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- USMLE Step 1 Review Series
Curriculum
- 17 Sections
- 1548 Lessons
- 100 Days
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- U01.01 BiochemistryThis biochemistry review for USMLE Step 1 covers essential topics including metabolism, enzymology, and molecular biology.126
- 1.1U01.01.001 Chromatin structure30 Minutes
- 1.2U01.01.002 Nucleotides30 Minutes
- 1.3U01.01.003 De novo pyrimidine and purine synthesis30 Minutes
- 1.4U01.01.004 Purine salvage deficiencies30 Minutes
- 1.5U01.01.005 Genetic code features30 Minutes
- 1.6U01.01.006 DNA replication30 Minutes
- 1.7U01.01.007 Mutations in DNA30 Minutes
- 1.8U01.01.008 Lac operon10 Minutes
- 1.9U01.01.009 DNA repair30 Minutes
- 1.10U01.01.010 Functional organization of a eukaryotic gene10 Minutes
- 1.11U01.01.011 Regulation of gene expression10 Minutes
- 1.12U01.01.012 RNA processing (eukaryotes)10 Minutes
- 1.13U01.01.013 RNA polymerases20 Minutes
- 1.14U01.01.014 Splicing of pre-mRNA30 Minutes
- 1.15U01.01.015 Introns vs exons15 Minutes
- 1.16U01.01.016 tRNA
- 1.17U01.01.017 Protein synthesis40 Minutes
- 1.18U01.01.018 Posttranslational modifications15 Minutes
- 1.19U01.01.019 Cell cycle phases30 Minutes
- 1.20U01.01.020 Rough endoplasmic reticulum10 Minutes
- 1.21U01.01.021 Smooth endoplasmic reticulum10 Minutes
- 1.22U01.01.022 Cell trafficking20 Minutes
- 1.23U01.01.023 Peroxisome15 Minutes
- 1.24U01.01.024 Proteasome10 Minutes
- 1.25U01.01.025 Cytoskeletal elements15 Minutes
- 1.26U01.01.026 Microtubule10 Minutes
- 1.27U01.01.027 Cilia structure15 Minutes
- 1.28U01.01.028 Sodium-potassium pump20 Minutes
- 1.29U01.01.029 Collagen30 Minutes
- 1.30U01.01.030 Collagen synthesis and structure25 Minutes
- 1.31U01.01.031 Osteogenesis imperfecta15 Minutes
- 1.32U01.01.032 Ehlers-Danlos syndrome15 Minutes
- 1.33U01.01.033 Elastin15 Minutes
- 1.34U01.01.034 Polymerase chain reaction15 Minutes
- 1.35U01.01.035 Reverse transcriptase polymerase chain reaction
- 1.36U01.01.036 CRISPR/Cas915 Minutes
- 1.37U01.01.037 Blotting procedures20 Minutes
- 1.38U01.01.038 Flow cytometry15 Minutes
- 1.39U01.01.039 Microarrays10 Minutes
- 1.40U01.01.040 Enzyme-linked immunosorbent assay15 Minutes
- 1.41U01.01.041 Karyotyping10 Minutes
- 1.42U01.01.042 Fluorescence in situ hybridization15 Minutes
- 1.43U01.01.043 Molecular cloning15 Minutes
- 1.44U01.01.044 Gene expression modifications20 Minutes
- 1.45U01.01.045 Genetic terms15 Minutes
- 1.46U01.01.046 Hardy-Weinberg population genetics
- 1.47U01.01.047 Disorders of imprinting15 Minutes
- 1.48U01.01.048 Modes of inheritance30 Minutes
- 1.49U01.01.049 Cystic fibrosis20 Minutes
- 1.50U01.01.050 X-linked recessive disorders20 Minutes
- 1.51U01.01.051 Muscular dystrophies20 Minutes
- 1.52U01.01.052 Rett syndrome15 Minutes
- 1.53U01.01.055 Fragile X syndrome15 Minutes
- 1.54U01.01.055 Trinucleotide repeat expansion diseases20 Minutes
- 1.55U01.01.056 Autosomal trisomies20 Minutes
- 1.56U01.01.057 Genetic disorders by chromosome20 Minutes
- 1.57U01.01.058 Robertsonian translocation10 Minutes
- 1.58U01.01.059 Cri-du-chat syndrome5 Minutes
- 1.59U01.01.060 Williams syndrome15 Minutes
- 1.60U01.01.061 Vitamins: fat soluble15 Minutes
- 1.61U01.01.062 Vitamins: Water soluble10 Minutes
- 1.62U01.01.063 Vitamin A10 Minutes
- 1.63U01.01.064 Vitamin B115 Minutes
- 1.64U01.01.065 Vitamin B215 Minutes
- 1.65U01.01.066 Vitamin B3
- 1.66U01.01.067 Vitamin B510 Minutes
- 1.67U01.01.068 Vitamin B610 Minutes
- 1.68U01.01.069 Vitamin B715 Minutes
- 1.69U01.01.070 Vitamin B910 Minutes
- 1.70U01.01.071 Vitamin B1215 Minutes
- 1.71U01.01.072 Vitamin C15 Minutes
- 1.72U01.01.073 Vitamin D
- 1.73U01.01.074 Vitamin E
- 1.74U01.01.075 Vitamin K15 Minutes
- 1.75U01.01.076 Zinc15 Minutes
- 1.76U01.01.077 Protein-energy malnutrition25 Minutes
- 1.77U01.01.078 Ethanol metabolism20 Minutes
- 1.78U01.01.079 Metabolism sites10 Minutes
- 1.79U01.01.080 Enzyme terminology15 Minutes
- 1.80U01.01.081 Rate-determining enzymes of metabolic processes*10 Minutes
- 1.81U01.01.082 Summary of pathways
- 1.82U01.01.083 ATP production15 Minutes
- 1.83U01.01.085 Activated carriers10 Minutes
- 1.84U01.01.086 Universal electron acceptors10 Minutes
- 1.85U01.01.087 Hexokinase vs glucokinase5 Minutes
- 1.86U01.01.088 Glycolysis regulation, key enzymes15 Minutes
- 1.87U01.01.089 Regulation by fructose-2,6- bisphosphate15 Minutes
- 1.88U01.01.090 Pyruvate dehydrogenase complex20 Minutes
- 1.89U01.01.091 Pyruvate dehydrogenase complex deficiency15 Minutes
- 1.90U01.01.092 Pyruvate metabolism20 Minutes
- 1.91U01.01.093 TCA cycle35 Minutes
- 1.92U01.01.094 Electron transport chain and oxidative phosphorylation15 Minutes
- 1.93U01.01.095 Gluconeogenesis, irreversible enzymes20 Minutes
- 1.94U01.01.096 Pentose phosphate pathway
- 1.95U01.01.097 Glucose-6-phosphate dehydrogenase deficiency15 Minutes
- 1.96U01.01.098 Disorders of fructose metabolism15 Minutes
- 1.97U01.01.099 Disorders of galactose metabolism10 Minutes
- 1.98U01.01.100 Sorbitol15 Minutes
- 1.99U01.01.101 Lactase deficiency15 Minutes
- 1.100U01.01.102 Amino acids15 Minutes
- 1.101U01.01.103 Urea cycle20 Minutes
- 1.102U01.01.104 Transport of ammonia by alanine20 Minutes
- 1.103U01.01.105 Hyperammonemia15 Minutes
- 1.104U01.01.106 Ornithine transcarbamylase deficiency15 Minutes
- 1.105U01.01.107 Amino acid derivatives15 Minutes
- 1.106U01.01.108 Catecholamine synthesis/tyrosine catabolism15 Minutes
- 1.107U01.01.109 Phenylketonuria20 Minutes
- 1.108U01.01.110 Maple syrup urine disease15 Minutes
- 1.109U01.01.111 Alkaptonuria15 Minutes
- 1.110U01.01.112 Homocystinuria15 Minutes
- 1.111U01.01.113 Cystinuria15 Minutes
- 1.112U01.01.114 Organic acidemias15 Minutes
- 1.113U01.01.115 Glycogen regulation by insulin and glucagon/epinephrine20 Minutes
- 1.114U01.01.116 Glycogen15 Minutes
- 1.115U01.01.117 Glycogen storage diseases15 Minutes
- 1.116U01.01.118 Lysosomal storage diseases30 Minutes
- 1.117U01.01.119 Fatty acid metabolism30 Minutes
- 1.118U01.01.120 Ketone bodies20 Minutes
- 1.119U01.01.121 Metabolic fuel use*20 Minutes
- 1.120U01.01.122 Fasting and starvation25 Minutes
- 1.121U01.01.123 Lipid transport15 Minutes
- 1.122U01.01.124 Key enzymes in lipid transport15 Minutes
- 1.123U01.01.125 Major apolipoproteins20 Minutes
- 1.124U01.01.126 Lipoprotein functions20 Minutes
- 1.125U01.01.127 Abetalipoproteinemia15 Minutes
- 1.126U01.01.128 Familial dyslipidemias15 Minutes
- U01.02 ImmunologyPrepare for USMLE Step 1 Immunology with a comprehensive review covering foundational concepts, immune system mechanisms, and key disorders to solidify your understanding and boost exam readiness.42
- 2.1U01.02.001 Immune system organs15 Minutes
- 2.2U01.02.002 Lymph node30 Minutes
- 2.3U01.02.003 Lymphatic drainage associations35 Minutes
- 2.4U01.02.004 Spleen20 Minutes
- 2.5U01.02.005 Thymus25 Minutes
- 2.6U01.02.006 Innate vs adaptive immunity30 Minutes
- 2.7U01.02.007 Major histocompatibility complex I and II25 Minutes
- 2.8U01.02.008 HLA subtypes associated with diseases20 Minutes
- 2.9U01.02.009 Natural killer cells20 Minutes
- 2.10U01.02.010 Major functions of B and T cells35 Minutes
- 2.11U01.02.011 Differentiation of T cells15 Minutes
- 2.12U01.02.012 Macrophage-lymphocyte interaction
- 2.13U01.02.013 Cytotoxic T cell30 Minutes
- 2.14U01.02.014 Regulatory T cells15 Minutes
- 2.15U01.02.015 T- and B-cell activation15 Minutes
- 2.16U01.02.016 Antibody structure and function15 Minutes
- 2.17U01.02.017 Immunoglobulin isotypes20 Minutes
- 2.18U01.02.018 Antigen type and memory15 Minutes
- 2.19U01.02.019 Complement35 Minutes
- 2.20U01.02.020 Complement disorders15 Minutes
- 2.21U01.02.021 Cytokines35 Minutes
- 2.22U01.02.022 Respiratory burst15 Minutes
- 2.23U01.02.023 Interferons15 Minutes
- 2.24U01.02.024 Cell surface proteins20 Minutes
- 2.25U01.02.025 Anergy
- 2.26U01.02.026 Passive vs active immunity15 Minutes
- 2.27U01.02.027 Vaccination40 Minutes
- 2.28U01.02.028 Hypersensitivity types40 Minutes
- 2.29U01.02.029 Blood transfusion reactions40 Minutes
- 2.30U01.02.030 Autoantibodies25 Minutes
- 2.31U01.02.031 Immunodeficiencies B-cell disorders20 Minutes
- 2.32U01.02.032 Immunodeficiencies T-cell disorders20 Minutes
- 2.33U01.02.032 Immunodeficiencies B- & T- cell disorders
- 2.34U01.02.033 Immunodeficiencies Phagocyte dysfunction30 Minutes
- 2.35U01.02.034 Infections in immunodeficiency20 Minutes
- 2.36U01.02.035 Transplant rejection25 Minutes
- 2.37U01.02.036 Immunosuppressants40 Minutes
- 2.38U01.02.037 Immunosuppression targets20 Minutes
- 2.39U01.02.038 Recombinant cytokines and clinical uses
- 2.40U01.02.039 Therapeutic antibodies: Cancer therapy15 Minutes
- 2.41U01.02.040 Therapeutic antibodies: Autoimmune disease therapy15 Minutes
- 2.42U01.02.041 Therapeutic antibodies: Other applications15 Minutes
- U01.03 MicrobiologyReview essential microbiology topics for the USMLE Step 1, covering key pathogens, mechanisms of disease, and antimicrobial principles critical for mastering infectious disease concepts.172
- 3.1Bacterial structures
- 3.2Cell envelope30 Minutes
- 3.3Stains40 Minutes
- 3.4Growth media20 Minutes
- 3.5Special culture requirements30 Minutes
- 3.6Aerobes15 Minutes
- 3.7Anaerobes30 Minutes
- 3.8Intracellular bacteria30 Minutes
- 3.9Encapsulated bacteria30 Minutes
- 3.10Urease-positive organisms
- 3.11Catalase-positive organisms
- 3.12Pigment-producing bacteria
- 3.13In vivo biofilmproducing bacteria
- 3.14Spore-forming bacteria
- 3.15Bacterial virulence factors
- 3.16Bacterial genetics
- 3.17Main features of exotoxins and endotoxins
- 3.18Bacteria with exotoxins
- 3.19Bacteria with endotoxin
- 3.20Gram-positive lab algorithm
- 3.21Gram-positive cocci antibiotic tests
- 3.22α-hemolytic bacteria
- 3.23β-hemolytic bacteria
- 3.24Staphylococcus aureus
- 3.25Staphylococcus epidermidis
- 3.26Staphylococcus saprophyticus
- 3.27Streptococcus pneumoniae
- 3.28Viridans group streptococci
- 3.29Streptococcus pyogenes (group A streptococci)
- 3.30Streptococcus agalactiae (group B streptococci)
- 3.31Streptococcus bovis
- 3.32Enterococci
- 3.33Bacillus anthracis
- 3.34Bacillus cereus
- 3.35Clostridia
- 3.36Corynebacterium diphtheriae
- 3.37Listeria monocytogenes
- 3.38Nocardia vs Actinomyces
- 3.39Mycobacteria
- 3.40Tuberculosis
- 3.41Leprosy
- 3.42Gram-negative lab algorithm
- 3.43Neisseria
- 3.44Haemophilus influenzae
- 3.45Acinetobacter baumannii
- 3.46Bordetella pertussis
- 3.47Brucella
- 3.48Legionella pneumophila
- 3.49Pseudomonas aeruginosa
- 3.50Salmonella vs Shigella
- 3.51Yersinia enterocolitica
- 3.52Lactose-fermenting enteric bacteria
- 3.53Escherichia coli
- 3.54Klebsiella
- 3.55Campylobacter jejuni
- 3.56Vibrio cholerae
- 3.57Helicobacter pylori
- 3.58Spirochetes
- 3.59Lyme disease
- 3.60Leptospira interrogans
- 3.61Syphilis
- 3.62Gardnerella vaginalis
- 3.63Chlamydiae
- 3.64Chlamydia trachomatis serotypes
- 3.65Zoonotic bacteria
- 3.66Rickettsial diseases and vector-borne illnesses
- 3.67Mycoplasma pneumoniae
- 3.68Systemic mycoses
- 3.69Cutaneous mycoses
- 3.70Opportunistic fungal infections
- 3.71Pneumocystis jirovecii
- 3.72Sporothrix schenckii
- 3.73Protozoa
- 3.74Giardia lamblia
- 3.75Entamoeba histolytica
- 3.76Cryptosporidium
- 3.77Toxoplasma gondii
- 3.78Naegleria fowleri
- 3.79Trypanosoma brucei
- 3.80Plasmodium P vivax/ovale P falciparum P malariae
- 3.81Babesia
- 3.82Trypanosoma cruzi
- 3.83Leishmania spp
- 3.84Trichomonas vaginalis
- 3.85Nematode routes of infection
- 3.86Enterobius vermicularis (pinworm)
- 3.87Ascaris lumbricoides (giant roundworm)
- 3.88Strongyloides stercoralis (threadworm)
- 3.89Ancylostoma spp, Necator americanus (hookworms)
- 3.90Trichinella spiralis
- 3.91Trichuris trichiura (whipworm)
- 3.92Toxocara canis
- 3.93Onchocerca volvulu
- 3.94Loa loa
- 3.95Wuchereria bancrofti
- 3.96Cestodes (tapeworms)
- 3.97Taenia solium
- 3.98Diphyllobothrium latum
- 3.99Echinococcus granulosus
- 3.100Trematodes (flukes)
- 3.101Schistosoma
- 3.102Clonorchis sinensis
- 3.103Ectoparasites
- 3.104Sarcoptes scabiei
- 3.105Pediculus humanus/ Phthirus pubis
- 3.106Parasite review list
- 3.107Viral structure—general features
- 3.108Viral genetics
- 3.109Phenotypic mixing
- 3.110DNA viral genomes
- 3.111RNA viral genomes
- 3.112Naked viral genome infectivity
- 3.113Viral envelopes
- 3.114DNA virus characteristics
- 3.115DNA viruses
- 3.116Herpesviruses
- 3.117Poxvirus
- 3.118Hepadnavirus
- 3.119Adenovirus
- 3.120Papillomavirus
- 3.121Polyomavirus
- 3.122Parvovirus
- 3.123Herpesviruses
- 3.124Herpes simplex virus-1
- 3.125Herpes simplex virus-2
- 3.126Varicella- Zoster virus (HHV-3)
- 3.127Epstein-Barr virus (HHV-4)
- 3.128Cytomegalovirus (HHV-5)
- 3.129Human herpesviruses 6 and 7
- 3.130Human herpesvirus 8
- 3.131HSV identificat
- 3.132Receptors used by viruses
- 3.133RNA viruses
- 3.134Reoviruses
- 3.135Picornaviruses
- 3.136Hepevirus
- 3.137Caliciviruses
- 3.138Flaviviruses
- 3.139Togaviruses
- 3.140Retroviruses
- 3.141Coronaviruses
- 3.142Orthomyxoviruses
- 3.143Paramyxoviruses
- 3.144Rhabdoviruses
- 3.145Filoviruses
- 3.146Arenaviruses
- 3.147Bunyaviruses
- 3.148Delta virus
- 3.149Negative-stranded viruses
- 3.150Segmented viruses
- 3.151Picornavirus
- 3.152Rhinovirus
- 3.153Yellow fever virus
- 3.154Rotavirus
- 3.155Influenza viruses
- 3.156Genetic/antigenic shift
- 3.157Genetic/antigenic drift
- 3.158Rubella virus
- 3.159Paramyxoviruses
- 3.160Acute laryngotracheobronchitis
- 3.161Measles (rubeola) virus
- 3.162Mumps virus
- 3.163Rabies virus
- 3.164Ebola virus
- 3.165Zika virus
- 3.166Hepatitis viruses
- 3.167Hepatitis serologic markers
- 3.168HIV
- 3.169HIV diagnosis
- 3.170Time course of untreated HIV infection
- 3.171Common diseases of HIV-positive adults
- 3.172Prions
- U01.04 General PathologyExplore key concepts in general pathology essential for the USMLE Step 1. This review covers fundamental principles, disease mechanisms, and clinical correlations to help you excel in your medical exam.35
- 4.1U01.04.001 Cellular adaptations20 Minutes
- 4.2U01.04.002 Cell injury25 Minutes
- 4.3U01.04.003 Apoptosis30 Minutes
- 4.4U01.04.004 Necrosis25 Minutes
- 4.5U01.04.005 Ischemia20 Minutes
- 4.6U01.04.006 Types of infarcts20 Minutes
- 4.7U01.04.007 Free radical injury15 Minutes
- 4.8U01.04.008 Types of calcification20 Minutes
- 4.9U01.04.009 Lipofuscin15 Minutes
- 4.10U01.04.010 Amyloidosis30 Minutes
- 4.11U01.04.011 Inflammation20 Minutes
- 4.12U01.04.012 Acute phase reactants20 Minutes
- 4.13U01.04.013 Erythrocyte sedimentation rate20 Minutes
- 4.14U01.04.014 Acute inflammation20 Minutes
- 4.15U01.04.015 Leukocyte extravasation30 Minutes
- 4.16U01.04.016 Chronic inflammation20 Minutes
- 4.17U01.04.017 Wound healing25 Minutes
- 4.18U01.04.018 Granulomatous inflammation30 Minutes
- 4.19U01.04.019 Scar formation15 Minutes
- 4.20U01.04.020 Neoplasia and neoplastic progression20 Minutes
- 4.21U01.04.021 Tumor nomenclature20 Minutes
- 4.22U01.04.022 Tumor grade vs stage15 Minutes
- 4.23U01.04.023 Hallmarks of cancer20 Minutes
- 4.24U01.04.024 Immune checkpoint interactions20 Minutes
- 4.25U01.04.025 Cancer epidemiology15 Minutes
- 4.26U01.04.026 Common metastases15 Minutes
- 4.27U01.04.027 Oncogenes30 Minutes
- 4.28U01.04.028 Tumor suppressor genes20 Minutes
- 4.29U01.04.029 Carcinogens30 Minutes
- 4.30U01.04.030 Oncogenic microbes20 Minutes
- 4.31U01.04.031 Serum tumor markers30 Minutes
- 4.32U01.04.032 Immunohistochemical stains20 Minutes
- 4.33U01.04.033 P-glycoprotein10 Minutes
- 4.34U01.04.034 Psammoma bodies10 Minutes
- 4.35U01.04.035 Cachexia15 Minutes
- U01.05 PharmacologyMaster key pharmacology concepts for the USMLE Step 1 with a focus on drug mechanisms, therapeutic uses, adverse effects, and interactions essential for high-yield exam performance.43
- 5.1U01.05.001 Enzyme kinetics45 Minutes
- 5.2U01.05.002 Bioavailability20 Minutes
- 5.3U01.05.003 Volume of distribution25 Minutes
- 5.4U01.05.004 Clearance (CL)25 Minutes
- 5.5U01.05.005 Half-life (t1/2)30 Minutes
- 5.6U01.05.006 Dosage calculations20 Minutes
- 5.7U01.05.007 Drug metabolism15 Minutes
- 5.8U01.05.008 Elimination of drugs20 Minutes
- 5.9U01.05.009 Urine pH and drug elimination20 Minutes
- 5.10U01.05.010 Efficacy vs potency15 Minutes
- 5.11U01.05.011 Receptor binding20 Minutes
- 5.12U01.05.012 Therapeutic index15 Minutes
- 5.13U01.05.013 Types of drug interactions15 Minutes
- 5.14U01.05.014 Autonomic receptors30 Minutes
- 5.15U01.05.015 Acetylcholine receptors15 Minutes
- 5.16U01.05.016 Micturition control20 Minutes
- 5.17U01.05.017 G-protein–linked second messengers40 Minutes
- 5.18U01.05.018 Autonomic drugs15 Minutes
- 5.19U01.05.019 Cholinomimetic agents25 Minutes
- 5.20U01.05.020 Anticholinesterase poisoning20 Minutes
- 5.21U01.05.021 Muscarinic antagonists45 Minutes
- 5.22U01.05.022 Atropine25 Minutes
- 5.23U01.05.023 Sympathomimetics40 Minutes
- 5.24U01.05.024 Norepinephrine vs isoproterenol20 Minutes
- 5.25U01.05.025 Sympatholytics (α2-agonists)25 Minutes
- 5.26U01.05.026 α-blockers35 Minutes
- 5.27U01.05.027 β-blockers25 Minutes
- 5.28U01.05.028 Phosphodiesterase inhibitors30 Minutes
- 5.29U01.05.029 Ingested seafood toxins20 Minutes
- 5.30U01.05.030 Beers criteria15 Minutes
- 5.31U01.05.031 Specific toxicity treatments20 Minutes
- 5.32U01.05.032 Drug reactions—cardiovascular20 Minutes
- 5.33U01.05.033 Drug reactions—endocrine/reproductive25 Minutes
- 5.34U01.05.034 Drug reactions—gastrointestinal20 Minutes
- 5.35U01.05.035 Drug reactions—hematologic30 Minutes
- 5.36U01.05.036 Drug reactions—musculoskeletal/skin/connective tissue30 Minutes
- 5.37U01.05.037 Drug reactions—neurologic25 Minutes
- 5.38U01.05.038 Drug reactions—renal/genitourinary25 Minutes
- 5.39U01.05.039 Drug reactions—respiratory20 Minutes
- 5.40U01.05.040 Drug reactions—multiorgan20 Minutes
- 5.41U01.05.041 Drugs affecting pupil size20 Minutes
- 5.42U01.05.042 Cytochrome P-450 interactions30 Minutes
- 5.43U01.05.043 Sulfa drugs20 Minutes
- U01.06 Public Health SciencesReview essential Public Health Sciences topics for the USMLE Step 1, covering epidemiology, biostatistics, health policy, and ethics to strengthen your understanding of foundational public health principles.53
- 6.1U01.06.001 Observational studies30 Minutes
- 6.2U01.06.002 Clinical trial20 Minutes
- 6.3U01.06.003 Evaluation of diagnostic tests30 Minutes
- 6.4U01.06.004 Likelihood ratio20 Minutes
- 6.5U01.06.005 Quantifying risk30 Minutes
- 6.6U01.06.006 Odds ratio20 Minutes
- 6.7U01.06.007 Relative risk30 Minutes
- 6.8U01.06.008 Relative risk reduction30 Minutes
- 6.9U01.06.009 Attributable risk30 Minutes
- 6.10U01.06.010 Absolute risk reduction
- 6.11U01.06.011 Number needed to treat
- 6.12U01.06.012 Number needed to harm
- 6.13U01.06.013 Case fatality rate
- 6.14U01.06.013 Incidence vs prevalence
- 6.15U01.06.014 Precision vs accuracy
- 6.16U01.06.015 Receiving operating characteristic curve
- 6.17U01.06.016 Bias and study errors
- 6.18U01.06.017 Statistical distribution
- 6.19U01.06.018 Nonnormal distributions
- 6.20U01.06.019 Statistical hypotheses
- 6.21U01.06.020 Outcomes of statistical hypothesis testing
- 6.22U01.06.021 Confidence interval
- 6.23U01.06.022 Meta-analysis
- 6.24U01.06.023 Common statistical tests
- 6.25U01.06.024 t-test
- 6.26U01.06.025 ANOVA
- 6.27U01.06.026 Chi-square (χ²)
- 6.28U01.06.027 Fisher’s exact test
- 6.29U01.06.028 Pearson correlation coefficient
- 6.30U01.06.029 Core ethical principles
- 6.31U01.06.030 Informed consent
- 6.32U01.06.031 Consent for minors
- 6.33U01.06.032 Decision-making capacity
- 6.34U01.06.033 Advance directives
- 6.35U01.06.034 Surrogate decisionmaker
- 6.36U01.06.035 Confidentiality
- 6.37U01.06.036 Ethical situations
- 6.38U01.06.037 Changes in the elderly
- 6.39U01.06.037 Disease prevention
- 6.40U01.06.038 Major medical insurance plans
- 6.41U01.06.039 Healthcare payment models
- 6.42U01.06.040 Medicare and Medicaid
- 6.43U01.06.041 Hospice care
- 6.44U01.06.042 Common causes of death (US) by age
- 6.45U01.06.043 Conditions with frequent hospital readmissions
- 6.46U01.06.044 Safety culture
- 6.47U01.06.045 Human factors design
- 6.48U01.06.046 PDSA cycle
- 6.49U01.06.047 Quality measurements
- 6.50U01.06.048 Swiss cheese model
- 6.51U01.06.049 Types of medical errors
- 6.52U01.06.050 Burnout vs fatigue
- 6.53U01.06.0 51 Medical error analysis
- U01.07 Cardiovascular systemComprehensive review of essential cardiovascular system topics to help you excel in the USMLE Step 1 exam, covering key concepts from anatomy to pathology.73
- 7.1U01.07 Quiz: Cardiovascular system10 Minutes0 Questions
- 7.2U01.07.001 Cardiac looping15 Minutes
- 7.3U01.07.002 Septation of the chambers30 Minutes
- 7.4U01.07.003 Heart embryology15 Minutes
- 7.5U01.07.004 Fetal circulation20 Minutes
- 7.6U01.07.005 Fetal-postnatal derivatives20 Minutes
- 7.7U01.07.006 Anatomy of the heart20 Minutes
- 7.8U01.07.007 Cardiac output variables30 Minutes
- 7.9U01.07.008 Cardiac output equations30 Minutes
- 7.10U01.07.009 Starling curves20 Minutes
- 7.11U01.07.010 Resistance, pressure, flow10 Minutes
- 7.12U01.07.011 Cardiac and vascular function curves25 Minutes
- 7.13U01.07.012 Pressure-volume loops and cardiac cycle20 Minutes
- 7.14U01.07.013 Pressure-volume loops and valvular disease25 Minutes
- 7.15U01.07.014 Splitting of S215 Minutes
- 7.16U01.07.015 Auscultation of the heart20 Minutes
- 7.17U01.07.016 Heart murmurs30 Minutes
- 7.18U01.07.017 Myocardial action potential30 Minutes
- 7.19U01.07.018 Pacemaker25 Minutes
- 7.20U01.07.019 Electrocardiogram30 Minutes
- 7.21U01.07.020 Torsades de pointes20 Minutes
- 7.22U01.07.021 Brugada syndrome15 Minutes
- 7.23U01.07.022 Wolff-Parkinson-White syndrome20 Minutes
- 7.24U01.07.023 ECG tracings30 Minutes
- 7.25U01.07.024 AV block25 Minutes
- 7.26U01.07.025 Atrial natriuretic peptide15 Minutes
- 7.27U01.07.026 B-type (brain) natriuretic peptide20 Minutes
- 7.28U01.07.027 Baroreceptors and chemoreceptors25 Minutes
- 7.29U01.07.028 Normal cardiac pressures25 Minutes
- 7.30U01.07.029 Auto-regulation25 Minutes
- 7.31U01.07.030 Capillary fluid exchange30 Minutes
- 7.32U01.07.031 Congenital heart diseases45 Minutes
- 7.33U01.07.032 Congenital cardiac defect associations25 Minutes
- 7.34U01.07.033 Hypertension30 Minutes
- 7.35U01.07.034 Hyperlipidemia25 Minutes
- 7.36U01.07.035 Arteriosclerosis30 Minutes
- 7.37U01.07.036 Atherosclerosis30 Minutes
- 7.38U01.07.037 Aortic aneurysm30 Minutes
- 7.39U01.07.038 Traumatic aortic rupture20 Minutes
- 7.40U01.07.039 Aortic dissection30 Minutes
- 7.41U01.07.040 Ischemic heart disease manifestations40 Minutes
- 7.42U01.07.041 Evolution of myocardial infarction25 Minutes
- 7.43U01.07.042 Diagnosis of myocardial infarction20 Minutes
- 7.44U01.07.043 ECG localization of STEMI25 Minutes
- 7.45U01.07.044 Myocardial infarction complications35 Minutes
- 7.46U01.07.045 Acute coronary syndrome treatments30 Minutes
- 7.47U01.07.046 Cardiomyopathies35 Minutes
- 7.48U01.07.047 Heart failure30 Minutes
- 7.49U01.07.048 Shock25 Minutes
- 7.50U01.07.049 Cardiac tamponade20 Minutes
- 7.51U01.07.050 Bacterial endocarditis30 Minutes
- 7.52U01.07.051 Rheumatic fever35 Minutes
- 7.53U01.07.052 Syphilitic heart disease30 Minutes
- 7.54U01.07.053 Acute pericarditis30 Minutes
- 7.55U01.07.054 Myocarditis25 Minutes
- 7.56U01.07.055 Vasculitides60 Minutes
- 7.57U01.07.056 Cardiac tumors30 Minutes
- 7.58U01.07.057 Kussmaul sign30 Minutes
- 7.59U01.07.058 Hereditary hemorrhagic telangiectasia20 Minutes
- 7.60U01.07.059 Hypertension treatment25 Minutes
- 7.61U01.07.060 Hydralazine25 Minutes
- 7.62U01.07.061 Hypertensive emergencies25 Minutes
- 7.63U01.07.062 Nitrates25 Minutes
- 7.64U01.07.063 Ranolazine15 Minutes
- 7.65U01.07.064 Sacubitril15 Minutes
- 7.66U01.07.065 Antianginal therapy40 Minutes
- 7.67U01.07.066 Lipid-lowering agents60 Minutes
- 7.68U01.07.067 Cardiac glycosides30 Minutes
- 7.69U01.07.068 Antiarrhythmics— sodium channel blockers (class I)30 Minutes
- 7.70U01.07.069 Antiarrhythmics— β-blockers (class II)30 Minutes
- 7.71U01.07.070 Antiarrhythmics— potassium channel blockers (class III)30 Minutes
- 7.72U01.07.071 Antiarrhythmics— calcium channel blockers (class IV)40 Minutes
- 7.73U01.07.072 Other antiarrhythmics30 Minutes
- U01.08 Endocrine systemMaster essential concepts of the endocrine system for USMLE Step 1, covering hormone regulation, feedback mechanisms, and key disorders to boost your exam readiness.51
- 8.1U01.08.01 Thyroid development15 Minutes
- 8.2U01.08.02 Pituitary Gland20 Minutes
- 8.3U01.08.03 Adrenal cortex and medulla20 Minutes
- 8.4U01.08.04 Hypothalamic-Pituitary Hormones30 Minutes
- 8.5U01.08.05 Growth hormone
- 8.6U01.08.06 Antidiuretic hormone15 Minutes
- 8.7Prolactin
- 8.8Thyroid hormones
- 8.9Parathyroid hormone
- 8.10Calcium homeostasis
- 8.11Calcitonin
- 8.12Insulin
- 8.13Adrenal steroids and congenital adrenal hyperplasias
- 8.14Cortisol
- 8.15Appetite regulation
- 8.16Signaling pathways of endocrine hormones
- 8.17Signaling pathways of steroid hormones
- 8.18Syndrome of inappropriate antidiuretic hormone secretion
- 8.19Diabetes insipidus
- 8.20Hypopituitarism
- 8.21Acromegaly
- 8.22Hypothyroidism vs hyperthyroidism
- 8.23Hypothyroidism
- 8.24Hyperthyroidism
- 8.25Thyroid cancer
- 8.26Diagnosing parathyroid disease
- 8.27Hypoparathyroidism
- 8.28Lab values in hypocalcemia
- 8.29Hyperparathyroidism
- 8.30Familial hypocalciuric hypercalcemia
- 8.31Diabetes mellitus
- 8.32Type 1 vs type 2 diabetes mellitus
- 8.33Diabetic ketoacidosis
- 8.34Hyperosmolar hyperglycemic state
- 8.35Cushing syndrome
- 8.36Nelson syndrome
- 8.37Adrenal insufficiency
- 8.38Neuroendocrine tumors
- 8.39Neuroblastoma
- 8.40Pheochromocytoma
- 8.41Multiple endocrine neoplasias
- 8.42Pancreatic islet cell tumors
- 8.43Carcinoid syndrome
- 8.44Zollinger-Ellison syndrome
- 8.45Diabetes mellitus therapy
- 8.46Thionamides
- 8.47Levothyroxine, liothyronine
- 8.48Hypothalamic/pituitary drugs
- 8.49Fludrocortisone
- 8.50Cinacalcet
- 8.51Sevelamer
- U01.09 Gastrointestinal systemReview key topics in the gastrointestinal system for the USMLE Step 1, covering essential concepts in anatomy, physiology, pathology, and pharmacology to reinforce your understanding and test readiness.131
- 9.1Normal gastrointestinal embryology
- 9.2Ventral wall defects
- 9.3Congenital umbilical hernia
- 9.4Tracheoesophageal anomalies
- 9.5Pancreas and spleen embryology
- 9.6Retroperitoneal structures
- 9.7Important gastrointestinal ligaments
- 9.8Digestive tract anatomy
- 9.9Digestive tract histology
- 9.10Abdominal aorta and branches
- 9.11Gastrointestinal blood supply and innervation
- 9.12Celiac trunk
- 9.13Portosystemic anastomoses
- 9.14Pectinate line
- 9.15Liver tissue architecture
- 9.16Biliary structures
- 9.17Femoral region
- 9.18Inguinal canal
- 9.19Abdominal wall
- 9.20Hernias
- 9.21Gastrointestinal regulatory substances
- 9.22Gastrointestinal secretory products
- 9.23Locations of gastrointestinal secretory cells
- 9.24Pancreatic secretions
- 9.25Carbohydrate absorption
- 9.26Vitamin and mineral absorption
- 9.27Peyer patches
- 9.28Bile
- 9.29Bilirubin
- 9.30Sialolithiasis
- 9.31Salivary gland tumors
- 9.32Achalasia
- 9.33Diffuse esophageal spasm
- 9.34Eosinophilic esophagitis
- 9.35Esophageal perforation
- 9.36Esophageal stricture
- 9.37Esophageal varices
- 9.38Esophagitis
- 9.39Gastroesophageal reflux disease
- 9.40Mallory-Weiss syndrome
- 9.41Plummer-Vinson syndrome
- 9.42Schatzki rings
- 9.43Sclerodermal esophageal dysmotility
- 9.44Barrett esopha
- 9.45Esophageal cancer
- 9.46Gastritis
- 9.47Ménétrier disease
- 9.48Gastric cancer
- 9.49Peptic ulcer disease
- 9.50Ulcer complications
- 9.51Malabsorption syndromes
- 9.52Celiac disease
- 9.53Lactose intolerance
- 9.54Pancreatic insufficiency
- 9.55Tropical
- 9.56Whipple disease
- 9.57Inflammatory bowel diseases
- 9.58Crohn disease
- 9.59Ulcerative colitis
- 9.60Irritable bowel syndrome
- 9.61Appendicitis
- 9.62Diverticula of the GI tract
- 9.63Zenker diverticulum
- 9.64Meckel diverticulum
- 9.65Hirschsprung disease
- 9.66Malrotation
- 9.67Intussusception
- 9.68Volvulus
- 9.69Acute mesenteric ischemia
- 9.70Adhesion
- 9.71Angiodysplasia
- 9.72Chronic mesenteric ischemia
- 9.73Colonic ischemia
- 9.74Ileus
- 9.75Meconium ileus
- 9.76Necrotizing enterocolitis
- 9.77Colonic polyps
- 9.78Hamartomatous polyps
- 9.79Hyperplastic polyps
- 9.80Inflammatory pseudopolyps
- 9.81Mucosal polyps
- 9.82Submucosal polyps
- 9.83Serrated polyps
- 9.84Polyposis syndromes
- 9.85Familial adenomatous polyposis
- 9.86Gardner syndrome
- 9.87Turcot syndrome
- 9.88Peutz-Jeghers syndrome
- 9.89Juvenile polyposis syndrome
- 9.90Lynch syndrome
- 9.91Colorectal cancer
- 9.92Molecular pathogenesis of colorectal cancer
- 9.93Cirrhosis and portal hypertension
- 9.94Spontaneous bacterial peritonitis
- 9.95Serum markers of liver pathology
- 9.96Reye syndrome
- 9.97Alcoholic liver disease
- 9.98Nonalcoholic fatty liver disease
- 9.99Hepatic encephalopathy
- 9.100Hepatocellular carcinoma/hepatoma
- 9.101Angiosarcoma
- 9.102Cavernous hemangioma
- 9.103Hepatic adenoma
- 9.104Metastases
- 9.105Budd-Chiari syndrome
- 9.106α1-antitrypsin deficiency
- 9.107Jaundice
- 9.108Physiologic neonatal jaundice
- 9.109Biliary atresia
- 9.110Hereditary hyperbilirubinemias
- 9.111Wilson disease
- 9.112Hemochromatosis
- 9.113Biliary tract disease
- 9.114Cholelithiasis and related pathologies
- 9.115Acute pancreatitis
- 9.116Chronic pancreatitis
- 9.117Pancreatic adenocarcinoma
- 9.118Acid suppression therapy
- 9.119Histamine-2 blockers
- 9.120Proton pump inhibitors
- 9.121Antacids
- 9.122Bismuth, sucralfate
- 9.123Misoprostol
- 9.124Octreotide
- 9.125Sulfasalazine
- 9.126Loperamide
- 9.127Ondansetron
- 9.128Metoclopramide
- 9.129Orlistat
- 9.130Laxatives
- 9.131Aprepitant
- U01.10 Hematology and OncologyThis review covers essential Hematology and Oncology topics for the USMLE Step 1, including hematopoiesis, coagulation, anemias, leukemias, lymphomas, and neoplastic syndromes.148
- 10.1Fetal erythropoiesis
- 10.2Blood groups
- 10.3Hemolytic disease of the newborn
- 10.4Hematopoiesis
- 10.5Neutrophils
- 10.6Erythrocytes
- 10.7Thrombocytes (platelets)
- 10.8Monocytes
- 10.9Macrophages
- 10.10Eosinophils
- 10.11Basophils
- 10.12Mast cells
- 10.13Dendritic cells
- 10.14Lymphocytes
- 10.15Natural killer cells
- 10.16B cells
- 10.17T cells
- 10.18Plasma cells
- 10.19Hemoglobin electrophoresis
- 10.20Platelet plug formation (Primary hemostasis)
- 10.21Thrombogenesis
- 10.22Coagulation and kinin pathways
- 10.23Vitamin K–dependent coagulation
- 10.24RBC morphology pathologies
- 10.25RBC inclusions
- 10.26Anemias
- 10.27Reticulocyte index
- 10.28Microcytic, hypochromic anemias
- 10.29Iron deficiency
- 10.30α-thalassemia
- 10.31β-thalassemia
- 10.32Lead poisoning
- 10.33Sideroblastic anemia
- 10.34Interpretation of iron studies
- 10.35Macrocytic anemias
- 10.36Megaloblastic anemia
- 10.37Folate deficiency
- 10.38Vitamin B12 (cobalamin) deficiency
- 10.39Orotic aciduria
- 10.40Nonmegaloblastic anemia
- 10.41Normocytic, normochromic anemias
- 10.42Nonhemolytic, normocytic anemias
- 10.43Anemia of chronic disease
- 10.44Aplastic anemia
- 10.45Hereditary spherocytosis
- 10.46G6PD deficiency
- 10.47Pyruvate kinase deficiency
- 10.48Paroxysmal nocturnal hemoglobinuria
- 10.49Sickle cell anemia
- 10.50HbC disease
- 10.51Extrinsic hemolytic anemias
- 10.52Autoimmune hemolytic anemia
- 10.53Microangiopathic hemolytic anemia
- 10.54Macroangiopathic hemolytic anemia
- 10.55Hemolytic anemia due to infection
- 10.56Leukopenias
- 10.57Neutrophil left shift
- 10.58Heme synthesis, porphyrias, and lead poisoning
- 10.59Lead poisoning
- 10.60Acute intermittent porphyria
- 10.61Porphyria cutanea tarda
- 10.62Iron poisoning
- 10.63Coagulation disorders
- 10.64Platelet disorders
- 10.65Bernard-Soulier syndrome
- 10.66Glanzmann thrombasthenia
- 10.67Immune thrombocytopenia
- 10.68Thrombotic microangiopathies
- 10.69Mixed platelet and coagulation disorders
- 10.70Hereditary thrombosis syndromes
- 10.71Antithrombin deficiency
- 10.72Factor V Leiden
- 10.73Protein C or S deficiency
- 10.74Prothrombin gene mutation
- 10.75Blood transfusion therapy
- 10.76Leukemia vs lymphoma
- 10.77Hodgkin vs non‑Hodgkin lymphoma
- 10.78Hodgkin lymphoma
- 10.79Non-Hodgkin lymphoma
- 10.80Burkitt lymphoma
- 10.81Diffuse large B-cell lymphoma
- 10.82Follicular lymphoma
- 10.83Follicular lymphoma
- 10.84Mantle cell lymphoma
- 10.85Marginal zone lymphoma
- 10.86Primary central nervous system lymphoma
- 10.87Adult T-cell lymphoma
- 10.88Mycosis fungoides/ Sézary syndrome
- 10.89Plasma cell dyscrasias
- 10.90Multiple myeloma
- 10.91Waldenstrom macroglobulinemia
- 10.92Monoclonal gammopathy of undetermined significance
- 10.93Myelodysplastic syndromes
- 10.94Leukemias
- 10.95Lymphoid neoplasms Acute lymphoblastic leukemia/lymphoma
- 10.96Chronic lymphocytic leukemia/small lymphocytic lymphoma
- 10.97Hairy cell leukemia
- 10.98Acute myelogenous leukemia
- 10.99Chronic myelogenous leukemia
- 10.100Chronic myeloproliferative disorders
- 10.101Polycythemia vera
- 10.102Essential thrombocythemia
- 10.103Myelofibrosis
- 10.104Polycythemia
- 10.105Chromosomal translocations
- 10.106Langerhans cell histiocytosis
- 10.107Tumor lysis syndrome
- 10.108Hemophagocytic lymphohistiocytosis
- 10.109Direct thrombin inhibitors
- 10.110Heparin
- 10.111Warfarin
- 10.112Heparin vs warfarin
- 10.113Direct factor Xa inhibitor
- 10.114Thrombolytics
- 10.115ADP receptor inhibitors
- 10.116Glycoprotein IIb/IIIa inhibitors
- 10.117Glycoprotein IIb/IIIa inhibitors
- 10.118Cancer therapy—targets
- 10.119Antitumor antibiotics
- 10.120Antimetabolites
- 10.121Azathioprine, 6-mercaptopurine
- 10.122Cladribine
- 10.123Cytarabine (arabinofuranosyl cytidine
- 10.1245-fluorouracil
- 10.125Methotrexate
- 10.126Alkylating agents
- 10.127Busulfan
- 10.128Cyclophosphamide, ifosfamide
- 10.129Nitrosoureas (eg, carmustine, lomustine)
- 10.130Procarbazine
- 10.131Microtubule inhibitors
- 10.132Paclitaxel, other taxanes
- 10.133Vincristine, vinblastine
- 10.134Cisplatin, carboplatin, oxaliplatin
- 10.135Etoposide, teniposide
- 10.136Irinotecan, topotecan
- 10.137Hydroxyurea
- 10.138Bevacizumab
- 10.139Erlotinib
- 10.140Cetuximab, panitumumab
- 10.141Imatinib, dasatinib, nilotinib
- 10.142Rituximab
- 10.143Bortezomib, carfilzomib
- 10.144Tamoxifen, raloxifene
- 10.145Trastuzumab
- 10.146Dabrafenib, vemurafenib
- 10.147Rasburicase
- 10.148Key chemotoxicities
- U01.11 Musculoskeletal, Skin, and Connective TissueReview essential topics for the USMLE Step 1 Musculoskeletal, Skin, and Connective Tissue systems, covering anatomy, physiology, pathology, and pharmacology fundamentals critical for exam success.178
- 11.1Rotator cuff muscles
- 11.2Arm abduction
- 11.3Upper extremity nerves
- 11.4Axillary (C5-C6)
- 11.5Musculocutaneous (C5-C7)
- 11.6Radial (C5-T1)
- 11.7Median (C5-T1)
- 11.8Ulnar (C8-T1)
- 11.9Recurrent branch of median nerve (C5-T1)
- 11.10Brachial plexus lesions
- 11.11Erb palsy (“waiter’s tip”)
- 11.12Klumpke palsy
- 11.13Thoracic outlet syndrome
- 11.14Winged scapula
- 11.15Wrist region
- 11.16Hand muscle
- 11.17Distortions of the hand
- 11.18Actions of hip muscles
- 11.19Lower extremity nerves
- 11.20Iliohypogastric (T12-L1)
- 11.21Genitofemoral nerve (L1-L2)
- 11.22Lateral femoral cutaneous (L2-L3)
- 11.23Obturator (L2-L4)
- 11.24Femoral (L2-L4)
- 11.25Sciatic (L4-S3)
- 11.26Common (fibular) peroneal (L4-S2)
- 11.27Tibial (L4-S3)
- 11.28Inferior gluteal (L5-S2)
- 11.29Superior gluteal (L4‑S1)
- 11.30Pudendal (S2-S4)
- 11.31Knee exam
- 11.32Anterior drawer sign
- 11.33Posterior drawer sign
- 11.34Abnormal passive abduction
- 11.35Abnormal passive adduction
- 11.36McMurray test
- 11.37Ankle sprains
- 11.38Signs of lumbosacral radiculopathy
- 11.39Neurovascular pairing
- 11.40Motoneuron action potential to muscle contraction
- 11.41Types of muscle fibers
- 11.42Vascular smooth muscle contraction and relaxation
- 11.43Muscle proprioceptors
- 11.44Bone formation
- 11.45Cell biology of bone
- 11.46Overuse injuries of the elbow
- 11.47Wrist and hand injuries
- 11.48Metacarpal neck fracture
- 11.49Carpal tunnel syndrome
- 11.50Guyon canal syndrome
- 11.51Clavicle fractures
- 11.52“Unhappy triad”
- 11.53Prepatellar bursitis
- 11.54Baker cyst
- 11.55De Quervain tenosynovitis
- 11.56Ganglion cyst
- 11.57Iliotibial band syndrome
- 11.58Limb compartment syndrome
- 11.59Medial tibial stress
- 11.60Plantar fasciitis
- 11.61Developmental dysplasia of the hip
- 11.62Legg-Calvé-Perthes disease
- 11.63Osgood-Schlatter disease
- 11.64Patellofemoral syndrome
- 11.65Radial head subluxation
- 11.66Slipped capital femoral epiphysis
- 11.67Greenstick fracture
- 11.68Achondroplasia
- 11.69Torus (buckle) fracture
- 11.70Osteoporosis
- 11.71Osteomalacia/rickets
- 11.72Osteitis deformans
- 11.73Avascular necrosis of bone
- 11.74Lab values in bone disorders
- 11.75Primary bone tumors
- 11.76Osteochondroma
- 11.77Osteoblastoma
- 11.78Osteoma
- 11.79Osteoid osteoma
- 11.80Giant cell tumor
- 11.81Chondroma
- 11.82Chondrosarcoma
- 11.83Osteosarcoma (osteogenic sarcoma)
- 11.84Ewing sarcoma
- 11.85Osteoarthritis vs rheumatoid arthritis
- 11.86Gout
- 11.87Calcium pyrophosphate deposition disease
- 11.88Systemic juvenile idiopathic arthritis
- 11.89Sjögren syndrome
- 11.90Septic arthritis
- 11.91Seronegative spondyloarthritis
- 11.92Psoriatic arthritis
- 11.93Ankylosing spondylitis
- 11.94Inflammatory bowel disease
- 11.95Reactive arthritis
- 11.96Systemic lupus erythematosus
- 11.97Mixed connective tissue disease
- 11.98Antiphospholipid syndrome
- 11.99Polymyalgia rheumatica
- 11.100Fibromyalgia
- 11.101Polymyositis
- 11.102Dermatomyositis
- 11.103Myasthenia gravis
- 11.104Lambert-Eaton myasthenic syndrome
- 11.105Raynaud phenomenon
- 11.106Scleroderma
- 11.107Skin layers
- 11.108Epithelial cell junctions
- 11.109Dermatologic macroscopic terms
- 11.110Dermatologic microscopic terms
- 11.111Albinism
- 11.112Melasma (chloasma)
- 11.113Vitiligo
- 11.114Seborrheic dermatitis
- 11.115Acne
- 11.116Atopic dermatitis (eczema)
- 11.117Allergic contact dermatitis
- 11.118Melanocytic nevus
- 11.119Pseudofolliculitis barbae
- 11.120Psoriasis
- 11.121Rosacea
- 11.122Seborrheic keratosis
- 11.123Verrucae
- 11.124Urticaria
- 11.125Angiosarcoma
- 11.126Bacillary angiomatosis
- 11.127Cherry hemangioma
- 11.128Glomus tumor
- 11.129Kaposi sarcoma
- 11.130Pyogenic granuloma
- 11.131Strawberry hemangioma
- 11.132Impetigo
- 11.133Erysipelas
- 11.134Cellulitis
- 11.135Abscess
- 11.136Necrotizing fasciitis
- 11.137Staphylococcal scalded skin syndrome
- 11.138Herpes
- 11.139Molluscum contagiosum
- 11.140Varicella zoster virus
- 11.141Hairy leukoplakia
- 11.142Pemphigus vulgaris
- 11.143Bullous pemphigoid
- 11.144Dermatitis herpetiformis
- 11.145Erythema multiforme
- 11.146Stevens-Johnson syndrome
- 11.147Acanthosis nigricans
- 11.148Actinic keratosis
- 11.149Erythema nodosum
- 11.150Lichen Planus
- 11.151Pityriasis rosea
- 11.152Sunburn
- 11.153Rule of 9’s
- 11.154Burn classification
- 11.155Skin cancer
- 11.156Basal cell carcinoma
- 11.157Keratoacanthoma
- 11.158Melanoma
- 11.159Squamous cell carcinoma
- 11.160Arachidonic acid pathways
- 11.161Acetaminophen
- 11.162Aspirin
- 11.163Celecoxib
- 11.164Nonsteroidal anti-inflammatory drugs
- 11.165Leflunomide
- 11.166Bisphosphonates
- 11.167Teriparatide
- 11.168Gout drugs
- 11.169Probenecid
- 11.170Allopurinol
- 11.171Pegloticase
- 11.172Febuxostat
- 11.173NSAIDs
- 11.174Glucocorticoids
- 11.175Colchicine
- 11.176TNF-α inhibitors
- 11.177Etanercept
- 11.178Infliximab, adalimumab, certolizumab
- U01.12 Neurology and Special SensesMaster the foundational concepts of Neurology and Special Senses with our USMLE Step 1 review, covering essential topics like neuroanatomy, neurophysiology, and sensory pathways.143
- 12.1Neural development20 Minutes
- 12.2Regional specification of developing brain
- 12.3Central and peripheral nervous systems origins
- 12.4Neural tube defects
- 12.5Spina bifida occulta
- 12.6Meningocele
- 12.7Myelomeningocele
- 12.8Myeloschisis
- 12.9Anencephaly
- 12.10Holoprosencephaly
- 12.11Lissencephaly
- 12.12Posterior fossa malformations
- 12.13Chiari I malformation
- 12.14Chiari II malformation
- 12.15Dandy-Walker malformation
- 12.16Syringomyelia
- 12.17Tongue development
- 12.18Neurons
- 12.19Astrocytes
- 12.20Microglia
- 12.21Ependymal cells
- 12.22Myelin
- 12.23Schwann cells
- 12.24Oligodendrocytes
- 12.25Sensory receptors
- 12.26Peripheral nerve
- 12.27Chromatolysis
- 12.28Neurotransmitter changes with disease20 Minutes
- 12.29Meninges
- 12.30Blood-brain barrier
- 12.31Vomiting center
- 12.32Sleep physiology
- 12.33Hypothalamus15 Minutes
- 12.34Thalamus
- 12.35Limbic system
- 12.36Dopaminergic pathways
- 12.37Cerebellum
- 12.38Basal ganglia
- 12.39Cerebral cortex regions
- 12.40Cerebral perfusion
- 12.41Homunculus
- 12.42Cerebral arteries—cortical distribution
- 12.43Watershed zones
- 12.44Circle of Willis
- 12.45Dural venous sinuses
- 12.46Ventricular system
- 12.47Brain stem—ventral view
- 12.48Brain stem—dorsal view (cerebellum removed)
- 12.49Cranial nerve nuclei
- 12.50Cranial nerve and vessel pathways
- 12.51Cranial nerves
- 12.52Vagal nuclei
- 12.53Cranial nerve reflexes
- 12.54Mastication muscles
- 12.55Spinal nerves
- 12.56Spinal cord—lower extent
- 12.57Spinal cord and associated tracts
- 12.58Spinal tract anatomy and functions
- 12.59Clinical reflexes
- 12.60Primitive reflexes
- 12.61Landmark dermatomes
- 12.62Common brain lesions20 Minutes
- 12.63Ischemic brain disease/stroke
- 12.64Ischemic stroke
- 12.65Transient ischemic attack
- 12.66Neonatal intraventricular hemorrhage
- 12.67Epidural hematoma
- 12.68Subdural hematoma
- 12.69Subarachnoid hemorrhage
- 12.70Intraparenchymal hemorrhage
- 12.71Effects of strokes20 Minutes
- 12.72Central poststroke pain syndrome
- 12.73Diffuse axonal injury
- 12.74Aphasia
- 12.75Aneurysms
- 12.76Seizures
- 12.77Fever vs heat stroke
- 12.78Headaches
- 12.79Movement disorders20 Minutes
- 12.80Neurodegenerative disorders
- 12.81Idiopathic intracranial hypertension
- 12.82Hydrocephalus
- 12.83Multiple sclerosis
- 12.84Other demyelinating and dysmyelinating disorders20 Minutes
- 12.85Neurocutaneous disorders15 Minutes
- 12.86Adult primary brain tumors25 Minutes
- 12.87Childhood primary brain tumors20 Minutes
- 12.88Herniation syndromes
- 12.89Motor neuron signs
- 12.90Spinal lesions
- 12.91Poliomyelitis
- 12.92Brown-Séquard syndrome
- 12.93Friedreich ataxia
- 12.94Friedreich ataxia
- 12.95Facial nerve lesions
- 12.96Auditory physiology
- 12.97Diagnosing hearing loss
- 12.98Types of hearing loss
- 12.99Cholesteatoma
- 12.100Vertigo
- 12.101Normal eye anatomy
- 12.102Conjunctivitis
- 12.103Refractive errors
- 12.104Presbyopia
- 12.105Cataract
- 12.106Aqueous humor pathway
- 12.107Glaucoma
- 12.108Uveitis
- 12.109Age-related macular degeneration
- 12.110Diabetic retinopathy
- 12.111Hypertensive retinopathy
- 12.112Retinal vein occlusion
- 12.113Retinal detachment
- 12.114Central retinal artery occlusion
- 12.115Retinitis pigmentosa
- 12.116Papilledema
- 12.117Leukocoria
- 12.118Pupillary control
- 12.119Marcus Gunn pupil
- 12.120Horner syndrome
- 12.121Ocular motility
- 12.122CN III, IV, VI palsies
- 12.123Visual field defects
- 12.124Cavernous sinus
- 12.125Internuclear ophthalmoplegia
- 12.126Epilepsy therapy
- 12.127Barbiturates
- 12.128Benzodiazepines
- 12.129Nonbenzodiazepine hypnotics
- 12.130Parkinson disease therapy
- 12.131Carbidopa/levodopa
- 12.132Selegiline, rasagiline
- 12.133Neurodegenerative disease therapy
- 12.134Anesthetics—general principles
- 12.135Inhaled anesthetics
- 12.136Intravenous anesthetics
- 12.137Local anesthetics
- 12.138Neuromuscular blocking drugs
- 12.139Spasmolytics, antispasmodics
- 12.140Opioid analgesics
- 12.141Mixed agonist and antagonist opioid analgesics
- 12.142Tramadol
- 12.143Glaucoma therapy
- U01.13 PsychiatryPsychiatry for the USMLE Step 1 focuses on understanding the pathophysiology, diagnosis, and treatment of psychiatric disorders, with an emphasis on key concepts like neurotransmitter imbalances, mental health disorders, and pharmacology.83
- 13.1Classical conditioning
- 13.2Operant conditioning
- 13.3Transference and countertransference
- 13.4Ego defenses
- 13.5Infant deprivation effects
- 13.6Child abuse
- 13.7Child neglect
- 13.8Vulnerable child syndrome
- 13.9Childhood and early-onset disorders
- 13.10Autism spectrum disorder
- 13.11Conduct disorder
- 13.12Disruptive mood dysregulation disorder
- 13.13Intellectual disability
- 13.14Oppositional defiant disorder
- 13.15Selective mutism
- 13.16Separation anxiety disorder
- 13.17Specific learning disorder
- 13.18Tourette syndrome
- 13.19Orientation
- 13.20Amnesias
- 13.21Dissociative disorders
- 13.22Delirium
- 13.23Psychosis
- 13.24Schizophrenia spectrum disorders
- 13.25Mood disorder
- 13.26Manic episode
- 13.27Hypomanic episode
- 13.28Bipolar disorder
- 13.29Major depressive disorder
- 13.30Depression with atypical features
- 13.31Peripartum mood disturbances
- 13.32Grief
- 13.33Electroconvulsive therapy
- 13.34Risk factors for suicide completion
- 13.35Anxiety disorders
- 13.36Panic disorder
- 13.37Phobias
- 13.38Generalized anxiety disorder
- 13.39Obsessive-compulsive disorders
- 13.40Trichotillomania
- 13.41Trauma and stress-related disorders
- 13.42Adjustment disorder
- 13.43Post-traumatic stress disorder
- 13.44Diagnostic criteria by symptom duration20 Minutes
- 13.45Personality
- 13.46Malingering
- 13.47Factitious disorders
- 13.48Somatic symptom and related disorders
- 13.49Eating disorders
- 13.50Gender dysphoria
- 13.51Sexual dysfunction
- 13.52Sleep terror disorder
- 13.53Narcolepsy
- 13.54Enuresis
- 13.55Substance use disorder
- 13.56Stages of change in overcoming addiction
- 13.57Psychiatric emergencies
- 13.58Serotonin syndrome
- 13.59Hypertensive crisis
- 13.60Neuroleptic malignant syndrome
- 13.61Delirium tremens
- 13.62Acute dystonia
- 13.63Lithium toxicity
- 13.64Tricyclic antidepressant toxicity
- 13.65Psychoactive drug intoxication and withdrawal
- 13.66Depressants
- 13.67Stimulants
- 13.68Hallucinogens
- 13.69Alcohol use disorder
- 13.70Psychotherapy
- 13.71Preferred medications for selected psychiatric condition20 Minutes
- 13.72Central nervous system stimulants
- 13.73Typical antipsychotics
- 13.74Atypical antipsychotics
- 13.75Lithium
- 13.76Buspirone
- 13.77Antidepressants
- 13.78Selective serotonin reuptake inhibitors
- 13.79Serotoninnorepinephrine reuptake inhibitors
- 13.80Tricyclic antidepressants
- 13.81Monoamine oxidase inhibitors
- 13.82Atypical antidepressants
- 13.83Opioid detoxification and relapse prevention
- U01.14 Renal SystemThe Renal System review for USMLE Step 1 covers key concepts including renal physiology, nephron function, acid-base balance, electrolyte regulation, and renal pathology, crucial for understanding both normal and abnormal kidney functions.81
- 14.1Kidney embryology
- 14.2Potter sequence (syndrome)
- 14.3Horseshoe kidney
- 14.4Congenital solitary functioning kidney
- 14.5Duplex collecting system
- 14.6Posterior urethral valves
- 14.7Kidney anatomy and glomerular structure
- 14.8Course of ureters
- 14.9Fluid compartments
- 14.10Glomerular filtration barrier
- 14.11Renal clearance
- 14.12Glomerular filtration rate
- 14.13Effective renal plasma flow
- 14.14Filtration
- 14.15Changes in glomerular dynamics
- 14.16Calculation of reabsorption and secretion rate
- 14.17Glucose clearance
- 14.18Nephron transport physiology
- 14.19Renal tubular defects
- 14.20Fanconi syndrome
- 14.21Bartter syndrome
- 14.22Gitelman syndrome
- 14.23Liddle syndrome
- 14.24Syndrome of Apparent Mineralocorticoid Excess
- 14.25Relative concentrations along proximal convoluted tubules
- 14.26Renin-angiotensin-aldosterone system
- 14.27Juxtaglomerular apparatus
- 14.28Kidney endocrine functions
- 14.29Hormones acting on kidney
- 14.30Potassium shifts
- 14.31Electrolyte disturbance
- 14.32Features of renal disorder20 Minutes
- 14.33Acid-base physiology
- 14.34Acidosis and alkalosis
- 14.35Renal tubular acidosis
- 14.36Casts in urine
- 14.37Nomenclature of glomerular disorders
- 14.38Glomerular diseases
- 14.39Nephritic syndrome
- 14.40Nephrotic syndrome
- 14.41Nephritic-nephrotic syndrome
- 14.42Acute poststreptococcal glomerulonephritis
- 14.43Rapidly progressive (crescentic) glomerulonephritis
- 14.44Diffuse proliferative glomerulonephritis
- 14.45IgA nephropathy (Berger disease)
- 14.46Alport syndrome
- 14.47Membranoproliferative glomerulonephritis
- 14.48Minimal change disease
- 14.49Focal segmental glomerulosclerosis
- 14.50Membranous nephropathy
- 14.51Amyloidosis
- 14.52Diabetic glomerulonephropathy
- 14.53Kidney stones20 Minutes
- 14.54Hydronephrosis
- 14.55Urinary incontinence
- 14.56Acute cystitis
- 14.57Pyelonephritis
- 14.58Acute kidney injury
- 14.59Acute interstitial nephritis
- 14.60Acute tubular necrosis
- 14.61Diffuse cortical necrosis
- 14.62Renal papillary necrosis
- 14.63Consequences of renal failure
- 14.64Renal osteodystrophy
- 14.65Renal cyst disorders20 Minutes
- 14.66Renovascular disease
- 14.67Renal cell carcinoma
- 14.68Renal oncocytoma
- 14.69Nephroblastoma
- 14.70Urothelial carcinoma of the bladder
- 14.71Squamous cell carcinoma of the bladder
- 14.72Diuretics site of action
- 14.73Mannitol
- 14.74Acetazolamide
- 14.75Loop diuretics
- 14.76Thiazide diuretics
- 14.77Potassium-sparing diuretics
- 14.78Diuretics: electrolyte changes
- 14.79Angiotensinconverting enzyme inhibitors
- 14.80Angiotensin II receptor blockers
- 14.81Aliskiren
- U01.15 Reproductive SystemThe USMLE Step 1 Reproductive System review covers key concepts in human reproduction, including anatomy, physiology, endocrinology, and common pathologies affecting both male and female reproductive health.124
- 15.1Important genes of embryogenesis25 Minutes
- 15.2Early fetal development30 Minutes
- 15.3Embryologic derivatives40 Minutes
- 15.4Types of errors in morphogenesis20 Minutes
- 15.5Teratogens
- 15.6Fetal alcohol syndrome10 Minutes
- 15.7Neonatal abstinence syndrome15 Minutes
- 15.8Twinning
- 15.9Placenta15 Minutes
- 15.10Umbilical cord
- 15.11Urachus15 Minutes
- 15.12Vitelline duct15 Minutes
- 15.13Aortic arch derivatives25 Minutes
- 15.14Pharyngeal apparatus15 Minutes
- 15.15Pharyngeal cleft derivatives15 Minutes
- 15.16Pharyngeal arch derivatives25 Minutes
- 15.17Pharyngeal pouch derivatives20 Minutes
- 15.18Cleft lip and cleft palate15 Minutes
- 15.19Genital embryology20 Minutes
- 15.20Sexual differentiation20 Minutes
- 15.21Uterine (Müllerian duct) anomalies
- 15.22Male/female genital homologs
- 15.23Congenital penile abnormalities
- 15.24Descent of testes and ovaries
- 15.25Gonadal drainage
- 15.26Female reproductive anatomy
- 15.27Adnexal torsion
- 15.28Female reproductive epithelial histology
- 15.29Male reproductive anatomy
- 15.30Urethral injury
- 15.31Autonomic innervation of male sexual response
- 15.32Seminiferous tubules
- 15.33Spermatogenesis
- 15.34Estrogen
- 15.35Progesterone
- 15.36Oogenesis
- 15.37Ovulation
- 15.38Menstrual cycle
- 15.39Abnormal uterine bleeding
- 15.40Pregnancy
- 15.41Human chorionic gonadotropin
- 15.42Human placental lactogen
- 15.43Apgar score
- 15.44Infant and child development
- 15.45Low birth weight
- 15.46Lactation
- 15.47Menopause
- 15.48Androgens
- 15.49Tanner stages of sexual development
- 15.50Tanner stages of sexual development
- 15.51Precocious puberty
- 15.52Sex chromosome disorder
- 15.53Diagnosing disorders of sex hormones
- 15.54Other disorders of sex development
- 15.55Placental aromatase deficiency
- 15.56Androgen insensitivity syndrome
- 15.575α-reductase deficiency
- 15.58Kallmann syndrome
- 15.59Abruptio placentae
- 15.60Morbidly adherent placenta
- 15.61Placenta previa
- 15.62Vasa previa
- 15.63Postpartum hemorrhage
- 15.64Ectopic pregnancy
- 15.65Amniotic fluid abnormalities
- 15.66Hydatidiform mole
- 15.67Choriocarcinoma
- 15.68Hypertension in pregnancy20 Minutes
- 15.69Gynecologic tumor epidemiology
- 15.70Bartholin cyst and abscess
- 15.71Lichen sclerosus
- 15.72Lichen simplex chronicus
- 15.73Vulvar carcinoma
- 15.74Extramammary Paget disease
- 15.75Imperforate hymen
- 15.76Vaginal tumors
- 15.77Dysplasia and carcinoma in situ
- 15.78Primary ovarian insufficiency
- 15.79Most common causes of anovulation
- 15.80Functional hypothalamic amenorrhea
- 15.81Polycystic ovarian syndrome
- 15.82Primary dysmenorrhea
- 15.83Ovarian cysts
- 15.84Ovarian neoplasms
- 15.85Epithelial tumors
- 15.86Germ cell tumors
- 15.87Sex cord stromal tumors
- 15.88Non-neoplastic uterine conditions
- 15.89Adenomyosis
- 15.90Asherman syndrome
- 15.91Endometrial hyperplasia
- 15.92Endometriosis
- 15.93Endometritis
- 15.94Endometrial carcinoma
- 15.95Leiomyoma (fibroid)
- 15.96Leiomyosarcoma
- 15.97Benign breast diseases
- 15.98Breast cancer20 Minutes
- 15.99Penile pathology25 Minutes
- 15.100Extragonadal germ cell tumors
- 15.101Scrotal masses
- 15.102Testicular tumors35 Minutes
- 15.103Hormone levels in germ cell tumors
- 15.104Epididymitis and orchitis
- 15.105Benign prostatic hyperplasia
- 15.106Benign prostatic hyperplasia
- 15.107Prostatic adenocarcinoma
- 15.108Control of reproductive hormones
- 15.109Goserelin, leuprolide
- 15.110Degarelix
- 15.111Estrogens
- 15.112Selective estrogen receptor modulators
- 15.113Aromatase inhibitors
- 15.114Hormone replacement therapy
- 15.115Progestins
- 15.116Antiprogestins
- 15.117Combined contraception
- 15.118Copper intrauterine device
- 15.119Tocolytics
- 15.120Danazol
- 15.121Testosterone, methyltestosterone
- 15.122Antiandrogens
- 15.123Tamsulosin
- 15.124Minoxidil
- U01.16 Respiratory SystemThe Respiratory System review for the USMLE Step 1 covers key concepts in anatomy, physiology, pathophysiology, and pharmacology essential for understanding respiratory diseases and treatments.61
- 16.1U01.16.001 Lung development25 Minutes
- 16.2U01.16.002 Congenital Lung Malformations20 Minutes
- 16.3U01.16.003 Respiratory Cell Types and Their Functions30 Minutes
- 16.4U01.16.004 Neonatal Respiratory Distress Syndrome (NRDS)35 Minutes
- 16.5U01.16.005 Respiratory tree15 Minutes
- 16.6U01.16.006 Lung Anatomy20 Minutes
- 16.7U01.16.007 Diaphragm structures20 Minutes
- 16.8U01.16.008 Lung volumes35 Minutes
- 16.9U01.16.009 Minute Ventilation15 Minutes
- 16.10U01.16.010 Chest Wall Mechanics30 Minutes
- 16.11U01.16.011 Hemoglobin and Oxygen Transport25 Minutes
- 16.12U01.16.012 Oxygen Content of Blood20 Minutes
- 16.13U01.16.013 Methemoglobin25 Minutes
- 16.14U01.16.014 Oxygen-Hemoglobin Dissociation Curve20 Minutes
- 16.15U01.16.015 Cyanide vs. Carbon Monoxide Poisoning30 Minutes
- 16.16U01.16.016 Pulmonary Circulation20 Minutes
- 16.17U01.16.017 Pulmonary vascular resistance15 Minutes
- 16.18U01.16.018 Alveolar Gas Equation30 Minutes
- 16.19U01.16.019 Oxygen deprivation25 Minutes
- 16.20U01.16.020 Ventilation/perfusion mismatch20 Minutes
- 16.21U01.16.021 Carbon dioxide transport25 Minutes
- 16.22U01.16.022 Response to High Altitude20 Minutes
- 16.23U01.16.023 Response to Exercise20 Minutes
- 16.24U01.16.024 Rhinosinusitis20 Minutes
- 16.25U01.16.025 Epistaxis (Nosebleed)20 Minutes
- 16.26U01.16.026 Head and Neck Cancer20 Minutes
- 16.27U01.16.027 Deep Venous Thrombosis (DVT)25 Minutes
- 16.28U01.16.028 Pulmonary Embolism (PE)25 Minutes
- 16.29U01.16.029 Mediastinal Pathology30 Minutes
- 16.30U01.16.030 Flow-Volume Loops in Lung Disease20 Minutes
- 16.31U01.16.031 Obstructive Lung Diseases60 Minutes
- 16.32U01.16.032 Restrictive Lung Diseases45 Minutes
- 16.33U01.16.033 Sarcoidosis20 Minutes
- 16.34U01.16.034 Inhalation Injury and Sequelae25 Minutes
- 16.35U01.16.035 Pneumoconioses45 Minutes
- 16.36U01.16.036 Mesothelioma20 Minutes
- 16.37U01.16.037 Acute Respiratory Distress Syndrome (ARDS)25 Minutes
- 16.38U01.16.038 Sleep apnea20 Minutes
- 16.39U01.16.039 Pulmonary hypertension35 Minutes
- 16.40U01.16.040 Physical Findings in Select Lung Diseases30 Minutes
- 16.41U01.16.041 Atelectasis20 Minutes
- 16.42U01.16.042 Pleural effusions25 Minutes
- 16.43U01.16.043 Pneumothorax40 Minutes
- 16.44U01.16.044 Lung cancer60 Minutes
- 16.45U01.16.045 Lung abscess25 Minutes
- 16.46U01.16.046 Superior Vena Cava Syndrome (SVCS)15 Minutes
- 16.47U01.16.047 Histamine-1 (H1) blockers20 Minutes
- 16.48U01.16.048 Guaifenesin15 Minutes
- 16.49U01.16.049 N-Acetylcysteine (NAC)15 Minutes
- 16.50U01.16.050 Dextromethorphan15 Minutes
- 16.51U01.16.051 Pseudoephedrine and Phenylephrine15 Minutes
- 16.52U01.16.052 Pulmonary Hypertension Drugs35 Minutes
- 16.53U01.16.053 β2-agonists35 Minutes
- 16.54U01.16.054 Inhaled corticosteroids (ICS)25 Minutes
- 16.55U01.16.054 Muscarinic antagonists30 Minutes
- 16.56U01.16.055 Antileukotrienes: Montelukast, Zafirlukast, and Zileuton35 Minutes
- 16.57U01.16.056 Anti-IgE Monoclonal Therapy: Omalizumab15 Minutes
- 16.58U01.16.057 Theophylline20 Minutes
- 16.59U01.16.058 Chromones20 Minutes
- 16.60U01.16.059 Anti-IL-5 Monoclonal Therapy30 Minutes
- 16.61U01.16.060 Summary of Anti-Asthma Drugs
- U01.17 Rapid Reviewhe USMLE Step 1 Rapid Review covers essential topics across multiple disciplines, providing a concise, high-yield overview to reinforce key concepts and optimize your exam preparation.5
- 17.1U01.17.001 Classic Presentations reviews120 Minutes
- 17.2U01.17.002 Classic Labs & associated findings review60 Minutes
- 17.3U01.17.003 Clinical Finding & associated Diagnosis Review150 Minutes
- 17.4U01.17.004 Clinical conditions & treatment review60 Minutes
- 17.5U01.17.005 Common tested equations review60 Minutes
U01.16.014 Oxygen-Hemoglobin Dissociation Curve
The oxygen-hemoglobin dissociation curve (ODC) illustrates the relationship between the partial pressure of oxygen (Po2) and the saturation of hemoglobin (Hb) with oxygen. This curve is essential for understanding how oxygen is transported in the blood and delivered to tissues.
Characteristics of the Oxygen-Hemoglobin Dissociation Curve
Sigmoidal Shape
- The ODC has a sigmoidal shape due to positive cooperativity.
- Hemoglobin (a tetrameric molecule) can bind up to four O2 molecules, and its affinity for oxygen increases with each subsequent O2 molecule bound.
Myoglobin
- Myoglobin is a monomeric protein and does not exhibit positive cooperativity.
- Its dissociation curve lacks a sigmoidal appearance, reflecting a different mechanism of oxygen binding and release.
Shifts in the Oxygen-Hemoglobin Dissociation Curve
Right Shift
A rightward shift in the ODC indicates a decrease in hemoglobin’s affinity for oxygen, facilitating oxygen unloading to tissues.
- Effects of Right Shift:
- Increased P50 (higher Po2 required for 50% saturation)
- Enhanced unloading of O2 to tissues
Left Shift
A leftward shift indicates an increase in hemoglobin’s affinity for oxygen, making it more difficult for oxygen to be unloaded.
- Effects of Left Shift:
- Decreased O2 unloading
- Increased renal hypoxia
- Enhanced erythropoietin (EPO) synthesis
- Compensatory erythrocytosis
Fetal Hemoglobin
Fetal hemoglobin (HbF) is composed of two alpha and two gamma subunits. It has a higher affinity for oxygen than adult hemoglobin due to reduced affinity for 2,3-bisphosphoglycerate (2,3-BPG). This results in a leftward shift of the dissociation curve, facilitating the transfer of oxygen from mother to fetus across the placenta.
Oxygen-Hemoglobin Dissociation Curve Table
| Factor | Left Shift (↑ Hb Affinity) | Right Shift (↓ Hb Affinity) |
|---|---|---|
| pH | Increased (alkalosis) | Decreased (acidosis) |
| PCO2 | Decreased | Increased |
| 2,3-BPG | Decreased | Increased |
| Temperature | Decreased | Increased |
| Carbon Monoxide | Increased | N/A |
| Methemoglobin | Increased | N/A |
| Fetal Hemoglobin | Higher affinity for O2 | N/A |
Points to Remember
- The ODC is sigmoidal due to positive cooperativity in hemoglobin.
- Myoglobin does not show positive cooperativity, leading to a hyperbolic curve.
- The right shift facilitates oxygen unloading, while the left shift indicates higher oxygen affinity.
- Fetal hemoglobin has a higher affinity for oxygen than adult hemoglobin, aiding in oxygen transfer across the placenta.
Bibliography
- Guyton, A. C., & Hall, J. E. (2020). Textbook of Medical Physiology (13th ed.). Elsevier.
- McDonagh, T. A., & Burch, M. (2017). Heart Failure: A Clinical Handbook. Wiley.
- Boron, W. F., & Boulpaep, E. L. (2017). Medical Physiology (3rd ed.). Elsevier.
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