URINARY SYSTEM

KIDNEY STRUCTURE

CAPSULE – CORTEX – MEDULLA

• The cortex is characterized by renal corpuscles and their tubules

• The medullary ray is an aggregation of straight tubules and straight collecting tubules

• The medulla is characterized by straight tubules, collecting ducts and a special capillary network

• The renal columns represent cortical tissue contained within the medulla

NEPHRON

THE NEPHRON IS THE STRUCTURAL AND FUNCTIONAL UNIT OF THE KIDNEY

CORTICAL - JUXTAMEDULLARY - INTERMEDIATERENAL CORPUSCLE:

GLOMERULUS

↑ ↓

afferent arteriole efferent arteriole↑

Renal or Bowman’s capsule:

-Podocytes

-The glomerular basement membrane

TUBULAR PART OF NEPHRON

• Proximal convoluted tubule• Proximal straight tubule acids, sugars, water,

electrolyte, polypeptides

• Thin segment – loop of Henle reabsorption

• Distal straight tubule Na+, bicarbonate ion• Distal convoluted tubule reabsorption

• Collecting tubules concentration of the urine• Collecting ducts

JUXTAGLOMERULAR APPARATUS

INCLUDES:

- Macula densa- Juxtaglomerular cells- Extraglomerular mesangial cells

The juxtaglomerular apparatus regulates blood pressure

BLOOD SUPPLY

RENAL ARTERY→

INTERLOBAR BRANCHES →

ARCUATE ARTERY (in between medulla and cortex)→

INTERLOBULAR ARTERIES →

AFFERENT ARTERIOLES→

GLOMERULUS (rete mirabile, primary capillary network)→

EFFERENT ARTERIOLES→

PERITUBULAR CAPILLARIES

(secondary capillary network )

EXCRETORY PASSAGES• Minor calyx

(1) MUCOSA• Major calyx

-Transitional epithelium• Renal pelvis -Lamina propria mucosae

-Lamina muscularis mucosae

• Ureter (2) MUSCULARIS

• Urinary (3) ADVENTITIA / SEROSAbladder

• Urethra