blood

(noun)

A vital liquid flowing in the bodies of many types of animals that usually conveys nutrients and oxygen. In vertebrates, it is colored red by hemoglobin, is conveyed by arteries and veins, is pumped by the heart, and is usually generated in bone marrow.

Related Terms

Examples of blood in the following topics:

  • Transfusions of Whole Blood

    • Whole blood refers to human blood transfusion from a standard blood donation.
    • Whole blood may also be altered and processed for use in blood transfusion.
    • Historically, blood was transfused as whole blood without further processing.
    • Most blood banks now split the whole blood into two or more components, typically red blood cells and a plasma component, such as Fresh Frozen Plasma, which is extracted frozen plasma from the blood splitting process.
    • Whole blood is a term used in transfusion medicine for human blood from a standard blood donation.

  • Introduction to Blood Pressure

    • Blood pressure is a vital sign, reflecting the pressure exerted on blood vessels when blood is forced out of the heart during contraction.
    • Blood Pressure is the pressure that blood exerts on the wall of the blood vessels.
    • The pressure originates in the contraction of the heart, which forces blood out of the heart and into the blood vessels.
    • Blood pressure (BP) is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs.
    • The rate of mean blood flow depends on the resistance to flow presented by the blood vessels.

  • Diagnostic Blood Tests

    • Blood tests are laboratory analyses performed on a blood sample typically taken from a vein in the arm for diagnostic purposes.
    • Although the term blood test is used, most routine tests (except for most hematology) are done on blood plasma instead of blood cells.
    • If only a few drops of blood are needed, a fingerstick is performed instead of drawing blood from a vein.
    • Also, respiratory therapists are trained to extract arterial blood for arterial blood gases.
    • Blood tests can also be used to analyze the blood cells.

  • Blood Flow in the Brain

    • Cerebral circulation is the movement of blood through the network of blood vessels supplying the brain, providing oxygen and nutrients.
    • Cerebral circulation refers to the movement of blood through the network of blood vessels supplying the brain.
    • The arteries deliver oxygenated blood, glucose and other nutrients to the brain and the veins carry deoxygenated blood back to the heart, removing carbon dioxide, lactic acid, and other metabolic products.
    • The amount of blood that the cerebral circulation carries is known as cerebral blood flow (CBF).
    • Too little blood flow (ischemia) results in tissue death.

  • Blood Groups and Blood Types

    • Blood type determines compatibility for receiving blood transfusions from other people.
    • Therefore, an individual with type AB blood can receive blood from any group, but can only donate blood to another group AB individual.
    • Therefore, a group O individual can only receive blood from a group O individual, but they can donate blood to individuals of any ABO blood group (ie A, B, O, or AB).
    • O blood is also known as "universal donor. "
    • Blood type (or blood group) is determined, in part, by the ABO blood group antigens present on red blood cell.

  • Blood Flow in the Skin

    • Blood flow to the skin provides nutrition to skin and regulates body heat through the constriction and dilation of blood vessels.
    • The skin contains a network of small blood vessels containing muscle fibers in their tunica media.
    • When vasoconstricted blood flow through the skin is reduced and so less core heat is lost.
    • With restricted blood flow the skin appears paler.
    • With increased blood flow the skin appears red.

  • Distribution of Blood

    • Blood is circulated around the body through blood vessels by the pumping action of the heart .
    • When blood vessels dilate, the flow of blood is increased due to a decrease in vascular resistance.
    • Therefore, dilation of arterial blood vessels (mainly the arterioles) causes a decrease in blood pressure.
    • Oxygenated arterial blood (red) and deoxygenated venous blood (blue) are distributed around the body.
    • Oxygen-rich blood is shown in red; oxygen-depleted blood in blue.

  • Artificial Blood Substitutes

    • Blood substitutes are substances used to mimic the oxygen-carrying capacity of blood, providing an alternative to blood transfusion.
    • A blood substitute (also called artificial blood or blood surrogates) is a substance used to mimic and fulfill some functions of biological blood, usually in the oxygen-carrying sense.
    • It aims to provide an alternative to blood transfusion, which is transferring blood or blood-based products from one person into another.
    • Blood substitutes are useful for many reasons.
    • Blood substitutes can be stored for much longer than transfusable blood, and can be kept at room temperature.

  • Complete Blood Count

    • A complete blood count (CBC), useful in diagnosing disease, yields a count of numbers or volumes of the cell types in the blood.
    • This can be diagnosed by drawing blood to analyze the complete blood count and reticulocyte count.
    • A complete blood count (CBC), also known as full blood count (FBC), full blood exam (FBE), or blood panel, is a test panel that gives information about the cells in a patient's blood, as requested by a doctor or other medical professional.
    • Therefore, blood counts are among the most commonly-performed blood tests in medicine as they can provide an overview of a patient's general health status.
    • In the past, counting the cells in a patient's blood was performed manually by viewing a slide prepared with a sample of the patient's blood under a microscope (a blood film or peripheral smear).

  • Typing and Cross-Matching for Transfusions

    • Blood banks test donor blood to ensure recipient compatibility; this reduces the risk of a hemolytic reaction, renal failure, and death.
    • Due to the different antigen types of blood, blood must be cross-matched during processing to avoid potential complications.
    • Much of the routine work of a blood bank involves testing blood from both donors and recipients to ensure that every individual recipient is given blood that is compatible and is as safe as possible.
    • Patients should ideally receive their own blood or type-specific blood products to minimize the chance of a transfusion reaction.
    • In this image, the blood serum contains anti-A3 antibodies, which attack and agglutinate type A blood.