1. Urinary system

2. Primary functions Maintenance of homeostasis
Removal of substances from the blood
Urea
Creatinine
Ammonia
Products of drugs
Regulation of:
Blood volume
Electrolytes
Acid-base balance
Blood pressure

3. Primary functions cont.
Secretion of Renin
Juxtaglomerular cells secrete renin, an enzyme, when BP decreases
Renin activates the renin-angiotensin mechanism to increase BP
Renin-angiotensin mechanism results in increased BP
Vasoconstriction
Stimulation of adrenal cortex to secrete aldosterone
Secretion of erythropoietin
Secreted during states of hypoxia
Stimulates red bone marrow to produce RBC’s

4. Primary functions cont…
The kidney and vitamin D
Converts vitamin D to calciferol
Calciferol increases small intestine’s ability to absorb calcium and phosphate

5. Main organs
2 kidneys
Ureters
Urinary bladder
Urethra

6. kIdneys Cleanse the blood of waste Maintain blood pressure
Maintain oxygen carrying ability of the blood
Maintain the pH and electrolyte balance

7. Kidney - anatomy Left kidney more elevated
Retroperitoneal – behind the peritoneum
Located at the level of the T11, T12, and L1 vertebra
Covered with fat to protect and hold in place
Adrenal glands sit on top
Hilum
Place where renal artery/vein enter/exit
Ureter exits
Renal nerves enter/exit

8. 3 major divisions of kidney
Renal cortex
Renal corpuscles
Convoluted tubules
Renal medulla
Loops of henle
Collecting tubules
Renal pyramids
Renal pelvis
Calyces
Collects urine draining from papillae

9. Nephron structure Most of the nephron located in cortex 1 million
Responsible for all urine formation

10. Nephron structure Renal Corpuscle Filtration takes place here
Bowman’s capsule
glomerulus

11. Nephron structure cont…
Proximal convoluted tubule
Site of most reabsorbtion of nutrients
Loop of henle
Water and sodium are reabsorbed and urine is concentrated
Distal convoluted tubule
Anything not already reabsorbed will be excreted with urine

12. Special cells in the nephron
JG cells – juxtaglomerular
Cells located in the afferent ateriole
Monitor blood pressure
Release renin to stimulate aldosterone to increase BP
Monitor oxygen in the blood
Release erythropoietin to increase RBC’s

13. Kidney blood supply Renal artery Afferent arterioles Glomerulus
Efferent arterioles
Peritublar capillaries
Veins
Renal vein

14. Ureter Carry urine to bladder Peristalsis
Connect to underside of bladder (trigone)
Right 10 inches left 12 inches
Trigone
Formed by the union of the 2 ureters and urethra
Most commonly infected area

15. bladder Muscular sac that stores urine for micturition Holds 500 mL
Located inferior to uterus in females
Located superior to prostate in males
Lined with transitional epithelium to allow stretch
Detrusor muscle
Internal urethral sphincter = involuntary

16. urethra Carries urine out of body 1-1.5 inches in females 7-8 in males
Higher incidence of UTI’s
7-8 in males
External urethral sphincter = voluntary

17. Major processes of urine formation
Filtration
Reabsorbtion
Secretion