A chemical that gives off hydrogen ions in water and forms salts by combining with certain metals. Acids have a sour taste and turn certain dyes red. Some acids made by the body, such as gastric acid, can help organs work the way they should. An example of an acid is hydrochloric acid. Acidity is measured on a scale called the pH scale. On this scale, a value of 7 is neutral, and a pH value of less than 7 to 0 shows increasing acidity.
Source: The National Cancer Institute's Dictionary of Cancer Terms (http://www.cancer.gov/dictionary)
carbohydrate (KAR-boh-HY-drayt)
A sugar molecule. Carbohydrates can be small and simple (for example, glucose) or they can be large and complex (for example, polysaccharides such as starch, chitin or cellulose).
Source: The National Cancer Institute's Dictionary of Cancer Terms (http://www.cancer.gov/dictionary)
cell (sel)
The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.
Source: The National Cancer Institute's Dictionary of Cancer Terms (http://www.cancer.gov/dictionary)
central nervous system (SEN-trul NER-vus SIS-tem)
The brain and spinal cord. Also called CNS.
Source: The National Cancer Institute's Dictionary of Cancer Terms (http://www.cancer.gov/dictionary)
chronic (KRAH-nik)
A disease or condition that persists or progresses over a long period of time.
Source: The National Cancer Institute's Dictionary of Cancer Terms (http://www.cancer.gov/dictionary)
membrane (MEM-brayn)
A very thin layer of tissue that covers a surface.
Source: The National Cancer Institute's Dictionary of Cancer Terms (http://www.cancer.gov/dictionary)
molecule (MAH-leh-kyool)
The smallest particle of a substance that has all of the physical and chemical properties of that substance. Molecules are made up of one or more atoms. If they contain more than one atom, the atoms can be the same (an oxygen molecule has two oxygen atoms) or different (a water molecule has two hydrogen atoms and one oxygen atom). Biological molecules, such as proteins and DNA, can be made up of many thousands of atoms.
Source: The National Cancer Institute's Dictionary of Cancer Terms (http://www.cancer.gov/dictionary)
nervous system (NER-vus SIS-tem)
The organized network of nerve tissue in the body. It includes the central nervous system (the brain and spinal cord), the peripheral nervous system (nerves that extend from the spinal cord to the rest of the body), and other nerve tissue.
Source: The National Cancer Institute's Dictionary of Cancer Terms (http://www.cancer.gov/dictionary)
neural (NOOR-ul)
Having to do with nerves or the nervous system, including the brain and the spinal cord.
Source: The National Cancer Institute's Dictionary of Cancer Terms (http://www.cancer.gov/dictionary)
PSA
A protein made by the prostate gland and found in the blood. PSA blood levels may be higher than normal in men who have prostate cancer, benign prostatic hyperplasia (BPH), or infection or inflammation of the prostate gland. Also called prostate-specific antigen.
Source: The National Cancer Institute's Dictionary of Cancer Terms (http://www.cancer.gov/dictionary)
reduction (ree-DUK-shun)
A chemical reaction that takes place when a substance comes into contact with hydrogen or another reducing substance.
Source: The National Cancer Institute's Dictionary of Cancer Terms (http://www.cancer.gov/dictionary)
stress (stres)
The response of the body to physical, mental, or emotional pressure. This may make a person feel frustrated, angry, or anxious, and may cause unhealthy chemical changes in the body. Untreated, long-term stress may lead to many types of mental and physical health problems.
Source: The National Cancer Institute's Dictionary of Cancer Terms (http://www.cancer.gov/dictionary)
tissue (TIH-shoo)
A group or layer of cells that work together to perform a specific function.
Source: The National Cancer Institute's Dictionary of Cancer Terms (http://www.cancer.gov/dictionary)
