Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «H»:
Histiocytosis, malignant: Histiocytosis in which
the histiocytes actually become cancerous. Treatment is by
radiation and chemotherapy, and in some cases bone-marrow
transplantation. See also histiocytosis....
Histiocytosis, sinus: A variant of histiocytosis
in which the lymph nodes are the main site of histiocyte
proliferation. The sinuses become filled with and distended
by masses of histiocytes. See also histiocytosis....
Histo: Popular name for the fungus histoplasma. Also medical school slang for histology....
Histo spot: A small circular punched-out spot in the retina at a site where spores of the fungus histoplasma (histo) seeded in the eye. Histo spots may be multiple, found in both eyes, and scattered throughout the retina. Histo spots in the macula are significant since they may stimulate the growth...
Histocompatibility: Literally, tissue compatibility. With full histocompatibility between a donor and recipient, tissue can be transplanted without being seen as foreign and being attacked by the immune system of the recipient....
Histocompatible: Literally, tissue compatible. If a donor and recipient are histocompatible, a transplant is expected to be easily accepted. ...
Histology: The study of the form of structures
seen under the microscope.
Also called microscopic anatomy, as opposed to gross
anatomy which involves
structures that can be observed with the naked eye.
gross anatomy and histology (microscopic anatomy) have been
studied in the...
Histone: A protein around which DNA coils to form chromatin. Without this protein material, DNA could not organize into chromosomes, and life as we know it would not exist....
Histoplasma: Full name: histoplasma capsulatum. A microscopic fungus that causes the disease histoplasmosis. The fungus is found throughout the world in river valleys and soil where bird or bat droppings accumulate. The spores of the fungus are released into the air when contaminated soil is distur...
Histoplasma capsulatum: See: Histoplasma....
Histoplasmosis: A disease caused by the fungus Histoplasma capsulatum. Most people with histoplasmosis have no symptoms. However, histoplasma can cause acute or chronic lung disease
and progressive disseminated histoplasmosis affecting a number of organs. It can be fatal if untreated.
History, developmental: An account of how and
when a person met developmental milestones, such as walking
and talking. For adults, information on social-emotional
development may be included. Used primarily in the
diagnosis of developmental disorders....
History, family: The family structure and relationships within the family, including information about diseases in family members.
The family history is often recorded in a family pedigree (family tree), which uses conventional symbols. The pedigree provides a ready view of problems or illnesses wit...
History, medical: See: Medical history....
History, social: An account of a patient that
puts his illness or behavior in context. It may include
aspects of the patient's developmental, family, and medical
history, as well as relevant information on life events,
social class, race, religion, and occupation. Useful for