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Comprehensive Osteopathic Medical Licensing Examination (COMLEX-USA) Foundational Biomedical Sciences Syllabus

The Foundational Biomedical Sciences syllabus for Comprehensive Osteopathic Medical Licensing Examination (COMLEX-USA) in full: 5 chapters, 20 topics and 38 sub-topics, every one listed below, plus 51 Foundational Biomedical Sciences flashcards with answers.

5Chapters
20Topics
38Sub-topics
51Flashcards

Foundational Biomedical Sciences syllabus: all 5 chapters

Expand any chapter to see its topics and sub-topics.

  1. Anatomy and Embryology

     4 topics
    • Gross and Regional Anatomy
      • Musculoskeletal and neurovascular relationships
      • Thoracic, abdominal, and pelvic viscera
    • Neuroanatomy
      • Central pathways and tracts
      • Peripheral and autonomic nervous system
      • Cranial nerves and brainstem
    • Histology
      • Epithelial, connective, muscle, and nervous tissue
      • Organ-specific microanatomy
    • Developmental Biology and Embryology
      • Germ layer derivatives
      • Congenital malformations and teratogenesis

  2. Physiology

     4 topics
    • Cellular and Membrane Physiology
      • Transport, signaling, and action potentials
    • Cardiovascular and Respiratory Physiology
      • Hemodynamics and cardiac cycle
      • Gas exchange and ventilation-perfusion
    • Renal, Endocrine, and GI Physiology
      • Fluid, electrolyte, and acid-base balance
      • Hormonal regulation and feedback loops
    • Neuromuscular and Integrative Physiology
      • Reflex arcs and motor control
      • Thermoregulation and exercise response

  3. Biochemistry, Genetics, and Molecular Biology

     4 topics
    • Metabolic Pathways
      • Carbohydrate, lipid, and amino acid metabolism
      • Energy production and bioenergetics
    • Molecular Biology
      • DNA replication, transcription, translation
      • Gene regulation and epigenetics
    • Medical Genetics
      • Mendelian and non-Mendelian inheritance
      • Chromosomal and single-gene disorders
    • Nutrition and Vitamins
      • Deficiency and toxicity syndromes

  4. Microbiology and Immunology

     4 topics
    • Bacteriology
      • Gram-positive and gram-negative pathogens
      • Mechanisms of pathogenicity and resistance
    • Virology, Mycology, and Parasitology
      • Major viral families and replication
      • Fungal and parasitic infections
    • Immunology
      • Innate and adaptive immunity
      • Hypersensitivity and immunodeficiency
    • Vaccines and Antimicrobial Principles
      • Active and passive immunization
      • Mechanisms of antimicrobial action

  5. Pathology and Pharmacology

     4 topics
    • General Pathology
      • Cell injury, inflammation, and repair
      • Neoplasia and tumor biology
    • Systemic Pathology
      • Organ-specific disease mechanisms
    • Pharmacokinetics and Pharmacodynamics
      • Absorption, distribution, metabolism, excretion
      • Receptor theory and dose-response
    • Pharmacology by Drug Class
      • Autonomic, cardiovascular, and CNS agents
      • Adverse effects and drug interactions

Comprehensive Osteopathic Medical Licensing Examination (COMLEX-USA) Foundational Biomedical Sciences flashcards — 51 questions with answers

  1. What are the borders of the femoral triangle, and what structures pass through it from lateral to medial?

    Borders: inguinal ligament (superior), sartorius (lateral), adductor longus (medial). Contents lateral-to-medial (NAVEL): femoral Nerve, Artery, Vein, Empty space (femoral canal), Lymphatics. The femoral nerve lies outside the femoral sheath.

  2. Which nerve roots form the brachial plexus, and what is the correct order of its components?

    Roots C5-T1. Order: Roots, Trunks, Divisions, Cords, Branches (mnemonic: Read That Damn Cadaver Book). Three trunks (upper, middle, lower), each split into anterior/posterior divisions, forming lateral, posterior, and medial cords.

  3. What are the four rotator cuff muscles and their primary actions?

    SITS: Supraspinatus (abduction, initiates 0-15 degrees), Infraspinatus (external rotation), Teres minor (external rotation), Subscapularis (internal rotation). They stabilize the glenohumeral joint.

  4. What are the major ascending and descending tracts of the spinal cord and what do they carry?

    Ascending: dorsal columns (fine touch, vibration, proprioception; decussate in medulla), spinothalamic (pain/temperature; decussate at the cord). Descending: lateral corticospinal tract (voluntary motor; decussates at the medullary pyramids).

  5. What is the function of cranial nerve VII (facial) and how is a central lesion distinguished from a peripheral (Bell's palsy) lesion?

    CN VII supplies muscles of facial expression, stapedius, anterior 2/3 tongue taste, lacrimal/salivary glands. Central (UMN) lesion spares the forehead (bilateral cortical input to upper face); peripheral (LMN) lesion affects the entire ipsilateral face including forehead.

  6. What are the three main components of the basal ganglia circuitry, and what neurotransmitter is deficient in Parkinson disease?

    Direct pathway (facilitates movement) and indirect pathway (inhibits movement), modulated by dopamine from the substantia nigra pars compacta. Parkinson disease results from loss of nigrostriatal dopamine, reducing facilitation of movement.

  7. What are the four types of epithelial tissue based on cell layers and shape, with an example of each?

    Simple squamous (alveoli/endothelium), simple cuboidal (kidney tubules), simple columnar (GI tract), stratified squamous (skin/esophagus). Also pseudostratified columnar (respiratory tract) and transitional/urothelium (bladder).

  8. What are the three types of muscle tissue and the distinguishing histologic features of cardiac muscle?

    Skeletal (striated, multinucleated, voluntary), cardiac (striated, single central nucleus, involuntary, intercalated discs with gap junctions and desmosomes), smooth (non-striated, spindle-shaped, single nucleus, involuntary).

  9. From which embryonic germ layers do the nervous system, gut epithelium, and muscle/bone derive?

    Ectoderm: epidermis and nervous system (neural tube/neural crest). Endoderm: gut epithelium, liver, pancreas, lung lining. Mesoderm: muscle, bone, connective tissue, blood, kidneys, gonads.

  10. What are the pharyngeal (branchial) arch derivatives of arches 1 and 2, including their nerves?

    Arch 1 (CN V3): muscles of mastication, malleus and incus, Meckel cartilage. Arch 2 (CN VII): muscles of facial expression, stapes, styloid process, hyoid (lesser horn).

  11. What is the Nernst equation and what does it calculate?

    E_ion = (61/z) x log([ion]_out/[ion]_in) mV at 37C. It calculates the equilibrium (reversal) potential for a single ion at which its electrochemical gradient is zero (no net flux).

  12. Describe the phases of a cardiac ventricular myocyte action potential and the ions responsible.

    Phase 0: rapid Na+ influx (depolarization). Phase 1: transient K+ efflux. Phase 2: plateau, Ca2+ influx balances K+ efflux. Phase 3: K+ efflux repolarization. Phase 4: resting potential maintained by K+ (and Na/K ATPase).

  13. What determines the resting membrane potential of a typical neuron and why is it near the K+ equilibrium potential?

    It is set primarily by the high resting permeability to K+ via leak channels, so it approaches E_K (about -90 mV); the Na/K ATPase maintains gradients and contributes a small electrogenic component. Actual RMP (~-70 mV) is slightly above E_K due to minor Na+ leak.

  14. State the Fick principle for cardiac output and give the formula.

    Cardiac output = O2 consumption / (arterial O2 content - venous O2 content). CO = VO2 / (CaO2 - CvO2). It measures CO from oxygen uptake and the arteriovenous O2 difference.

  15. What is the oxygen-hemoglobin dissociation curve, and what factors shift it to the right?

    Sigmoidal curve relating PO2 to Hb saturation. A right shift (decreased O2 affinity, easier unloading) is caused by increased CO2, increased H+ (lower pH), increased temperature, and increased 2,3-BPG (Bohr effect).

  16. Define preload and afterload, and how does the Frank-Starling mechanism relate to preload?

    Preload = ventricular end-diastolic volume/wall stretch; afterload = resistance the ventricle pumps against (approx. aortic pressure/wall stress). Frank-Starling: increased preload (sarcomere stretch) increases stroke volume up to an optimal length.

  17. Write the equation for glomerular filtration rate using clearance, and why is inulin/creatinine used?

    Clearance = (U x V)/P. GFR is estimated by inulin clearance because it is freely filtered and neither reabsorbed nor secreted; creatinine clearance is the clinical approximation (slightly overestimates GFR due to minor secretion).

  18. What is the action of aldosterone on the kidney and what stimulates its release?

    Aldosterone acts on principal cells of the collecting duct to increase Na+ reabsorption and K+/H+ secretion (water follows Na+). It is stimulated by angiotensin II and by hyperkalemia.

  19. How do insulin and glucagon oppositely regulate blood glucose?

    Insulin (beta cells) lowers glucose: promotes glycogenesis, glycolysis, lipogenesis, GLUT4-mediated uptake in muscle/fat. Glucagon (alpha cells) raises glucose: promotes glycogenolysis and gluconeogenesis in the liver.

  20. What are the main GI hormones gastrin, secretin, and CCK, and their primary stimuli/actions?

    Gastrin (G cells, stimulated by peptides/vagus): increases gastric acid. Secretin (S cells, stimulated by acid in duodenum): increases pancreatic bicarbonate. CCK (I cells, stimulated by fatty acids/amino acids): gallbladder contraction and pancreatic enzyme secretion.

Show the other 31 Foundational Biomedical Sciences flashcards

  1. Describe excitation-contraction coupling at the neuromuscular junction and skeletal muscle.

    ACh released, binds nicotinic receptors causing end-plate depolarization; action potential travels down T-tubules; DHP receptor activates ryanodine receptor releasing Ca2+ from sarcoplasmic reticulum; Ca2+ binds troponin C, exposing actin for myosin cross-bridge cycling.

  2. Compare the sympathetic and parasympathetic nervous systems by origin and primary neurotransmitters.

    Sympathetic: thoracolumbar (T1-L2), short pre/long postganglionic; preganglionic ACh (nicotinic), postganglionic norepinephrine (except sweat glands = ACh). Parasympathetic: craniosacral (CN III, VII, IX, X; S2-S4), long pre/short post; ACh at both synapses.

  3. What are the net ATP yields of glycolysis, the citric acid cycle, and complete aerobic oxidation of one glucose?

    Glycolysis: net 2 ATP + 2 NADH. Per acetyl-CoA in TCA: 3 NADH, 1 FADH2, 1 GTP. Complete aerobic oxidation of glucose yields approximately 30-32 ATP.

  4. What is the rate-limiting (committed) step of glycolysis and how is it regulated?

    Phosphofructokinase-1 (PFK-1), converting fructose-6-phosphate to fructose-1,6-bisphosphate. Activated by AMP and fructose-2,6-bisphosphate; inhibited by ATP and citrate.

  5. Which enzymes are unique to gluconeogenesis (bypassing irreversible glycolytic steps)?

    Pyruvate carboxylase (pyruvate to oxaloacetate), PEP carboxykinase (OAA to PEP), fructose-1,6-bisphosphatase, and glucose-6-phosphatase. These bypass pyruvate kinase, PFK-1, and hexokinase respectively.

  6. What is the central dogma of molecular biology and the enzymes mediating each step?

    DNA -> RNA -> protein. Replication (DNA polymerase), transcription (RNA polymerase), translation (ribosome). Reverse transcription (RNA -> DNA via reverse transcriptase) occurs in retroviruses.

  7. Compare DNA polymerase functions in prokaryotic replication (Pol I vs Pol III).

    DNA Pol III is the main replicative enzyme (5'->3' synthesis, 3'->5' proofreading exonuclease). DNA Pol I removes RNA primers via 5'->3' exonuclease activity and fills the gaps.

  8. Distinguish autosomal dominant, autosomal recessive, and X-linked recessive inheritance patterns.

    AD: affected in every generation, 50% offspring risk, both sexes (e.g., Marfan). AR: skips generations, carriers, 25% risk from two carriers (e.g., cystic fibrosis). X-linked recessive: males affected, no male-to-male transmission, carrier mothers (e.g., hemophilia).

  9. What are the modes of inheritance and key examples of mitochondrial and trinucleotide repeat disorders?

    Mitochondrial: maternal inheritance, all offspring of affected mother at risk, heteroplasmy (e.g., MELAS, Leber optic neuropathy). Trinucleotide repeat: anticipation, e.g., Huntington (CAG), Fragile X (CGG), myotonic dystrophy (CTG).

  10. Match these fat-soluble vitamins to their deficiency: A, D, E, K.

    Vitamin A deficiency: night blindness, xerophthalmia. Vitamin D: rickets/osteomalacia. Vitamin E: hemolytic anemia, neuropathy. Vitamin K: bleeding (impaired clotting factors II, VII, IX, X).

  11. Which water-soluble vitamin deficiencies cause beriberi, pellagra, and megaloblastic anemia?

    Thiamine (B1) deficiency: beriberi and Wernicke-Korsakoff. Niacin (B3) deficiency: pellagra (diarrhea, dermatitis, dementia). Folate (B9) or B12 deficiency: megaloblastic anemia (B12 also causes neurologic deficits).

  12. What are the structural and Gram-stain differences between Gram-positive and Gram-negative bacteria?

    Gram-positive: thick peptidoglycan, retains crystal violet (purple), no outer membrane, has teichoic acid. Gram-negative: thin peptidoglycan, outer membrane with LPS (endotoxin), stains red/pink with safranin counterstain.

  13. Compare exotoxins and endotoxins.

    Exotoxins: secreted proteins from Gram-positive and Gram-negative bacteria, often highly toxic, antigenic (induce antibodies/toxoids), specific effects. Endotoxin: LPS lipid A of Gram-negative outer membrane, released on lysis, causes fever/shock/DIC, poorly antigenic, heat stable.

  14. What are the main mechanisms of bacterial antibiotic resistance?

    Enzymatic inactivation (e.g., beta-lactamases), target modification (e.g., altered PBPs in MRSA, ribosomal methylation), decreased uptake/increased efflux, and bypass pathways. Genes spread via plasmids, transposons, and transformation/conjugation.

  15. Classify viruses by genome: give examples of a dsDNA, ssRNA positive-sense, and ssRNA negative-sense virus.

    dsDNA: herpesviruses, adenovirus. ssRNA (+): picornavirus, coronavirus, flavivirus (directly translated). ssRNA (-): influenza, rabies, paramyxovirus (require RNA-dependent RNA polymerase carried in virion).

  16. Differentiate the malaria species Plasmodium falciparum and P. vivax/ovale clinically.

    P. falciparum: most severe, irregular fever, cerebral malaria, high parasitemia, no dormant stage. P. vivax/ovale: tertian fever, form dormant hypnozoites in liver (cause relapse), require primaquine for radical cure.

  17. What are the major dimorphic fungi and their characteristic feature?

    Dimorphic fungi are mold at ambient temperature (25C) and yeast at body temperature (37C): Histoplasma, Blastomyces, Coccidioides (spherule form), Paracoccidioides, Sporothrix. Mnemonic: mold in the cold, yeast in the heat.

  18. Compare the four hypersensitivity reaction types with a prototype example of each.

    Type I: IgE-mediated immediate (anaphylaxis, allergy). Type II: antibody-mediated cytotoxic (autoimmune hemolytic anemia). Type III: immune complex (serum sickness, SLE). Type IV: delayed T-cell mediated (TB skin test, contact dermatitis).

  19. Distinguish MHC class I and class II in terms of structure, cells, and T-cell interaction.

    MHC I: on all nucleated cells, presents endogenous (cytosolic) peptides to CD8+ T cells. MHC II: on antigen-presenting cells (dendritic, macrophages, B cells), presents exogenous peptides to CD4+ T cells.

  20. What are the functions of the five immunoglobulin classes (IgG, IgA, IgM, IgE, IgD)?

    IgG: most abundant, crosses placenta, opsonization/secondary response. IgA: mucosal/secretory, in breast milk. IgM: first produced, pentamer, best complement activator. IgE: allergy and antiparasitic (mast cells). IgD: B-cell receptor, unclear function.

  21. Compare live attenuated, inactivated, and toxoid vaccines including the type of immunity.

    Live attenuated: weakened organism, strong cellular + humoral immunity, lifelong, risk in immunocompromised (e.g., MMR). Inactivated/killed: humoral only, needs boosters, safer (e.g., rabies, polio Salk). Toxoid: inactivated toxin, antibody to toxin (e.g., tetanus, diphtheria).

  22. What is the difference between bactericidal and bacteriostatic antibiotics, and name examples.

    Bactericidal kill bacteria (beta-lactams, vancomycin, aminoglycosides, fluoroquinolones, metronidazole). Bacteriostatic inhibit growth, relying on the immune system (tetracyclines, macrolides, clindamycin, sulfonamides, chloramphenicol).

  23. What are the cardinal signs of acute inflammation and the principal cell type and mediators?

    Rubor (redness), calor (heat), tumor (swelling), dolor (pain), functio laesa (loss of function). Neutrophils are the predominant cells; mediators include histamine, prostaglandins, leukotrienes, bradykinin, and cytokines (TNF, IL-1).

  24. Differentiate hypertrophy, hyperplasia, metaplasia, dysplasia, and anaplasia.

    Hypertrophy: increased cell size. Hyperplasia: increased cell number. Metaplasia: reversible change of one mature cell type to another. Dysplasia: disordered, atypical growth (premalignant). Anaplasia: loss of differentiation, hallmark of malignancy.

  25. Compare the four types of tissue necrosis: coagulative, liquefactive, caseous, and fat.

    Coagulative: ischemic infarcts of most organs, architecture preserved. Liquefactive: brain infarcts and abscesses, enzymatic digestion. Caseous: TB and fungal, cheese-like granulomas. Fat necrosis: pancreatitis/trauma, saponification with calcium.

  26. What is the difference between transudate and exudate effusions?

    Transudate: low protein, low specific gravity, from increased hydrostatic or decreased oncotic pressure (e.g., heart failure, cirrhosis). Exudate: high protein, high specific gravity, cloudy, from increased vascular permeability (inflammation, infection, malignancy).

  27. Define zero-order versus first-order pharmacokinetic elimination with examples.

    Zero-order: constant amount eliminated per unit time, independent of concentration, saturable enzymes (e.g., ethanol, phenytoin, aspirin at high doses). First-order: constant fraction eliminated per unit time, rate proportional to concentration (most drugs).

  28. What is the loading dose formula and the maintenance dose formula in pharmacokinetics?

    Loading dose = (Cp x Vd)/F. Maintenance dose = (Cp x CL x tau)/F, where Cp = target plasma concentration, Vd = volume of distribution, CL = clearance, F = bioavailability, tau = dosing interval.

  29. Define therapeutic index, efficacy, and potency.

    Therapeutic index = TD50/ED50 (or LD50/ED50); higher = safer. Efficacy = maximal effect a drug can produce (Emax). Potency = amount of drug needed for a given effect (related to EC50); a more potent drug needs less dose.

  30. Compare the mechanisms and key adverse effects of beta-blockers and ACE inhibitors.

    Beta-blockers: block beta-adrenergic receptors, decrease heart rate/contractility/renin; adverse: bradycardia, bronchospasm, masking hypoglycemia. ACE inhibitors: block angiotensin II formation, lower aldosterone/BP; adverse: dry cough (bradykinin), hyperkalemia, angioedema, teratogenic.

  31. What is the mechanism of action of beta-lactam antibiotics, aminoglycosides, and fluoroquinolones?

    Beta-lactams (penicillins, cephalosporins): inhibit cell wall synthesis by binding penicillin-binding proteins (transpeptidases). Aminoglycosides: bind 30S ribosomal subunit, blocking protein synthesis (bactericidal). Fluoroquinolones: inhibit DNA gyrase (topoisomerase II) and topoisomerase IV.

Comprehensive Osteopathic Medical Licensing Examination (COMLEX-USA) Foundational Biomedical Sciences FAQ

What is in the Comprehensive Osteopathic Medical Licensing Examination (COMLEX-USA) Foundational Biomedical Sciences syllabus?

Comprehensive Osteopathic Medical Licensing Examination (COMLEX-USA) Foundational Biomedical Sciences is split into 5 chapters: Anatomy and Embryology, Physiology, Biochemistry, Genetics, and Molecular Biology, Microbiology and Immunology and Pathology and Pharmacology. Together they contain 20 topics and 38 sub-topics.

How many chapters are in Comprehensive Osteopathic Medical Licensing Examination (COMLEX-USA) Foundational Biomedical Sciences?

5 chapters, containing 20 topics and 38 sub-topics. The largest chapter is Anatomy and Embryology, with 4 topics.

Are there flashcards for Comprehensive Osteopathic Medical Licensing Examination (COMLEX-USA) Foundational Biomedical Sciences?

Yes — a 51-card Foundational Biomedical Sciences deck, printed in full in the flashcards section of this page and available in the Examius app with spaced repetition. The free plan covers one exam of your choice, including its flashcards; Examius Pro, a one-time purchase, unlocks every other exam and deck.