Animal Kingdom and Human Excretory System

Practice flashcards covering the basis of animal classification, Phylum characteristics from Porifera to Chordata, and the human excretory system including urine formation and regulation.

Porifera

A phylum of pore-bearing animals commonly called sponges, mostly marine and sessile, featuring a cellular level of organization and a water transport or canal system.

Choanocytes

Also known as collar cells, these flagellated cells line the spongocoel and canal system in sponges and help in filtering food.

Cnidoblasts

Stinging cells containing nematocysts found on the tentacles and body of organisms in Phylum Cnidaria, used for anchorage, defense, and capturing prey.

Metagenesis

The alternation of generation between polyp and medusa forms, as seen in the coelenterate Obelia.

Ctenophora

A phylum of exclusively marine animals called sea walnuts or comb jellies, bearing 8 external ciliated comb plates for locomotion and exhibiting bioluminescence.

Flame cells

Specialized cells in Platyhelminthes (flatworms) used for excretion and osmoregulation.

Renette cell

An H-shaped cell used for excretion and osmoregulation in members of Phylum Aschelminthes.

Parapodia

Lateral appendages found in aquatic annelids like Nereis that assist in swimming and gaseous exchange.

Arthropoda

The largest phylum of the animal kingdom, characterized by jointed appendages, a chitinous exoskeleton, and representing more than 2/3rd of all named species on earth.

Radula

A file-like rasping organ used for feeding found in the mouth of many molluscs.

Water Vascular System (WVS)

Also known as the ambulacral system, it is a hallmark feature of Echinodermata used for locomotion, respiration, and the capture/transport of food.

Aristotle's lantern

A masticatory organ present in Echinus (sea urchin).

Stomochord

A hollow, ectodermal structure present in the collar region of Hemichordates that was earlier considered similar to a notochord.

Anadromous Migration

The migration of marine cyclostomes like Petromyzon (lamprey) to freshwater for spawning, after which the adults die.

Chondrichthyes

Cartilaginous fishes with a ventral mouth, placoid scales, and a heart that receives only deoxygenated blood (venous heart).

Osteichthyes

Bony fishes with a terminal mouth, cycloid or ctenoid scales, and a swim bladder that provides buoyancy.

Cloaca

A common chamber for the alimentary canal, urinary tract, and reproductive tract found in amphibians, reptiles, and some other vertebrates.

Pneumatic Bones

Hollow, air-filled long bones found in the endoskeleton of birds (Aves) to facilitate flight.

Thecodont

A type of dentition where teeth are embedded in the bony socket of the jaw bone, characteristic of mammals.

Ammonotelism

The process of excreting ammonia, a highly toxic nitrogenous waste that requires significant water for elimination, common in bony fishes and aquatic amphibians.

Glomerular Filtration Rate (GFR)

The amount of filtrate formed by all nephrons of both kidneys per minute, which is approximately $125\,ml/min$ or $180\,l/day$.

Filtration Membrane

A three-layer structure consisting of the endothelium of glomerular blood vessels, the basement membrane, and the podocyte epithelium of Bowman's capsule.

Columns of Bertini

Extensions of the renal cortex that project between the medullary pyramids.

Vasa Recta

A network of blood capillaries running parallel to the Loop of Henle, well-developed in juxtamedullary nephrons to help form concentrated urine.

RAAS (Renin-Angiotensin-Aldosterone System)

A hormonal feedback mechanism where JGA cells release Renin in response to low GFR, leading to the production of Angiotensin II and Aldosterone to increase blood pressure and GFR.

Micturition

The process of releasing urine from the urinary bladder to the outside.

Uremia

A disorder of the excretory system characterized by the accumulation of urea in the blood due to kidney malfunction.