kidneys – two, produce urine – fluid filtered from blood plasma, contains water,
ions and small solutes
urinary tract: composed of ureters (leave kidneys), urinary bladders, urethra
(carries urine to outside); the job of the urinary tract is storage and removal of
urine after it is generated
The kidneys have several functions:
Removing waste from the blood, and thus generating urine – all water soluble
waste will leave via the kidney (with the exception of CO2)
Regulation of blood volume and blood pressure
Regulation of plasma concentration of electrolytes
Regulation of blood pH
Thus the kidneys are a vital component in controlling most homeostatic parameters (with
the exception of body temperature)
located on either side of vertebral column.
Each has an adrenal gland on top.
Connective tissue capsules:
renal capsule, collagen fibers that cover the outer surface of organ
adipose capsule, adipose tissue that covers renal capsule
renal fascia, anchors renal capsule to surrounding structures and to deep fascia
if any of this attachment comes apart, will cause floating kidney, which is very dangerous
Kidney has 2 layers:
cortex, outer portion, in contact with renal capsule
medulla, consists of 6-12 conical/triangular structures called pyramids.
pyramid faces cortex, tip (papilla) faces into renal sinus (internal cavity inside
Adjacent pyramids separated by renal columns, cortical tissue that
projects into medulla.
urine is produced in renal lobes.
Ducts in papilla drain into minor calyx, which merge to
form a major calyx, and these form the renal pelvis, which connects to the ureter.
Nephrons – functional unit of the kidney, network of tubules where urine is filtered
20-25% of cardiac output goes to kidneys.
Approx 1.2 L of blood a
minute flows through!
functional unit of the kidney.
Consists of a renal tubule and renal
long tubular passage way
starts tubule, consists of Bowman’s capsule (cup shaped
chamber) and glomerulus, capillary network.
Blood arrives at glomerulus from capillaries, projects into Bowman’s capsule.
Capillaries drain into efferent arteriole that forms capillaries around renal tubule.
Filtration happens at renal corpuscle – pressure forces water and solutes out of capillaries
and into capsular space that is continuous with lumen of renal tubule.