Urinary System Flashcards
Kidney
Either one of a pair of organs in the dorsal region of the vertebrate abdominal cavity, functioning to maintain proper water and electrolyte balance, regulate acid-base concentration and filter the blood of metabolic wastes, which are then excreted as urine.
Urine
The waste product secreted by the kidneys that in mammals is a yellow to amber coloured, slightly acidic fluid discharged from the body through the urethra.
Bladder
A distensible membranous sac that serves as a receptacle for fluid or gas.
Urea
A water soluble compound that s the major nitrogenous end product of protein metabolism and is the chief nitrogenous component of the urine.
Sodium chloride
A colourless or white crystalline compound, the major cation of the extracellular fluid, constituting 90-95% of all cations in the blood plasma and interstitial fluid, thus determining the osmolality of the extracellular fluid.
Nutrients
A food or biochemical substance used by the body that must be supplied in adequate amounts from foods comsumed. There are 6 classes of nutrients; water, proteins, carbohydrates, fats, minerals and vitamins.
Capillary bed
Capillaries of a tissue, area or organ considered collectively and their volume capacity.
Vasa recta
Straight vessels into which the efferent arteriole of the juxtamedullary glomeruli breaks up, they form a leash of vessels that run through the renal medulla towards the apex of each pyramid.
Peritubular capillaries
Blood capillary beds surrounding the renal tubules of nephrons.
Renal artey
Branches from the abdominal aorta at L1 vertebral level, the second and largest pair of lateral visceral branches. Supplies oxygenated blood to the kidneys.
Osmolarity
The concentration of a solution in terms of osmoles of solutes per liter of solution
Filtration
Passage through a filter or other material that prevents passage of certain molecules, particles or substances.
Renal veins
Large veins formed at the renal hilus, opening into the inferior vena cava at the level of the 2nd lumbar vertebra. The left renal vein receives the left suprarenal vein and the left gonadal vein.
Ions
An atom or group of atoms that has acquired a net electric charge by gaining or losing one or more electrons.
Filtrate
A liquid or gas that has passed through a filter.
Nephron
The functional excretory unit of the vertebrate kidney that regulates the amount of water in the body and filters wastes from the blood to produce urine.
Glucose
A monosaccharide sugar that is used by living things to obtain energy through the process of aerobic respiration within cells.
Renal cortex
The granular outer layer of the kidney, composed mainly of glomeruli and convoluted tubules, extending in columns between the pyramids that consitute the renal medulla.
Renal medulla
The inner part of the substance of the kidney, composing chiefly of collecting tubules and organized into a group of structures called the renal pyramids.
Renal calyx
Chambers of the kidney through which urine passes, from the apex of the renal pyramids though the renal papilla to the minor calyx. Two or three converge to form a major calyx, through which urine passes to the renal pelvis and into the urether.
Renal pelvis
The funnel like dilated proximal part of the ureter in the kidney. The point of convergence of 2 or 3 major calyces.
Urethra
The canal through which urine is discharged from the bladder.
Ureter
Tubes made of smooth muscle fibers that propel urine from the kidneys to the urinary bladder.
Hilum
Part of an organ where structures such as blood vessels an nerves enter.
Homeostasis
A state of equilibrium, an organism or cell being maintained by self regulating processes.
pH
A measure of the degree to which a solution is acidic or alkaline. The more acidic a solution, the greater the hydrogen ion concentration and the lower the pH.
Blood pressure
The pressure of the blood against the walls of any blood vessel, usually within the arteries. Determined by the pumping action of the heart, the resistance to the flow of blood in the arterioles, elasticity of the walls of the main arteries, blood volume, extracellular fluid volume and blood’s viscosity or thickness.
Glomerular filtration rate
An expression of the quantity of glomerular filtrate formed each minute in the nephrons of both kidneys, calculated by measuring the clearance of specific substances e.g inulin or creatinine.
Arteriole
A minute arterial branch.
Afferent arteriole
Any arteriole that connects the terminal branch of an artery with a capillary.
Efferent arteriole
Blood vessels in the urinary tract that form a convergence of the capillaries of the glomerulus. They play an important role in maintaining the glomerular filtration rate despite fluctuations in blood pressure.
Glomerulus
Globular structures of entwined vessels, fibers or neurons.