Kidney
Two bean shaped organs about the size of a fist located against the posterior back wall (right peritoneal) where the right kidney is lower than the left. It is covered by a fibrous capsule composed of dense irregular connective tissue
Renal fat pad
Shock absorbing layer of adipose layer that covers the capsule of kidney
Functions of the kidney (8)
Paired ureters
Transports urine from the kidneys to the bladder
Urinary bladder
Provides a temporary storage reservoir for urine (approx. 700-800mL)
Urethra
Transports urine from the bladder out of the body
Male urethra
Passes through the prostate gland located immediately inferior (below) bladder and also serves as the duct where semen is discharged
Female urethra
Short in length (4cm) which is the reason why many women get UTI’s
Layers of the kidney (3)
Renal cortex
Outer layer of the kidney that filters blood
Renal medulla
Inner layer of the kidney that contains renal pyramids where urine formation takes place
Renal pelvis
Hollow portion in the middle of each kidney collect urine as its produced
Path of urine drainage (6)
Collecting duct:
Consists of a series of tubules and ducts that connect nephrons to minor calyx or directly to renal pelvis
Blood supply of kidney
1/4 (1200mL) of systemic cardiac output flows through the kidneys each minute and the entire blood volume of the body is filtered by the kidneys 60 times a day
Pathway of blood through renal blood vessels (15)
Nephron
Basic structural and functional unit of the kidney and consists of a million filtering units on the kidney; has a vascular & tubular component
Vascular components of nephron (5)
Tubular components of nephron (5)
3 basic systems in urine formation:
Glomerular filtration
Use of passive pressure to force fluids and solutes into Bowman’s capsule
Bowman’s capsule
Two walled pouch that covers the glomerulus and filters all blood components except blood cells and most proteins
Reasons why glomerular filtration is efficient (3)
Tubular reabsorption
Process by which about 99% water and most solutes are removed from the tubular fluid and returned to blood stream (160L a day), can be active transport, facilitated, or simple diffusion based on size