Anatomy and Physiology: The Urinary System
Kidney
Either of a pair of organs that are located in the rear of the abdominal cavity in vertebrates. The kidneys regulate fluid balance in the body and filter out wastes from the blood in the form of urine. The functional unit of the kidney is the nephron.
Detrusor muscle
Smooth muscle that compresses the urinary bladder and expels urine into the urethra.
Renal pelvis
The area at the center of the kidney. Urine collects in the renal pelvis and is funneled into the ureter.
Renal tubule
each of the long, fine, convoluted tubules conveying urine from the glomeruli to the renal pelvis in the vertebrate kidney. Water and salts are reabsorbed into the blood along their length.
Glomerulus
A ball of capillaries surrounded by Bowman's capsule in the nephron and serving as the site of filtration in the vertebrate kidney.
Ureter
A duct leading from the kidney to the urinary bladder.
Uric Acid
A nitrogenous waste excreted in the urine.
Collecting duct
A segment of the nephron that returns water form the filtrate to the bloodstream.
Glomerular capsule
Bowman's capsule (or the Bowman capsule, capsula glomeruli, or glomerular capsule) is a cup-like sack at the beginning of the tubular component of a nephron in the mammalian kidney that performs the first step in the filtration of blood to form urine. A glomerulus is enclosed in the sac.
Urethra
Duct through which urine is discharged.
Glomerular filtrate
Fluid filtered through the glomerular capillaries into the glomerular capsule of the renal tubules.
Urine
Fluid wastes removed from the body by the kidneys
Nephron
Functional unit of the kidney
Renal corpuscle
In the kidney, a renal corpuscle is the initial blood-filtering component of a nephron. It consists of two structures: a glomerulus and a Bowman's capsule. The glomerulus is a small tuft of capillaries containing two cell types.
Renal cortex
The renal cortex is the outer portion of the kidney between the renal capsule and the renal medulla. In the adult, it forms a continuous smooth outer zone with a number of projections (cortical columns) that extend down between the pyramids
Renal medulla
The renal medulla is the innermost part of the kidney. The renal medulla is split up into a number of sections, known as the renal pyramids
Efferent arteriole
The small artery that carries blood away from the capillaries of the glomerulus.
Afferent arteriole
The small artery that carries blood toward the capillaries of the glomerulus.
Urea
a colorless crystalline compound that is the main nitrogenous breakdown product of protein metabolism in mammals and is excreted in urine.
Bowman's capsule
cup-shaped strucutre of the nephron of a kidney which encloses the glomerulus and which filtration takes place.
Distal convoluted tubule
is a portion of kidney nephron between the loop of Henle and the collecting duct system.
Urinary bladder
saclike organ in which urine is stored before being excreted
Proximal convoluted tubule
the convoluted portion of the vertebrate nephron that lies between Bowman's capsule and the loop of Henle and functions especially in the resorption of sugar, sodium and chloride ions, and water from the glomerular filtrate —called also proximal tubule
Micturition
the ejection of urine from the urinary bladder through the urethra to the outside of the body
Loop of Henle
the part of a kidney tubule that forms a long loop in the medulla of the kidney, from which water and salts are resorbed into the blood.
Tubular reabsorption
the process that moves solutes and water out of the filtrate and back into your bloodstream.
Tubular secretion
the transfer of materials from peritubular capillaries to the renal tubular lumen; it is the opposite process of reabsorption. This secretion is caused mainly by active transport and passive diffusion. Usually only a few substances are secreted, and are typically waste products.
