MBBS Pathology 3

Question 1

Which type of infarction is characterized by pale, firm tissue without hemorrhage?

Accepted Answer

White (anemic) infarction

Answer

White (anemic) infarctions occur in solid organs with single arterial supply (heart, spleen, kidney) where blood cannot re-enter the necrotic tissue.

Question 2

The oncogene RAS encodes a protein with what function?

Accepted Answer

GTPase signal transduction protein

Answer

RAS encodes a GTP-binding protein; mutations lock it in the active GTP-bound state, constitutively activating downstream proliferation signals.

Question 3

Which of the following best describes metaplasia?

Accepted Answer

Replacement of one differentiated cell type by another

Answer

Metaplasia is the reversible replacement of one mature cell type by another, typically as an adaptation to chronic irritation or stress.

Question 4

Virchow's triad describes the three factors predisposing to thrombosis. Which of the following is NOT part of the triad?

Accepted Answer

Thrombocytopenia

Answer

Virchow's triad consists of endothelial injury, abnormal blood flow, and hypercoagulability; thrombocytopenia actually reduces thrombosis risk.

Question 5

Which type of edema is caused by increased vascular permeability due to inflammation?

Accepted Answer

Exudate

Answer

Inflammatory edema is an exudate, characterized by high protein content and specific gravity >1.020, reflecting increased vascular permeability.

MBBS - Bachelor of Medicine and Bachelor of Surgery Practice Test