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Structure and Function of the Urinary System


afferent arteriole

incoming blood vessel that supplies blood to the glomerulus of the nephron and helps to regulate blood pressure within the kidneys

efferent arteriole

outgoing blood vessel that carries blood away from the glomerulus of the nephron


cluster of capillaries located at the end of a kidney tubule where material is filtered from the blood


entrance to the renal sinus


bean-shaped structure located near the middle of the back that filters waste from the bloodstream. It also plays an important part in water, electrolyte, and blood pressure regulation and helps maintain normal pH, calcium, and red blood cell levels.

major calyx

junction of two to three minor calyces in the kidney that collects urine flowing from the kidney and passes it to the ureter


process whereby urine is released from the bladder and exits through the urethra

minor calyx

cavity that collects droplets of urine from the renal pyramids. Two to three minor calyces converge to deposit collected urine into a major calyx.


primary structure in the kidney that produces urine as part of the process of filtering the blood

peritubular capillary

capillary that surrounds the proximal and distal convoluted tubules in the kidney

pyramid of the renal medulla

one of several sections of tissue in the medulla that contains tubes that transport urine from the cortex to the calyces

renal artery

one of two blood vessels that leads from the abdominal aorta and supplies blood to the kidneys

renal column

extension of the renal cortex into the medulla between the renal pyramids providing support and connection for the cortex

renal cortex

outer layer of the kidney; granular in structure. It is composed of glomeruli and tubules and connects the pyramids of the renal medulla.

renal medulla

middle or inner region of the kidney that functions as a collecting area for the waste and water that has been filtered by the renal cortex

renal pelvis

large, funnel-shaped, upper portion of the ureter that serves to collect the urine before it flows into the bladder. It is also the point where two or three major calyces converge.

renal sinus

main cavity of the kidney that contains the renal pelvis, the renal calyces, blood vessels, and nerves

renal vein

large vein that carries blood away from the kidney


tube that carries urine from the kidney to the bladder


tube that carries urine from the bladder to the external urethral orifice and out of the body

urinary bladder

saclike organ that collects urine from the kidneys and is able to store it for a period of time until it is disposed of via urination