SBA — Single Best Answer · Review
Question 347
Physiology → Haematology
Classification
Question
SSBAQuestion Header
Platelet granules are separated into alpha and dense granules according to their contents.
Question Stem
Which combination is confined to the listed contents of alpha granules?
Options
A
Serotonin, calcium and phospholipids
B
Fibrinogen, factor V and thrombospondin
C
Nucleotides, serotonin and lysosomes
D
Calcium, factor XIII and nucleotides
E
Phospholipids, serotonin and platelet-derived growth factor
Explanation
Alpha granules contain clotting factors including fibrinogen and factors V and XIII, together with platelet-derived growth factor, vascular endothelial growth factor, basic fibroblast growth factor, endostatin and thrombospondin. Dense granules contain nucleotides, serotonin, phospholipids, calcium and lysosomes.
Option Validity
A) Serotonin, calcium and phospholipids are dense-granule constituents.
C) Nucleotides, serotonin and lysosomes are dense-granule contents.
D) Factor XIII is an alpha-granule constituent, but calcium and nucleotides are dense-granule constituents.
E) Platelet-derived growth factor is present in alpha granules, whereas phospholipids and serotonin are dense-granule constituents.
Further Reading
Saxena. Textbook for MRCOG-1. Physiology - Haematology - Platelets, Table 3.4, pp.70–71.