<prompt> In thromboasthenia there is a defect in -Platelet aggregationPlatelet adhesionDecreased ADP releaseDisordered platelet secretion  <response>: Platelet adhesionPlatelet adhesion refers to the binding of platelets to subendothelial matrix.Platelet membrane glycoprotein Ib - IX is essential for platelet adhesion to subendothelial matrix.Platelet aggregationPlatelet aggregation refers to adherence of platelets to one another.Platelet membrane glycoprotein IIb - IIIa helps in aggregation.Congenital dysfunction of platelet1. Bernard-Soulier syndromeDefect in platelet adhesion due to inherited deficiency of glycoprotein Ib - IX.2. Glanzmanns thrombastheniaDefect in platelet aggregation due to inherited deficiency of glycoprotein IIb - IIIa. 