What is Blood?
Blood is a combination of plasma and cells that circulates throughout the body. This fluid supplies essential substances, such as sugar, oxygen, and hormones, to cells and organs throughout the body.
Another function of blood is to transport waste and chemical substances resulting from the metabolism from body cells. Not only that, blood also acts as a defense against viruses or bacteria that can cause various serious health problems.
Blood consists of two parts, namely liquid and solid. The liquid half of blood is called plasma which is made of a mixture of water, protein, and salt. While the solid part is made of white blood cells, red blood cells, and platelets.
All of these cells are continuously produced by the bone marrow to replace old cells that die. Red blood cells can survive for 120 days, white blood cells only live for one day, while platelets last up to six days.
Blood Type
A person’s blood type is determined by antigens on red blood cells. Antigens are protein molecules that reside on the surface of cells.
Blood also contains antibodies, which are proteins in the plasma that alert the immune system to the presence of potentially harmful foreign substances.
Knowing your blood type is very important if someone wants to receive or donate blood.
This is because antibodies will attack new blood cells if the blood type is wrong, causing life-threatening complications.
For example, anti-A antibodies will attack cells that have antigen A. Each blood type can also have positive or negative rhesus. Well, here are the types of blood types and their rhesus:
- Type A positive or A negative: Has antigen A on the surface of blood cells and anti-B antibodies in the plasma.
- Type B positive or B negative: Has B antigen on the surface of blood cells and anti-A antibodies in the plasma.
- AB positive or AB negative blood group: Has A and B antigens on the surface of blood cells but no antibodies in the plasma.
- Type O positive and O negative: No antigens on the surface of blood cells. Both anti-B and anti-A antibodies are present in the plasma.
People with blood type O can donate to almost any blood type, and people with blood type AB+ can usually receive blood from any type.
It is important to check your blood type first before accepting a donor or donating blood.
Blood type is also very important during pregnancy. Because a mother who has rhesus negative but the fetus inherits rhesus positive can affect the safety of the fetus.
Treatment is needed to prevent a condition known as hemolytic disease of the newborn.
Blood Function
Blood has various functions that are important for survival. Here are the important functions that blood performs:
- Supplying oxygen to cells and tissues.
- Provides essential nutrients for cells, such as amino acids, fatty acids, and glucose.
- Excretes waste, such as carbon dioxide, urea, and lactic acid.
- Protects the body from disease, infection, and foreign objects.
- Regulates body temperature.
- Stops bleeding and forms a scab to protect the wound from infection.
Blood Structure
The main components of blood consist of plasma, red blood cells, white blood cells, and platelets. Here are the contents and functions of each blood component:
1. Plasma
55 percent of human blood fluid is plasma. This component is made up of 92 percent water and the remaining 8 percent is glucose, hormones, proteins, mineral salts, fats, and vitamins.
Most of the water contained in blood plasma is obtained from food and fluids digested by the intestines. Well, the other 45 percent of blood content consists of red and white blood cells and platelets. Each has an important role in maintaining blood function.
2. Red Blood Cells (Erythrocytes)
Red blood cells are disc-shaped cells that are slightly indented. They carry oxygen to and from the lungs. This type of blood cell contains hemoglobin, a type of protein that contains iron and carries oxygen to its destination.
The lifespan of red blood cells is 4 months and the bone marrow produces them regularly to replace cells that have died.
You need to know that the human body is capable of producing about 2 million blood cells every second. Normally, one drop (microliter) of blood contains 4.5-6.2 million red blood cells in men and 4.0-5.2 million in women.
3. White Blood Cells (Leukocytes)
White blood cells make up less than 1 percent of the blood. Although they are the smallest in number, they play an important role in fighting disease and infection.
The number of white blood cells in one microliter of blood normally ranges from 3,700 to 10,500. Higher or lower levels of white blood cells can indicate disease.
4. Platelets
Platelets interact with clotting proteins to prevent or stop bleeding. A microliter of blood normally contains 150,000-400,000 platelets.
Blood Test
A blood test or blood test is used to measure or examine cells, chemicals, proteins, or other substances in the blood. Blood tests are also often performed as part of a routine examination.
Through blood tests, doctors can diagnose diseases, monitor diseases, and find the right type of treatment.
In addition, blood tests are also useful for identifying how well the body’s organs are working, such as the liver, kidneys, heart, and thyroid.
Blood tests also help doctors determine if the immune system is having trouble fighting off infections. Here are the types of blood tests you need to know about:
- Complete blood count (CBC). This test measures various parts of the blood, including red and white blood cells, platelets, and hemoglobin. A complete blood count is often included as part of a routine exam.
- Basic metabolic panel. This is a group of tests that measure certain chemicals in the blood, including glucose, calcium, and electrolytes.
- Blood enzyme tests. Enzymes are substances that control chemical reactions in the body. There are many different types of blood enzyme tests. Some of the most common are troponin and creatine kinase tests. These tests are used to find out if someone has had a heart attack and/or if the heart muscle is damaged.
- Blood tests to check for heart disease. These include cholesterol tests and triglyceride tests.
- Blood clotting tests or coagulation panels. These tests can show whether a person has a disorder that causes too much bleeding or too much clotting.
Blood Disorders
Blood disorders and diseases can disrupt the function of the blood and organs in the body. Some common blood disorders are:
- Anemia. This disease occurs when the level of red blood cells or hemoglobin is low so that the cells do not carry enough oxygen. Symptoms of anemia include fatigue, pale skin, and others.
- Blood clots. Clotting helps wounds and injuries heal, but blood clots that form in blood vessels can create blockages. These blockages can be life-threatening. If a clot breaks free and travels from the heart to the lungs, a pulmonary embolism can occur.
- Blood cancers. Cancers such as leukemia, myeloma, and lymphoma occur when blood cells begin to divide uncontrollably without dying at the end of their life cycle.
- Hemophilia. This condition occurs when a person has low levels of blood clotting factors. As a result, people with hemophilia bruise easily or bleed easily.
- Sickle cell disease. This disease is inherited. Sickle cell disease is characterized by red blood cells that are crescent-shaped.
- Thalassemia. This condition is also an inherited disease in which the body produces an unusual form of hemoglobin.
