Anatomy and physiology is the study of the structure and function of the human body. For pre-health students, this subject is not just a prerequisite to check off but the intellectual foundation for nearly everything you will encounter in clinical training. When a physician interprets an ECG, they are applying cardiac electrophysiology. When a physical therapist designs a rehabilitation plan, they are applying musculoskeletal anatomy. When a nurse assesses a patient’s breathing, they are applying respiratory physiology. This guide covers the key topics by organ system, the best free resources, and study strategies that help you build lasting, clinically relevant knowledge.

Why Anatomy and Physiology Matters

Unlike some prerequisite courses where the connection to clinical practice can feel abstract, anatomy and physiology is immediately and directly applicable. Every organ system you study will reappear in pathology, pharmacology, physical examination, and clinical decision-making. Students who invest deeply in anatomy and physiology find that later coursework is significantly easier because they already understand the normal structure and function that disease disrupts. The MCAT® tests organ system physiology extensively in the Bio/Biochem section. The USMLE®, COMLEX-USA®, NCLEX®, PANCE®, and NPTE® all assume thorough knowledge of normal anatomy and physiology as the baseline for understanding pathology.

Key Topics by Organ System

Cardiovascular System: Heart anatomy (chambers, valves, great vessels, coronary circulation), cardiac cycle (systole, diastole, pressure-volume loops), electrical conduction system (SA node, AV node, bundle of His, Purkinje fibers), ECG basics (P wave, QRS complex, T wave), blood pressure regulation (baroreceptor reflex, renin-angiotensin-aldosterone system, ANP), hemodynamics (cardiac output, stroke volume, preload, afterload, Frank-Starling mechanism), and vascular anatomy. This is one of the highest-yield systems on every health professions exam.

Respiratory System: Airway anatomy (trachea, bronchi, bronchioles, alveoli), mechanics of breathing (diaphragm, intercostals, intrapleural pressure, compliance, surfactant), gas exchange (partial pressures, diffusion, oxygen-hemoglobin dissociation curve, Bohr effect), ventilation-perfusion matching, respiratory regulation (central and peripheral chemoreceptors), and lung volumes (tidal volume, vital capacity, residual volume, FEV1/FVC ratio). Understand how altitude, exercise, and disease states alter respiratory function.

Renal System: Kidney anatomy (cortex, medulla, nephron structure), glomerular filtration (GFR, filtration fraction, Starling forces), tubular reabsorption and secretion (proximal tubule, loop of Henle, distal tubule, collecting duct), concentration and dilution of urine (countercurrent multiplier, ADH), acid-base regulation (bicarbonate reabsorption, hydrogen ion secretion, ammonium excretion), and electrolyte balance (sodium, potassium, calcium). Renal physiology is essential for understanding fluid and electrolyte disorders, hypertension, and pharmacology of diuretics.

Gastrointestinal System: Digestive tract anatomy (esophagus through rectum), accessory organs (liver, gallbladder, pancreas), mechanical and chemical digestion, absorption of nutrients (carbohydrates, proteins, lipids, vitamins), GI motility (peristalsis, segmentation, migrating motor complex), GI hormones (gastrin, secretin, cholecystokinin, GIP), hepatic function (bile production, drug metabolism, protein synthesis, detoxification), and the gut microbiome.

Endocrine System: Hypothalamic-pituitary axis, thyroid hormones (T3, T4, TSH, feedback regulation), adrenal hormones (cortisol, aldosterone, catecholamines), pancreatic hormones (insulin, glucagon), reproductive hormones (estrogen, progesterone, testosterone, LH, FSH), calcium regulation (PTH, calcitonin, vitamin D), and the concept of negative feedback. Endocrine physiology connects directly to biochemistry (hormonal regulation of metabolic pathways) and pharmacology (hormone replacement, receptor agonists and antagonists).

Nervous System: Neuron structure and function (resting membrane potential, action potentials, saltatory conduction), synaptic transmission (neurotransmitters, receptor types, excitatory and inhibitory postsynaptic potentials), central nervous system organization (cerebral cortex, brainstem, cerebellum, spinal cord), peripheral nervous system (cranial nerves, spinal nerves, dermatomes), autonomic nervous system (sympathetic vs. parasympathetic, fight-or-flight vs. rest-and-digest), sensory systems (vision, hearing, somatosensation, taste, smell), and motor systems (upper and lower motor neurons, basal ganglia, cerebellum).

Musculoskeletal System: Bone structure and remodeling, joint types and range of motion, skeletal muscle structure (sarcomere, sliding filament theory, excitation-contraction coupling), muscle fiber types (type I, type IIa, type IIx), neuromuscular junction, and major muscle groups and their actions. This system is especially important for physical therapy students preparing for the NPTE® and is tested on the MCAT® in the context of muscle physiology and biomechanics.

Immune System: Innate immunity (barriers, phagocytes, complement, inflammation), adaptive immunity (B cells, T cells, antibodies, MHC molecules, antigen presentation), immunoglobulin classes (IgG, IgA, IgM, IgE, IgD), vaccination, and immunopathology (autoimmunity, hypersensitivity, immunodeficiency). See our microbiology guide for related infectious disease content.

Free Study Resources

Khan Academy® (Free): Khan Academy® offers extensive anatomy and physiology content covering all major organ systems with video lectures and practice questions. The MCAT® collection includes physiology-focused content aligned with exam requirements. See our Khan Academy® guide.

OpenStax Anatomy and Physiology (Free): OpenStax publishes a free, comprehensive anatomy and physiology textbook with detailed illustrations and clinical correlations. It is used at many institutions as the primary course textbook. See our free textbooks page.

Visible Body and 3D Anatomy Apps (Free and Paid): Interactive 3D anatomy applications allow you to rotate, zoom, and dissect virtual anatomical structures. Some offer free basic versions. These tools are particularly useful for visual learners who struggle with flat textbook illustrations. Your university library may provide institutional access to premium anatomy software.

Anki Flashcard Decks (Free): Anatomy and physiology Anki decks cover organ system structures, physiological processes, and clinical correlations. Image-based cards with anatomical diagrams are especially effective. See our spaced repetition guide.

Study Strategies

Study Structure and Function Together: Always connect anatomy (structure) with physiology (function). Do not memorize the chambers of the heart without understanding how blood flows through them and why the walls differ in thickness. This integrated approach mirrors how the information is tested on exams and applied in clinical settings.

Use Clinical Correlations: For every normal structure and function you learn, think about what happens when it goes wrong. A stenotic heart valve changes the pressure-volume relationship. Damage to the recurrent laryngeal nerve affects the voice. Demyelination disrupts saltatory conduction. These clinical connections deepen your understanding and prepare you for pathology coursework.

Draw and Label Diagrams: Drawing anatomical structures and physiological processes from memory is one of the most effective study methods for this subject. Draw the nephron and label each segment with its functions. Draw the cardiac conduction pathway and trace the electrical signal. Draw the oxygen-hemoglobin dissociation curve and annotate the factors that shift it. See our active learning guide for more on diagram-based study techniques.

For exam-specific preparation, see our guides for the MCAT®, USMLE® Step 1, NCLEX-RN®, NPTE®, and PANCE®. For related subject guides, see biology and biochemistry.

Reproductive System: Male and female reproductive anatomy, gametogenesis (spermatogenesis and oogenesis), the menstrual cycle (follicular phase, ovulation, luteal phase, hormonal regulation), pregnancy physiology (fertilization, implantation, placental function, fetal circulation), and lactation. Reproductive physiology is important for obstetrics and gynecology and is tested on both the MCAT® and licensing exams. Know the hormonal feedback loops involving GnRH, LH, FSH, estrogen, progesterone, and testosterone.

Integumentary System: Skin structure (epidermis, dermis, hypodermis), skin functions (protection, thermoregulation, sensation, vitamin D synthesis), wound healing phases (hemostasis, inflammation, proliferation, remodeling), and common skin conditions. While less heavily tested on the MCAT®, the integumentary system is clinically important and appears on nursing, PA, and physical therapy licensing exams, particularly in the context of wound care and pressure injury prevention.

Laboratory Values: Familiarize yourself with normal ranges for common laboratory tests: complete blood count (CBC) components, basic metabolic panel (BMP) values, liver function tests, thyroid function tests, coagulation studies, and arterial blood gas (ABG) interpretation. You do not need to memorize exact numbers during your anatomy and physiology course, but understanding what each test measures and why values might be elevated or depressed builds a critical foundation for clinical reasoning.

References

Khan Academy. “Health and Medicine.” Khan Academy, 2025. https://www.khanacademy.org/science/health-and-medicine. Accessed March 2026.
OpenStax. “Anatomy and Physiology.” Rice University, 2025. https://openstax.org/details/books/anatomy-and-physiology-2e. Accessed March 2026.
AAMC. “MCAT Content Outline.” AAMC, 2025. https://students-residents.aamc.org/mcat-exam. Accessed March 2026.