The document describes the anatomy and physiology of the urinary system. It discusses the kidneys, which filter blood to produce urine and regulate electrolytes and acid-base balance. Urine travels from the kidneys through ureters to the bladder, where it is stored until voiding through the urethra. The kidneys contain nephrons that filter blood and reabsorb necessary substances. The document also reviews urinary system diseases, diagnostic workup, bladder function, nerve supply, the process of urination, and common urinary problems.

1. Functioning of urinary system
Urinary system consists of
Kidneys, Ureters, Bladder,
Urethra

2. Kidney- anatomy
 Bean shaped organ in retroperitoneum
 At vertebral level- T12-L3
 R- slightly lower; L- slightly larger
 Functional structure- NEPHRON, spans cortex &
medulla, ends in papilla (tip of renal pyramid)
 Empties into ureter
 Blood supply- renal artery, branch of Aorta
 Nerve supply-
 Sympathetic- causes vasoconstriction
 Sensory- T10-T11  flank pain

3. Kidney- function
 Excretion of waste- urea & ammonia
 Reabsorption of water, glucose, amino acids
 Regulation of electrolytes
 Maintain acid-base balance
 Regulation of blood pressure
 Hormone production
 Calcitriol- calcium absorption, phosphate excretion
 Renin- maintain blood pressure
 Erythropoietin- stimulates erythropoiesis

4. Kidney- physiology
 Nephron- functional unit
of kidneys, includes
glomerulus & tubule
 Basic functions-
 Filtration- of blood in
glomerulus
 Reabsorption- in tubule
 Secretion- in tubule
Net result- excretion

5. Kidney- homeostasis
 Proximal tubule- reabsorption of glucose,
amino acids, urea, Na, Cl, K, HCO3, Ca, Mg
 Loop of henle-
 Reabsorption of water in descending limb
 Reabsorption of Na, Cl, K, HCO3, Ca, Mg
in ascending limb
 Distal tubule- reabsorption of NaCl, Mg
 Collecting duct- secretion of H, K;
Na reabsorption (aldosterone);
water reabsorption (AVP)

6. Kidney- physiology

7. Kidney- diseases
 Congenital
 ADPKD
 Horseshoe kidney, renal agenesis
 Acquired
 Diabetic nephropathy, Glomerulonephritis
 Nephrotic syndrome
 Interstitial nephritis, Tubular necrosis
 Nephrolithiasis, Hydronephrosis, Pyelonephritis
 Tumors- RCC, Wilm’s tumor

8. Work-up
 History
 Examination
 CBC
 BUN, Cr
 Calcium, phosphate, alk. phosphatase
 Urine analysis, 24-hr. urine analysis
 US KUB

9. Urinary bladder
Organ controlling urination

10. Nerve supply of bladder
 Detrusor- sympathetic- T11-L2
Storage of urine
 Sensory afferent- pelvic n.- S2-4
Bladder full
 Detrusor- parasympathetic- S2-4
Voiding
 External sphincter- pudendal n.- S2-4
Voluntary control

11. Urination
 Micturition is a spinal reflex
 Facilitated & inhibited by pontine
micturition center through reticulospinal
tract in spinal cord
 Subject to voluntary facilitation &
inhibition

12. Phases of micturition
 Storage phase- bladder stores urine
Sympathetic stimulation contracts internal sphincter & relaxes
detrusor muscle
 Voiding phase- bladder empties
Bladder afferent signals reach pontine micturition center that fires,
Parasympathetic stimulation relaxes internal sphincter & contracts
detrusor
 External sphincter is under voluntary control

13. Problems of urination
 Incontinence- stress, urge, mixed
 Retention
 Overactive bladder
 Interstitial cystitis
 BPH
 UTI