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  • Acid-Base Balance

    The body’s maintenance of a healthy pH range for blood and tissues that is slightly basic (pH between 7.35 – 7.45). This balance is achieved through the use of systems in the blood (which help to minimize pH changes) and by the lungs and kidneys, which eliminate excess amounts of acids or bases from the body.

  • Acidosis

    A condition in which there is a shift in the acid-base balance of the body to have more acid than normal, often causing the pH of the blood and body tissues to fall below the healthy range (7.35-7.45). It may be caused by decreased CO2 eliimination in respiratory disorders such as emphysema, by metabolic problems such as kidney disease and diabetes, or as the result of ingesting poisons (ethlylene glycol, methanol) or overdosing on certain medication (salicylates); it can also be caused by losing HCO3, as in diarrhea.

  • Acute

    1. A condition or illness that usually has a rapid onset of symptoms and may resolve within days with or without treatment. It is the opposite of chronic.
    2. A condition or illness that is sudden or severe.

  • Acute coronary syndrome (ACS)

    A group of potentially life-threatening disorders resulting from insufficient blood flow to the heart caused by the narrowing or blockage of one or more blood vessels to the heart; the conditions included in this group range from unstable angina to heart attack and are usually characterized by chest pain, upper body discomfort with pain in one or both arms, shoulders, stomach or jaw, shortness of breath, nausea, sweating or dizziness.

  • Adrenal Gland

    One of a pair of glands located above each kidney that secretes hormones directly into the bloodstream. Each gland has two parts that perform different functions.

    1. The adrenal cortex produces and secretes hormones such as cortisol, aldosterone and sex steroids. They are involved in many different body functions.

    2. The adrenal medulla produces and secretes catecholamines such as adrenaline (epinephrine) and norepinephrine.

  • Alkalosis

    A condition in which a there is a shift in the acid-base balance of the body to have more base than normal, often causing the pH of the blood and body tissues to rise above the healthy range (7.35-7.45). It may have respiratory causes such as hyperventilation and pneumonia or metabolic causes such as prolonged vomiting and severe dehydration.

  • Allele

    Any one of the possible alternative forms in which a specific gene can occur

  • Allergen

    Substance (e.g., ragweed pollen) that can cause an allergy

  • Amino Acid

    One of a group of chemical compounds (organic acids) that have an amino group (NH2); many are the building blocks of proteins.

  • Analyte

    In the clinical laboratory, a substance from the body that is undergoing analysis.  In lay terms, often referred to as a test.””

  • Anaphylaxis

    Severe allergic reaction that can cause intensely itchy welts (hives) on the skin, low blood pressure, and difficulty breathing. Anaphylaxis can be life-threatening so those who have been affected by it may be advised to carry an emergency injection of epinephrine.

  • Androgens

    Hormones that are responsible for the induction of sexual differentiation and produce secondary male physical characteristics such as a deep voice and facial hair. An example is the hormone testosterone. They are also present in females as precursors to female hormones (such as estrogen).

  • Aneurysm

    Weakened portion of a blood vessel wall that widens or bulges and may eventually rupture; a ruptured aneurysm can bleed heavily and may be fatal.

  • Antibiotic resistance

    Ability of a microorganism to grow despite the presence of an antibiotic

  • Antibody

    A protein produced by lymphoid tissue in response to the presence of an antigen.

  • Anticoagulant

    1. Drug that delays blood clotting (e.g., heparin, warfarin); used in patients with or at risk for blood clots
    2. Substance used to prevent clotting in blood used for transfusions and certain laboratory tests

  • Antigen

    1. Substance that causes the production of an antibody that binds to the antigen in order to damage, neutralize or kill it.

    2. The presence of certain antigens on blood cells is the basis for blood typing for transfusions. Antigens that are present on tissue allow for donor-recipient matching in transplant medicine.

  • Antihistamine

    A class of drugs that is used to treat allergies, hypersensitivity reactions, and the symptoms of colds. These drugs work by reducing the effects of histamine, a naturally-occurring substance that is released in response to inflammation and allergies.

  • Arrhythmia

    Changes in the rhythm of heartbeats or in the strength of heart contractions

  • Assay

    Procedure used to detect or measure a substance or reaction; test

  • Atherosclerosis

    Common disorder of the arteries in which deposits consisting mostly of cholesterol and lipids form on the inner arterial wall. As a result, the vessels become nonelastic and narrowed, leading to decreased blood flow. One of the most important examples is coronary artery disease.

  • Atrial Fibrillation

    Condition characterized by an irregular, often rapid, heart rhythm

  • Autoimmunity

    Misdirected immunity with production of antibodies that act against the tissues of one’s own body

  • Bacterium

    Plural: Bacteria

    Unicellular microscopic organisms, some of which cause disease

  • Bence Jones protein

    A protein that may be found in the urine of people with certain forms of protein disorders, such as amyloidosis and multiple myeloma. In most cases of multiple myeloma, a single type of intact (whole) immunoglobulin is produced in excess. In a minority of cases, only one section of an immunoglobulin called a free light chain” is produced in large amounts. These excess free light chains are released into the bloodstream and since they are relatively small molecules

  • Benign

    1. Mild, non-cancerous, and/or not spreading (compare Malignant)

  • Beta Blockers

    A group of drugs that blocks the effect of adrenaline, slows the heart rate, and decreases the strength of the heart’s contractions and thereby lowers blood pressure and relieves symptoms of angina and arrhythmias

  • Bile

    Thick, yellow-green-brown fluid made by the liver, stored in the gallbladder, and discharged into the upper part of the digestive tract (duodenum), where it dissolves fats, preparing them for further digestion.

  • Biliary

    Pertaining to bile or the ducts of the liver and gall blader

  • Biomarker

    A substance produced by the body, often detectable in body fluids such as blood or urine, that indicates a specific process, condition or disease

  • Biopsy

    Removal of a small amount of tissue and/or fluid; the specimen is usually obtained by cutting or by suction through a needle.

  • Bone Marrow

    Specialized soft tissue found within bone. Red bone marrow, widespread in the bones of children and found in some adult bones (e.g., pelvis, spine, ribs), is essential for the formation of mature red blood cells. Fat-laden yellow bone marrow, more common in adults, is found primarily at the ends of long bones.

  • Capillary

    The tiniest of blood vessels. Through the one-cell-layer-thick walls of capillaries, oxygen and nutrients are delivered to body tissues and carbon dioxide and other wastes are cleared from body tissues.

  • Carbohydrate

    The starches and sugars that are the chief energy sources of the body

  • Carcinoid tumor

    Slow-growing mass that can develop in the mucous membrane of the gastrointestinal (GI) tract and sometimes the lungs

  • Cardiovascular System

    The heart and blood vessels involved in the pumping of blood and the transport of nutrients, oxygen, and waste products throughout the body

  • Carrier

    1. Person, generally in apparent good health, who harbours organisms that can infect and cause disease in others

    2. Person who has one copy of a recessive disease gene but is not affected themselves

  • Catheter

    1. long, thin, flexible tube inserted into a body cavity or vessel to allow the passage of fluids
    2. thin, flexible tube inserted into a vessel in the body for the purpose of opening (distending) the vessel

  • Central Nervous System (CNS)

    One of the two main divisions of the human nervous system, consisting of the brain and the spinal cord; the other division is the peripheral nervous system.

  • Cerebrospinal Fluid (CSF)

    Normally clear liquid, produced in the ventricles of the brain, that surrounds the brain and spinal cord

  • Chemotherapy

    In the treatment of cancer, the use of medicines or drugs to stop or slow the growth of cancer cells; because chemo can also harm healthy cells, it can be associated with side effects, such as fatigue, hair loss, mouth sores, and nausea/vomiting.

  • Chorionic villus sampling (CVS)

    This test is not routinely performed but may be discussed with or offered to pregnant women who are at an increased risk of having a baby with certain chromosome disorders

  • Chromosome

    Threadlike structure in every cell nucleus that carries the inheritance factors (genes) composed of DNA (deoxyribonucleic acid, the gene material) and a protein (usually histone). A human cell normally contains 46 chromosomes, or 22 homologous pairs and 1 pair of sex chromosomes; one member of each pair of chromosomes is derived from each parent.

  • Chronic

    A condition or illness that arises slowly over days or weeks and may or may not resolve with treatment. It is the opposite of acute.

  • Clone

    (noun) Cell, group of cells, or organisms that descend from a single cell or organism; clones are genetically identical

    (verb) To replicate or produce identical copies

  • Collagen

    A group of proteins that form elongated fibers that are the main component in connective tissues such as skin, ligaments, tendons, cartilage and bone

  • Colposcopy

    a procedure in which a health practitioner uses a lighted magnifying instrument to examine a woman’s cervix for abnormal areas, to take samples for biopsy, and/or treat as indicated

  • Creatine Kinase (CK)
    No definition
  • Culture

    Deliberate growing of cells, especially microorganisms, in a solid or liquid medium (e.g. agar, gelatin), as of bacteria in a Petri dish

  • Cytokine

    one of a group of proteins released by cells of the immune system that carry signals to neighboring cells to regulate and/or promote an immune response

  • Cytology

    The microscopic assessment of individual cells or groups of cells that are either shed in body fluids or collected by smears and scrapings (e.g., the Pap smear) or by aspiration from deeper tissues through a very fine needle

  • Dementia

    Progressive state of mental decline, especially of memory function and judgment

  • Diabetes insipidus

    A disorder similar to diabetes mellitus in that it causes symptoms such as increased thirst and increased urine production

  • Digital Rectal Exam (DRE)

    Part of a physical examination performed in order to examine nearby structures (e.g., the prostate in men)

  • DNA (deoxyribonucleic acid)

    The unique genetic code found in all living cells (bacteria, viruses, parasites, plants, and animals).

  • Dominant gene

    One of a pair of genes whose action is expressed even when only one copy is present

  • E. coli

    A species of bacteria that normally resides in the gastrointestinal tract as harmless normal flora; these rod-shaped bacteria commonly cause urinary tract infections, and some strains produce toxins that cause diarrheal disease.

  • Eclampsia

    Coma and convulsive seizures that occur at or after the 20th week of pregnancy. Associated with pregnancy-induced hypertension, it can be fatal if untreated.

  • Ectopic Pregnancy

    Abnormal pregnancy in which the fertilized egg implants outside of the uterus, most often (90%) in the fallopian tube (tubal pregnancy)

  • Embolism & Thromboembolism

    Embolism— a condition in which material (tissue, fat, air, blood clot, etc.—called an embolus) travels through the bloodstream and then becomes lodged in a vein or artery and blocks the flow of blood through that blood vessel.

    Thromboembolism—a blood clot (thrombus) that breaks free in the blood stream and blocks a blood vessel. This can occur in a vein (venous thromboembolism) or in an artery (arterial thromboembolism).

  • Endocrine

    Cells or tissue that produce hormones released into the bloodstream that have an affect on other cells; for example, the thyroid gland produces thyroid hormone that affects metabolism of many cells.

  • Endometriosis

    Condition marked by the presence, growth, and function of endometrial tissue (lining of the uterus) outside of its normal location in such sites as the uterine walls, the fallopian tubes, the ovaries, and other sites within the pelvis or, rarely, out of the pelvic region

  • Enzyme

    Protein produced in cells that speeds up the rate of biological reactions; the names of many enzymes end in -ase”.

  • Exocrine

    Cells or tissue that produce substances that are released through a duct and into another organ; for example, the pancreas releases digestive juices into the intestine.

  • False-Negative

    Test or procedure result inappropriately indicating a normal or negative result when, in fact, an abnormal condition is actually present.

  • False-Positive

    Test or procedure result inappropriately indicating a positive or abnormal result when, in fact, no abnormal condition is actually present.

  • Fluorochrome

    a dye that gives off specific colors of light (fluoresces) when struck by light rays, often in the ultraviolet light region

  • Fungus

    Plural: Fungi
    One of the four major groups of microorganisms (bacteria, viruses, parasites and fungi) that occurs in nature as a yeast (small unicellular structure similar to bacteria) or a mold (large filamentous forms that may be seen with the naked eye)

  • Fusion gene

    Fusion genes are the result of chromosomes breaking and rejoining incorrectly so that two different genes are joined together. The new locations of the genes or the combination of the genes themselves may produce a new protein or effect. Often, the normal function of one of the genes involved is altered in such a way that it then promotes cell growth without responding to the normal checks and balances that cells use to stay healthy, which can lead to cancer.

  • Gene

    Basic unit of genetic material; in humans, a segment of DNA on a chromosome that usually codes for the production of a specific protein

  • Gene expression

    Properties exhibited by an organism due to genes present in cells

  • Gene Sequence

    Section of genetic code; particular arrangement of nucleotides along a segment of DNA on a chromosome

  • Genetic Counseling

    Process of determining the risk of a particular genetic disorder occurring within a family and providing information and advice based on that determination

  • Genetic variant

    Differences in the genes that make up our DNA are referred to as variations” or “variants” and they have different effects on the body. Most genetic variations in DNA do not affect a person’s health. Sometimes

  • Genome

    The total of a person’s genetic information

  • Genotype

    Specific combination of genes within a cell or cells

  • Germ cell

    Reproductive cell that develops into a sperm in males and an egg in females; germ cells contain one-half of the normal complement of the 46 chromosomes from each parent.

  • Globulin

    Collective term for most blood proteins other than albumin

  • Glomerulus

    Plural: glomeruli; one of a number of specialized structures in the kidney, composed of loops of specialized capillaries that filter blood, allowing small substances to pass through towards the urine but preventing loss of larger proteins and blood cells.

  • Granuloma

    Special form of chronic inflammation; often forms one or more nodules that can involve the skin, lymph nodes, lung, liver, spleen, or other organs. Granulomas often form in response to certain types of infection (especially to mycobacteria such as in tuberculosis and to fungi) or to foreign bodies, but sometimes have no known cause, as in sarcoidosis.

  • Hematopoietic stem cell transplantation

    Transplantation of the cells that are able to develop into all the types of blood cells; hematopoietic stem cells are usually obtained from circulating blood (peripheral), bone marrow, or umbilical cord blood. This type of transplant may use the person’s own stem cells (autologous) or stem cells from a donor (allogenic).

  • Hemodialysis

    A procedure that removes waste substances from the circulating blood; often performed on patients with kidney disease

  • Hemolytic Disease of the Newborn

    A condition in which antibodies in a pregnant woman’s blood cross the placenta and destroy her baby’s red blood cells; develops when the mother and baby have differences in one or more blood group antigens

  • Hemorrhoid

    Swelling of vein(s) in the lower part of the rectum or anus

  • Hemosiderosis

    Abnormal deposition of an iron-containing compound (hemosiderin) in tissues, often associated with diseases in which there is extensive destruction of red blood cells (e.g., thalassemia)

  • Hereditary

    Genetic; passed from parent to offspring

  • Heterophile Antibody

    A human antibody that reacts with proteins from another species; may lead to innaccurate results in immunoassay tests; sometimes used to refer to antibodies associated with infectious mononucleosis

  • Heterozygous

    Having two different copies of a particular gene, one of which may be abnormal

  • Homozygous

    Having two identical copies of a particular gene, either both normal or both abnormal

  • Hormone

    A chemical substance produced and secreted by endocrine (ductless) glands that travels through the bloodstream and controls or regulates the activity of another organ or group of cells – its target organ. (For example, growth hormone released by the pituitary gland controls the growth of long bones of the body.) There are two main types of hormones – steroids (e.g., estrogen, testosterone, aldosterone, cortisol) and nonsteroidal. Secretion of hormones is regulated by feedback mechanisms and neurotransmitters.

  • Human leukocyte antigens

    Group of proteins present on the surface of white blood cells (leukocytes) and other nucleated cells (containing a nucleus). These proteins help the body’s immune system to identify its own cells and to distinguish between “self” and “nonself.” Each person has an inherited combination of HLA antigens and, while not as unique as a fingerprint, the presence or absence of each antigen creates a distinctive HLA combination for each person. HLA antigens are divided into types: Class I (A, B, C) and Class II (DR, DP, DQ).

  • Hypoglycemia

    Lower than normal glucose levels in the blood

  • Hypothalamus

    Area of the brain located just above the brainstem that controls the pituitary gland and regulates many bodily functions, such as body temperature, hunger, thirst, sleep, and mood through the release of hormones

  • Immune System

    The body’s means of protection against microorganisms and other foreign substances; it is composed of two major parts: the humoral response (B lymphocytes and production of antibodies) and the cell-mediated response (T lymphocytes that attack foreign substances directly). 

  • Immunity

    1) Resistance to infection because of previous exposure to an infectious agent naturally or by vaccination

    2) State of activation of the immune system to recognize a foreign substance

  • Immunocompromised

    Reduced ability of one’s immune system to mount a normal response to infection

  • Immunoglobulin A (IgA)

    One of the five classes of immunoglobulins; one of the most common immunoglobulins

  • Immunoglobulin D (IgD)

    One of the five classes of immunoglobulins; it is present in small amounts in serum and is thought to function in certain allergic responses

  • Immunoglobulin E (IgE)

    One of the five classes of immunoglobulins; it is present primarily in the skin and mucous membranes and is believed to function in response to environmental antigens and to play a role in allergic reactions.

  • Immunoglobulin G (IgG)

    One of the five classes of immunoglobulins; widespread in the body

  • Immunoglobulin M (IgM)

    One of the five classes of immunoglobulins; a large molecule

  • Immunosuppressive

    Pertaining to a substance that decreases the body’s normal immune response

  • Incidence

    Rate at which new cases of a disease occur within a population

  • Inflammation

    The response of body tissues to injury such as trauma or infection. Inflammation is a complex process that can be localized or systemic. When localized, it causes pain, heat, swelling and redness of the affected area; when systemic, it may present as a general feeling of malaise with fatigue and fever.

  • Klinefelter syndrome

    A rare genetic condition in boys and men caused by an extra X chromosome. (Males normally have one X and one Y chromosome.) The presence of the extra X chromosome may or may not produce obvious signs and symptoms (usually in teens and adults), such as low testosterone, small penis and testicles, enlarged breasts, tall stature and/or behavioral, learning, speech or language disabilities. Most of these individuals are infertile.

  • Latent

    Condition or infectious agent that is present in the body but not causing symptoms and/or actively multiplying; the condition may progress from a latent to active form if the immune system of the patient is no longer able to hold the condition or infection in check.

  • Lipids

    Any of a group of fats and fat-like substances, including oils, waxes, steroids, and triglycerides. Lipids are easily stored in the body, and triglycerides serve as a fuel source. Some (such as cholesterol and phospholipids) are an important constituent of cell structures and are involved in many biological functions. Lipids can combine with other compounds to form complexes, such as lipoproteins, phospholipids, and glycolipids.

  • Lipoprotein

    Protein in the blood whose primary purpose is to transport cholesterol, tryglycerides, and other fats throughout the body

  • Lymphatic system

     (also Lymph, Lymph tissue, Lymph node)

    The extensive network of nodes, vessels, and ducts that collects lymph from tissues and carries it in one direction to the blood. Lymph is clear, watery fluid consisting of a number of substances including fat, protein and lymphocytes, the white blood cells that fight infections. Lymph and the lymphatic system serve to transport these substances, remove fluid and bacteria from tissues, and supply mature lymphocytes to the blood.

  • Lynch Syndrome

    Also known as hereditary nonpolyposis colon cancer or HNPCC.
    An inherited condition that increases the risk of many types of cancer, especially colon cancer. People who inherit mutations in the MLH1, MSH2, MSH6, PMS2, or EPCAM gene have an increased risk of developing Lynch syndrome. Besides colon cancer, examples of other cancers associated with Lynch syndrome include cancers of the stomach, liver, bile ducts, brain, skin, ovaries and lining of the uterus (endometrium).

  • Malignant

    Harmful and potentially fatal

  • Metabolism

    Chemical reactions that occur in living organisms to convert one substance into another or produce energy

  • Microorganism

    Life form that is not visible to the naked eye such as bacteria, fungi, parasites, and viruses

  • Monoclonal antibody

    Antibody produced by or derived from a single type (clone) of plasma cell

  • Monoclonal gammopathy

    Abnormal condition in which clones of a single plasma cell or B lymphocyte produce greatly increased amounts of an immunoglobulin molecule; analysis of serum or urine will show a distinct monoclonal” band

  • Mutation

    Change in the genetic structure (DNA); it may occur spontaneously or be induced (e.g., by radiation, drugs, or certain mutagenic chemicals).

  • Mycobacteria

    A diverse group of rod-shaped bacteria that include Mycobacterium tuberculosis (which causes tuberculosis) and Mycobacterium leprae (which causes leprosy) and more than 100 different species found in the environment; the environmental mycobacteria may be referred to as nontuberculous mycobacteria (NTM), mycobacteria other than tuberculosis (MOTT), and/or atypical mycobacteria.

  • Nasopharynx

    The area at the back of the nasal passages and above and behind the soft palate

  • Neuroendocrine

    1. Pertaining to the interaction between the nervous system and glands that produce hormones
    2. Relating to or involving cells that produce hormones in response to the stimulation of nerves or the nervous system

  • Next Generation Sequencing

    A type of laboratory test method that rapidly sequences large amounts of DNA; sequencing determines the order of DNA building blocks (nucleotides) in a person’s genetic code. Changes in the building blocks (mutations) in the regions of DNA that are responsible for making proteins can lead to genetic disorders. Next-gen sequencing can look for mutations in any of the protein-producing regions of DNA.

  • Normal flora

    Microorganisms that live harmlessly on or in the body and do not cause disease unless the normal protective barriers (skin, mucosa) are compromised

  • NSAIDs

    Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are a group of painkillers that includes drugs such as ibuprofen and aspirin; they reduce fever as well as decrease pain and inflammation; can cause side effects such as stomach ulcers.

  • Nucleus

    The structure in cells that contains the chromosomes, genes, DNA.

  • Opportunistic Infection

    Infection that affects people with suppressed immune systems

  • Oxidative Stress

    Damage to cells in the body caused by free radicals; free radicals, groups of atoms containing an oxygen atom and a free electron, can damage and sometimes destroy cells.

  • Paraganglioma

    tumor that releases excess hormones called catecholamines (e.g., dopamine, epinephrine (adrenaline), norepinephrine and their metabolites, such as metanephrines) and usually occurs somewhere in the abdomen but outside the adrenal glands

  • Parasite

    One of the four major groups of microorganisms (bacteria, viruses, fungi, and parasites) that may live freely in nature, live on another organism without harming it, or live at the expense of the host organism

  • Pathogen

    Organism that causes disease

  • Pathologist

    A physician who diagnoses and characterizes disease by examining a patient’s tissues, blood, and other body fluids. Pathologists work in two broad areas:

    Anatomic pathology is the examination of the physical appearance and microscopic structure of tissues. Anatomic pathologists look at biopsies and organs removed at surgery (surgical pathology) as well as cells that are collected from brushings or body fluids (cytology). They also perform autopsies to investigate the cause of death (autopsy pathology).

    Clinical pathology deals with the measurement of chemical constituents of blood and other body fluids (clinical chemistry), analysis of blood cells (hematology), identification of microorganisms (microbiology), and the collection, preparation and use of blood for transfusion (transfusion medicine). Clinical pathologists direct the laboratories that perform these tests and provide consultation to other doctors on the significance of test results.

  • Pericardium

    Sac-like membrane that surrounds the heart and the base of the blood vessels that lead into it

  • Peripheral nervous system

    All parts of the nervous system except the brain and spinal cord

  • Peritoneum

    Membranes that cover the abdominal cavity and the outside of abdominal organs

  • pH

    Measurement of the acidity or alkalinity of a substance. A pH of 7.0 is neutral. A substance with a pH less than 7.0 is an acid, with increasing acidity as the pH decreases toward zero. Likewise, a substance with a pH greater than 7.0 is a base (alkali), with increasing alkalinity as the pH moves toward 14.0.

  • Phenotype

    The observable physical or biochemical characteristics of a person, as determined by both their genetic makeup and environmental influences

  • Pheochromocytoma

    tumor located in one or both of the adrenal glands that releases excess hormones called catecholamines (e.g., dopamine, epinephrine (adrenaline), norepinephrine and their metabolites, such as metanephrines)

  • Phospholipid

    A substance in the body that contains both lipid (fat) and phosphorous; phospholipids are found in all cells throughout the body because they are a major component of the cell membrane, the outermost layer of a cell.

  • Pituitary gland

    Pea-sized gland located in the center of the head behind the sinus cavity at the base of the brain; the pituitary consists of two parts that produce different hormones: 1) in the anterior portion, growth hormone (GH), adrenocorticotropin (ACTH), thyroid-stimulating hormone (TSH), lutenizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin (PRL) are produced; 2) in the posterior portion, oxytocin and antidiuretic hormone (ADH) (produced in the hypothalamus) are stored for release.

  • Placenta

    The organ that connects a pregnant woman with her developing baby in the uterus; blood from the mother and baby do not mix directly, but a thin membrane within the placenta allows nutrients from the mother to pass to the baby and waste products to pass from the baby to the mother for elimination.

  • Plaque

    1. Deposit on the inner arterial walls in atherosclerosis
    2. Flat, raised patch on the skin or mucous membrane
    3. Deposit of saliva and bacteria on teeth that encourages the development of caries

  • Plasma cell

    Mature lymphocyte (B cell) that produces and secretes antibodies

  • Pleura

    One of the two membranes that surrounds each lung and lines the chest cavity

  • Polyp

    A growth, such as on the lining of the mouth or intestines, that is usually benign; examples include uterine polyps and colorectal polyps”

  • Prevalence

    The number of people with a particular disease at any given time in a population

  • Prion Protein

    An infectious agent (not bacteria or virus) that is an irregular form of a normal protein; prion proteins cause a variety of infections, including Mad Cow Disease and Creutzfeld-Jacob disease. Prion proteins are thought to induce normal brain proteins to assume an irregular shape, rendering them dysfunctional.

  • Prognosis

    1) prediction about the course or outcome of a disease or illness
    2) the likelihood of recovery from a disease or illness

  • Preeclampsia

    A condition during pregnancy characterized by high blood pressure, protein in the urine, and fluid retention. If untreated, it can lead to eclampsia and convulsions that can be life-threatening to the mother and baby.

  • Raynaud phenomenon

    Intermittent episodes of pallor, cyanosis (bluing), and redness in the fingers or toes due to constricted blood vessels; it is seen with a variety of conditions and is precipitated by exposure to cold and emotional stress. It may cause numbness, tingling, and burning.

  • Reagent

    Substance used in performing a laboratory test

  • Recessive Gene

    One of a pair of genes whose action is expressed only when two copies are present. For example, the gene for cystic fibrosis is recessive, and the disease will not occur if one normal gene is present.

  • Retina

    sensing part of the eye that collects images from the lens and translates them to chemical signals that can be interpreted by the brain

  • Reye syndrome

    A rare condition that causes degeneration of the brain and is characterized by vomiting, fever, accumulation of fat in the liver, swelling of kidneys and brain, disorientation and coma; often occurs in children and following another illness, such as the flu or chickenpox.

  • RNA

    RNA (ribonucleic acid) is a nucleic acid that can carry genetic information (especially in some viruses), perform various activities in the cell, and help form proteins that are encoded in DNA. Several types of RNA exist. Some lab tests measure messenger RNA (mRNA), which is a copy of the DNA code that is translated into amino acids to form a protein.

  • Sensitivity

    In the clinical laboratory:

    1. a test’s ability to correctly identify individuals who have a given disease or disorder;

    2. ability of a test to detect small amounts of a substance or to measure a reaction

  • Septicemia

    Serious infection in which disease-causing organisms are present in the blood, usually resulting from spread of an infection from a specific site

  • Shock

    A condition in which blood flow is inadequate to keep critical organs performing properly; it is often recognized by markedly low blood pressure with evidence of poor function of the brain, kidneys, heart, and/or liver. It is a medical emergency that can lead to serious damage and/or death.

  • Sign

    Evidence of a disease or condition perceived by a physician or person other than the patient

  • Specificity

    In the clinical laboratory:
    1. a test’s ability to correctly exclude individuals who do not have the given disease or disorder;
    2. a test’s ability to correctly detect or measure only the substance of interest and exclude other substances

  • Spina bifida

    A birth defect in which the bones of the spine do not close around the spinal cord (the continuation of brain tissue that normally is surrounded by the spinal bones); this opening may be covered by skin (also called spina bifida occulta, which means hidden), in which case there may be no or mild symptoms. In other cases, the skin does not cover the defect, allowing the covering of the brain and spinal cord, the meninges, to protrude out through the skin (meningocele) or, in some cases, to rupture, exposing the spinal cord itself (meningomyelocyle). These latter two examples may cause severe damage to the nerves of the legs and lower abdomen, causing paralysis and bowel and bladder malfunction.

  • Spleen

    organ located in the abdomen that functions mainly to store blood cells, remove old blood cells from circulation, produce lymphocytes to fight infection, and filter foreign substances from the blood

  • Sporadic cancer

    Sporadic cancer is the term used to describe cancers that develop in an individual as a result of chance as opposed to a strong inherited risk factor for developing cancer. Many factors influence the chance that a person will develop cancer in their lifetime, including overall health, environment, and genetics. In a sporadic cancer, it is likely that many factors have combined to produce the disease.

  • Sputum

    Viscous material that is derived from the lower air passages such as the lungs and bronchi that may contain substances such as mucus, blood, pus and/or bacteria; it is not the saliva that is produced by the glands in the mouth.

  • Stage

    In medicine, a defined period or phase in the development, progress or extent of a disease or condition; the process of determining the period or phase of a disease or condition. In cancer, the stage is the degree to which the cancer has grown or spread. Generally, lower numbers and/or letters mean less extensive stages.

  • Statins

    A group of drugs that reduce the production of cholesterol and promote the clearance of low-density lipoprotein (LDL) from the blood by the liver.

  • Stem cells

    Cells that are able to develop into many (or all) types of cells

  • Steroids

    A group of chemicals derived from cholesterol that typically functions as hormones; common types of steroids include sex steroids (estrogen, progesterone, testosterone), glucocorticosteroids (cortisol, prednisone, dexmethasone), and mineralacorticosteroids (aldosterone).

  • Symptom

    Evidence of a disease or condition experienced or perceived by a patient

  • Syndrome

    A group of signs and symptoms that are associated with a physical or physiological anomaly; they represent a frame of reference, not a cause.

  • Thymus

    Organ located behind the upper breastbone at the base of the neck that is part of the lymphatic and immune systems; disease-fighting white blood cells called T-cells develop and mature in the thymus before entering circulation. In humans, the thymus is normally active in childhood but becomes less active after puberty, eventually losing most immune activity by adulthood.

  • Tissue

    A collection of cells having a common purpose in the body, such as muscle tissue or kidney tissue

  • Titer

    In the clinical laboratory, titer is a unit of measurement. It is most often thought of as the lowest dilution of a substance in which a reaction takes place. It is usually expressed as a ratio (i.e., 1:20). For example, serum containing an antibody can be diluted with saline in a serial manner producing dilutions 1:5, 1:10, 1:20, 1:40, etc. If the lowest dilution that a reaction can still be detected between the antibody and the antigen it is directed against is 1:20, then that is the result of the antibody titer.

  • Toxin

    Generally, anything that injures, is destructive, or can cause death; specifically, a poisonous substance made within living cells or organisms (plants or animals); may also include some medicines if taken in large amounts and certain metals

  • Tracer

    In radiology, radioactive isotope (e.g., iodine-131) introduced into the body to allow biological structures to be seen as part of diagnostic X-ray techniques.

  • Translocation

    (v. translocate) In genetics, movement of one section of a chromosome to a different position on another chromosome resulting in abnormal chromosome structure

  • Transplantation

    Process of removing cells, tissue, or organ(s) from one body and inserting them into another body, especially using surgery

  • Tubule

    A long, thin hollow tube; in the kidney, a structure that connects to the glomerulus and helps the kidney retain needed small substances (such as water, electrolytes, glucose, calcium) while allowing elimination of waste products. Its contents eventually drain into the collecting system of the kidney as urine.

  • Tumor

    Growth of tissue characterized by uncontrolled cell proliferation; benign or malignant, localized or invasive

  • Turner Syndrome

    A disorder involving the X chromosomes in females. Normally, there are two functioning X chromosomes in every cell in the female body. In Turner syndrome, one of the X chromosomes is missing or is abnormal, or there are two normal X chromosomes present but in only some of the cells. Women with Turner syndrome usually have underdeveloped female sexual characteristics.

  • Tyrosine kinase inhibitor

    Drug used to treat certain types of cancer; it inhibits the action of tyrosine kinase, an enzyme involved in cell growth, thus impeding the growth of cancer cells.

  • U.S. Preventive Services Task Force

    The U.S. Preventive Services Task Force (USPSTF) is an independent, volunteer panel of health professionals and experts. It regularly reviews the latest scientific evidence, such as research studies, to develop and update recommendations on various preventive services. The panel issues the findings as draft documents open for public comment before officially adopting them. The USPSTF is convened by the Agency for Healthcare Research and Quality (AHRQ) as authorized by the U.S. Congress.

  • Ulcer

    A defect in the skin or lining of the mouth or intestines resulting from an infectious, malignant

  • Ulcerative colitis

    A chronic disease of unknown cause that is characterized by inflammation, ulcers, and fluid collection in the lining of the colon; this condition may cause diarrhea with blood and/or mucus and stomach cramping and pain.

  • Ultrasound

    An imaging test that uses an instrument called a transducer or a probe to produce sound waves. When moved over or within a cavity of the body the transducer or probe produces pictures of the body’s soft tissues and organs that typically don’t show up well on x-rays. It can also be used to view a developing fetus in pregnant women.

  • Urethra

    Tube through which urine passes from the bladder to outside of the body; in men, it is also the tube that runs through the penis and through which semen is discharged

  • Viral load

    Number of copies of viral genetic material

  • Virus

    A microorganism consisting of a nucleic acid (either DNA or RNA) core and a protein coat. A virus requires a host cell to reproduce. It reproduces by infecting a host cell and taking over the nucleic acid of that host cell, making more virus nucleic acid and protein.

  • X-linked trait

    A genetic trait found on the X chromosome; women have two copies of this chromosome, while men have only one.

  • Yeast

    Small, one-celled fungus that reproduces by budding

Acid-Base Balance

The body’s maintenance of a healthy pH range for blood and tissues that is slightly basic (pH between 7.35 – 7.45). This balance is achieved through the use of systems in the blood (which help to minimize pH changes) and by the lungs and kidneys, which eliminate excess amounts of acids or bases from the body.