This topic covers the structure and function of the kidneys, including nephron anatomy, filtration, reabsorption, and secretion processes.
Anatomy & Physiology of the Kidneys
(A concise, study‑ready outline)
| Structure | Key Features | Clinical Relevance |
|---|---|---|
| Renal Capsule | Fibrous outer covering | Protects parenchyma; site of perinephric abscess |
| Renal Cortex | Outer renal tissue; contains glomeruli & proximal tubules | Site of many glomerular diseases |
| Renal Medulla | Inner pyramidal tissue; contains loops of Henle & collecting ducts | Medullary concentration gradient |
| Renal Pelvis | Funnel‑shaped cavity → ureter | Obstruction → hydronephrosis |
| Renal Hilum | Entry/exit point for renal artery, vein, ureter, nerves, lymphatics | Vascular injuries often involve hilum |
| Segment | Main Functions | Histological Highlights |
|---|---|---|
| Glomerulus (capillary tuft) | Filtration of plasma (≈180 L/day) | Fenestrated endothelium, basement membrane, podocyte foot processes |
| Bowman's capsule | Collects filtrate | Parietal epithelium (simple squamous) |
| Proximal convoluted tubule (PCT) | Reabsorption of ~65 % of filtered Na⁺, glucose, amino acids, HCO₃⁻, water | Brush border (microvilli) → high surface area |
| Loop of Henle (descending & ascending limbs) | Generates medullary osmotic gradient; concentrates urine | Descending: permeable to water; Ascending: impermeable to water, active Na⁺/K⁺/Cl⁻ transport |
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