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Aster a starburst cluster of microtubules of tubulin produced
by the centriole^
Astrocytes star-shaped cells that twine around nerve cells to
form a supporting network in the brain and spinal cord^
Atherosclerosis disease of the arteries in which plaque accu-
mulates on the inside of arterial walls^
Atlas first cervical vertebra that supports the head by articu-
lation with the condyles of the occipital bone^
Atelectasus a collapsed lung
Atom the smallest particle of an element that maintains all the
characteristics of that element^
Atomic number the number of protons or electrons in an
atom
Atrioventricular bundle bundle of His; part of the
conduction system of the heart running through the top of the
interven-tricular septum^
Atrioventricular (AV) node part of the conduction system of
the heart located in the lower portion of the right atrium^
Atrophy a decrease in muscle bulk due to a lack of exercise
Auditory ossicles another name for the ear bones
Auditory tubes the ear canals located in the middle ear that
equalize air pressure preventing hearing distortion; eusta-chian
tubes^
Auricle external appendage of an atrium
Autolysis the process of self-destruction in old or weakened
cells
Autonomic nervous system (ANS) conducts impulses from
the brain and spinal cord to smooth muscle tissue, cardiac
muscle tissue, and glands^
Axillary artery part of the subclavian artery that runs down
the arm^
Axillary vein found in the
armpit Axis the second vertebra
Axon the long extension of a nerve cell body; a neuron has
only one axon^
Axon endings the terminal portions of
axons Axon terminals the endings of axons
Azygos vein drains the thorax
B^
B cells lymphocytes found in lymph nodes, spleen, and other
lymphoid tissue where they replicate^
B lymphocytes cells that produce antibodies and provide hu-
moral immunity; also known as B cells^
Ball-and-socket joint a type of synovial or diarthrosis joint,
also called a multiaxial joint, like the shoulder or hip joint^
Basal cell carcinoma most common type of skin cancer
Base a substance that combines with H+ ions when dissolved
in water^
Basement membrane anchors epithelial cells to each other
and to underlying tissues
GLOSSARY
Basilic vein drains the medial part of the arm
Basophils WBCs that release heparin, histamine, and sero-
tonin during an allergic reaction^
Bell’s palsy paralysis of the facial nerve on one side of the
face Beta cells secrete the hormone insulin, found in the
pancreas
Biceps brachii muscle that flexes the arm and forearm and
supinates the hand^
Biceps femoris muscle that flexes the leg; rotates laterally
after flexed^
Bicuspids molar teeth with two cusps
Bicuspid valve mitral valve; valve between the left atrium
and^ left ventricle^
Bile duct part of the gallbladder that transports bile to the
duodenum of the small intestine^
Bipolar neurons sensory neurons that consist of one dendrite
and one axon^
Black eye pariorbital bruise from a blow to supraorbital ridge
Blastula a hollow ball of cells produced by mitotic divisions
of^ the zygote; blastocyst^
Blood specialized connective tissue
Body term for the large central portion of the stomach and the
pancreas^
Body of the uterus central tapering region of uterus
Bonds formed when atoms combine chemically with one
anotherBone specialized connective tissue
Bone marrow transplant used to treat leukemia lymphomas
and immunological deficiencies^
Bowel large intestine
Bowman’s glomerular capsule double-walled globe
located in^ the cortex of the kidney^
Brachial artery extension of the axillary artery that runs
down^ the arm^
Brachial vein drains the arm and empties into the axillary
veinBrachialis muscle that flexes the forearm; assists the biceps
muscle^
Brachiocephalic artery first branch of the aortic arch
Brachioradialis muscle that flexes the forearm; assists the
biceps muscle^
Brainstem one of the four major parts of the brain; it connects
the brain to the spinal cord^
Breast cancer leading cause of death in women
Bronchial arteries supply blood to the lungs
Bronchial tree branching of the bronchi
Bronchioles smaller branches of segmental
bronchi Bronchitis inflammation of the bronchi
Bronchomediastinal trunk drains lymph from the thorax,
lungs, heart, diaphragm, and portions of the liver^
Bronchopulmonary segment segment of lung tissue that
each of the tertiary bronchi supplies