B cells (B sels): Lymphocytes that act by differentiating into an antibody-secreting plasma cell.

Babinski sign (bă-BIN-skē sīn): Dorsiflexion of the foot with extension and splaying of the toes in response to the plantar reflex, normally suppressed by corticospinal input.

bacteria, bacterium (bak-TĒR-ē-ŭm): Single-celled microorganism that reproduces by cell division and may cause infection by invading body tissue.

balanitis (bal-ă-NĪT-ĭs): Inflammation of the glans penis.

balanoplasty (BAL-ă-nō-plaăs-tē): Surgical repair of the glans penis.

balanorrhea (BAL-ă-nō-RĒ-ă): Discharge from the glans penis.

barrier defenses (BAR-ē-ĕr dĕ-FEN-s): Antipathogen defenses deriving from a barrier that physically prevents pathogens from entering the body to establish an infection.

Bartholin’s glands (BAR-tō-lĭns glăns): Responsible to secrete mucus to keep the vestibular area moist.

basal cell carcinoma (BĀ-săl sel kar-sĭn-Ō-ma): Form of cancer that affects the mitotically active stem cells in the stratum basale of the epidermis.

benign (bē-NĪN): Noncancerous, harmless.

benign prostatic hyperplasia (BPH) (bē-NĪN prŏs-TĂT-ĭk hī-pĕr-PLĀ-zh(ē-)ă): Excessive development pertaining to the prostate gland.

bicarbonate (bī-KĂR-bō-nāt): A by-product of the body’s metabolism.

bilateral (bī-LAT-ĕ-răl): Pertaining to both sides.

binocular (bĭn-ŎK-ū-lăr): Pertaining to both eyes.

biopsy (BĪ-op-sē): View of life (removal of living tissue to be viewed under a microscope).

bipolar (bī-PŌL-ăr): Shape of a neuron with two processes extending from the neuron cell body—the axon and one dendrite.

blepharitis (blĕf-ăr-Ī-tĭs): Inflammation of eyelids.

blepharoplasty (BLĔF-ă-rō-plăs-tē): Surgical repair of the eyelid.

blepharoptosis (BLĔF-ă-rō-TŌ-sĭs): Drooping of the eyelid.

blood-brain barrier (BBB) (blŭd- brān BAR-ē-ĕr): Physiological barrier between the circulatory system and the central nervous system that establishes a privileged blood supply, restricting the flow of substances into the CNS.

bone marrow (bōn MAR-ō): Tissue found inside bones, the site of all blood cell differentiation and maturation of b lymphocytes.

brachial artery (BRĀ-kē-ăl ART-ĕ-rē): Large artery in the upper arm near the biceps muscle.

bradycardia (brād-i-KARD-ē-ă): Pertaining to a slow heart (rate).

bradykinesia (brăd-ē-kĭ-NĒ-sē-ă): Condition of slow movement.

brain (brān): The large organ of the central nervous system composed of white and gray matter, contained within the cranium and continuous with the spinal cord.

brain stem (brān stem): Region of the adult brain that includes the midbrain, pons, and medulla oblongata and develops from the mesencephalon, metencephalon, and myelencephalon of the embryonic brain.

breast cancer (KAN-sĕr): Malignant tumor of the breast.

breech (brēch): The position of the fetus is feet first. Ideally, the position of the fetus should be headfirst for a safer delivery.

Broca’s area (brō-KAS AR-ē-ă): Region of the frontal lobe associated with the motor commands necessary for speech production and located only in the cerebral hemisphere responsible for language production, which is the left side in approximately 95 percent of the population.

Brodmann’s areas (BRŌD-mans AR-ē-ă): Mapping of regions of the cerebral cortex based on microscopic anatomy that relates specific areas to functional differences, as described by Brodmann in the early 1900s.

bronchitis (brong-KĪT-ĭs): Inflammation of the bronchus.

bronchoalveolar (brong-kō-al-VĒ-ŏ-lăr): Pertaining to the bronchi and alveoli.

bronchodilators (BRONG-kō-dī-LĀT-ŏrs): Substance that dilates the bronchi and bronchioles.

bronchogenic carcinoma (brŏng-kō-JĔN-ĭk kar-sĭn-Ō-mă): Cancerous tumor originating in a bronchus.

bronchopneumonia (brong-kō-noo-MŌ-nē-ă): Diseased state of bronchi and lungs.

bronchoscope (BRŎNG-kō-skōp): Instrument used for visual examination of the bronchi.

bronchoscopy (bron-KOS-kŏ-pē): Visual examination of the bronchi.

bronchospasm (BRŎNG-kō-spăzm): Spasmodic contraction of the bronchi.

bronchus-associated lymphoid tissue (balt) (BRONG-kŭs ă-sō-s(h)ē-ĀTE LIM-foyd TISH-oo): Lymphoid nodule associated with the respiratory tract.

bruit (brwē): Abnormal blowing, swishing heart sound heard on auscultation.

bulbourethral glands: Glands that secrete a lubricating mucus that cleans and lubricates the urethra prior to and during ejaculation.

bursectomy (bŭr-SĔK-tō-mē): Excision of bursa.