Bleeding Disorders Glossary

AIDS. Acquired Immune Deficiency Syndrome. A disease caused by a breakdown in the immune system (which defends us from germs) that follows when someone has become infected with human immunodeficiency virus (HIV).

Arteries. Blood vessels that carry blood from the heart and lungs to other parts of the body.

Blood vessels. Tubes that carry blood to cells in all parts of the body.

Bruise. A black and blue mark under the surface of the skin, caused by bleeding under the skin.

Capillaries. The smallest blood vessels that reach into the tiniest areas of the body.

Carrier. A person whose body carries a gene with the information that transmits a certain characteristic, but who does not show that characteristic.

Cartilage. A tough, elastic substance that covers and protects the bone ends in many movable joints.

Cell. The smallest unit of living tissue capable of functioning independently. All human life starts as a single cell inside the mother.

Chromosome. A structure made up of genes, located in each cell.

Clot. A plug that develops to stop the body from bleeding.

Clotting factors. 1. Proteins made by the body that act as a team to relay the message to make a fibrin net. There are at least 14 clotting factors, identified by roman numerals. A deficiency in one of the clotting factors causes prolonged bleeding and is known as hemophilia. 2. Medicine made from human blood sources, or derived from genes, that replaces the missing clotting factor in people with hemophilia, allowing their blood to clot successfully.

Deficiency. Lacking something that belongs or is needed.

Enzymes. Substances (proteins) in the blood that break down tissue. When enzymes break down old blood pooled in a joint following a joint bleed, they clean up the joint but also may damage normal tissue such as cartilage.

Factor. Medicine used to stop bleeding in people with hemophilia. Also known as factor concentrate, or clotting factor, it is infused directly into the bloodstream.

Factor VIll deficiency. A blood disorder in which a person is lacking or has nonfunctioning factor VIII in the blood, causing prolonged bleeding. Also known as hemophilia A, or classical hemophilia.

Factor IX deficiency. A blood disorder in which a person is missing or has nonfunctioning factor IX in the blood, causing prolonged bleeding. Also known as hemophilia B, or "Christmas" disease.

Fibrin.A protein that appears as a tangle of threads, created by the blood's clotting factors. Fibrin acts like a net to hold a platelet plug over a torn blood vessel wall in order to form a clot and stop bleeding.

Gene.A bundle of chemical information that lies on the chromosomes. Contains chemical information that tells the body how to develop. Genes also carry the directions for blood clotting.

Genetics.The study of the transmission of characteristics from parent to child through genes.

Gene therapy.Using or altering genes to help cure diseases.

Hemophilia.A blood disorder characterized by prolonged bleeding, and the inability of the blood to clot properly.

Immune system.The part of the body responsible for defending it against invading foreign substances including germs, bacteria and viruses.

Infuse. To inject a substance directly into the veins.

Inherit. To receive physical characteristics from the parents through the genes.

Inhibitor. A blood protein that destroys or "inhibits" factor VIII when it is infused into the bloodstream, making it useless.

Joint. A place, where two bones meet, that allows movement.

Joint cavity. The space created where two bones meet in a joint.

Mild hemophilia. A type of hemophilia in which 5% to 40% of a specific blood factor works successfully. Characterized by infrequent bleeding, sometimes after only severe injuries or surgery.

Moderate hemophilia. A type of hemophilia in which 1% to 4% of a specific blood factor works successfully. Characterized by bleeding after injury.

Myths. Stories, legends or invented explanations that are retold so often that they are accepted as truth.

Plasma. The clear, yellowish liquid part of the blood that contains the clotting factors.

Platelets. Donut-shaped substances in the blood that stick together and help plug a torn blood vessel to stop bleeding.

Prophylaxis. Prevention. In hemophilia, infusing with clotting factor regularly to prevent bleeds from occurring.

Proteins. Microscopic substances in the body, responsible for all growth and maintenance of living tissue.

Red blood cells. Blood cells that carry food and oxygen to all cells in the body.

Scab. A dried-up blood clot on the surface of the skin.

Severe hemophilia. A type of hemophilia in which less than 1% of a specific blood factor works. Characterized by frequent and spontaneous bleeding.

Sex chromosomes. One of the 23 pairs of chromosomes in each cell, denoted as XX or XY, that determines whether the organism will be a female or male.

Spontaneous bleeding. Bleeding that appears to have no direct cause.

Symptoms. Physical or behavioral signs of a suspected injury or disease.

Target joint. A joint that has repeated bleeds with eventual signs of damage.

Veins. Blood vessels that carry blood lacking oxygen and food back to the heart and lungs.

White blood cells. Colorless blood cells that help protect the body from foreign particles and bacteria by destroying them.

XX. A chromosome pair that determines a baby's sex as female.

XY. A chromosome pair that determines a baby's sex as male.