B-cells - B-cells play an important role in humoral immunity because they synthesize and secrete antibodies which protect us from infection, viruses, etc.

Bacteria - Bacteria are single-celled life forms visible only through a microscope. Bacteria live all around us and within us. Our lives are closely intertwined with theirs, and the health of our planet depends very much on their activities.

Barium enema - A radiographic diagnostic procedure that involves the introduction of a barium containing contrast material into the lower gastrointestinal tract via the anus. X-rays taken after instillation of the barium will outline the course and anatomy of the lower GI tract.

Barrett esophagus - A change in the cells of the tissue that lines the bottom of the esophagus. The esophagus may become irritated when the contents of the stomach back up (reflux). Reflux that happens often over a period of time can lead to Barrett's esophagus.

Basal & squamous cell carcinoma - Most cancer registries in North America do not register cases of basal and squamous cell carcinoma. Most often, basal and squamous cell carcinomas pose little harm to the individuals if they are detected early and treated properly. Mortality from basal and squamous cell carcinoma is low. Therefore, with our limited public health dollars, and because there are so many diagnoses of basal and squamous cell carcinoma which rarely are serious enough to cause mortality, most registries elect to not register these skin tumors.

Basal bodies - at the base of each flagellum and cilium and appear to organize their development.

Basement membrane - Basement membrane is a structure that supports an overlying epithelium or endothelium. Keratinocytes, glandular cells, and endothelial cells reside on basement membranes. Basement membrane consists of an electron dense membrane called basal lamina, about 300-700 angstrom in thickness, and an underlying network of reticular collagen fibrils which average 300 angstrom in diameter. This network is 0.1-2 micron in thickness.

Basilar - adjective, Latin basis = base.

Basilaris - (G., L., basis, base). Pertaining to the base, body, or lower part of a structure, e.g., base of the skull.

Basilic - adjective, Greek basilikos = royal (king-sized).

Basophil - Basophils make up less than 1% of your white blood cells. They are active in inflammation. Basophils contain histamine and heparin.

Belly - the part of the muscle between the origin and insertion.

Benzene - A colorless and flammable toxic liquid used in organic synthesis, as a solvent, and as a motor fuel. Exposure to benzene can increase the risk of cancer and lead to anemia and a decrease in blood platelets.

Biceps - Latin bis = double, and caput = head, hence 2-headed, adjective - bicipital.

Bifid - adjective, Latin bis = double, and findo = to split.

Bifurcate - Latin bis = double, and furco = fork, hence to divide into two.

Bilateral - Latin bi = two, lateral = side, hence, pertaining to two (both) sides.

Billroth operation i (billroth i anastomosis) - Excision of the pylorus with end-to-end anastomosis of stomach and duodenum.

Billroth operation ii (billroth ii anastomosis) - Resection of the pylorus with the greater part of the lesser curvature of the stomach, closure of the cut ends of the duodenum and stomach, followed by a gastrojejunostomy.

Biopsy - A procedure used to remove cells or tissues in order to look at them under a microscope to check for signs of disease.

Bipennate - adjective, Latin bis = double, and pinna = feather, hence converging from 2 sides.

Biventer - (L. bi, two + venter, belly). Muscle having two bellies.

Bloom syndrome - Congenital telangiectatic erythema, primarily in butterfly distribution, of the face and occasionally of the hands and forearms, with sensitivity of skin lesions and dwarfism with normal body proportions except for a narrow face and dolichocephalic skull; chromosomes are excessively fragile; autosomal recessive inheritance.

Body - the main part.

Border - see margin.

Boyle's law - describes the relationship between the pressure (P) and the volume (V) of a gas. The law states that if the volume increases, then the pressure must decrease (or vice versa).

Bph (benign prostatic hyperplasia) - A benign condition in which an overgrowth of prostate tissue pushes against the urethra (which passes through the prostate) and the bladder, blocking the release of urine.

Brachialis - (G. brachion, arm). Muscles relating to the arm.

Brachii - (G. brachion, arm). Muscles of the arm.

Brachio - (G. brachion, arm) Relating to the arm.

Brachiocephalic - Latin brachium = arm, and Greek kephale = head, hence a blood vessel related to the upper limb and head.

Brachium - Latin = arm, adjective - brachial.

Branchia - Greek = gills, adjective - branchial.

Brca1 - BRCA1 or "Breast Cancer 1," is a genetic mutation that is present in about two-thirds of heritable breast cancers and a smaller number of heritable ovarian cancers. Only about 5% of the female breast cancer in the world is attributable to having the BRCA1 mutation.

Brca2 - BRCA2 or "Breast Cancer 2," is a genetic mutation that is present in both male and female heritable breast cancer, heritable ovarian cancer, and heritable prostate cancer. Less than 5% of cancers of the male and female breast, ovary, and prostate are attributable to the BRCA2 mutation.

Bregma - from a Greek word implying moist, referring to the site of the anterior fontanelle (q.v.), a little fountain, the site of junction of the coronal and sagittal sutures, where the brain can be felt pulsating in infancy.

Brenner tumor - Brenner tumors are comprised of solid to partly cystic epithelial nests surrounded by stroma composed of bundles of tightly packed spindle-shaped cells. The epithelial cells are polygonal and of squamoid type, with pale, eosinophilic cytoplasm and oval nuclei with distinct nucleoli and longitudinal grooving, which is commonly described as "coffee-bean" in appearance.

Brevis - (L. brevis, short, brief).A short muscle or head, e.g., short head of biceps brachii.

Bronchiole - diminutive of bronchus, hence a small bronchus (bronchi have cartilage in their walls, bronchioles have no cartilage).

Bronchus - derivation unhelpful - a branch of the trachea, adjective - bronchial.

Buccal - adjective, Latin bucca = cheek.

Buccinator - Latin = trumpeter - hence the muscle which blows air out from the cheek under pressure. (L. buccinator, trumpeter). A muscle of the cheek.

Bucco - (L. bucca, cheek) Pertaining to the cheek.

Bulbo - (L. bulbus, a bulbus root). Any globular or fusiform structurs. A muscle covering a bulbar structure.

Bulbus - Latin = bulb or onion.

Bulla - Latin = bubble.

Burkitt's lymphoma - Burkitt's lymphoma is a solid tumor of B lymphocytes, the lymphocytes that the immune system uses to make antibodies. Burkitt's lymphoma is a form of cancer that primarily affects children living in certain areas of Africa. Burkitt's lymphoma is also found in North America, but it is rare.

Bursa - Greek = a purse, hence a flattened sac containing a film of fluid.

By-pass - Surgical formation of a passage (anastomosis) between two normally distinct spaces or organs. For example, a shunt to divert blood from one part of the body to the other is a by-pass. A colostomy to short circuit the GI tract, when there is an obstruction of the colon, is a by-pass.