BHSC 206
Systems Anatomy & Physiology
Renal, Reproductive & Musculoskeletal Systems
Basic Health Sciences (BHSC) Program
Academic Year 2024–2025
, 1. The Renal (Urinary) System
1.1 Anatomy
• Kidneys (2): filter blood; produce urine
• Ureters: carry urine from kidneys to bladder
• Urinary bladder: stores urine (~400–600 mL capacity)
• Urethra: carries urine from bladder to outside; female (4 cm) vs. male (20 cm)
1.2 The Nephron — Functional Unit of the Kidney
• Renal corpuscle: glomerulus + Bowman’s capsule; filtration
• Proximal convoluted tubule (PCT): reabsorbs ~65% of filtered Na+, water,
glucose, amino acids
• Loop of Henle: descending limb (water permeable); ascending limb
(impermeable to water; reabsorbs NaCl)
• Distal convoluted tubule (DCT): fine-tuning of Na+, K+, Ca2+; regulated by
aldosterone and PTH
• Collecting duct: regulated by ADH (water reabsorption) and aldosterone
1.3 Glomerular Filtration
• GFR (Glomerular Filtration Rate): ~125 mL/min; ~180 L/day filtered
• ~1.5 L of urine produced per day
• Filtered: water, ions, glucose, amino acids, urea, creatinine
• Not filtered: blood cells, most proteins (too large)
1.4 Renal Regulation of Homeostasis
• Blood pressure: RAAS system; renin released when BP falls
• Acid-base balance: secretes H+; reabsorbs HCO3⁻
• Red blood cell production: secretes erythropoietin (EPO) when O2 is low
• Vitamin D activation: converts 25-OH vitamin D to active calcitriol
Systems Anatomy & Physiology
Renal, Reproductive & Musculoskeletal Systems
Basic Health Sciences (BHSC) Program
Academic Year 2024–2025
, 1. The Renal (Urinary) System
1.1 Anatomy
• Kidneys (2): filter blood; produce urine
• Ureters: carry urine from kidneys to bladder
• Urinary bladder: stores urine (~400–600 mL capacity)
• Urethra: carries urine from bladder to outside; female (4 cm) vs. male (20 cm)
1.2 The Nephron — Functional Unit of the Kidney
• Renal corpuscle: glomerulus + Bowman’s capsule; filtration
• Proximal convoluted tubule (PCT): reabsorbs ~65% of filtered Na+, water,
glucose, amino acids
• Loop of Henle: descending limb (water permeable); ascending limb
(impermeable to water; reabsorbs NaCl)
• Distal convoluted tubule (DCT): fine-tuning of Na+, K+, Ca2+; regulated by
aldosterone and PTH
• Collecting duct: regulated by ADH (water reabsorption) and aldosterone
1.3 Glomerular Filtration
• GFR (Glomerular Filtration Rate): ~125 mL/min; ~180 L/day filtered
• ~1.5 L of urine produced per day
• Filtered: water, ions, glucose, amino acids, urea, creatinine
• Not filtered: blood cells, most proteins (too large)
1.4 Renal Regulation of Homeostasis
• Blood pressure: RAAS system; renin released when BP falls
• Acid-base balance: secretes H+; reabsorbs HCO3⁻
• Red blood cell production: secretes erythropoietin (EPO) when O2 is low
• Vitamin D activation: converts 25-OH vitamin D to active calcitriol
