Chapter 8: A&P Flashcards
ABO system
The commonly used blood classification system, based on the antigens present or absent in the blood.
Accessory Muscles
The muscles not normally used during quiet breathing; examples include the sternocleidomastoid muscles of the neck, the chest pectorals major muscles, and the abdominal muscles.
Accommodation
The ability of the lens of the eye to change its shape to focus on a close object.
Acetabulum
The socket formed by the coxal (hip) bone into which the ball-shaped femoral head fits snugly.
Acetylcholine (ACh)
A neurotransmitter released at synapses within the autonomic nervous system and by motor neurons to stimulate skeletal muscle contraction.
Acetylcholinesterase
An enzyme found in the CNS, in red blood cells, and in motor endplates of skeletal muscle that causes the decomposition of acetylcholine.
Acid
Any molecule that can give up a hydrogen ion, and therefore increases the concentration of hydrogen ions in a water solution.
Acidosis
A pathologic condition resulting from the accumulation of acids in the body (blood pH less than 7.35).
Acromion Process
The tip of the shoulder and the site of attachment for the clavicle and various shoulder muscles.
Action Potential
Sequence of changes in the membrane potential that occurs when an excitable cell (neuron or muscle) is stimulated.
Actin
A contractile protein found in the thin filaments of skeletal muscle cells.
Active Transport
A method used to move compounds across across a cell membrane to create or maintain an imbalance of charges, usually against a concentration gradient and requiring the expenditure of energy.
Adaptation
The temporary or permanent reduction of sensitivity to a particular stimulus.
Adenosine Triphosphate (ATP)
The nucleotide formed from the metabolism of nutrients in the cell; involved in energy metabolism; used to store energy.
Adrenal Cortex
The outer layer of the adrenal gland; it produces hormones that are important in regulating the water and salt balance of the body.
Adrenal Glands
Paired endocrine glands located on top of the kidneys that release epinephrine and norepinephrine when stimulated by the sympathetic nervous system; each adrenal gland consists of an inner adrenal medulla and an adrenal cortex.
Adrenergic
Having the characteristics of the sympathetic division of the autonomic nervous system.
Adrenocorticotropic Hormone (ACTH)
Hormone that targets the adrenal cortex to secrete cortisol (a glucocorticoid).
Aerobic Metabolism
Metabolism that can proceed only in the presence of oxygen.
Afterimage
The perception that a stimulus is still present after the stimulus has been removed.
Afterload
The pressure in the aorta against which the left ventricle must pump blood.
Albumins
The smallest of plasma proteins; they make up around 60% of the plasma proteins and are responsible for oncotic pressure in the vasculature, thereby controlling the movement of water into and out of the circulation.
Aldosterone
A hormone responsible for the reabsorption of sodium and water from the kidney tubules.
Alkalosis
A pathologic condition resulting from the accumulation of bases in the body (blood pH greater than 7.45).
Alleles
Variant forms of a gene, which can be identical or slightly different in a sequence of deoxyribonucleic acid.
Alveoli
The air sacs of the lungs in which the exchange of oxygen and carbon dioxide takes place; also, the bony sockets for the teeth that reside in the mandible and maxilla (singular, alveolus).
Anabolism
The building of larger substances from smaller substances, such as the building of proteins from amino acids.
Anaerobic Metabolism
Metabolism that occurs in the absence of oxygen.
Anatomy
The study of the structure of an organism and its parts.
Angle of Louis
A prominence of the sternum that indicates the point where the second rib joints that sternum; also called the sternal angle or manubriosternal junction.
Antagonist
A molecule that blocks that ability of a given chemical to bind to its receptor, preventing a biologic response.
Antigens
Proteins, polysaccharides, glycoproteins, or glycolipids commonly found on the surfaces of red blood cells that stimulate an immune system response and cause formation of antibodies; cells learn to recognize antigens as either “self” or “nonself” (foreign).
Aorta
The principle artery leaving the left side of the heart and carrying freshly oxygenated blood to the body; the largest artery in the body.
Aortic Valve
The semilunar valve that regulates blood flow from the left ventricle to the aorta.
Apneustic Center
A portion of the pons that is thought to work with the pontine respiratory group to regulate the length and depth of inspiration.
Appendicular Skeleton
The portion of the skeletal system made up of the upper extremities, shoulder girdle, pelvic girdle, and lower extremities.
Aqueous Humor
Watery fluid filling the anterior eye cavity; the quantity determines the intraocular pressure, which is critical to sight.
Areolar Tissue
A type of loose connective tissue that binds skin to underlying organs and fills in spaces between muscles.
Arytenoid Cartilages
Six paired cartilages stacked on top of each other in the larynx.
Astigmatism
Condition where parts of the image are out of focus and others are in focus; caused by irregularities in the shape of the eye lens.
Atlas
The first cervical vertebrae (C1), which provides support for the head.
Atria
The two upper chambers of the heart (singular, atrium).
Atrial Natriuretic Peptide
A hormone produced by the atria when they are distended by increased blood volume; it inhibits the absorption of water and sodium in the renal tubules, thereby increasing the elimination of water.
Atrioventricular (AV) Node
A group of cells that conduct an electrical impulse through the heart; located in the floor of the right atrium immediately behind the tricuspid valve and near the opening of the coronary sinus.
Atrioventricular (AV) Valves
The mitral and tricuspid valves through which blood flows from the atria to the ventricles.
Automaticity
Ability of cardiac pacemaker cells to initiate an electrical impulse spontaneously without being stimulated from another source (such as a nerve).
Autonomic Nervous System (ANS)
A subdivision of the nervous system that controls primarily involuntary body functions; comprised of the sympathetic and parasympathetic nervous system.
Autosomes
The chromosomes that do not carry genes that determine sex.
Axial Skeleton
The portion of the skeleton made up of the skill, thoracic cage and vertebral column.
Axis
Imaginary line joining the positive and negative electrodes of a lead; also the second cervical vertebra.
Axon
Long, slender extension of a neuron (nerve cell) that conducts electrical impulses away from the nerve cell body to adjacent cells.
B Lymphocytes
Lymphocytes that exist in the blood, and are abundant in the lymph nodes, bone marrow, intestinal lining, and spleen; also called B cells.
Baroreceptors
Nerve endings that are stimulated by pressure changes, including increased arterial blood pressure; they are located in the aortic arch and carotid posture.
Basal Ganglia
Structures located deep within the cerebrum, diencephalon, and midbrain that have an important role in coordination of motor movements and posture.
Basal Metabolic Rate
The rate at which nutrients are consumed in the body.
Basophils
White blood cells that contain histamine granules and other substances that are released during inflammatory and allergic responses.
Bilirubin
A waste product of red blood cell destruction that undergoes further metabolism in the liver.
Binocular Vision
The merging of two images into one.
Blood-Brain Barrier
A layer of tightly-adhered cells that protects the brain and spinal cord from exposure to medications, toxins, and infectious particles.
Bone Marrow
Soft tissue that fills the inside of the bones and is the site of production of red blood cells, platelets, and most white blood cells.
Bony Labyrinth
The collection of hollows in the bone of the inner ear that provide protection to the structures of the inner ear form damage and from extraneous stimulation.
Boyle’s Law
Gas law that demonstrates that as pressure increases, volume decreases; at a constant temperature, the volume of a gas is inversely proportional to its pressure (if the pressure on a gas is doubled, then its volume is halved); written as PV=K, where P=pressure, V=volume, and K=a constant.
Brain
The part of the CNS located within the cranium; contains billions of neurons that serve a variety of functions including consciousness, perception, control of reactions to the environment, emotional responses, and judgement.
Brainstem
The rea of the brain between the spinal cord and cerebrum that contains the midbrain, pons, and medulla; controls functions that are necessary for life such as breathing.
Bruit
Abnormal whoosing sounds indicating turbulent blood flow within a narrowed blood vessel, usually heard in the carotid arteries.
Buffer System
Fast-acting defenses for acid-base changes, providing almost immediate protection against changesin the hydrogen ion concentration of extracellular fluid.
Bundle of His
The portion of the conduction system of the heart located in the upper portion of the interventricular septum that conducts an electrical impulse form the atrioventricular junction to the right and left bundle branches.
Bursa
A small, padlike sac or cavity filled with a small amount of synovial fluid that helps reduce the amount of friction between a tendon and a bone or between a tendon and a ligament, usually located near a joint.
Calcaneus
The heel bone; the largest of the tarsal bones.
Calorie
The amount of heat needed to raise the temperature of a gram of water by 33 degrees F (1 degree C); the amount of energy that can be obtained from the nutrients you eat; also called a kilocalorie.
Carbohydrate
Substances (including sugars and starches) that provide much of the energy required by the body’s cells, as well as helping to build cell structures.
Cardiac Cycle
The repetitive pumping process that begins with the onset of cardiac muscle contraction and ends just before the beginning of the next contraction; each one consists of ventricular contraction (systole) and relaxation (diastole).
Carina
The point of bifurcation of the right and left primary (mainstem) bronchi.
Carpal Bones
The eight small bones of the wrist.
Cartilaginous Joints
Those connected by hyaline cartilage, or fibrocartilage, such as the joints that separate the vertebrae.
Catabolism
The breakdown of larger molecules into smaller ones.
Cataract
Clouding of the lens of the eye or its surrounding transparent membrane.
Catecholamines
Amine substances such as dopamine, epinephrine, and norepinephrine that function as neurotransmitters, hormones, or both.
Cell Membrane
The cell wall; as selectively permeable layer of cells that surround intracellular contents and control movement of substances into and out of the cell; also called the cytoplasmic membrane of plasma membrane.
Cellular Respiration
A biochemical process resulting in the production of energy in the form of adenosine triphosphate.
Central Nervous System (CNS)
The brain and spinal cord.
Cerebellum
Area of the brain involved in fine and gross muscle coordination; responsible for interpretation of actual movement and correction of any movements that interfere with coordination of the body’s position.
Cerebral Cortex
The outer covering of gray matter that covers the cerebral hemispheres; regulates voluntary skeletal movement and plays an important role in one’s level of awareness.
Cerebral Perfusion Pressure (CPP)
Pressure inside the cerebral arteries and an indicator of brain perfusion; calculated by subtracting intracranial pressure from mean arterial pressure.
Cerebrospinal Fluid (CSF)
Fluid produced in the ventricles of the brain that flows in the subarachnoid space and bathes the meninges.
Cerebrum
The largest part of the brain; made up of several lobes that control movement, hearing, balance, speech, visual perception, emotions, and personality; divided into right and left hemispheres; also called gray matter.
Cervical Canal
The interior of the cervix.
Cervix
The lower one-third or neck of the uterus.
Chemoreceptors
Sense organs that monitor the levels of oxygen and carbon dioxide and the pH of CSF and blood and provide feedback to the respiratory centers to modify the rate and depth of breathing based on the body’s needs at any given time.
Cholinergic
Having the characteristics of the parasympathetic division of the autonomic nervous system also refers to other structures or functions that are related to acetylcholine.
Chordae Tendineae
Thin bands of fibrous tissue that attach to the atrioventricular valves in the heart and prevent them from inverting.
Choroid
The vascular, pigmented middle layer of the eye wall.
Choroid Plexus
Group of specialized cells in the ventricles of the brain; filters blood through cerebral capillaries to create CSF.
Chromosomes
Structures formed from condensed fibers protein of DNA; they are threadlike, and are contained within the nucleus of the cells.
Chronotropic Effect
Related to the effect of the rate of contraction of the heart.
Ciliary Body
The structure associated with the choroid layer of the eye that secretes aqueous humor and contains the ciliary muscle.
Circulatory System
The complex arrangement of connected tubes, including the arteries, arterioles, capillaries, venules, and veins, that moves blood, oxygen, nutrients, carbon dioxide, and cellular waste throughout the body.
Circumflex Coronary Artery
One of two branches of the left main coronary artery.
Citric Acid Cycle
A sequence of enzymatic reactions involving the metabolism of carbon chains of glucose, fatty acids, and amino acids to yield carbon dioxide, water, and high-energy phosphate bonds; also known as the Krebs cycle or tricarboxylic acid cycle.
Clotting Cascade
A set of interactions that lead to the formation of a fibrin clot; also called the coagulation cascade.
Cochlea
The portion of the inner ear that has hearing receptors
Compound
A substance that can be broken down into the two or more elements contained within it.
Conductivity
The property that allows a cardiac cell to receive an electrical impulse and pass it on to an adjoining cardiac cell.
Cones
One of two photoreceptors of the retina that can distinguish colors, but requires a greater amount of light to activate and create an image.
Conjunctiva
The membranous covering on the anterior surface of the eye that also lines the eyelids.
Connective Tissues
Tissues that bind, support, protect, fame, and fill body structures; they also store fat, produce blood cells, repair tissues, and protect against infection.
Conjunctivitis
Inflammation of the conjunctiva.
Contracitility
The ability of myocardial cells to shorten in response to an impulse, which results in contraction.
Cornea
The transparent tissue layer in front of the pupil and iris of the eye.
Coronary Sinus
Venous drain for the coronary circulation into the right atrium.
Corpus Callosum
A deep bridge of nerve fibers connecting the brain hemispheres.
Corticosteroids
Any of the several steroids secreted by the adrenal gland.
Cortisol
A glucocorticoid of the middle adrenal cortex that influences protein and fat metabolism and stimulates glucose to the synthesized from noncarbohydrates.
Cranial Nerves
The 12 pairs of nerve that arise from the base of the brain.
Cranial Vault
The bones that encase the protect that brain, including the parietal, temporal, frontal, occipital, sphenoid, and ethmoid bones; the roof of the skull (cranium).
Cranium
The area of the had above the ears and eyes; the part of the skull that houses the brain.
Cribriform Plate
A horizontal bone perforated with numerous openings for the passage of the olfactory nerve filaments form the nasal cavity.
Cricoid Cartilage
A firm ridge of cartilage that forms the lower part of the larynx; the first ring of the trachea and the only upper airway structure that forms a complete ring; also called the cricoid ring.
Cricothyroid Membrane
A thin sheet of fascia located between the thyroid of cricoid cartilage that is relatively avascular and contains few nerves; the site for emergency access to the airway.
Cytoplasm
The gel-like material that sills out a cell; it makes up most of the volume of the cell, and suspends the organelles of the cell.
Deep Fascia
A dense layer of fibrous tissue below the subcutaneous tissue; composed of tough bands of tissue that surround muscles and other internal structures.
Dendrites
Branchlike projections of nerve cells that receive impulses or sensory information from nearby cells and conduct impulses toward the nerve cell body.
Deoxyribonucleic Acid (DNA)
Specialized structure within the cell that carries genetic material for reproduction.
Depolarization
In response to an action potential, the rapid movement of electrolytes across a cell membrane that changes overall charge of the cell. This rapid shifting of electrolytes and cellular charges is the main catalyst for muscle contraction and neural transmissions.
Dermatome
The area of the skin supplied by a specific sensory spinal nerve.
Descending Aorta
The portion of the aorta that extends through the thorax and abd into the pelvis.
Diapedesis
A process whereby leukocytes move through the wall of a capillary and out to the tissues where they are needed most.
Diaphragm
Large skeletal muscle that plays a major role in breathing and separates the chest cavity from the abd cavity.
Diaphysis
The shaft of a long bone.
Diastole
Phase of cardiac cycle in which the atria and ventricles relax between contractions and blood enters these chambers.
Diencephalon
Portion of the brain between the brainstem and cerebrum; contains the epithalamus, the thalamus, the hypothalamus, and the subthalamus.
Differentiation
The process of specialization of a cell.
Diffusion
The process of particles moving from an area of higher concentration to an area of lower concentration along a concentration gradient until equilibrium is achieved.
Digestion
The chemical breakdown of food material into smaller fragments that can be absorbed into the circulatory system.
Diploid Cells
Cells that carry two of each of the 23 chromosomes—one form the father and one from the mother.
Dorsal Respiratory Group (DRG)
A portion of the medulla oblongata that functions as an respiratory integration center; it receives input from several sources including the pontine respiratory group, sensory input through the glossopharyngeal and vagus nerves, central chemoreceptors in the medulla, the peripheral chemoreceptors.
Dura Mater
The outermost of the three meninges that enclose the brain and spinal cord; it is the toughest meningeal layer.
Electrolytes
Salt or acid substances that become ionic conductors when dissolved in a solvent (such as water); chemicals dissolved in the blood.
Endocardium
The thin membrane lining the inside of the heart.
Endocrine Glands
Glands that have no ducts and secrete directly into tissue fluid or blood.
Endolymph
The fluid containing nerve receptors that resides inside the membranous labyrinth. Sound waves converted into pressure waves are transmitted through this fluid to the auditory nerves.
Enteric Nervous System (ENS)
A subdivision of the autonomic nervous system that controls the digestive system.
Enzymes
Substances designed to speed up the rate of specific biochemical reactions.
Eosinophil
A leukocyte that may play a role following infection in various areas in the body.
Epicardium
The layer of the serous pericardium that lies closely against the heart; also called the visceral pericardium.
Epiglottis
A thin, flaplike structure that allows air to pass into the trachea but prevents food and liquid from entering.
Epinephrine
A hormone produced by the adrenal medulla that has a vital role in the function of the sympathetic division of the autonomic nervous system; mediates the fight-or-flight response; also called adrenaline.
Epiphyseal Plate
The growth plate of a long bone; a major site of bone development during childhood; also called a physis.
Epithelial Tissues
Body tissues that cover organs, form the inner lining of cavities, and line hollow organs.
Estrogen
A hormone released from the ovaries that stimulates the uterine lining during the menstrual cycle.
Eustachian Tube
A branch of the internal auditory canal that connects the middle ear to the oropharynx.
Excitability
The ability of cardiac muscle cells to respond to an electrical, chemical, or mechanical stimulus.
Exhalation
The passive part of the breathing process in which the diaphragm and the intercostal muscles relax, forcing air out of the lungs.
Exocrine Glands
Glands that secrete chemicals into ducts that open onto a surface for elimination.
Expiratory Reserve Volume
The amount of air that can be exhaled following a normal exhalation; average volume is about 1,200 mL.
Extracellular Fluid (ECF)
Fluid outside of the cell, in which most of the body’s supply of sodium is contained; accounts for 15-20% of body weight.
Extrinsic Muscles
Referring to the eye; six muscles that attach to the exterior of the globe and are controlled by the cranial nerves.
Fascia
A sheet or band of tough fibrous connective tissue that covers, supports, and separates muscles, and which also covers arteries, veins, tendons, and ligaments.
Fibrin
A white, insoluble protein formed by the action of thrombin on fibrinogen during the blood clotting process; forms the matrix of a blood clot.
Fibrinogen
A plasma protein that is important for blood clotting.
Fibrous Joints
Joints that lie between bones that closely contact each other, joined by thin, dense connective tissue.
Filtration
The movement of fluid from intravascular fluid under high pressure to interstitial fluid, which is generally under lower pressure.
Fluid Balance
The process of maintaining homeostasis through equal intake (water taken into the body) and output (water excreted form the body) of fluids.
Fontanelles
The soft spots in the skull of a newborn and infant where the sutures of the skull have not yet grown together.
Fraction of Inspired Oxygen (FIO2)
The percentage of oxygen in inhaled air.
Gag Reflex
A normal neutral reflex elicited by touching the soft palate or posterior pharynx; the responses are symmetric elevation of the palate, retraction of the tongue, and contraction of the pharyngeal muscles.
General Senses
Sensations monitored throughout the body by receptors scattered throughout many different tissues.
Genotype
The arrangement of a person’s genes and their characteristics is based on the combination of alleles, for one gene or many.
Glaucoma
A disease of the eye caused by an increase in intraocular pressure; when severe enough, this may damage the optic nerve and potentially cause permanent loss of vision.
Globulins
Antibodies made by the liver and lymphatic tissues that make up around 36% of the plasma proteins.
Glottis
The true vocal cords and the opening between them.
Gluconeogenesis
A process that stimulates both he liver and the kidneys to produce glucose from noncarbohydrate molecules.
Glycogen
A polymer from which glucose is converted in the liver (animal scratch).
Glycogenolysis
The breakdown of glycogen to glucose.
Glycolysis
Process by which glucose and other sugars are broken down to yield lactic acid (anaerobic glycolysis) or pyruvic acid (aerobic glycolysis). The breakdown releases energy in the form of adenosine triphosphate.
Haploid Cells
Cells that carry genetic instructions via 23 individual chromosomes.
Hard Palate
The anterior portion of the palate that is supported by bone (primarily the maxillae bone).
Hematocrit
A measure of the relative percentage of blood cells (mainly erythrocytes) in a given volume of whole blood.
Hamatopoietic System
The blood components and the organs involved in their development and production.
Hemoglobin (Hb or Hgb)
An iron-containing pigment found in red blood cells that carries oxygen to the cells from the lungs and carbon dioxide away form the cells to the lungs.
Hemostasis
The stoppage of bleeding; involves the steps of blood vessel spasm, platelet plug formation and blood clotting.
Henry’s Law
A law of gas that states that the amount of a gas in a solution varies directly with the partial pressure of a gas over a solution.
Hepatic Portal System
A specialized part of the venous system that carries blood from the digestive tract to the liver and then to the inferior vena cava.
Hering-Breuer Reflex
A protective mechanism that terminates inhalation, thus preventing overexpansion of the lungs.
Histamine
A substance found in large amounts in basophils that increases tissue inflammation.
Homeostasis
A tendency of constancy or stability in the body’s internal environment; processes that balance the supply and demand of the body’s needs.
Homologous Chromosomes
A chromosomes of the same numbered pair form the opposite parent.
Hormone
A substance that is produced in one tissue or organ and is released into the blood and carried to other (target) organs, where it acts to produce a specific response.
Hydrostatic Pressure
The pressure of water against eh walls of its container.
Hyoid Bone
A small, horseshoe-shaped bone to which the jaw, tongue, epiglottis, and thyroid cartilage attach.
Hypertonic
Concentration of solute is lower compared with another solution.
Hypoxic Drive
A situation in which a person’s stimulus to breathe comes from a decrease in Pao2 rather than the normal stimulus, an increase in Paco2.
Immunity
The body’s ability to protect itself form acquiring a disease.
Inhalation
The active process of moving air into the lungs; also called inspiration; also a route of medication delivery.
Inotropic Effect
The effect on the contractility of muscle tissue, especially cardiac muscle.
Insertion
A moveable part of the body to which a skeletal muscle is fastened at a moveable joint; its action opposes that of an origin.
Inspiratory Reserve Volume
The additional amount of air that can be inhaled after the normal tidal volume has been reached.
Integumentary System
The largest organ system in the body, consisting of the skin and accessory structures (eg, hair, nails, glands).
Interstitial Space
The fluid located outside of the blood vessels in the spaces between the body’s cells.
Intracellular Fluid (ICF)
Fluid within cells but inside the circulatory system; the majority of it is plasma which is the fluid component of blood.
Intravascular Fluid
Fluid outside cells but inside the circulatory system; the majority of it is plasma, which is the fluid component of blood.
Ionic Bond
A chemical bond where oppositely charged ions attract each other.
Ions
Atoms that have become positively or negatively charged, either by giving up or acquiring an electron.
Islets of Langerhans
Groups of cells located in the pancreas that produce insulin, glucagon, somatostatin, and pancreatic polypeptide.
Isotonic Solution
A solution in which there is an equal concentration of solutes and water on either side of a semipermeable membrane. In this case, water does not shift, and no change in cell shape occurs.
Joint Capsule
A saclike envelope that encloses that cavity of a synovial joint.
Kilocalorie
The amount of heat needed to raise the temperature of a gram of water by 33 degree F (1 degree C); the amount of energy that can be obtained from the nutrients you eat; also known as a calorie.
Labia Majora
Two prominent, rounded folds of skin lateral to the labia minora of the female external genitalia.
Labia Glands
A pair of skin folds in the female external genitalia that border the vestibule.
Lacrimal Glands
The glands that produce fluids to keep the eye moist; also called tear glands.
Lactic Acid
A metabolic end product of the breakdown of glucose that accumulates when metabolism proceeds in the absence of oxygen.
Larynx
A complete structure formed by the epiglottis thyroid cartilage, cricoid cartilage, arytenoid cartilage, corniculate cartilage, and cuneiform cartilage; also called the voice box.
Left Anterior Descending Artery
One of the two branches of the left main coronary artery that supplies blood of the left ventricle and other areas of the heart.
Lens
The transparent disc within the eye that refers light to focus images on the retina.
Lipids
Fats, fatlike substances (cholesterol and phospholipids), and oils that supply energy for body processes and building of certain structures.
Lymph
: A thin liquid formed from interstitial fluid that flows through the lymphatic vessels and lymph nodes and aids in immune response and debris removal.
Lymph Nodes
Round or bean-shaped structures interspersed along the course of the lymph vessels which filer the lymph and serve as a source of lymphocytes.
Lymph Vessels
Unidirectional, thin-walled vessels through which lymph circulates through the body; they travel close to the major veins.
Lymphatic System
A network of capillaries, vessels, ducts, nodes, and organs that helps to maintain the fluid environment of the body by producing lymph and transporting it through the body.
Lymphocytes
A type of white blood cell that has an important role in immunity.
Macrophages
Large cells, usually derived from monocytes, that are specialized for phagocytosis; they kill pathogens, absorb foreign materials, and slow infections and infectious agents.
Macula
A yellow depression in the retina where acute vision arises; also known as the macula lutea.
Mast Cells
Cells located in connective tissues to which antibodies, formed in response to allergens attach, bursting the cells and releasing chemical mediators in response to an antigen-antibody reaction.
Mediastinum
The space between the lungs, in the center of the chest, that contains the heart, great vessels, part of esophagus, lymphatic channels, trachea, primary bronchi, and paired vagus and phrenic nerves.
Medulla Oblongata
Inferior par of the brainstem that is continuous inferiorly with the spinal cord; serves as a conduction pathway for ascending and descending nerve tracts; responsible for maintenance of basic life functions, such as heart rate and breathing.
Meiosis
A type of cell division that occurs in the production of eggs and sperm.
Melanin
The pigment that gives skin its color.
Menarche
The first menstrual cycle; the onset of menses.
Meninges
A set of three tough membranes, the dura mater, arachnoid, and pia mater, that enclose the entire brain and spinal cord.
Menopause
The period when a woman’s reproductive cycle ceases; also called the female climacteric.
Menstruation
Cyclical shedding of the endometrial lining.
Metacarpals
The five bones that form the palm and back of the hand.
Midbrain
The most superior portion of the brainstem; it works with the pons to route information from higher within the brain to the spinal cord and vice versa.
Mineral
An inorganic element essential for human metabolism.
Minute Volume
The amount of air that moves in and out of the lungs per minute minus the dead space; also called minute ventilation.
Mitosis
The division of chromosomes in a cell nucleus.
Mitral Valve
The atrioventricular valve in the heart that separates the left atrium from the left ventricle.
Monocytes
White blood cells that mature in the blood and then travel to the tissues, where they differentiate into macrophages; these function primarily as scavengers for the tissues.
Monosaccharides
The simplest carbohydrate molecule.
Motor Nerve
Nerve that carries information from the CNS to the muscles of the body.
Motor Neurons
Nerve cells that transmit instructions from the CNS to the end organs; also known as efferent neurons.
Mucous Membranes
The lining of body cavities and passages that communicate directly or indirectly with the environment outside the body.
Mucus
The opaque, sticky secretion of the mucous membranes that lubricates the body openings.
Murmur
An abnormal heart sound, heard as a “whooshing,” indicating turbulent blood flow within the heart.
Muscle Tissue
Contractile tissue consisting of filaments of actin and myosin, which slide past each other, shortening cells.
Musculoskeletal
The bones and voluntary muscles of the body.
Myocardium
The middle and thickest layer of the heart; it contains the cardiac muscle fibers that cause contraction of the heart, as well as the conduction system and blood supply.
Myoglobin
A pigment synthesized in the muscles to give skeletal muscles their red-brown color.
Myopia
Nearsighted; the ability to see objects close with difficulty seeing objects far away.
Myosin
A contractile protein found in the thick filaments of skeletal muscle cells.
Nasopharynx
The part of the pharynx that lies above the level of the palate.
Negative Feedback
The concept that once the desired effect of a process has been achieved, further action is inhibited until it is needed again; also called feedback inhibition.
Negative Pressure Ventilation
Drawing of air into the lungs; airflow from a region of higher pressure (outside the body) to a region of lower pressure (the lungs); occurs during normal breathing.
Neoplasm
A mass of tissue produced by abnormal cell growth and division that may be malignant (cancerous) or benign.
Nephrons
The functional (urine-producing) units of the kidney.
Nervous System
The system that controls virtually all activities of the body, both voluntary and involuntary.
Nervous Tissue
Composed of neurons and neuroglia.
Neuroglia
Supporting cells that provide a supporting skeleton for neural tissue, isolate and protect the cell membranes of neurons, regulate the composition of interstitial fluid, defend neural tissue from pathogens, and aid in the repair of injury.
Neuromuscular Junction
The connection between a motor neuron and a muscle fiber.
Neurons
The basic nerve cells of the nervous system containing a nucleus within a cell body and extending one or more processes; they exist in masses to form nervous tissue.
Neurotransmitter
A chemical released from one nerve that crosses the synaptic cleft to reach a receptor.
Neutrophils
One of the three types of granulocytes; they have multi-lobed nuclei that resemble a string of baseballs held together by a thin strand of thread; they destroy bacteria, antigen-antibody complexes, and foreign matter.
Norepinephrine
A naturally occurring catecholamine that functions as a neurotransmitter and adrenal hormone; it is synthesized by the adrenal medulla, the peripheral sympathetic nerves, and the CNS. It is also available as a drug sometimes used in the treatment of severe hypotension; produces vasoconstriction through its alpha-ribonucleic properties.
Nucleic Acids
Large organic molecules, or macromolecules, that carry genetic information or form structures within cells, and include deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
Nucleus
In the context of the cell, a cellular organelle that contains the genetic information; controls the function and structure of a cell. In the context of an atom, the central portion of an atom that contains protons and neutrons.
Nutrients
Substances that provide nourishment for growth such as carbohydrates, lipids, proteins, vitamins, minerals, and water.
Oligosacchride
A simple sugar composed of 2-10 monosaccharides.
Oncotic Pressure
The pressure of water to move, typically into the capillary, as the result of the presence of plasma proteins.
Oocyte
Immature female sex cell produced in the ovary that may develop by meiosis into an ovum (egg).
Oogenesis
The process of egg cell formation, which begins at puberty.
Optic Chiasm
Location where approximately half of the nerve fibers from each eye cross over to the opposite side of the brain.
Orbit
An eye socket of the skull.
Organ of Corti
The organ that is the primary receptor for sound, and is made up of thousands of individual cilia, each with their own associated nerve.
Organelles
Structures within cells that have specialized functions.
Origin
A relatively immovable part of the body where a skeletal muscle is fastened at a moveable joint; its action opposes that of an insertion.
Oropharynx
A tubular structure that extend vertically from the back of the mouth to the esophagus and trachea.
Osmosis
The movement of a solvent, such as water, from an area of low solute concentration to one of high concentration through a selectively permeable membrane to equalize concentrations of a solute on both sides of the membrane.
Osmotic Pressure
The pressure exerted by the concentration of the solutes in a given space to stop the flow of solvent across a semipermeable membrane.
Ossification
The formation of bone by osteoblasts.
Osteoblasts
Cells involved in the formation of body tissue.
Osteoclasts
Mature bone cells.
Otoliths
A pair of fluid-filled sacs within the inner ear that are used by the CNS to collect information about movement and orientation in space.
Oval Window
The opening between the stapes and inner ear.
Ovaries
Female glands that produce sex hormones and ova (eggs).
Ovulation
Midcycle release of an ovum during the menstrual cycle.
Oxygenation
The process of loading oxygen molecules onto hemoglobin molecules in the bloodstream.
Oxyhemoglobin
Hemoglobin that has oxygen molecules bound to it.
Palate
The roof of the nasal cavity; it separates the nasal cavity form the oral cavity.
Pancreas
An organ with both endocrine and exocrine functions; it is a major source of digestive enzymes and produces the hormone insulin.
Papillary Muscles
Muscles attached to the chordae tendineae of the atrioventricular heart valves and the ventricular muscle of the heart.
Paranasal Sinuses
The sinuses, or hallowed sections of bone in the front of the head, which are lined with mucous membrane and drain into the nasal cavity; the frontal, ethmoid, sphenoid, and maxillary sinuses.
Parathyroid Glands
Four glands that are embedded in the posterior portion of each lobe of the thyroid; they produce and secrete parathyroid hormone.
Parathyroid Hormone (PTH)
Hormone produced and secreted by the parathyroid glands; it maintains normal levels of calcium in the blood and normal neurotransmitter function.
Parietal Pleura
The lining of the pleural cavity attached tightly to the interior of the of the chest cage.
Partial Pressure
The pressure exerted by an individual gas in a mixture.
Pelvis
The attachment of the lower extremities to the body, consisting of the sacrum and two pelvic bones.
Penis
The cylindrical male sex organs; it conveys urine and semen through the urethra.
Peptide
Protein molecule consisting of amino acids held together by peptide bonds.
Perception
Becoming aware of or understanding something using the senses.
Perfusion
The circulation of oxygenated blood within an organ or tissue in adequate amounts to meet the cells’ current needs.
Pericardium
A thin, double-layered membrane made up of the fibrous pericardium and serous pericardium.
Perilymph
Fluid within the body labyrinth that surrounds and protects the membranous labyrinth while allowing transmission of pressure waves caused by sound.
Peripheral Nervous System (PNS)
The part of the nervous system that consists of 31 pairs of spinal nerves and 12 pairs of cranial nerves that are responsible for communication between the CNS and the rest of the body. These may be sensory nerves, motor nerves, or connecting nerves.
Peristalsis
The wavelike contraction of smooth muscle by which the ureters or other tubular organs propel their contents.
Peritoneum
Double-layered serous membrane that lines the abdominal cavity and covers the organs located in the abdominopelvic cavity.
pH
The measure of acidity or alkalinity of a solution.
Phagocytosis
A form of endocytosis in which a cell surrounds a foreign particle and engulfs it.
Phantom Pain
A sensation of pain in a part of the body that is no longer present.
Pharynx
The area between the nasal cavity and the larynx and posterior to the oral cavity; the throat.
Phenotype
The appearance, health condition, or other characteristics associated with a particular genotype.
Phospholipid
A type of lipid molecule that comprises the cell membrane.
Physiology
The study of the processes and functions of the living organism.
Pia Mater
The innermost of the three meninges that enclose the brain and spinal cord; it rest directly on the brain and spinal cord.
Pineal Gland
A gland in the brain the synthesizes and secretes melatonin, a hormone that affects patterns of sleep and wakefulness.
Pinna
A formation of cartilage within the inner ear that protects the ear and collects sounds into the ear canal, while allowing some perception of the direction from which the sound comes; also called the auricle.
Pinocytosis
A form of endocytosis in which the cell membrane sinks inward and ingests droplets of extracellular fluid.
Pituitary Gland
An endocrine gland responsible for directly or indirectly affecting all body functions; also called the hypophysis.
Plasma
A watery, yellow fluid that carries the blood cells and nutrients and transports cellular waste material to the organs of excretion.
Plasmin
A naturally occurring enzyme that dissolves the fibrin fibers in blood clots; usually present in the body in its inactive form, plasminogen.
Platelets
Formed elements of the blood that function in blood clotting; also called thrombocytes.
Pleura
The serous membranes covering the lungs and lining the thoracic cavity.
Pleural Space
The potential space between the parietal pleura and the visceral pleura.
Plexus
A cluster of nerve roots that permits peripheral nerve roots to rejoin and function as a group.
Polarized
When a cell is at rest, ions are actively transported into and out of the cell to create an electrochemical gradient across the cell membranes.
Polypeptide
Formed from many amino acids bound into a chain. When this has more than 100 molecules, it is considered to be a protein. Certain protein molecules have more than one.
Polysaccharides
Complex carbs that contain many simple joined sugar units, such as plant starch. Some, such as cellulose, cannot be broken down for nutrition in humans but play important roles in digestion.
Pons
Area of the brainstem that contains the sleep and respiratory centers for the body, which along with the medulla, control breathing.
Pontine Respiratory Group (PRG)
A portion of the pons that communicates info to both the ventral and dorsal respiratory groups; it is thought to smooth the transition between each phase of the ventilatory cycle and alter breathing by making each breathe shorter and shallower or longer and deeper, depending on the body’s needs.
Precapillary Sphincters
Smooth muscle located at the entrances to the capillaries; responsive to local tissue needs.
Preload
The volume of blood in the ventricle at the end of diastole; it is primarily a reflection of venous return (the blood that is returned to the heart).
Presbyopia
The increased difficulty in focusing on objects that occurs with aging.
Progesterone
A female hormone released form the ovaries that promotes changes in the uterus during the reproductive cycle, affects the mammary glands, and helps regulate gonadotropin secretion.
Proprioception
The awareness of motion and position of a body part.
Prostaglandins
Lipids made from arachidonic acid that usually act more locally than hormones, are very potent, stimulate hormone secretions, and help to regulate blood pressure.
Proteins
Created from amino acids, they include enzymes, plasma proteins, muscle components (actin and myosin), hormones, and antibodies.
Prothrombin
A protein made in the liver and released into the blood where it is converted into thrombin during the process of blood clotting.
Pulmonary Artery
One of two arteries that carry deoxygenated blood from the right ventricle to the lungs.
Pulmonary Circulation
The flow of the blood from the right ventricle through the pulmonary arteries and all of their branches and capillaries in the lungs and back to the left atrium through the venules and pulmonary veins; also called the lesser circulation.
Pulmonary Veins
The four veins that return oxygenated blood from the lungs to the left atrium of the heart.
Pulmonary Valve
The semilunar valve that regulates blood flow between the right ventricle and the pulmonary artery; also called the pulmonary semilunar valve.
Pulse Pressure
The difference between the systolic and diastolic pressures.
Purkinje Fibers
A system of fibers in the ventricles that conducts the excitation impulse from the bundle branches to the myocardium.
Referred Pain
Pain that feels as if it is originating from a body part other than the site being stimulated.
Reflex Arc
A sensory message that reaches the spinal cord and meets with a motor nerve to cause an action; the reflex action occurs without the message first having to reach the brain to voluntarily cause the action.
Refracting System
A series of transparent structures within the eye that redirect light as it passes through mediums of different densities.
Renal Corpuscle
The initial blood-filtering component of the nephrons
Renal Cortex
The outer portion of each kidney; it forms renal columns and has tiny tubules associated with the nephrons.
Renal Medulla
The inner portion of each kidney; it is made of conical renal pyramids, and has striations.
Renal Pelvis
A cone-shaped collecting area that connects the ureter and the kidney.
Renal Tubule
The portion of the nephron containing the tubular fluid filtered through the glomerulus.
Renin
A hormone produced by cells in the juxtaglomerular apparatus when the blood pressure is low.
Repolarization
The process by which ions are moved across the cell membrane to return to a polarized state.
Reproductive System
The system in males and females that controls the reproductive processes via organs and glands that create sex cells and transport them to areas where fertilization can occur.
Residual Volume
The amount of air remaining in the lungs and airway passages that is unable to be expelled after a maximal forced exhalation.
Respiration
The exchange of gases between a living organism and its environment.
Respiratory Membrane
Where gas exchange takes place; oxygen is picked up in the bloodstream and carbon dioxide is eliminated through the lungs.
Respiratory System
All the structures of the body that contribute to the process of breathing, consisting of the upper and lower airways and their component parts.
Reticular Activating System (RAS)
Group of specialized neurons in the brainstem; involved in sleep and wake cycles; maintains consciousness.
Retina
The inner layer of the eye wall, including the visual receptors.
Rh Factor
An antigen found on the red blood cells of most people, when a woman without this protein is impregnated by a man with this protein, the woman’s body can create antibodies against the protein and attack future pregnancies.
Right Coronary Artery
Blood vessel that provides oxygenated blood to the right side of the heart muscle.
Rods
One of two photoreceptors of the retina sensitive to light, but does not discriminate colors, producing a picture that is somewhat less focused and essentially black and white.
Sacroiliac Joint
The point of attachment of the ilium to the sacrum.
Saddle Joint
Two saddle-shaped articulating surfaces oriented at right angles to each other so that complementary surfaces articulate with each other, such as is the case with the thumb.
Schwann Cells
Neuroglial cells in the PNS that form a myelin sheath around axons.
Sclera
The white, fibrous outer layer of the eyeball.
Scrotum
A pouch of skin and subcutaneous tissue hanging form the lower abd region, posterior to the penis.
Sebaceous Glands
Glands that produce an oily substance called sebum, which discharges along the shafts of the hairs.
Semilunar (SL) Valves
The two valves, the aortic and pulmonic valves, that are shaped like half-moons and separate the heart form the aorta and pulmonary arteries.
Semipermeable
Property of the cell membrane that describes the ability to allow certain elements to pass through while not allowing others to do so.
Sensory Nerves
The nerves that carry sensations of touch, taste, heat, cold, pain, and other modalities from the body to the CNS.
Sensory Receptors
Structures located in the dermis that initiate nerve impulses that can reach one’s conscious awareness.
Sex Chromosomes
The X and Y chromosomes, which determine sex.
Sinoatrial (SA) Node
The normal site of the origin of electrical impulses; located high in the right atrium, it is the natural pacemaker of the heart.
Sinuses
Cavities formed by the cranial bones that trap contaminants from entering the respiratory tract and act as tributaries for fluid to and from the eustachian tubes and tear ducts.
Skeletal Muscle Tissue
Voluntary muscle tissue attached to bones and composed of long, threadlike cells that have light and dark striations.
Sliding Filament Theory
A method of action of muscle contraction involving how sarcomeres shorten, with thick and thin filaments sliding past each other toward the center of the sarcomere from both ends.
Sodium-Potassium Pump
The mechanism by which the cell brings in two potassium ions and releases three sodium ions.
Soft Palate
The posterior portion of the palate that is made up of mucous membrane, muscular fibers, and mucous glands; it is so named because it has no bony support.
Solute
The dissolved particles contained in a solvent.
Solution
A mixture of a solvent and a solute.
Solvent
The fluid that dissolves a solute, or the substance in which a solute is dissolved or mixed.
Somatic Nervous System
The part of the nervous system that regulates activities over which there is voluntary control.
Somatic Pain
Pain caused by the activation of pain receptors in the body’s superficial tissues, such as the skin, bones, muscles, and joints; in contrast to visceral pain, this is generally more intense and more precisely localized.
Spermatogenesis
The process by which sperm cells are formed.
Sphincters
Muscles arranged in circles that are able to decrease the diameter of tubes. Ex.s are found within the rectum, bladder, and blood vessels.
Spinal Nerves
31 pairs of nerves that originate from the spinal cord and exit the spine on either side between vertebrae; each has a sensory root and a motor root and is responsible for sending the receiving sensory and motor messages to and from the CNS from a portion of the body.
Stem Cells
Cells that retain the ability to divide repeatedly without specializing, and that allow for continual growth and renewal.
Strabismus
Loss of perception of depth and overlapping or doubled images.
Stratum Corneum
The outermost or dead layer of the skin.
Stroke Volume (SV)
The volume of blood pumped forward with each ventricular contraction.
Subarachnoid Space
The space located between the pia mater and the arachnoid membrane.
Suprasternal Notch
The indentation formed by the superior border of the manubrium and the clavicles, often used as a landmark for procedures such as subclavian vein access; also known as the jugular notch.
Surfactant
A liquid protein substance that coats the alveoli in the lungs, decreases alveolar surface tension, and keep the alveoli expanded; a low level in a premature infant contributes to respiratory distress syndrome.
Sutures
Seams that occur only between the bones of the skull; they are a type of fibrous joint.
Sweat Glands
The glands that secrete sweat, located in the dermal layer of the skin.
Synapse
A functional connection where neurons communicate with other cells.
Synaptic Cleft
The space between neurons; also called the synaptic gap.
Synaptic Vesicles
Small sacs that contain neurotransmitters.
Synovial Fluid
The fluid secreted by synovial membranes that lubricates synovial joints.
Synovial Joints
Complex joints that allow free movement of the component bones are are lubricated with synovial fluid.
Systemic Vascular Resistance
The resistance that blood must overcome to be able to move within the blood vessels; related to the amount of dilation or constriction in the blood vessel.
T Lymphocytes
Lymphocytes that interact directly with antigens, producing the cellular immune response; they also stimulate the B lymphocytes to produce antibodies; also called T cells.
Tentorium
A horizontal projection of the dura that separates the cerebellum from the cerebrum.
Testosterone
The most important male sex hormone (androgen).
Thalamus
Structure of the diencephalon that is the sensory switchboard of the brain, through which almost all signals travel on their way in or out of the brain.
Thermoregulation
The process by which the body maintains temperature through a combination of heat gain by metabolic processes and muscular movement and heat loss through breathing, evaporation, conduction, convection, and perspiration.
Thoracic Duct
One of two great lymph vessels; it empties into the superior vena cava.
Thrombin
An enzyme that causes the conversation of fibrinogen to fibrin, which binds to a platelet plug, forming a final mature clot.
Thromboplastin
A chemical the stimulates blood clotting.
Thymus
A lymphatic organ located in the thorax that is important in early immunity; it shrinks with age and is eventually replaced by other types of tissue.
Thyroid Cartilage
A firm prominence of cartilage that forms the upper part of the larynx; the Adam’s apple.
Thyroid Gland
A large endocrine gland that is located at the base of the neck and produces and excretes hormones that influence growth, development, and metabolism.
Tidal Volume
The amount of air moved in and out of the lungs in one relaxed breath; about 500 mL for an adult.
Tissue
A group of cells that are similar in structure and function.
Titin
A noncontractile protein found in sarcomeres of cardiac and skeletal muscle.
Total Body Water (TBW)
Total amount of fluid in the human body; accounts for about 60% of the weight of a healthy adult male; divided into various compartments.
Transcellular Fluid
Fluid classified as extracellular but distinct because it is formed form the transport activities of cells. Examples include CSF, bladder urine, and aqueous humor, and the synovial fluid of the joints.
Tricuspid Valve
The atrioventricular valve that separates the right atrim from the right ventricular.
Tropomyosin
An actin-binding protein that regulates muscle contraction and other actin-related mechanical functions of the body.
Troponin
A regulatory protein in the actin filaments of skeletal and cardiac muscle that attaches to tropomyosin.
Tubular Reabsorption
The process that moves substances form the tubular fluid into the blood, within the peritubular capillary.
Tubular Secretion
The process that moves substances from the blood in the peritubular capillary into the renal tissue.
Tunica Adventitia
The outer layer of tissue of a blood vessel wall, composed of elastic and fibrous connective tissue.
Tunica Intima
The smooth, thin, inner lining of a blood vessel.
Tunica Media
The middle and thickest layer of tissue of a blood vessel wall, composed of elastic and fibrous connective tissue.
Ureter
A small, hollow tube that carries urine from the kidneys to the bladder.
Urethra
The canal that conveys urine from the bladder to outside the body.
Urinary Bladder
A sac behind the pubic symphysis made of smooth muscle that collects and stores urine.
Urinary System
The organs that control the discharge of certain waste materials filtered from the blood and excreted as urine.
Uterus
A muscular, inverted pear-shaped organ that lies situated between the urinary bladder and the rectum.
Ventilation
The mechanical process of moving air into and out of the lungs in two separate phases: inhalation (inspiration) and exhalation (expiration).
Ventral Respiratory Group (VRG)
An area of the medulla oblongata that can cause inspiration or expiration depending on which motor neurons are stimulated.
Vestibule
The structure into which the vagina opens posteriorly, and the female urethra opens into in the midline; also the central part of the labyrinth of the ear, behind the cochlea and in front of the semicircular canals.
Visceral Pain
Deep pain caused by activation of pain receptors in internal areas of the body that are enclosed within a cavity, such as the chest, abd, or pelvis.
Visceral Pleura
Lining of the pleural cavity that adheres tightly to the surface of the lung.
Vital Capacity
The amount of air moved in and out of the lungs with maximum inspiration and exhalation.
Vitamins
Organic compounds required for normal metabolism.
Vitreous Humor
A jellylike fluid filling the posterior eye cavity that helps the globe maintain its shape without distorting light.
White Matter
Bundles of myelinated nerves.
