Blood

Blood is the fluid which circulates throughout the body carrying nourishment and oxygen to the cells and tissue, and at the same time takes away waste matter and carbon dioxide. It is made up of plasma, red blood cells (erythrocytes), white blood cells (leukocytes), and platelets. Blood circulates through the body's heart, arteries, veins, and capillaries, which jointly comprise the circulatory system.

Several times in the Old Testament blood is referred to as being, or containing, the life of a creature.

But be sure you do not eat the blood, because the blood is the life, and you must not eat the life with the meat. Deuteronomy 12:23

Another mention is Leviticus 17:11 .

Composition

Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte.

Blood is composed of a liquid called plasma and cellular elements, including leukocytes (white blood cells), thrombocytes (platelets), and erythrocytes (red blood cells). The normal adult has approximately six liters of blood and comprises about 7% to 8% of the total body weight. Plasma makes up approximately 55% of the blood volume, the erythrocytes makes up about 45% of the volume, and about 1% of the volume is composed of leukocytes and thrombocytes.

Plasma is a portion of the blood, which is a straw colored clear type of liquid. This liquid is comprised largely of water in which dissolved ions, proteins, carbohydrates, fats, hormones, vitamins, and enzymes are suspended and circulate throughout the body. The platelets, which help with blood clotting are carried by the plasma. Without platelets one could bleed to death from common injuries. It is the river of life and provides transport for oxygen from the lungs to the body tissue and carbon dioxide from the body tissue to the lungs.

Erythrocytes

Main Article: Red blood cells

Red blood cells (also known as erythrocytes) are cells in the blood that carry oxygen to all parts of the body. They are made in the spongy marrow inside the large bones of the body. Bone marrow constantly makes new red blood cells to replace old ones. Normal red blood cells last about 120 days in the bloodstream and then die. Their main role is to carry oxygen, but they also remove carbon dioxide (a waste product) from cells and carry it to the lungs to be exhaled.

Leukocytes

Main Article: White blood cells

White blood cells are the type of blood cells that fight infection in the body by seeking-out and destroying disease-causing microorganisms. Also known as leukocytes, the white blood cells are responsible for maintaining the immune system’s response to foreign substances and infection. They play a number of roles in immune response, including antibody production, attacking and destroying cancer cells, and producing substances that kill tumors. They are divided into many different categories on the basis of their functions and appearance.

Thrombocytes

Main Article: Hemostasis

Thrombocytes, or platelets, are not complete cells, but are small fragments of very large cells called megakaryocytes. Megakaryocytes develop from hemocytoblasts in the red bone marrow. Thrombocytes become sticky and clump together to form platelet plugs that close breaks and tears in blood vessels. They also initiate the formation of blood clots.

Blood type

There are four basic blood types, and they are O, A, B, and AB. We know that our blood type is determined by the "alleles" that we inherit from our parents. For the blood type gene, there are three basic blood type alleles: A, B, and O. We all have two alleles, one inherited from each parent. The possible combinations of the three alleles are OO, AO, BO, AB, AA, and BB. Blood types A and B are "co-dominant" alleles, whereas O is "recessive". A codominant allele is apparent even if only one is present; a recessive allele is apparent only if two recessive alleles are present. Because blood type O is recessive, it is not apparent if the person inherits an A or B allele along with it.

So, the possible allele combinations result in a particular blood type in this way:

• OO = blood type O
• AO = blood type A
• BO = blood type B
• AB = blood type AB
• AA = blood type A
• BB = blood type B

You can see that a person with blood type B may have a B and an O allele, or they may have two B alleles. If both parents are blood type B and both have a B and a recessive O, then their children will either be BB, BO, or OO. If the child is BB or BO, they have blood type B. If the child is OO, he or she will have blood type O.

Disease

High Blood Pressure

High blood pressure (also called hypertension) is a serious illness that affects nearly 65 million adults in the United States. It can cause life-threatening illnesses like kidney problems, stroke, heart failure, blindness, and heart attacks. It is often called a "silent killer" because many people have it but don't know it. Over time, people who do not get treated for high blood pressure can get very sick or even die.

Anemia

Anemia (uh-NEE-me-uh) is a condition in which a person’s blood has a lower than normal number of red blood cells, or the red blood cells don’t have enough hemoglobin (HEE-muh-glow-bin). Hemoglobin is an iron-rich protein that gives blood its red color and carries oxygen from the lungs to the rest of the body.

In sickle cell anemia, a genetic disorder causes a lower-than-normal number of red blood cells occurs because sickle cells don’t last very long. Sickle cells die faster than normal red blood cells, usually after only about 10 to 20 days. The bone marrow can’t make new red blood cells fast enough to replace the dying ones. The result is anemia.

Sickle cell anemia

Misshapen red blood cells characteristic of sickle cell anemia.

Main Article: Sickle cell anemia

Sickle cell anemia is a serious circulatory system disorder affecting the integrity of red blood cells. Its name is derived from the shape of the cells, which become round and flat resembling a sickle.[1]

Normal red blood cells are smooth and round and move easily through blood vessels to carry oxygen to all parts of the body. Sickle-shaped cells don’t move easily through blood because they’re stiff and sticky and tend to form clumps and get stuck in blood vessels. The clumps of sickle cells block blood flow in the blood vessels that lead to the limbs and organs. Blocked blood vessels can cause pain, serious infections, and organ damage.

Bloodborne pathogens

A number of microorganisms can be found in blood that cause disease (pathogenic). In humans, these pathogens include, hepatitis and human immunodeficiency virus (HIV).

References

• Blood by Wikipedia
• "Blood" Encyclopedia Britannica 2007 Ultimate Reference Suite
• Textbook of Hematology, second edition, c. 1996, Shirlyn B. McKenzie

See Also

• Blood clotting
• Blood clotting is irreducibly complex Response to Talk.Origins
• Moses reveals that blood is the essence of life Response to Talk.Origins