🫀 Anatomy & Physiology

Cardiovascular System

• Heart Chambers – Right atrium → right ventricle (pulmonary) → left atrium → left ventricle (systemic).
• Cardiac Output (CO) – CO = Heart Rate × Stroke Volume. Normal: 4–8 L/min.
• Conduction System – SA node → AV node → Bundle of His → Bundle branches → Purkinje fibers.
• Coronary Arteries – Left main (LAD + circumflex) and right coronary artery (RCA) supply myocardium.
• Blood Pressure Regulation – Renin-angiotensin-aldosterone system (RAAS), baroreceptors, ADH.

Respiratory System

• Upper Airway – Nose, pharynx, larynx; warm, filter, and humidify air.
• Lower Airway – Trachea → bronchi → bronchioles → alveoli (gas exchange).
• Surfactant – Produced by type II pneumocytes; reduces surface tension, prevents alveolar collapse.
• Gas Exchange – O₂ diffuses into blood; CO₂ diffuses out. Driven by partial pressure gradients.
• Control of Breathing – Primary: CO₂ levels (medullary chemoreceptors). Secondary: O₂ (peripheral chemoreceptors).

Renal System

• Nephron – Glomerulus, Bowman's capsule, proximal tubule, loop of Henle, distal tubule, collecting duct.
• GFR – Normal: ~120 mL/min. Estimated by eGFR (CKD staging uses eGFR and albumin-to-creatinine ratio).
• Functions – Fluid/electrolyte balance, acid-base regulation, waste excretion, BP regulation, erythropoietin production.
• Urinalysis Key Values – pH 4.5–8, specific gravity 1.001–1.030, no glucose/protein normally.

Neurological System

• CNS – Brain (cerebrum, cerebellum, brainstem) + spinal cord.
• PNS – Somatic (voluntary) and autonomic (sympathetic/parasympathetic) nervous systems.
• Glasgow Coma Scale (GCS) – Eyes (4), Verbal (5), Motor (6). Max 15; ≤8 = coma.
• Cranial Nerves – 12 pairs; mnemonic: On Old Olympus Towering Tops A Finn And German Viewed Some Hops.
• ICP – Normal: 5–15 mmHg. Cushing's triad (↑BP, ↓HR, irregular respirations) = imminent herniation.

Endocrine System

Acid-Base Balance