Aplasia
Encyclopedia
Aplasia is defined in general as "defective development or congenital absence of an organ
or tissue
." In the field of hematology
, the term refers to "incomplete, retarded, or defective development, or cessation of the usual regenerative process."
Organ (anatomy)
In biology, an organ is a collection of tissues joined in structural unit to serve a common function. Usually there is a main tissue and sporadic tissues . The main tissue is the one that is unique for the specific organ. For example, main tissue in the heart is the myocardium, while sporadic are...
or tissue
Tissue (biology)
Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...
." In the field of hematology
Hematology
Hematology, also spelled haematology , is the branch of biology physiology, internal medicine, pathology, clinical laboratory work, and pediatrics that is concerned with the study of blood, the blood-forming organs, and blood diseases...
, the term refers to "incomplete, retarded, or defective development, or cessation of the usual regenerative process."
Examples
- Acquired pure red cell aplasiaAcquired pure red cell aplasiaPure red cell aplasia or erythroblastopenia refers to a type of anemia affecting the precursors to red blood cells but not to white blood cells. In PRCA, the bone marrow ceases to produce red blood cells...
- Aplasia cutis congenitaAplasia cutis congenitaAplasia cutis congenita is the most common congenital cicatricial alopecia, and is a congenital focal absence of epidermis with or without evidence of other layers of the skin....
- Aplastic anemiaAplastic anemiaAplastic anemia is a condition where bone marrow does not produce sufficient new cells to replenish blood cells. The condition, per its name, involves both aplasia and anemia...
- Germ cell aplasia, also known as Sertoli cell-only syndromeSertoli cell-only syndromeSertoli cell-only syndrome is a disorder characterized by male sterility without sexual abnormality...
- Radial aplasiaRadial aplasiaRadial aplasia is a congenital defect which affects the formation of the radius bone in the arm. The radius is the lateral bone which connects to the wrist via articulation with the carpal bones. A child born with this condition has either a short or absent radius bone in one or both of his or her...
- Thymic aplasia, which is found in DiGeorge syndromeDiGeorge syndrome22q11.2 deletion syndrome, which has several presentations including DiGeorge syndrome , DiGeorge anomaly, velo-cardio-facial syndrome, Shprintzen syndrome, conotruncal anomaly face syndrome, Strong syndrome, congenital thymic aplasia, and thymic hypoplasia is a syndrome caused by the deletion of a...