Excretory Products and Their Elimination

A complete set of vocabulary flashcards covering excretory products, animal excretory structures, the human excretory system, urine formation, and related clinical disorders based on the lecture notes.

Ammonotelism

The process of excreting ammonia, which is the most toxic nitrogenous waste and requires large amounts of water for its elimination.

Ammonotelic animals

Animals such as many bony fishes, aquatic amphibians, and aquatic insects that excrete ammonia.

Ureotelic animals

Animals including mammals, many terrestrial amphibians, and marine fishes that mainly excrete urea.

Uricotelic animals

Animals like reptiles, birds, land snails, and insects that excrete nitrogenous wastes as uric acid in the form of pellet or paste with minimum water loss.

Protonephridia (flame cells)

Excretory structures in Platyhelminthes (e.g., Planaria), rotifers, some annelids, and the cephalochordate - Amphioxus, primarily concerned with osmoregulation.

Nephridia

Tubular excretory structures of earthworms and other annelids that help remove nitrogenous wastes and maintain fluid and ionic balance.

Malpighian tubules

Excretory structures of most insects, including cockroaches, which help in the removal of nitrogenous wastes and osmoregulation.

Antennal glands (green glands)

Excretory structures that perform the excretory function in crustaceans like prawns.

Kidney dimensions

In adult humans, each kidney measures $10-12\,cm$ in length, $5-7\,cm$ in width, $2-3\,cm$ in thickness, and weighs an average of $120-170\,g$.

Hilum

A notch located towards the center of the inner concave surface of the kidney through which the ureter, blood vessels, and nerves enter.

Columns of Bertini

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

Nephrons

The functional units of the kidney; each kidney contains nearly $1 \times 10^{6}$ of these complex tubular structures.

Malpighian body (renal corpuscle)

The structure formed by the glomerulus along with the Bowman's capsule.

Podocytes

Epithelial cells of the Bowman's capsule arranged to leave minute spaces called filtration slits or slit pores.

Ultra filtration

The process where blood is filtered so finely through glomerular membranes that almost all plasma constituents except proteins pass into the lumen of the Bowman's capsule.

Glomerular filtration rate (GFR)

The amount of filtrate formed by the kidneys per minute, which is approximately $125\,ml/minute$ or $180\,litres$ per day in a healthy individual.

Juxta glomerular apparatus (JGA)

A special sensitive region formed by cellular modifications in the distal convoluted tubule and the afferent arteriole at their point of contact.

Proximal Convoluted Tubule (PCT)

A segment of the nephron lined by simple cuboidal brush border epithelium, where $70-80$ per cent of electrolytes and water are reabsorbed.

Henle's Loop

A hairpin shaped tube with a descending limb permeable to water and an ascending limb that allows transport of electrolytes but is impermeable to water.

Vasa recta

A minute 'U' shaped vessel of the peritubular capillary network that runs parallel to the Henle's loop.

Counter current mechanism

The special arrangement of the Henle's loop and vasa recta that maintains an increasing osmolarity gradient in the medullary interstitium from $300\,mOsmolL^{-1}$ to $1200\,mOsmolL^{-1}$.

Antidiuretic hormone (ADH)

Also known as vasopressin, it is released from the neurohypophysis to facilitate water reabsorption from the latter parts of the tubule, preventing diuresis.

Renin-Angiotensin mechanism

A complex regulatory mechanism where a fall in GFR triggers the release of renin, eventually producing Angiotensin II to increase blood pressure and GFR.

Atrial Natriuretic Factor (ANF)

A hormone released by the heart atria that causes vasodilation and decreases blood pressure, acting as a check on the renin-angiotensin mechanism.

Micturition

The process of releasing urine from the urinary bladder initiated by a voluntary signal from the CNS and the micturition reflex.

Glycosuria

The presence of glucose in urine, which is often indicative of diabetes mellitus.

Ketonuria

The presence of ketone bodies in urine, which is often indicative of diabetes mellitus.

Uremia

A condition caused by the accumulation of urea in the blood due to kidney malfunctioning, which may lead to kidney failure.

Renal calculi

Stone or insoluble mass of crystallised salts, such as oxalates, formed within the kidney.

Glomerulonephritis

Inflammation of the glomeruli of the kidney.