerular capillaries into the Bowman's capsule per unit of time.

The liver is the primary site for the urea cycle, where toxic ammonia is converted into urea. The kidneys then filter this urea from the blood for excretion.

The Ornithine cycle, also known as the urea cycle, is a series of biochemical reactions in the liver that produce urea from ammonia.

Ammoniotelic animals are those that excrete nitrogenous waste primarily as ammonia. This is common in aquatic animals like fish, which have access to abundant water to dilute the highly toxic ammonia.

ADH stands for Antidiuretic Hormone, also known as vasopressin, which helps the body retain water by increasing water reabsorption in the kidneys.

ADH (Antidiuretic Hormone) is also known as vasopressin due to its ability to cause vasoconstriction at high concentrations.

DCT stands for Distal Convoluted Tubule, a portion of the nephron between the loop of Henle and the collecting duct.

Vasopressin (ADH) is synthesized in the hypothalamus and stored and released into the bloodstream by the posterior pituitary gland.

Uric acid is the least toxic and least soluble nitrogenous waste, which allows animals like birds and reptiles to conserve water by excreting it as a semi-solid paste.

The kidneys are located in the abdominal cavity and are partially protected by the lower two pairs of ribs (the floating ribs).

Uricotelic animals are those that excrete nitrogenous waste primarily as uric acid. Birds, such as pigeons, and many reptiles are uricotelic.

As birds, pigeons are uricotelic, meaning they excrete uric acid to minimize water loss.

Ammoniotelic animals include many aquatic invertebrates, bony fish, and larval amphibians, as they excrete ammonia directly into their water-rich environment.

Arginine is directly involved in the urea cycle as an intermediate; it's hydrolyzed by arginase to produce urea and regenerate ornithine. Tryptophan and phenylalanine are aromatic amino acids unrelated to nitrogen excretion. Leusine is also not part of the urea cycle.

In the proximal convoluted tubule of the nephron, glucose, amino acids, and various ions are reabsorbed from the filtrate back into the blood via active transport.

Ammonia is highly soluble in water, which is why aquatic animals can easily excrete it into their surrounding water.

Ammoniotelic animals are defined by their excretion of ammonia as the primary nitrogenous waste product.

The kidneys produce the enzyme renin, which is part of the renin-angiotensin-aldosterone system that regulates blood pressure.

Urea is reabsorbed in the collecting ducts of the nephron primarily through passive diffusion, driven by the concentration gradient.

The urinary bladder acts as a temporary reservoir for urine before it is excreted from the body via the urethra.

The Malpighian body (or renal corpuscle) consists of the glomerulus and the Bowman's capsule combined.

Osmoregulation is the physiological process by which an organism maintains the balance of water and dissolved salts (electrolytes) in its body fluids.

Micturition is the medical term for the act of emptying the urinary bladder, which involves the passage of urine through the urethra.