PSP1- UNIT
8
GENITOURINARY
SYSTEM
,Imaan Qureshi
1) Anatomy and physiology of male and female urinary systems
What is the urinary system?
● Urine= Excretory fluid formed in kidneys
● Has nitrogenous waste, drugs, metabolites and ions
● Chemical composition of urine provides info for health, diet, drugs and
pollutant exposure
Structure of urinary system:
● 2 kidneys: located in abdominal cavity, the right m kidney is below liver. Left
kidney is below spleen
● 2 ureters: each kidney is attached to a ureter that extends to the urinary
bladder. Ureters transport urine from kidneys to bladder
● Urinary bladder: located within pelvic cavity
● Single urethra: for females urine is transferred from bladder to external space.
For males, urine is transported from bladder to external space and ejaculation
of seminal fluid
Structure of kidney:
● The cortex and medulla are composed of nephrons which are the functional
units of the kidney
● Types of nephrons:
- Cortical nephron: lie in cortex of kidney, shorter loop of henle and form
80%
- Juxta medullary nephron: Bowman’s capsule close to cortex and
medulla, have long loops of Henle extending deep into the medulla.
, Imaan Qureshi
Functions of kidney:
● Regulate blood volume and pressure
● Regulate plasma conc of ions (quantities of Na+ and Cl-)
● Maintaining plasma PH (regulating H+ and HCO3-)
● Conserving valuable nutrients (reabsorbing glucose and amino acids)
● Adjust red blood cell count in response to oxygen demands
● Maintain calcium and phosphate balance (via nephrons)
● Eliminate toxic substances (eliminate urea and other waste)
Blood supply:
● Kidney receives blood through:
● Renal artery —> smaller arteries—>afferent renal arterioles in renal cortex—>
glomerulus—-> efferent renal arteriole —-> 2nd network of capillaries
(peritubular)
● The peritubular capillaries of juxtamedullary nephrons are longer and enter
the medulla and are referred to as vasa recta
● The capillaries drain blood into small venules from where it flows into small
veins. These veins open into the renal vein which carries blood away from the
kidney
Nephron function:
● glomerulus/ bowman's capsule/ corpuscle: filtrate production
● Proximal convoluted tubule: reabsorption of water, Na+, Cl-, HCO3-, glucose
and amino acids
● Loop of henle: further reabsorption of water (descending limb), and of NA
+ and Cl- (ascending limb)
● Distal convoluted tube: Secretion of ions, acids, drugs, toxins; variable
reabsorption of water, Na+ and Ca2+ (all under hormonal control)
● Collecting duct: Variable reabsorption of water and reabsorption or secretion
of Na+ , H+ , K+ and HCO3 − ions
Process of urine formation:
Glomerular filtration Tubular reabsorption Tubular secretion
Separates cell free and Reabsorbs the small Adds substances from the
protein free filtrate from molecules and blood to the urine which
blood into kidney tubule electrolytes which the may have been
body requires from tubule incompletely filtered at the
and back into blood glomerulus