Practice 7 structured short- and long-answer medical questions on Renal Anatomy and Physiology. Review model answers for exam revision.
Answer: #### Renal Hilum The renal hilum is a deep indentation on the concave side of the kidney, acting as the gateway for several important structures: - **Renal artery**: Delivers oxygenated blood to the kidney for filtration. - **Renal vein**: Transports filtered, deoxygenated blood out of the kidney. - **Ureter**: A tube responsible for carrying urine from the kidney to the bladder. #### Renal Capsule The kidney is surrounded by the renal capsule, a thin layer of fibrous connective tissue. Its functions include: - **Maintaining kidney shape**: Composed of dense irregular connective tissue for strength. - **Support**: Contains loose reticular connective tissue providing a framework for internal tissues. #### Renal Cortex Located directly beneath the capsule, the cortex is highly vascularized and responsible for blood filtration. It houses the renal corpuscles and proximal/distal convoluted tubules. #### Renal Medulla and Pyramids The renal medulla lies beneath the cortex and contains approximately 7 cone-shaped renal pyramids. - The bases face the cortex, while the apices (papillae) point toward the renal pelvis. - **Renal columns**: Extensions of the cortex that separate the pyramids. - **Minor calyx**: Collects urine from the apex of each pyramid. #### Renal Calyces and Pelvis Urine flows from minor calyces into 3 major calyces, which converge to form the renal pelvis. This funnel-shaped structure directs urine into the ureter. --- ### Renal Blood Supply #### Arterial Pathway
Answer: Model answer pending
Answer: Model answer pending
Answer: #### Glomerulus and Bowman’s Capsule Together, these form the renal corpuscle. - **Bowman’s capsule**: A double-layered epithelial cup surrounding the glomerulus. - **Podocytes**: Specialized cells in the inner layer that form the filtration barrier. #### Efferent Arterioles and Peritubular Capillaries - **Efferent arterioles**: Transport blood away from the glomerulus. - **Peritubular capillaries**: Surround the renal tubules; essential for reabsorption and secretion. - **Venous Return**: Capillaries merge into renal veins, which drain into the inferior vena cava. --- ### The Nephron and Renal Tubule The nephron is the functional unit of the kidney. It consists of the renal corpuscle and the renal tubule. #### Proximal Convoluted Tubule (PCT) - Highly coiled to increase surface area. - Primary site for the reabsorption of water, glucose, amino acids, and sodium. #### Loop of Henle - **Descending limb**: Permeable to water but not solutes. Water is reabsorbed osmotically into the medulla. - **Ascending limb**: Impermeable to water. Actively reabsorbs sodium and chloride ions. - Maintains the medullary osmotic gradient. #### Distal Convoluted Tubule (DCT) - **Ion Regulation**: Reabsorbs Na+ and Cl-; secretes K+ and H+. - **Hormonal Target**: Aldosterone increases Na+ reabsorption; PTH increases Ca2+ reabsorption. #### Collecting Duct - Final site for urine concentration. - Permeability to water is controlled by Antidiuretic Hormone (ADH). --- ### Renal Physiology and Homeostasis #### Water Homeostasis and Hormonal Control - **Antidiuretic Hormone (ADH/Vasopressin)**: Released by the posterior pituitary; inserts aquaporins in the collecting ducts to increase water reabsorption. - **Aldosterone**: Released by the adrenal cortex; promotes Na+ reabsorption, leading to osmotic water retention. - **Atrial Natriuretic Peptide (ANP)**: Released by the heart; promotes Na+ and water excretion to lower blood pressure. #### Blood Pressure Regulation (RAAS) When blood pressure or Na+ levels drop, the juxtaglomerular cells release **Renin**.
Answer: Model answer pending
Answer: Model answer pending
Answer: #### Acid-Base Homeostasis The kidneys maintain blood pH (approx. 7.4) by: - Excreting Hydrogen ions (H+) into the tubular fluid. - Reabsorbing and generating Bicarbonate ions (HCO3-). - Working in tandem with the respiratory system (CO2 excretion). #### Electrolyte Balance - **Sodium (Na+)**: 99% is reabsorbed; critical for blood volume and nerve impulses. - **Potassium (K+)**: Regulated via secretion in the DCT/collecting duct; vital for cardiac function.