URINARY SYSTEM
URINARY SYSTEM:
• paired kidneys.• Ureters.
• Urinary bladder.
• Urethra.
Functions:
• Excretion of waste products
• Regulation of fluid & Electrolytes.
• Production of Renin.
• Production of Erythropoietin.
• Excretion of Drugs& Toxins.
• Activation of VIT D
KidneyBean shaped, reddish brown in color
Concave medial border(hilum) convex lateral border
Hilum of the kidneyvein /artery / ureter
Capsule
Cortex/medulla
Cortex & medulla microscopically
Medullary Rays / Renal column
Renal papilla
Minor calyx
Major calyx
pelvis
Pelvicalyceal system
ureter
Pelvicalyceal systemlined by special type of epithelium (urothelium)
Renal papilla (Area cribrosa)
Kidney lobe
Nephron (functional unit of kidney)
• Renal corpuscle.• Proximal convoluted tubule(PCT).
• Loop of Henle.
• Distal Convoluted Tubule (DCT).
Nephron
Cortical & Juxtamedulary Nephrons
Renal corpuscleGlomerulus + Bowman’s capsule
Bowman’s capsuleParietal layer (simple squamous)visceral layer (podocytes)urinary space
Urinary space
Vascular pole
Urinary pole
Bowman’s capsule (EM) Parietal layer Visceral layer (podocytes) Urinary space
Afferent & Efferent Arterioles of Glomerulus
Glomerulus (EM)
1
2
3
Podocytes (primary 1⁰, secondary2⁰ processes& pedicles)
Filtration slits
The Filtration(barrier) Blood Urine Barrier EM
Blood Urine Barrier (EM)Podocyte PBasement membrane BL (central lamina densa surrounded by two lamina raraEndothelium E
Mesangial cells (macrophage of kidney)Adherent to glomerular capillariesstructural support synthesize extracellular matrix
Mesangial cellsReceptors for (Angiotensin II, ANP).Endocytose and dispose of normal and pathological (immune complex). Produce chemical mediators such as cytokines, prostaglandins, interleukin-1, and platelet-derived growth factor.
Proximal Convoluted Tubule PCTbegin at urinary pole
PCT
DCT
Henle’s loop
PCT functionReabsorption & Secretion
Proximal Convoluted Tubule PCT
Brush border
PCT
PCT & DCT
DCT , Henley's loop
Juxtaglomerular Apparatus:
Macula Densa
Macula Densa
Histology of ureter
Urinary bladder epithelium
Urinary bladder epithelium (stretched)
• The epithelium varies in different parts of the urethra.
• Both in the male and female the greater part of the urethra is lined by stratified columnar and pseudostratified epithelium.• A short part adjoining the urinary bladder is lined by transitional epithelium.
• while the part near the external orifice is lined by stratified squamous epithelium.
Urethra
