Glossary of Terms

Activation
The portion of the blood clotting process in which platelets change their shape so they can signal and stick to each other.

Acupressure
The practice of pressing down on certain parts of the body, sometimes to relieve pain.

Acupuncture
A Chinese practice in which fine needles pierce certain points on the body to cure illness or relieve pain.

Adhesion
The process of platelets sticking to the wall of a torn blood vessel.

Aggregation
The portion of the blood clotting process in which activated platelets stick to each other to form a platelet plug.

Agonist
A chemical substance that binds to a specific receptor on a platelet and triggers a reaction.

AHF
Antihemophilic factor.

Alpha Storage Pool Deficiency
A type of Storage Pool Disease in which the alpha granules inside a platelet are missing. Also called Gray Platelet Syndrome.

Amicar®
Epsilon aminocaproic acid; a drug that prevents the breakdown of newly formed blood clots in the mouth or nose.

Analgesic
Medicine that reduces pain.

Anemia
When there is not enough of the oxygen-carrying part of the blood or not enough red blood cells.

Angiodysplasia
 A condition in which the blood vessels in the stomach or intestines become large and prone to bleed.

Antibody
A protein made by the body's immune system when it encounters a foreign substance. The foreign substance could be a virus or germ or even factor concentrate.

Antihistamine
A type of medicine used to treat the symptoms of an allergic reaction.

Artery
A blood vessel that carries oxygen-rich blood away from the heart to the body's tissues.

Arthritis
Inflammation of a joint.

Autosome
A chromosome that is not a sex chromosome.

Bernard Soulier Syndrome
A very rare disorder in which a person's platelets do not have enough of the receptor (glycoprotein Ib/IX) needed to bind von Willebrand factor.

Biofeedback
A process in which a person uses a machine to become aware of certain body responses such as heart rate, blood pressure, or skin temperature. The person later learns to control these responses without using the machine.

Birth Control Pills
(Also known as oral contraceptives or hormonal therapy) contain the hormones estrogen and progesterone. They may be given to women with bleeding disorders to control heavy menstrual bleeding. The hormones may increase the level of von Willebrand factor and factor VIII in the blood.

Bleeding Time Test
 A test in which a cut is made on the forearm and the length of time for bleeding to stop is measured.

Bruise
An injury to the tissue underneath the skin without breaking the skin. Bleeding under the skin can cause it to appear a dark color.

Butterfly Needle
A type of needle commonly used to infuse factor. It is a small needle with plastic "wings" connected to plastic tubing.

Capillaries
Very small blood vessels which connect the smallest arteries with the smallest veins. The capillaries allow oxygen and nutrients to pass from the blood to the body's cells. They also carry waste away from the cells.

Carrier
In genetics, a person who has a certain gene but doesn't have the condition caused by that gene. The gene can be passed on to offspring.

Cartilage
Tough, yet flexible connective tissue that is found at the end of bones and in the nose and ears. Cartilage in a joint helps the bones glide smoothly.

Chorionic Villus Sampling (CVS)
A test in which a small amount of the placenta is removed from a woman during the 9th to 12th week of pregnancy. The tissue from the placenta is checked to see if the baby has defects such as hemophilia.

Christmas Disease
Hemophilia B or Factor IX deficiency hemophilia. "Christmas" was the last name of the boy in whom the disorder was first diagnosed.

Chromosome
A tiny rod-shaped structure in the nucleus of each body cell. The body's genes are on the chromosomes.

Collagen
The major protein that forms bone, cartilage, tendons, and other connective tissue.

Comprehensive Care
A way of giving health care in which a team of professionals works with the patient to improve his or her physical, emotional, and mental well-being. The care is usually given in one place, a hemophilia treatment center (HTC), so the experts can work together.

Congenital
The condition of being present from birth. A congenital disorder is one that a person has had all of his or her life.

Cryoprecipitate
A layer of blood plasma that is rich in factor VIII. Cryoprecipitate is made through a process of freezing and thawing plasma.

DDAVP®
Desmopressin acetate. A medicine used to treat some factor deficiencies and some types of von Willebrand Disease.

Degenerative Arthritis
A chronic disease of the joints in which the cartilage is destroyed and the joints are damaged.

Delta Storage Pool Deficiency
A type of Storage Pool Disease in which the platelets have few or no dense (or delta) granules.

Diluent
A liquid that is used to form or thin a solution. Normal saline or sterile water are diluents that can be mixed with the factor powder.

DNA
Deoxyribonucleic acid. The substance in chromosomes that carries the genetic information.

Dominant
In genetics, dominant and recessive refer to the relationship of a pair of genes. In a person, there are two genes, one on each of a matching pair of chromosomes, for traits such as curly hair, eye color, or hemophilia. The genes, which come from the mother and the father, may be the same or different. If they are different, the trait which shows up and the gene directing it are said to be dominant. The gene for the trait or characteristic that does not show up is recessive. A gene for a recessive trait never shows its effect unless it joins with another recessive gene or a dominant gene is not present.

Electron Microscopy
The use of an electron microscope to see objects up to two million times larger than their actual size.

EMLA Cream
A cream that is 2.5% lidocaine and 2.5% prilocaine that is used to numb the skin. It requires a doctor's prescription.

Endometrial Ablation
A medical procedure that removes or destroys the lining of the uterus, resulting in decreased bleeding from periods.

Endothelial Cells
The cells that line the inside walls of blood vessels. Together they are called endothelium.

Epistaxis
The medical name for a nosebleed.

Estrogen
The primary sex hormone in women. Men have this hormone in their bodies also, though in much lower amounts.

Factor Concentrate
A factor protein that has been made into a powder.

Factor IX
(Factor nine.) The clotting factor protein that is decreased in people with hemophilia B.

Factor Replacement Therapy
The method in which a person with hemophilia is given, through a needle in a vein, the blood clotting factor he lacks.

Factor VIII
(Factor eight.) The clotting factor protein that is decreased in people with hemophilia A.

Fibrin
Strands of protein which weave around and through a platelet plug to form a blood clot.

Gene
The basic unit of heredity. Genes are the blueprints for the body. Each gene has a certain position on a chromosome.

Gene Modifiers
Genes that change the severity or progression of a disorder in someone with a disorder caused by a single gene. For example, someone may have the gene for a bleeding disorder but has fewer symptoms than expected because he or she has other genes that are modifying the effect of the bleeding disorder gene.

Gene Mutation
A change that alters the instructions carried by a gene, producing a baby that is unlike either parent in a certain way. This change in the gene is permanent.

Gene Therapy
An experimental technique that involves taking uanffected genes (the ones that tell the body to make clotting factor) and placing them into the body of a person with hemophilia in hopes that his body will begin to make clotting factor on its own.

Genetics
The type of science that studies heredity.

Genetic Defect
A mutation in a gene that causes it to no longer work correctly.

Glanzmann Thrombasthenia
A very rare bleeding disorder in which platelets are missing glycoprotein IIb/IIIa, so fibrinogen is not able to stick the platelets together to form a platelet plug.

Glycoprotein Ib/IX
A receptor on the surface of a platelet where von Willebrand factor normally attaches. The platelets of people with Bernard-Soulier Syndrome do not have enough glycoprotein Ib/IX. Without enough glycoprotein Ib/IX, von Willebrand factor is not able to glue the platelet to the wall of an injured blood vessel.

Glycoprotein IIb/IIIa
A receptor on the surface of a platelet where fibrinogen can attach. The fibrinogen binds platelets together (aggregation). People with Glanzmann's thrombasthenia have decreased amounts of, or abnormal, glycoprotein IIb/IIIa.

Granules
Storage spaces inside platelets that normally hold different chemicals and proteins.

Half-life
The time it takes for the factor activity level to drop by half after an infusion.

Hematologist
A doctor who specializes in disorders of the blood.

Hematoma
A swelling under the skin caused by a mass of clotted or partly clotted blood that has leaked out of a blood vessel.

Hemophilia
A life-long, hereditary blood disorder in which bleeding lasts longer than normal. It is caused by a defect in a protein needed for blood clotting.

Hemophilia Treatment Center (HTC)
A system of clinics established by the federal government to provide specialized, comprehensive care to people with inherited bleeding disorders.

Hepatitis
Inflammation of the liver, sometimes caused by a virus.

Hereditary
Passed in the genes from parent to offspring. The basic unit of heredity is the gene.

HIV
Human Immunodeficiency Virus, the virus that causes AIDS.

Hives
Red, itchy bumps on the skin caused by an allergic reaction.

HLA-matching
A way of determining the compatibility of donated blood. Blood that has been HLA-matched will not cause a reaction by the immune system of the person receiving the blood.

Home Care
A treatment program in which a person with hemophilia or a family member is taught to give factor in his or her own home.

Immune System
The body's defense network which fights harmful germs or substances.

Immune Tolerance
A way to try to reduce an inhibitor to factor by giving frequent doses over a long period.

Inflammation
The body's defensive reaction to injury or irritation. Signs of inflammation are heat, swelling, redness, and pain.

Infusion
Putting fluid other than blood into a vein.

Inhibitor
An antibody in the blood that reacts to infused factor and hinders clotting.

IV Line
Putting fluid into a vein by means of a needle passing through the skin. The needle is attached to tubing or a syringe containing the fluid.

Joint
The place where two or more bones come together.

Known Donor Pool
A way of trying to reduce the risk of infection from a blood transfusion by only using blood from people who have been identified and screened by the person receiving the blood.

Leukocyte
Another name for a white blood cell. Leukocytes are part of the immune system to defend the body against infection.

Ligament
A band of tough, thread-like tissue that supports muscles or connects bones at the joints.

Macrophage
A large scavenger blood cell which gobbles up germs, foreign matter, or other cells in the body.

Menorrhagia
Heavy and prolonged menstrual bleeding. Periods that consistently last longer than seven days with heavy bleeding.

Menstrual period
Also called menstruation or just a "period." The shedding of the lining of the uterus through the vagina. On average, it occurs every 28 days and lasts from three to five days.

Menstruation
A woman's monthly flow of blood and tissue from her uterus, often called her "period." Menstruation begins at puberty and ends at menopause.

Miscarriage
The sudden ending of a pregnancy before the fetus is able to survive outside the womb. A miscarriage is most likely to happen early in the pregnancy (during the first trimester).

Multimer
One of the parts of the von Willebrand factor protein.

Obligate Carrier
The daughter of a man with hemophilia. Since she has the affected X chromosome from her father, she must be a carrier.

Obstetrician
A doctor who specializes in pregnancy and childbirth.

Orthopedist
A doctor who treats disease, injuries, and deformities of body parts such as joints, muscles, or bones that are used in movement.

PFA-100®
A Platelet Function Analyzer, a machine that measures the closure time of a sample of blood. This is a measure of the adhesion and aggregation abilities of the platelets in the blood.

Physical Therapy
Methods used to maintain the health of, and to treat diseases of, muscles, joints, and nerves. Some of the methods used are regular exercise, water, and ice.

Placenta
In a pregnant woman, the structure that is formed inside the womb to provide nourishment to the developing infant.

Plasma
The liquid part of the blood. Plasma contains the clotting factors.

Plasmapheresis
A way of donating blood in which a unit of blood is taken from the person's arm, the liquid (plasma) portion is separated from the blood cells, and the cells are put back in the donor's body. Since only plasma is taken from the donor, the recovery time is shorter than with donating whole blood.

Platelet Aggregation Testing
A test to determine how well platelets clump together after a chemical (called an agonist) is added to a blood sample.

Platelet Count
A blood test to see how many platelets are present in the blood. In an adult, the normal count is about 150,000 to 400,000 platelets in each cubic millimeter (mm³) of blood.

Platelet Plug
A weak fix of a leaking blood vessel. It is made when platelets begin sticking to each other at the site. Platelet plug formation is part of the blood clotting process.

Prophylactic
Something that protects against or prevents disease. In hemophilia, a prophylactic treatment is factor given to prevent a bleed from happening.

PUBS
Percutaneous umbilical blood sampling. A test for birth defects done after the 20th week of pregnancy. It involves taking blood from the umbilical vein which runs from the baby to the placenta.

Recessive
In genetics, dominant and recessive refer to the relationship of a pair of genes. In a person, there are two genes, one on each of a matching pair of chromosomes, for traits such as curly hair, eye color, or hemophilia. The genes, which come from the mother and the father, may be the same or different. If they are different, the trait which shows up and the gene directing it are said to be dominant. The gene for the trait or characteristic that does not show up is recessive. A gene for a recessive trait never shows its effect unless it joins with another recessive gene or a dominant gene is not present.

Recombinant Factor Concentrate
A very pure type of factor concentrate that is not made from human blood. It is produced by certain animal cells that have been genetically altered to make human factor.

Red Blood Cells
Also called erythrocytes. The most common cells in the blood. They carry oxygen from the lungs to all parts of the body.

Ristocetin
An antibiotic that is no longer used to treat infections. It is now used to diagnosis certain bleeding disorders. In normal blood, ristocetin acts as an agonist to cause platelets to clump together (agglutination). If platelets do not clump normally when exposed to ristocetin, it can indicate a problem with the von Willebrand factor.

Secretion
The process of forming a platelet plug in which platelets release chemicals into the bloodstream. These chemicals signal other platelets to come and help cover the tear in the blood vessel.

Self-infusion
The act of giving factor to yourself with little or no outside help.

Spontaneous Bleed
A bleed that begins without an injury or any other known cause.

Sterile
Free of germs.

Stimate®
A brand name for the nasal spray form of desmopressin acetate (DDAVP).

Symptomatic Carrier
A woman who carries the gene for hemophilia and experiences bleeding problems herself.

Synovectomy
Surgery to remove part or all of an inflamed synovial membrane.

Synovitis
Inflammation or irritation of the synovial membrane.

Tendon
The tough band of tissue that attaches a muscle to a bone.

Thyroid Gland
A butterfly-shaped gland in the neck that produces hormones. It helps control metabolism - how quickly or slowly the body uses energy.

Ultrasound or Ultrasonography
A type of medical test in which sound waves are used to produce images or photographs of body organs or tissues. Ultrasound can be used on a pregnant woman to create a picture of the developing fetus.

Umbilical Cord
The cord that attaches a fetus at the navel to the placenta. Blood vessels in the umbilical cord carry oxygen and nutrients to the fetus.

Vein
Blood vessel which carries blood from any part of the body back to the heart.

Virus
A tiny particle that causes disease. Viruses take over living cells and use them to reproduce.

von Willebrand Disease (VWD)
A blood clotting disorder in which the platelets have a decreased ability to plug tears in the walls of blood vessels. It is transmitted genetically and can affect both men and women.

von Willebrand factor (VWF)
A blood protein important in the clotting process. It carries the factor VIII protein in the blood until it is needed. It also binds platelets to an injured blood vessel to stop bleeding.