Saturday 24 December 2022

How does blood work, and what problems can occur?


Blood is a combination of plasma and cells that circulate through the body. It supplies essential substances, such as sugars, oxygen, and hormones, to cells and organs, and removes waste from cells.

Hematologists work to identify and prevent blood and bone marrow diseases. They also study and treat the immune system, blood clotting, and blood vessels.

Health conditions that affect the blood can be life threatening, but effective treatment is often available. In the United States, blood diseases accounted for 10,066Trusted Source deaths in 2008, mostly different types of anemia.

Plasma

Red blood cells, or erythrocytes

White blood cells, or leukocytes

Platelets, or thrombocytes

A person’s blood type is determined by the antigens on the red blood cells. Antigens are protein molecules on the surface of these cells.

Antibodies are proteins in plasma that alert the immune system to the presence of potentially harmful foreign substances. The immune system protects the body from the threat of disease or infection.

Knowing a person’s blood type is essential if they are receiving an organ donation or blood transfusion. Antibodies will attack new blood cells if the blood is the wrong type, leading to life threatening complications. For example, anti-A antibodies will attack cells that have A antigens.

Red blood cells sometimes contain another antigen called RhD. Doctors also note this as part of the blood group. A positive blood group means that RhD is present.

Humans can have one of four main blood groups. Each of these groups can be Rhd-positive or -negative, forming eight main categories.

  • Group A positive or A negative: A antigens are present on the surfaces of blood cells. Anti-B antibodies are present in the plasma.
  • Group B positive or B negative: B antigens are present on the surfaces of blood cells. Anti-A antibodies are present in the plasma.
  • Group AB positive or AB negative: A and B antigens are present on the surfaces of blood cells. There are no antibodies in the plasma.
  • Group O positive and O negative: There are no antigens on the surfaces of blood cells. Both anti-B and anti-A antibodies are present in the plasma.

People with group O blood can donate to virtually any blood type, and people with group AB+ blood can usually receive blood from any group.

People can talk with their doctor to find out their blood type or find out by donating blood.

Blood groups are important during pregnancy. If a pregnant person has RhD-negative blood, for example, but the fetus inherits RhD-positive blood, treatment will be necessary to preventTrusted Source a condition known as hemolytic disease of the newborn.

Disorders and diseases of the blood can impair the many functions that blood performs.

Some common blood disorders are:

  • Anemia: This happens when low red blood cell or hemoglobin levelsTrusted Source mean the cells do not transport oxygen effectively, leading to fatigue, pale skin, and other symptoms.
  • Blood clotting: Clotting helps wounds and injuries heal, but blood clots that form inside a blood vessel can create a blockage, which can be life threatening. If clots become dislodged and move through the heart to the lungs, a pulmonary embolism can form.
  • Blood cancers: Cancers such as leukemia, myeloma, and lymphoma occur when blood cells start to divide uncontrollably without dying off at the end of their life cycle.
  • Hemophilia: If a person has low levels of clotting factors in the blood, they can bruise or bleedTrusted Source very easily. They may bleed for too long after a minor injury or surgery, or during menstruation. It affects around 18,000 peopleTrusted Source in the U.S.
  • Sickle cell disease: An inherited trait causes red blood cells to take on a crescent shape. It affects over 100,000Trusted Source people in the U.S., mostly Black Americans. It can severely impact how blood functions and can be life threatening.
  • Thalassemia: This is also a type of inherited anemia in which the body produces an unusual form of hemoglobin. It affected around 1,000Trusted Source people in the U.S. in 2008 and is most common in people from around the Mediterranean and parts of Asia.

If symptoms suggest a person may have a blood disorder, they should seek medical advice. A doctor may refer them to a specialist in blood disorders, known as a hematologist.

Learn more here about different blood disorders.

Blood is essential for maintaining the health and life of the human body. It has many functions, including delivering nutrients and oxygen. The four main components of blood are red blood cells, white blood cells, plasma, and platelets.

Problems that arise due to illness or blood loss can be life threatening, but effective treatment is available for many blood-related disorders.

Source - Medical News Today

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