Free APMLE Pathology Questions and Answers — Questions and Answers
Question 1: Which cellular adaptation involves an increase in cell size due to an increased functional demand?
- Hyperplasia
- Hypertrophy (Correct answer)
- Atrophy
- Metaplasia
Correct answer: Hypertrophy
Hypertrophy is a cellular adaptation characterized by an increase in the size of individual cells, which in turn leads to an increase in the size of the organ or tissue. This typically occurs in response to increased workload or functional demand, such as muscle growth from exercise or cardiac muscle enlargement in hypertension.
Question 2: What is the primary mechanism of coagulative necrosis?
- Protein denaturation (Correct answer)
- Enzymatic digestion
- Lipid peroxidation
- Calcium influx
Correct answer: Protein denaturation
Coagulative necrosis is the most common type of necrosis and is primarily caused by the denaturation of structural proteins and enzymatic proteins within the cell. This denaturation inhibits proteolysis, preserving the basic cell outline for a period, giving the tissue a firm, opaque appearance, often seen in ischemic injury.
Question 3: Which type of hypersensitivity reaction is responsible for rheumatoid arthritis?
- Type I
- Type II
- Type III (Correct answer)
- Type IV
Correct answer: Type III
Rheumatoid arthritis is primarily considered a Type III hypersensitivity reaction, although Type IV mechanisms also contribute. In Type III reactions, immune complexes (antigen-antibody complexes) are formed and deposited in tissues, such as joints. This deposition triggers inflammation, complement activation, and subsequent tissue damage characteristic of the disease.
Question 4: What is a common microscopic feature of acute inflammation?
- Granuloma formation
- Neutrophil infiltration (Correct answer)
- Lymphocyte aggregation
- Fibrosis
Correct answer: Neutrophil infiltration
Acute inflammation is the immediate and early response of tissue to injury or infection. A hallmark microscopic feature is the rapid influx and accumulation of neutrophils, a type of white blood cell, at the site of injury. These neutrophils are crucial for phagocytosing pathogens and cellular debris, initiating the healing process.
Question 5: Which pigment is commonly associated with aging and is seen in atrophic tissues?
- Hemosiderin
- Lipofuscin (Correct answer)
- Melanin
- Bilirubin
Correct answer: Lipofuscin
Lipofuscin, often referred to as the 'wear-and-tear' or 'aging pigment,' is a yellowish-brown granular pigment composed of lipid-containing residues of lysosomal digestion. It accumulates in various tissues, particularly in long-lived postmitotic cells like neurons and cardiac myocytes, and is commonly seen in atrophic tissues associated with aging.
Free APMLE Pathology Questions and Answers
Which cellular adaptation involves an increase in cell size due to an increased functional demand?