Step 1 Content | Physiology

General Physiology

- Homeostasis and feedback mechanisms (positive & negative) - Membrane transport (diffusion, osmosis, active transport) - Cell signaling and second messengers - Thermoregulation - Fluid compartments and electrolyte balance

- Dehydration and fluid imbalances - Electrolyte disturbances (hyper/hyponatremia, hyper/hypokalemia) - Acid-base disorders (acidosis, alkalosis)

Hematopoietic & Lymphoreticular

- Erythropoiesis and hemoglobin function - Hemostasis and coagulation cascade - Immune response and lymphatic circulation

- Anemia (iron deficiency, pernicious, hemolytic) - Clotting disorders (hemophilia, DIC) - Immune deficiencies (SCID, HIV/AIDS)

Central & Peripheral Nervous

- Neural conduction (action potentials, synaptic transmission) - Autonomic nervous system (sympathetic vs. parasympathetic) - Sensory and motor function - Neurotransmitter systems (dopamine, serotonin, GABA) - Sleep-wake regulation and circadian rhythms

- Epilepsy (abnormal neuronal firing) - Neurodegenerative disorders (Alzheimer’s, Parkinson’s) - Autonomic dysfunction (orthostatic hypotension) - Sleep disorders (insomnia, narcolepsy)

Skin & Connective Tissue

- Thermoregulation and sweat gland function - Wound healing and tissue regeneration - Skin barrier function and vitamin D synthesis

- Hyperthermia, hypothermia - Delayed wound healing (diabetes, malnutrition) - Skin infections and barrier dysfunction

Musculoskeletal

- Muscle contraction (actin-myosin interaction, ATP usage) - Neuromuscular junction and excitation-contraction coupling - Bone remodeling and calcium homeostasis

- Muscular dystrophies (Duchenne, Becker) - Myasthenia gravis (neuromuscular junction disorder) - Osteoporosis, osteomalacia

Respiratory

- Mechanics of breathing (inspiration, expiration) - Gas exchange and transport (oxygen, CO2) - Ventilation-perfusion matching (V/Q ratio) - Control of respiration (chemoreceptors, brainstem centers)

- Respiratory acidosis/alkalosis - Chronic obstructive pulmonary disease (COPD) - Hypoxia (altitude sickness, lung disease) - Sleep apnea

Cardiovascular

- Cardiac cycle and hemodynamics - Blood pressure regulation (baroreceptors, RAAS system) - Electrical conduction of the heart (SA node, AV node, Purkinje fibers) - Capillary exchange and microcirculation

- Hypertension, hypotension - Arrhythmias (atrial fibrillation, ventricular tachycardia) - Heart failure (systolic vs. diastolic) - Shock (cardiogenic, hypovolemic)

Gastrointestinal

- Motility (peristalsis, segmentation) - Digestion and enzyme activity - Absorption of nutrients and water - Hormonal regulation (gastrin, secretin, CCK) - Gut microbiome and immunity

- Gastroesophageal reflux disease (GERD) - Malabsorption syndromes (celiac disease, Crohn’s) - Peptic ulcers - Irritable bowel syndrome (IBS)

Renal/Urinary

- Glomerular filtration and renal blood flow - Tubular reabsorption and secretion - Urine concentration and osmoregulation - Acid-base balance

- Acute and chronic kidney disease - Renal tubular acidosis - Hyponatremia, hyperkalemia - Nephrotic and nephritic syndromes

Reproductive

- Hypothalamic-pituitary-gonadal axis - Gametogenesis (spermatogenesis, oogenesis) - Fertilization, implantation, and pregnancy physiology - Lactation and hormonal control

- Infertility (hormonal imbalances, structural abnormalities) - Polycystic ovary syndrome (PCOS) - Erectile dysfunction - Menopausal symptoms

Endocrine

- Hormonal signaling and feedback mechanisms - Glucose homeostasis (insulin, glucagon) - Thyroid hormone synthesis and action - Adrenal gland function (cortisol, aldosterone)

- Diabetes mellitus (Type 1, Type 2) - Hypothyroidism (Hashimoto’s), hyperthyroidism (Graves) - Addison’s disease, Cushing’s syndrome - Obesity and metabolic syndrome