Curriculum

17 Sections
1548 Lessons
100 Days

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U01.01 Biochemistry
This biochemistry review for USMLE Step 1 covers essential topics including metabolism, enzymology, and molecular biology.
126
U01.02 Immunology
Prepare 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
U01.03 Microbiology
Review essential microbiology topics for the USMLE Step 1, covering key pathogens, mechanisms of disease, and antimicrobial principles critical for mastering infectious disease concepts.
172
U01.04 General Pathology
Explore 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
U01.05 Pharmacology
Master 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
U01.06 Public Health Sciences
Review 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
U01.07 Cardiovascular system
Comprehensive review of essential cardiovascular system topics to help you excel in the USMLE Step 1 exam, covering key concepts from anatomy to pathology.
73
U01.08 Endocrine system
Master essential concepts of the endocrine system for USMLE Step 1, covering hormone regulation, feedback mechanisms, and key disorders to boost your exam readiness.
51
U01.09 Gastrointestinal system
Review 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
U01.10 Hematology and Oncology
This review covers essential Hematology and Oncology topics for the USMLE Step 1, including hematopoiesis, coagulation, anemias, leukemias, lymphomas, and neoplastic syndromes.
148
U01.11 Musculoskeletal, Skin, and Connective Tissue
Review 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
U01.12 Neurology and Special Senses
Master the foundational concepts of Neurology and Special Senses with our USMLE Step 1 review, covering essential topics like neuroanatomy, neurophysiology, and sensory pathways.
143
U01.13 Psychiatry
Psychiatry 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
U01.14 Renal System
The 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
U01.15 Reproductive System
The 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
U01.16 Respiratory System
The 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
U01.17 Rapid Review
he 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

U01.07.036 Atherosclerosis

Atherosclerosis is a common and serious condition affecting both elastic and muscular arteries. It is a type of arteriosclerosis caused by the accumulation of cholesterol plaques in the intima of arteries, leading to various complications.

1. Location of Atherosclerosis

Atherosclerosis tends to affect specific arteries in the body, with the distribution influenced by factors such as blood flow and the structure of the arterial wall. The primary locations include:

Location	Common Site
Abdominal Aorta	Most affected artery
Coronary Artery	Common cause of myocardial infarction (heart attack)
Popliteal Artery	Can lead to peripheral vascular disease
Carotid Artery	Risk of stroke due to reduced cerebral blood flow
Circle of Willis	Can cause ischemic stroke

2. Risk Factors for Atherosclerosis

Atherosclerosis is influenced by both modifiable and non-modifiable risk factors. Understanding these factors is essential for prevention and management.

A. Modifiable Risk Factors

Smoking: Damages the endothelial lining of arteries, promoting plaque formation.
Hypertension: Increases arterial pressure, contributing to endothelial injury.
Dyslipidemia: Elevated LDL cholesterol and decreased HDL cholesterol levels promote plaque buildup.
Diabetes: High blood sugar damages blood vessels and accelerates atherosclerosis progression.

B. Non-modifiable Risk Factors

Age: The risk increases with age.
Sex: Higher risk in men and postmenopausal women.
Family History: Genetic predisposition can increase risk.

3. Symptoms of Atherosclerosis

Symptoms can vary depending on the location and severity of the disease. Common symptoms include:

Angina: Chest pain due to reduced blood flow to the heart.
Claudication: Pain in the legs due to reduced blood flow during physical activity.
Asymptomatic: Many individuals may not experience symptoms until complications occur.

4. Pathogenesis and Progression

Atherosclerosis develops in several stages, starting from endothelial cell dysfunction to the formation of complex atheromas.

Endothelial Dysfunction: The lining of the arteries becomes damaged, leading to inflammation.
Macrophage and LDL Accumulation: Low-density lipoprotein (LDL) particles are trapped in the intima and oxidized, attracting macrophages.
Foam Cell Formation: Macrophages engulf oxidized LDL and become foam cells.
Fatty Streaks: Accumulation of foam cells forms fatty streaks in the vessel walls.
Smooth Muscle Cell Migration: Growth factors (e.g., PDGF, FGF) stimulate smooth muscle migration to the intima.
Fibrous Plaque Formation: Smooth muscle proliferation leads to the formation of fibrous plaques.
Complex Atheromas: Further plaque growth leads to the development of complex atheromas with calcification.

Stage	Key Event
Endothelial Dysfunction	Damage to the arterial lining.
Foam Cell Formation	LDL accumulation and macrophage infiltration.
Fatty Streak	Initial fatty deposits in the artery.
Fibrous Plaque Formation	Smooth muscle proliferation and extracellular matrix deposition.
Complex Atheromas	Plaque progression with calcification.

5. Complications of Atherosclerosis

If left untreated, atherosclerosis can lead to severe complications, including:

Aneurysms: Localized arterial dilation, which can rupture.
Ischemia: Insufficient blood flow to tissues, causing organ damage.
Infarcts: Tissue death due to lack of oxygen, such as in the heart (myocardial infarction) or brain (stroke).
Peripheral Vascular Disease: Reduced blood flow to limbs, often leading to claudication.
Thrombus and Emboli: Blood clots that can travel and block blood vessels in other areas.

6. Aortic Aneurysms: Associated with Atherosclerosis

Aneurysms often arise from atherosclerosis and can occur in both the abdominal and thoracic aorta. They may be asymptomatic until rupture.

A. Abdominal Aortic Aneurysm

Presentation: May present with abdominal or back pain, often associated with leaking, dissection, or rupture.
Risk Factors: Tobacco use, male sex, family history, and advanced age.
Signs: Palpable pulsatile mass in the abdomen. On imaging, a dilated aortic wall may be seen with non-opacification due to blood clots.

B. Thoracic Aortic Aneurysm

Associated with: Hypertension and connective tissue disorders.
Symptoms: Chest pain, difficulty breathing, or signs of compression on adjacent structures.

7. Key Points to Remember

Atherosclerosis affects large and medium-sized arteries, primarily the abdominal aorta, coronary, and carotid arteries.
Modifiable risk factors such as smoking, hypertension, and dyslipidemia can accelerate the disease process.
Endothelial damage, LDL accumulation, and smooth muscle migration play crucial roles in plaque formation.
Complications like aneurysms, ischemia, and infarcts can result in serious clinical consequences if not managed properly.

8. Visual Summary

Normal vs. Diseased Artery: A comparison of a normal artery, fatty streak, fibrous plaque, and atherosclerotic lesion with foam cell accumulation, smooth muscle migration, and fibrous plaque formation.

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USMLE Step 1 Review Series