ANATOMY & PHYSIOLOGY GLOSSARY
DR. NUGENT
ABDOMEN: The area between the diaphragm and pelvis
ABDOMINAL: Superior portion of the abdominalpelviccavity, that contains the stomach, spleen, liver, gallbladder, most of the small intestines, and part of the large intestines
ABDOMINALPELVIC: Inferior to the diaphragm that is subdivided into a superior abdominal cavity and an inferior pelvic cavity
ABDUCTION: Movement away from the midline of the body
ABSCESS: Localized collection of pus and liquefied tissue in a cavity
ABSORPTION: Intake of fluids or other substances by cells of the skin or mucous membranes; the passage of digested foods from the gastrointestinal tract into blood or lymph
ACCESSORY DUCT: A duct in the pancreas that empties into the duodenum about 2.5 cm superior to the ampulla of Vater; also called the duct of Santorini
ACETABULUM: The rounded cavity on the external surface of the hip bone that receives the head of the femur
ACETYLCHOLINE: A neurotransmitter liberated by many peripheral nervous system (PNS) neurons & some CNS neurons. It is excitatory at neuromuscular junctions (NMJ) but inhibitory at some other synapses for example it slows done heart rate.
ACHILLES TENDON: The tendon of the soleus, gastrocnemius, and plantaris muscles at the back of the heel
ACINI: Groups of cells in the pancreas that secrete digestive enzymes
ACOUSTIC: Pertaining to sound or the sense of hearing
ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS): A serious disease caused by the human immunodeficiency virus (HIV). Characterized by a + HIV antibody test, low helper T cell count, and certain indicator diseases for example: Kaposi Sarcoma, pneumocystiscarinii pneumonia, tuberculosis, fungal diseases.
ACROSOME: A lysosome-like organelle in the head of a sperm cell containing enzymes that facilitate the penetration of a sperm cell into a secondary oocyte.
ACTIN: A contractile protein that is past of thin filaments in muscle fibers
ACTION POTENTIAL: Electrical signal that propagates along the membrane of a neuron or muscle fiber (cell); a rapid change in membrane potential that involves a depolarization followed by a repolarization.
ACTIVATION ENERGY: The minimum amount of energy required for a chemical reaction to occur
ACTIVE TRANSPORT: The movement of substances across a cell membrane against a concentration gradient, requiring the expenditure of cellular energy (ATP)
ACUTE: Having rapid onset, severe symptoms, and a short course, not chronic
ADAPTATION: The adjustment of the pupil of the eye to changes in light intensity
ADDUCTION: Movement toward the midline of the body
ADENOSINE TRIPHOSPHATE (ATP: The main energy currency in living cells; used to transfer the chemical energy needed for metabolic reactions. ATP consists of a purine base adenine and the 5-carbon sugar ribose, to which are added in linear display 3 high energy phosphate groups
ADHESION: Abnormal joining of tissues to each other
ADIPOCYTE: Fat cell, derived from a fibroblast
ADIPOSE: Tissue composed of adipocytes specialized for triglyceride storage and present in the form of soft pads between various organs for support, protection, and insulation
ADRENAL CORTEX: The outer portion of an adrenal gland, divided into three zones, the zonaglomerulosa secretes mineralcorticoids, the zonafasiculata secretes glucocorticoids, and the zonareticularis secretes androgens.
ADRENAL GLANDS: Two glands located superior to each kidney
ADRENAL MEDULLA: The inner part of the adrenal gland, consisting of cells that secrete epinephrine, norepinephrine, and a small amount of dopamine in response to stimulation by the sympathetic preganglionic neurons.
ADRENERGIC NEURON: A neuron that release epinephrine or norepinephrine as its neurotransmitter
ADRENOCORTICOTROPIC HORMONE (ACTH): Hormone produced by the anterior pituitary that influences the production and secretion of certain hormones of the adrenal cortex
ADVENTITIA: Outermost covering of a structure or organ
AEROBIC: Requiring molecular oxygen
AFFERENT NEURON: Neuron carrying nerve impulse toward the CNS, a sensory neuron
AGGLUTINATION: Clumping of microorganisms or blood cells typically due to and antigen-antibody reaction
ALDOSTERONE: Amineralcorticoid produced by the adrenal cortex , that promotes sodium & water reabsorption by the kidneys, & potassium excretion in urine
ALLELES: Alternate forms of a single gene that control the same inherited trait & are located on the same position on homologous chromosomes
ALLERGEN: An antigen that evokes a hypersensitivity reaction
ALOPECIA: Partial or complete lack of hair as a result of factors such as genetics, aging, endocrine disorders, chemotherapy, and skin disease
ALPHA CELL: Type of cell in the pancreatic islets (islets of Langerhans) that secretes the hormone glucagon
ALPHA RECEPTOR: Type of receptor for norepinephrine & epinephrine on postganglionic sympathetic neurons
ALVEOLAR DUCT: Branch of a respiratory bronchiole around which alveoli & alveolar sacs are arranged
ALVEOLAR MACROPHAGE: Highly phagocytic cell found in the alveolar walls of the lungs. Also called a dust cell
ALVEOLAR SAC:A cluster of alveoli that share a common opening
ALVEOLUS: A small hollow or cavity; an air sac in the lungs; milk secreting portion of a mammary gland
ALZHEIMER DISEASE: Disabling neurologic disorder characterized by dysfunction & death of specific cerebral neurons, resulting in widespread intellectual impairment, personality changes, and fluctuations in alertness
AMENORRHEA: Absence of menstruation
AMNESIA: A lack or loss of memory
AMNION: A thin, protective fetal membrane that holds the fetus suspended in amniotic fluid
AMNIOTIC FLUID: Fluid in the amniotic cavity, the space between the developing embryo (or fetus) and amnion; the fluid is initially produced as a filtrate from maternal blood and later includes fetal urine. It functions as a shock absorber, helps regulate fetal body temperature, and helps prevent dessication
AMPHIARTHROSIS: A slightly movable joint, in which the articulating bony surfaces are separated by fibrous connective tissue or fibrocartilage to which both are attached; subtypes are syndesmosis and symphysis
AMPULLA: A sac-like dilatation of a canal or duct
AMPULLA of VATER: Small raised area in the wall of the duodenum where the combined common bile duct & the main pancreatic duct empty into the duodenum
ANABOLISM: Synthetic, energy-requiring reactions whereby small molecules are built up into larger molecules
ANAEROBIC: Not requiring oxygen
ANAL CANAL: The last 2 or 3 cm of the rectum, opens to the exterior through the anus
ANALGESIA: Pain relief, absence of the sensation of pain
ANAPHASE: Third stage of mitosis in which the chromatids that have separated at the centromeres move to opposite poles of the cell
ANAPHYLAXSIS: A hypersensitivity (allergic) reaction in which Ig E antibodies attach to mast cells and basophils, causing them to produce mediators of anaphylaxis (histamine, leukotrienes, kinins, and prostaglandins) that bring about increased blood permeability, increased smooth muscle contractions, and increased mucus production.
ANASTOMOSIS: An end-to-end union or joining of blood vessels, lymphatic vessels, or nerves
ANATOMIC DEAD SPACE: Spaces of the nose, pharynx, larynx, trachea, bronchi, and bronchioles totaling about 150 mL of the 500 mL in a quiet breath (tidal volume); air in the anatomic dead space does not reach the alveoli to participate in gas exchange
ANATOMICAL POSITION: A position of the body universally used in anatomical descriptions in which the body is erect, the head is level, the eyes face forward, the upper limbs are at the sides, the palms face forward, and the feet are flat on the floor
ANATOMY: The structure, or study of the structure of the body and the relation of its parts to each other
ANDROGENS: Masculinizing sex hormones produced by the testes in males and the adrenal cortex in both sexes; responsible for libido (sex desire); the two main androgens are testosterone and dihydrotestosterone
ANEMIA: Condition of the blood in which the number of functional RBCs or their Hgb content is below normal
ANESTHESIA: A total or partial loss of feeling or sensation; may be general or local
ANEURYSM: A sac-like enlargement of a blood vessel caused by a weakening of its wall
ANGINA PECTORIS: A pain in the chest related to reduced coronary circulation due to coronary artery disease or spasms of vascular smooth muscle in coronary arteries
ANGIOGENESIS: The formation of blood vessels in the extraembryonic mesoderm of the yolk sac, connecting stalk, & chorion at the beginning of the third week of development
ANKYLOSIS: Severe or complete loss of movement at a joint as the result of a disease process
ANTAGONIST: A muscle that has an action opposite that of the prime mover (agonist) & yields to the movement of the prime mover
ANTERIOR: Nearer to or at the front of the body
ANTERIOR ROOT: Structure composed of azons of motor (efferent) neurons that emerges from the anterior aspect of the spinal cord and extends laterally to join a posterior root, forming a spinal nerve. Also call a ventral root.
ANTEROLATERAL PATHWAY: Sensory pathway that conveys information related to pain, temperature crude touch, pressure, tickly, and itch.
ANTIBODY: A protein produced by plasma cells in response to a specific antigen; the antibody combines with that antigen to neutralize, inhibit, or destroy it. Also called an immunoglobulin,
ANTICOAGULANT: A substance that can delay, suppress, prevent the clotting of blood
ANTIDIURETIC: Substance that inhibits urine formation
ANTIDIURETIC HORMONE (ADH):Hormone produced by the neurosecretory cells in the hypothalamus and stimulates water reabsorption from the kidney tubule cells into the blood & vasoconstriction of arterioles. Also called vasopressin
ANTIGEN: A substance that can cause an immune response and reactivity (with antibodies or cells of the immune system)
ANTIGEN-PRESENTING CELL: Special class of migratory cell that processes & presents antigen to T cells during an immune response
ANURIA: Absence of urine formation or daily urine output < 50 mL
ANUS: The distal end & outlet of the rectum
AORTA: the main systemic trunk of the arterial system of the body that emerges from the left ventricle
AORTIC BODY: Cluster of chemoreceptors on or near the arch of the aorta that respond to changes in blood levels of oxygen, carbon dioxide, and hydrogen ions
AORTIC REFLEX: A reflex that helps to maintain normal systemic blood pressure; initiated by barorecptors in the wall of the ascending aorta and arch of the aorta. When activated these baroreceptos send impulse to the cardiovascular center via sensory axons of the vagus nerve
APEX: The pointed end of a conical structure
APHASIA: Loss of ability to express oneself properly through speech or loss of verbal communication
APNEA:T cessation of breathing
APNEUSTIC: Part of the respiratory center in the pons that sends stimulatory nerve impulses to the inspiratory area that activate & prolong inhalation and inhibit exhalation
APOCRINE GLAND: A type of gland in which the secretory products gather at the free end of the secreting cell and are pinched off, along with some of the cytoplasm, to become the secretion, as in mammary glands
APONEUROSIS: Asheathlike tendon joining one muscle to another or with bone
APOPTOSIS: Programmed cell death; a normal type of cell death that removes unneeded cells during embryologic development, regulates the number of cells in tissues, and eliminates many potentially dangerous cells, such as cancer cells. During apoptosis, the DNA fragments, the nucleus condenses, mitochondria cease to function, and the cytoplasm shrinks, but the plasma membrane remains intact. Phagocytes engulf and digest the apoptotic cells, and an inflammatory response does not occur.
APPOSITIONAL GROWTH: Growth due to surface deposition of material, as in the growth in diameter of cartilage and bone
AQUEOUS HUMOR: Watery fluid, similar in composition to CSF that fills the anterior cavity of the eye
ARACHINOID MATER: The middle of the three meninges of the brain & spinal cord
ARACHNOID VILLUS: Berry-like tufts of arachnoid mater that protrudes into the superior sagittal sinus & through which CSF is reabsorbed into the bloodstream.
ARBOR VITAE: White matter tracts of the cerebellum which have a tree-like appearance
ARCH of the AORTA: The most superior portion of the aorta, lying between the ascending and descending portions of the aorta
AREOLA: Any tiny space within a tissue; the pigments area around the nipple
ARM: The part of the upper limb from the shoulder to the elbow
AROUSAL: Awakening from sleep, a response due to stimulation of the reticular activating system
ARRECTOR PILI: Smooth muscles attached to hairs; contraction pulls hairs into a vertical position, resulting in “goose bumps”
ARRHYTHMIA: Irregular heart rhythm
ARTERIOLE: A small, almost microscopic artery that delivers blood to a capillary
ARTERIOSCLEROSIS: Group of diseases characterized by thickening of the walls of arteries & loss of elasticity in those walls
ARTERY: A blood vessel that carries blood away from the heart
ARTHRITIS: Inflammation of a joint
ARTHROPLASTY: Surgical replacement of joints, for example, the hip and knee joints
ARTHROSCOPY: Procedure for examining the interior of a joint, by inserting an arthrscope into a small incision; used to determine the extent of damage, remove torn cartilage, repair cruciate ligaments, or biopsy tissue for analysis
ARTHROSIS: A joint or articulation
ARTICULAR CAPSULE: Sleeve-like structure around a synovial joint composed of a fibrous capsule and a synovial membrane
ARTICULAR CARTILAGE: Hyaline cartilage attached to articular bone surfaces
ARTICULATION: A joint; a point of contact between bones, cartilage and bones, or teeth and bones
ARYTENOID CARTILAGES: A pair of small pyramidal cartilages of the larynx, that attach to the vocal folds and intrinsic pharyngeal muscles and can move the vocal folds
ASCENDING COLON: Part of the large intestine that superiorly from the cecum to the inferior border of the liver, where it bends at the right colic flexure (hepatic flexure) to become the transverse colon
ASCITES: Abnormal collection of serous fluid in the peritoneal cavity
ASTHMA: Usually an allergic reaction characterized by smooth muscle spasms to bronchi resulting in wheezing & difficulty breathing
ASTIGMATISM: An irregularity of the lens or cornea of the eye causing the image to be out of focus & producing faulty vision
ASTROCYTE: A neurologic cell having a star shape that participates in brain development and the metabolism of neurotransmitters, helps form the blood-brain-barrier, helps maintain the proper balance of K+ for generation of nerve impulses, and provides a link between neurons and blood vessels
ATAXIA:A lack of muscle coordination, lack of precision
ATHEROSCLEROTIC PLAQUE: A lesion that results from accumulated cholesterol & smooth muscle fibers of the tunica media of an artery; may become obstructive
ATRESIA: degeneration & reabsorption of an ovarian follicle before it fully matures and ruptures; abnormal closure of a passage
ATRIAL FIBRILLATION: Asynchronous contraction of cardiac muscle fibers in the atria that results in the cessation of atrial contractions
ATRIAL NATRIURETIC PEPTIDE (ANP): Peptic hormone produced by the atria of the heart in response to stretching, that then inhibits aldosterone production & this lowers blood pressure, also increases urinary output of sodium
ATRIOVENTRICULAR (AV) BUNDLE: The part of the conduction system of the heart that begins at the AV node, passes through the area of the heart that separates the atria and ventricles, then extends down the interventricular septum before splitting into right & left bundle branches
ATRIOVENTRICULAR VALVE:Heart valve made up of membranous flaps or cusps that allows blood to flow in one direction only, from an atrium to a ventricle
ATRIUM: A superior chamber of the heart, receive blood into the heart and pass it to the ventricles
ATROPHY: Wasting away or decrease in size of a part, due to a failure, abnormality of nutrition, or lack of use
AUDITORY OSSICLE: One of three small bones of the middle ear: the malleus, incus, stapes
AUDITORY TUBE: Tube that connects the middle ear with the nose and nasopharynx region of the throat. a.k.a. Eustachian tube, pharyngotympanic tube
AUSCULTATION: Examination by listening to sounds
AUTOIMMUNITY: An immunological response to a person’s own tissues
AUTOLYSIS: Self-destruction of cells by their own lysosomal digestive enzymes after death or in a pathological process
AUTONOMIC GANGLION: Cluster of cell bodies of sympathetic or parasympathetic neurons located outside the CNS
AUTONOMIC NERVOUS SYSTEM (ANS): Visceral sensory (afferent) and visceral motor (efferent) neurons. Autonomic motor neurons, both sympathetic and parasympathetic, conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands.
AUTOPHAGY: Process by which worn-out organelles are digested within lysosomes
AUTOPSY: The examination of the body after death
AUTOSOME: Any chromosome other than the X or Y chromosomes (sex chromosomes)
AXILLA: The armpit; the small hollow beneath the arm where it joins the body at the shoulders
AXON: The usually single, long process of a neuron that propagates a nerve impulse away from the cell body toward the axon terminal
AXON TERMINAL: Terminal branch of an axon where synaptic vesicles undergo exocytosis to release neurotransmitter
B CELL: A lymphocyte that can develop into a clone of antibody-producing plasma cells or memory cells when properly stimulated by a specific antigen
BABINSKI SIGN: Extension of the great toe, with or without fanning of the other toes, in response to stimulation of the outer margin of the sole, normal up to 18 months of age and indicative of damage to descending motor pathways such as the corticospinal tracts after that
BALL-AND-SOCKET JOINT: A synovial joint in which the rounded surface of one bone moves within a cup-shaped depression or socket of another bone, as in the shoulder or hip joint
BARORECEPTOR: Neuron capable of responding to changes in blood, air, or fluid pressure. Also called a pressoreceptor
BASAL GANGLIA: Paired clusters of gray matter deep to each cerebral hemisphere
BASEMENT MEMBRANE: Thin, extracellular layer between epithelium and connective tissue consisting of a basal lamina and reticular lamina
BASILAR MEMBRANE: Membrane in the cochlea of the inner ear that separates the cochlear duct from the scala tympana & on which the spiral organ (organ of Corti) rests