Glossary

ABO blood groups
A system for classifying human blood based on the antigenic components of red blood cells and their corresponding antibodies. The ABO blood group is identified by the presence or absence of two different antigens, A and B, on the surface of the red blood cell. The four blood types in this grouping A, B, AB, O are determined by and named for these antigens.

Acne
An inflammatory, papulopustula skin eruption occuring usually in or near the sebaceous glands of the face, neck, shoulders and upper back.

Acupuncture
A method producing analgesia or altering the function of a system of the body by inserting fine, wire-thin needles into the skin at specific sites on the body.

Acquired immunodeficiency syndrome (AIDS)
A disease involving a defect in cell-mediated immunity that has a long incubation period, follows a protracted and debilitating course, is manifested by various opportunistic infections and has a poor prognosis.

Additive solution
Specifically formulated to maintain beneficial properties of cellular components during storage.

Anaemia
Deficiency in either quality or quantity of red blood cells that can cause weakness, fatigue, pallor.

Aneurysm
A localized dilation of the wall of a blood vessel, usually caused by arterosclerosis and hypertension.

Angina
A spasmodic, cramplike choking feeling, suffocation or crushing pressure and pain in the chest, due to decreased blood supply to the heart muscle.

Antibiotic
An agent/substance that has the ability to destroy or interfere with the development of a living organism.

Antibody
A specific form of blood protein produced in the lymphoid tissue and able to counteract the effects of bacterial antigens or toxins.

Anticoagulant
A substance which prevents blood from clotting.

Antigen
Any substance, usually a protein, that causes the formation of an antibody and reacts specifically with that antibody.

Antiglobulin testing technique 
The direct antiglobulin test detects antibody or complement bound to erythrocytes.

Anti-IgA antibodies
IgG or occasionally IgM anti-IgA produced by an IgA-deficient patient. Severe anaphylactoid transfusion reactions can occur in such a patient.

Antihypertensive medication
A substance or procedure that reduces high blood pressure.

Aorta
The large artery that carries blood from the heart to the rest of the body.

Aortic aneurysm
A localized dilatation of the wall of the aorta caused by atherosclerosis, hypertension or less frequently syphillis.

Autoimmune
Pertaining to the development of an immune response to one's own tissues.

Apheresis
Method of obtaining one or more blood components by machine processing of whole blood in which the residual components of blood are returned to the donor during or at the end of the process.

Arteriole
The smallest vascular branch of the arterial circulation. Blood flowing from the heart is pumped through the arteries to the arterioles to the cappilleries into the veins and returned to the heart.

Arteriosclerosis
A common arterial disorder characterized by thickening, loss of elasticity and calcification of arterial walls, resulting in decreased blood supply.

Artery
One of the large blood vessels carrying blood in a direction away from the heart.

Asthma
A respiratory disorder charachterized by recurring episodes of paroxymal dyspnoea, wheezing on expiration/inspiration due to constriction of the bronchi, coughing and viscous mucoid bronchial secretions.

Autoimmune condition/disease
One of a large group of diseases charachterized by the subversion or alteration of the function of the immune system of the body.

Autologous donation
Blood and blood components collected from an individual, intended solely for subsequent autologous transfusion to the individual.

Autologous donors
Individuals may donate blood for their own use if the need for blood can be anticipated and a donation plan developed.

Autologous transfusion
Transfusion, in which the donor and the recipient are the same person and in which predeposited blood and blood components are used.  

Bacteria
A small unicellular microorganism.

Basophil
A granulocytic white blood cell characterized by cytoplastic granules that stain blue when exposed to a basic dye.

Beta cells
Insulin-producing cells situated in the islets of Langerhans, in the pancreas.

Bilirubin
The orange-yellow pigment of bile, formed principally by the breakdown of heamoglobin in red cells after termination of their normal lifespan.

Benign
Noncancerous and therefore not an immediate threat, even though treatment eventually may be required.

Blood
Whole blood collected from a single donor and processed either for transfusion or further manufacturing.

Blood bag
Blood component unit.

Blood bank
A n organizational unit responsible for collecting, processing and storing blood for transfusion. The blood bank is usually a subdivision of a laboratory in a hospital.

Blood circulation
The circuit of blood through the body, from the heart through the arteries, arterioles, capilleries, venules, and vein and back to the heart.

Blood clotting
The conversion of blood from a free liquid to a semisolid gel.

Blood component
Therapeutic components of blood (red cells, white cells, platelets, plasma) that can be prepared by centrifugation, filtration, and freezing using conventional blood bank methodology.

Blood donor
Anyone who donates his or her blood.

Blood drive
When the blood donation mobile unit visits a town or village, we call this event a blood drive.

Blood establishment
Any structure or body that is responsible for any aspect of the collection and testing of human blood or blood components, whatever their intended purpose, and their processing, storage and distribution when intended for transfusion. This does not include hospital blood banks.

Blood group
The classification of blood based on the presence or absence of genetically determined antigens on the surface of red cells. Several different grouping systems have been described.

Blood pressure
The pressure exerted by the circulating volume of blood on the walls of the arteties, the veins, and the chambers of the heart.

Blood product
Any therapeutic product derived from human blood or plasma.

Blood test
Any test that determines something about the characteristics or properties of the blood.

Blood transfusion
The administartion of whole blood or a blood product such as packed red blood cells, to replace blood loss due to trauma, surgery or disease.

Blood typing
Identification of genetically determined antigens on the surface of the red blood cell used to determine blood groups.

Blood vessels
Any one of the network of muscular tubes that carry blood.

Body temperature
The level of heat produced and sustained by the body processes. Variations and changes in the body temperature are major indicators of disease and other abnormalities.

Bone marrow
A specialized, soft tissue filling the spaces in cancellous bone of the epiphyses. Fatty, yellow marrow is found in the compact bone of most adult epiphyses(the head of a long bone). Red marrow is found in many bones of infants and children.

Brain tumor
An invasive neoplasm of the intracranial portion of the central nervous system.

Brucellosis
A disease caused by any several species of the gram-negative coccobacillus Brucella. Brucellosis is most prevalent in rural areas among farmers, veterinarians, meat packers, slaughterhouse workers, and live-stock producers. Primarily it is a disease of animals, humans usually acquire it by ingesting contaminated milk or milk products or through a break in the skin.

Buffy coat
Blood component prepared by centrifugation of a unit of whole blood which contains a considerable proportion of the leukocytes and platelets.

Burn
Any injury to tissues of the body caused by heat, electricity, chemicals, radiation, or gases in which the extent of the injury is determined by the amount of exposure of the cell to the agent and to the nature of the agent.

Bypass
Any one of the various surgical procedures to diver the flow of blood or other natural fluids from normal anatomic courses.

 

Cancer
A neoplasm characterized by the uncontrolled growth of anaplastic cells that tends to invade surrounding tissue and to metastasize to distant body sites. It is also any of a large group of malignant neoplastic diseases chracterized by the presence of malignant cells.

Capillary
One of the tiny blood vessles joining arterioles and venules. Through their very thin walls, blood and tissue cells exchange various substances.

Carbon dioxide
A colorless, odorless gas produced by the oxidation of carbon. It is a product of cell respiration that is carried out by the blood to the lungs and is exhaled.

Cell
The fundamental unit of all living tissue.

Centrifugation
Technique applicable for separation based on density differences between cells.

Chest pain
A physical complaint that requires immediate diagnosis and evaluation as it may be symptomatic of cardiac disease such as angina.

Chemotherapy
The treatment of infections and other diseases with chemical agents.

Chicken pox
An acute highly contageous viral disease caused by a herpes virus, varicella zozter virus. It occurs primarily in young children and is characterized by crops of pruritic vesicular eruptions on the skin.

Chlamydia
A micro-organism of the genus 'chlamydia', that lives as an intracellular parasite, has a number of properties in common with gram-negative bacteria and is currently classified as specialized bacteria.

Cholesterol
A fat-soluble crystalline steroid found in animal fats and oils and in egg yolks, and widely distributed in the body, especially in the bile, blood, brain tissue, liver, kidneys, adrenal glands and in myelin sheaths of nerve fibres. It also facilitates the absorbtion and transport of fatty acids and acts as a precursor for the synthesis of Vitamin D at the surface of the skin.

Cholesterolemia
The presence of excessive amounts of cholesterol in the blood.

Cirrhosis
A chronic degenerative disease of the liver in which the lobes are covered with fibrous tissue, the parenchyma degenartes and the lobules are infiltrated with fat.

Coagulation disorder
Also referred to as "coagulopathy" or "clotting disorder", is a bleeding disorder caused by a defect in the body's mechanism for blood clotting.

Common cold
A contageous viral infection of the upper respiratory tract.

Colonoscope
An long instrument with light and a lens that permits examination of the interior of the colon.

Colonoscopy
The examination of the mucosal lining of the colon using a colonoscope.

Counselling
The act of providing advice and guidance to a patient or the patient's family or donor and donor's family.

Creutzfeldt-Jakob Disease (CJD)
Disease is a degenerative neurological disorder (brain disorder) that is very rare, incurable and invariably fatal. There is currently no cure for CJD.

Cryoprecipitate
Plasma component prepared from fresh frozen plasma by freeze-thaw precipitation of proteins and subsequent concentration and resuspension of the precipitated proteins in a small volume of the plasma.

Cytapheresis
An apheresis procedure intended for the collection of a cellular component of blood, such as red cells, leukocytes or platelets. 

 

Electrolysis
1) A process in which electric energy causes a chemical change in a conducting medium, usually a solution;
2) method of permanently removing unwanted hair from the body performed by inserting a tiny needle into a hair follicle aid passing an electrical current..

Electrolyte
An element or compound that when melted or dissolved in water or other solvent, dissociates into ions and is able to conduct an electric current. Electrolytes differ in their concentrations in blood plasma, interstitial fluid, and cell fluid and affect the movement of substances between those compartments. An example of these: calcium is necessary for relaxation of skeletal muscles and contraction of the cardiac muscle.

Electrolyte balance
The equilibrium between electrolytes in the body.

Eosinophil
A granulocytic, leukocyte somewhat larger than a neutrophil. They increase in number with allergy.

Epileptic fits
Neurological disorder were there is an uncontrolled electric discharge from the nerve cells to the cerebral cortex.

Erythroblast
An immature form of red blood cell. It is normally found in the bone marrow.

Erythrocyte
A mature red blood cell. The cells contain heamoglobin and serve to transport oxygen.

Elective surgery
Refers to planned operation. 

 

Gallbladder
A pear-shaped excretory sac loged in a fossa on the visceral surface on the right lobe of the liver. It serves as a reservoir for bile.

Gastrointestinal tract
It is a tube about 9m long, extending from the mouth to the anus. Its various portions are the mouth, esophagus, stomach, small intestine and large intestine.

Genetic
Pertaining to genetics or heredity; inherited.

Granulocytes
Are a cathegory of white blood cells characterised by the presence of granules in their cytoplasm.

Growth hormone
A single-chain peptide secreted by the anterior pituitary gland in response to growth hormone releasing factor. Growth hormone promotes protein synthesis in all cells, increases fat metabolism, and uses fatty acids for energy, and decreases use of carbohydrates.

Gonorrhoea
A common sexually transmitted disease most often affecting the genitourinary tract and occassionally the pharynx, conjunctiva or rectum. This can be transmittted from contact with an infected person or by contact with secretions containing the causative organism.

G6PD Deficiency
An inherited condition in which the body doesn't have enough of the enzyme glucose-6-phosphate dehydrogenase (G6PD), which helps red blood cells function normally. This deficiency can cause haemolytic anaemia, usually after exposure to certain medications, food or even infections.

 

Haematocrit result
Obtained by the instrument of the volume of red cells in blood, after centrifugation, expressed as a percentage or as a ratio in the system.

Haemoglobin
The complex protein molecule contained within the red blood cells which gives them their colour and by which oxygen is transported.

Haemolysis
The breaking of red blood cells causing the release of haemoglobin into the surrounding fluid.

Heart disease
Any disorder that effects the heart's ability to function normally, influenced by hereditary lifestyle and environmental factors.

Hepatitis
An inflammatory condition of the liver, characterised by jaundice, anorexia, abdominal and gastric discomfort, abnormal liver function, clay coloured stools, tea-coloured urine.

Hepatitis A
A form of viral hepatitis caused by the hepatitis A virus (HAV), characterised by the slow onset of signs and symptoms. The virus may be spread by direct contact through faecal-contaminated food or water, via the faeco-oral route.

Hepatitis B
A form of viral hepatitis caused by the hepatitis B virus (HBV). The virus is transmitted via contaminated serum in blood transfusion, sexual contact with an infected person or by the use of contaminated needles and instruments. The infection may be severe and result in prolonged illness, destruction of liver cells, cirrhosis or death.

Hernia
Protrusion of a tissue, structure or part of an organ through the muscle tissue or the membrane by which it is normally contained.

Herpes viruses
Any of seven related viruses including herpes simplex viruses.

Hormone
A complex chemical substance produced in one part or organ of the body that initiates or regulates the activity of an organ or a group of cells in another part of the body.

Hospital blood bank
Hospital unit which stores and distributes, and may perform compatibility tests, on blood and blood components exclusively for use within the hospital facilities, including hospital based transfusion activities

Human immunodeficiency virus (HIV)
A type of retrovirus that causes AIDS. Retroviruses produce the enzyme reverse transcriptase, which allows transcription of the viral genome onto the DNA of the host cell. It is transmitted through contact with an infected individual's blood, semen, cervical secretions, cerebrospinal fluid or synovial fluid.

 

Illness
An abnormal process in which aspects of social, physical, emotional or intellectual condition and function of a person are diminished or impaired compared with the person's previous condition.

Infection
The invasion of the body by pathogenic microorganisms that reproduce and multiply, causing disease by local cellular injury.

Influenza
A highly contageous infection of the respiratory tract caused by the Influenza virus that is transmitted by airborne droplet infection.

Insulin
A naturally occuring hormone secreted by the beta cells of the islets of Langerhans in the pancreas, in response to increased levels of glucose in the blood.

Intervention
Any act perfomed to prevent harm from occuring to a patient or to improve the mental, emotional or physical function of a patient.

Islets of Langerhan
Clusters of cells within the pancreas that produce insulin, glucagon, and pancreatic polypeptide.

 

Jaundice
A yellow discoloration of the skin, mucous membrane, and sclera of the eyes, caused by greater than normal amounts of bilirubin in the blood.

 

Kidney
One of a pair of bean-shaped urinary organs in the dorsal part of the abdomen, one on each side of the vertebral coloumn. They produce and eliminate urine through a complex filtration network.

Kidney failure
See renal failure.

 

Laboratory
A facility, room or building in which scientific reasearch, tests, experiments, or other investigative activities are carried out.

Landsteiner's blood group system
The classification of blood groups A, B, AB, O on the basis of the presence or absence of two agglutinogens A and B on the erythrocyes in human blood, found by Karl Landsteiner, an American pathologist in 1868.

Leishmania
A genus of trypanosome protozoa and is reponsible for the disease Leishmanisis. It is transmitted to humans by the bite of certain species of sandflies.

Leishmanisis
Is a paracytic disease caused by the genus of trypanosome protozoa and is spread by the bite of certain species of sandflies.

Leukemia
A malignant neoplasm of blood-forming tissues characterized by diffuse replacement of bone marrow with proliferating leukocyte precursors, abnormal numbers and forms of immature white cells in the circulation, and infiltration of lymph nodes, the spleen and liver.

Leukocyte
A white blood cell, one of the formed elements circulating in the blood system. There are five types of leukocytes and these are classified by the presence or absence of granules. These are neutrophils, basophils, eoisnophils, lymphocytes and monocytes.

Leukocyte depletion
The removal of leukocytes from blood.

Liver
It is the largest gland of the body and one of its most complex organs. It has more than 500 of its functions that have been identified.

Liver failure
A condition in which the liver fails to fulfill its function or is unable to meet the demands made on it.

Lung
One of a pair of light, spongy organs in the thorax, constituting the main component of the repiratory system. The two highly elastic lungs are the main mechanism in the human body for inspiring air from which oxygen is extracted for the arterial blood system and for exhaling carbon dioxide, from the venous system.

Lymphocyte
These are small, agranulocytic leukocytes, originating from fetal stem cells and developing in the bone marrow. They comprise 25% of white blood cells but they increase in number in response to infection.

Malaria
A serious infectious illness caused by one or more of at least four species of the protozoan genus Plasmodium. This is characterized by chills, fever, aneamia, an enlarged spleen and a tendency to recur. The disease is transmitted from human to human by a bite from an infected mosquito. It can also be spread by blood transfusion.

Malignant
Tending to become worse and cause death; describing a cancer.

Measels
An acute highly contageous, viral disease involving the respiratoty tract characterized by a spreading rash that occurs primarily in young children who have not been immunized. Measels can be transmitted by direct contact with droplet spread from the nose, throat or mouth of infected people.

Menstruation
The periodic discharge through the vagina of a bloody secretion contaning tissues and debris from the shedding of the edometrium from the non pregnant uterus.

Microorganism
Any tiny, usually microscopic, entity capable of carrying on living processes. It may be pathogenic. Some kinds of microorganisms include bacteria, viruses and protozoa.

Minor surgery
Any surgical procedure that does not require general anaesthesia or respiratory assistance.

Miscarriage
A termination of pregnancy before the twentieth week of gestation as a result of abnormalities of the conceptus or maternal environment. Also called spontaneous abortion.

Monoblast
An immature monocyte. Increase in production of monoblasts in the bone marrow and the presence of these forms in the peripheral circulation are found in certain leukemias.

Monocyte
A large mononuclear leukocyte with an ovial or kidney-shaped nucleus.

Mucous membrane
Any one of four major sheets of tissue that cover or line various parts of the body that open to the outside such as the lining of the mouth.

Myloblast
One of the earliest precursors of the granulocytic leukocytes. When seen on a stained blood smear through a microscope, the cytoplasm appears light blue, scanty and nongranular.

 

Nasal allergies
Allergies that pertain to the nose or nasal cavity.

Neoplasm
Any abnormal growth of new tissue, benign or malignant.

Neutrophil
A granular leukocyte that stains easily with neutral dyes. The nucleus stains dark blue.

Nucleus
The central controlling body within a living cell.

Nutrient
A substance that provides nourishment and affects the nutritive and metabolic processes of the body.

Newborn
A recently born baby/infant.

 

Obstetrician
A physician who specializes in obstetrics.

Obstetrics
The branch of medicine that is concerned with pregnancy and childbirth including the study of the physiology and pathology of the female reproductive tract.

Organ
A structural part of a system of the body that is composed of tissues and cells that enable it to perform a particular function, such as the liver, spleen, kidneys etc.

Organ transplant
The transfering of an organ from one person to another to replace a diseased structure, or to restore function.


Oxygen
A tasteless, oderless, colorless gas essential for human respiration. 

 

Rabies
An acute usually fatal, viral disease of the central nervous system of animals. It is transmitted from animals to people by infected blood, tissue or most commonly, saliva.

Rat typhus
Also known as murine typhus. An acute arbovirus infection caused by Rickettsia typhi and transmitted by the bite of an infected flea. The disease is similar to epidemic typhus but less severe. It is characterised by headache, chills, fever, myalgia and rash.

Reaction
A response in opposition to a substance, treatment, or other stimulus, such as antigen-antibody reaction in immunology, a hypersensitivity rection in allergy, or an adverse reaction in pharmacology.

Recruitment
Refers to the process of screening and selecting qualified people for a job at an organization or firm, example donor recruitment for blood donation.

Red cells
A component obtained from single whole blood donation by removal of part of the plasma, without further processing.

Red cells, leukocyte-depleted
A component obtained by removing the majority of leukocytes from red cells.

Regular donor
Someone who routinely donates their blood or plasma (i.e. within the last two years), in accordance with minimum time intervals, in the same donation centre.

Renal failure
The inability of the kidneys to excrete wastes, concentrate urine, and conserve electrolytes.

Rh factor
An antigenic substance present in the erythrocytes of 85% of the people. A person having the factor is Rh+ (Rh positive), a person lacking the factor is Rh- (Rh negative). If an Rh - recieves Rh+ blood, hemolysis and aneamia occur. Rh+ in infants may be exposed to antibodies to the factor produced in the Rh- mother's blood resulting in red cell destruction and a condition called Erytroblastosis Fetalis. Transfusion, blood-typing and cross matching depend on Rh+ and ABO classification.

Rh Immunoglobulin
Rh immunoglobulin specific for D is given routinely to Rh-negative mothers bearing Rh-positive infants to protect them from red cell exposure during pregnancy and delivery, and so prevent alloimmunisation (Anti-D).

Repeat donor
Someone who has donated before but not within the last two years in the same donation centre.

Rubella
A contageous viral disease characterised by fever, symptopms of mild upper respiratory tract infection, lymph node enlargement, arthralagia, and a diffuse, fine, red, maculopapular rash. The virus is spread by droplet infection, and the incubation time is from 12 to 23 days. This is also called German measels.

 

Scald
A burn caused by exposure of the skin to hot liquid or vapour.

Sebaceous gland
One of the many small sacculated organs in the dermis. They are located throughout the body in close association with all types of body hair but are especially abundant in the scalp, the face, the anus, the nose, the mouth and the external ear.

Serious adverse reaction
Unintended response in a donor or in a patient, associated with the collection or transfusion of blood or blood components that is fatal, life-threatening, disabling, incapacitating, or which results in, or prolongs, hospitalization or morbidity.

Serum
This is also called blood serum. The clear thin and sticky fluid portion of the blood that remains after coagulation. Serum contains no blood cells, platelets or fibrinogen.

Sickle cell
An abnormal crescent-shaped red blood cell containing hemoglobin.

Sexual transmitted disease (STD)
A contageous disease usually aquired by sexual intercourse or genital contact. May also be called venereal disease.

Sore throat
Any inflammation of the larynx, pharynx or tonsils.

Spleen
A soft, highly vascular, roughly ovoid organ situated betweeen the stomach and the diaphragm in the left upper part of the abdomen. It is considered as part of the lymphatic system because it contains lymphatic nodules. It has a dark purple colour and varies in shape in different individuals and within the same individual at different times. There has been lots of studies regarding its function but the most recent research indicates that it perfoms various tasks such as defense, hemopoeisis, blood storage, and the destruction of red blood cells and platelets.

Splenectomy
Is the surgical removal of the spleen.

Substance
Any drug, chemical or biological entity, any material that is capable of being self-administered or abused because of its physiologic or psychologic effects.

Surgery
The branch of medicine concerened with disease and trauma requiring operative methods.

Surgeon
A medical professional who is trained to perform operations and taking care of the patient before and after operations.

Symptom
A subjective indication of a disease or a change in condition as perceived by the patient.

Syphilis
A sexually transmitted disease caused by the spirochete, Treponema pallidum, characterised by distinct stages of effects over a period of years. Any organ system may become involved.. It is also capable of passing through the human placenta, producing congenital syphillis.

 

Thalassemia
A hemolytic hemoglobinopathy aneamia characterised by microcytic, hypochromic and short-lived red blood cells caused by deficient hemoglobin synthesis. Mediterranean people are often more affected than others.

Thrombocyte
A blood platelet, essential for the clotting of shed blood.

Thrombocytopenia
A reduction in the number of platelets in the blood; bleeding may occur.

Thrombotic thrombocytopenic purpura (TTP)
First described by Moschowitz, this syndrome associates the classical pentad of clinical findings:
1) fever;
2) thrombocytopenia;
3) microangiopathic haemolytic anameia;
4) neurological abnormalities, and
5) renal involvement.

Trauma
From the Greek 'wound'. May be physical or psychological.

Treatment
A method of combating or preventing disease, disorder or injury.

Triglyceride
A compound consisting of a fatty acid and glycerol. These make up most of the vegetable and animal fats and are the principal lipids in the blood, where they circulate, bound to a protein, forming high- and low- density lipoproteins.

Trypanosoma
A genus of parisitic organisms, several species of which can cause significant diseases in humans. Most Trypanosoma organisms live part of their life cycle in insects and are transmitted to humans by insect bites.

Trypanosomiasis
An infection by an organism of the Trypanosoma genus.

 

Universal donor
A person with type O, Rh factor negative (O-) red blood cells. Packed red blood cells of this type may be used for emergency transfusion with minimal risk of incompatibility.

Universal recipient
A person with blood type AB, Rh factor positive (AB+), who can recieve a transfusion of blood of any group type without agglutination or precipitation effects.

 

Vaccine
A suspension of attenuated or killed microorganisms, such as bacteria, viruses, or rickettsia, administered to induce immunity or to reduce the effects of associated infectious diseases.

Varicella
See Chicken pox

Varicella-zoster virus (VZV)
A member of the herpes virus family, which causes the diseases varicella (chicken pox) and herpes zoster (shingles). The virus may be spread by direct contact or droplets. Thus it is highly contageous.

Vein
One of the many vessels that convey blood from capilleries to the heart as part of the pulmonary venous system, the systemic venous network or the portal venous complex.

Venous blood
Dark red blood that has been deoxygenated during passage from the left ventricle through the systemic circulation, en route to the right atrium.

Ventricle
A small cavity, such as the right and left ventricles of the heart, the ventricular system in the brain or the ventricle in the larynx.

Venule
Any one of the small blood vessels that gather blood from the capillery plexus and anastomose to form the veins.

Viral infection
Any of the diseases caused by one of approximately 200 viruses pathogenic to humans. Some are the most communicable and dangerous diseases known, while some are milder pass virtually unoticed.

Virus
A minute parasitic microorganism much smaller than the bacterium that having no independent metabolic activity, may replicate only within a cell of a living plant or an animal host.

 

Wheeze
A continous, coarse, whistling sound produced in the respiratory airways during inspiration or expiration. It is caused by a high-velocity flow of air through a narrowed airway. Wheezing is associated with asthma and chronic bronchitis.

White blood cells
See leukocyte

Whole blood
Single unprocessed blood donation.