Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «B»:
Blastocyst: A thin-walled hollow structure in early embryonic development that contains a cluster of cells called the inner cell mass from which the embryo arises. The outer layer of cells gives rise to the placenta and other supporting tissues needed for fetal development within the uterus while th...
Blastocystis hominis: The parasitic organism that causes blastocystosis. See Blastocystosis....
Blastocystis infection: See: Blastocystosis....
Blastocystosis: Infection with Blastocystis hominis, a common microscopic parasite found worldwide. Symptoms may include watery or loose stools, diarrhea, abdominal pain, anal itching, weight loss, and excess gas. Some people have no symptoms. The organism can remain in the intestines for weeks, mon...
Blastokinin: See: Uteroglobin....
Blastoma: A tumor thought to arise in embryonic tissue. The term "blastoma" is commonly used as part of the name for a tumor as, for examples, in glioblastoma and
medulloblastoma (types of brain tumors),
hepatoblastoma (a liver tumor),
Wilms tumor of the
Blastomyces dermatitidis: The fungus that causes a disease called blastomycosis....
Blastomycosis: Infection with a fungus called Blastomyces dermatitidis. The infection causes symptoms in about 50% of cases. It usually presents as a flu-like illness with fever, chills, productive cough, myalgia, arthralgia and pleuritic chest pain. Some patients fail to recover and develop chronic...
Blasts: Immature blood cells. Leukemic blasts do not
grow and age normally; they proliferate wildly and fail to
Bleb: A bladder-like structure more than 5 mm in diameter with thin
walls that may be full of fluid. Also called a bulla....
Blender experiment: See: Hershey-Chase experiment....
Blepharitis: Inflammation of the eyelids.
Blepharitis occurs in two forms, anterior and posterior:
Anterior blepharitis affects the outside front of the eyelid, where the eyelashes are attached. The two most common causes of anterior blepharitis are bacteria (Staphylococcus) and scalp dandruff.
Blepharophimosis: Horizontal narrowing of the palpebral fissures (eye slits)....
Blepharoplasty: Plastic surgery on the eyelids. Blepharoplasty may be done to correct ptosis (sagging eyelids), remove fatty bulges around the eyes, and eliminate hanging skin from the eyelids....
Blepharospasm: Involuntary forcible closure of the
eyelids. The first symptom may be uncontrollable blinking. Only one eye may be affected initially, but eventually both eyes are usually involved. The spasms may leave the eyelids completely closed causing functional blindness even though the eyes an...