Besides water, plasma also contains dissolved salts and minerals like calcium, sodium and magnesium and a complex mixture of proteins, vitamins and hormones. Microbe-fighting antibodies also travel to the battlefields of disease by hitching a ride in the plasma.
Without plasma, the life-giving blood cells would be left without any transportation.
Never underestimate the importance of plasma.
Red blood cells are small round cells with no nucleus. They are concave on both sides and look a bit like doughnuts!
Red blood cells make up over 99% of your blood cells.
Blood gets its red color from the protein hemoglobin within the red blood cells.
Hemoglobin enables red blood cells to transport oxygen around the body. When hemoglobin combines with oxygen, it forms a bright red compound called oxyhemoglobin. When oxygen is released, the compound darkens and becomes deoxyhemoglobin.
Hemoglobin contains the element Iron,
making it an excellent vehicle for transporting oxygen and carbon dioxide.
As blood passes through the lungs, oxygen molecules attach to the hemoglobin. As the blood passes through the body's tissue, the hemoglobin releases the oxygen to the cells. The empty hemoglobin molecules then bond with the tissue's carbon dioxide or other waste gases, transporting it away.
White blood cells, or leukocytes, play a key part in your body's defense against infection. They protect your body from disease by either phagocytizing (eating) bacteria or producing antibodies that destroy infectious particles. Though most of white blood cell activity takes place outside of the circulatory system, these cells use the blood to reach sites of infection and disease.
A drop of blood can contain anywhere from 7000 to 25,000 white blood cells at a time. If an invading infection fights back and persists, that number will significantly increase.
However a consistently high number of white blood cells is a symptom of Leukemia, a cancer of the blood. A Leukemia patient may have as many as 50,000 white blood cells in a single drop of blood.
- Platelets are irregularly shaped, colourless bodies that are present in blood.
- Platelets are fragments of cells that are tiny in comparison to red blood cells.
Platelets help repair blood vessels by sticking to damaged walls and along with other substances they coagulate (form a clot) to prevent blood escaping from the damaged blood vessel.
When bleeding from a wound suddenly occurs, the platelets gather at the wound and attempt to block the blood flow. The mineral calcium, vitamin K, and a protein called fibrinogen help the platelets form a clot.
A clot begins to form when the blood is exposed to air. The platelets sense the presence of air and begin to break apart. They react with the fibrinogen to form a mesh of blood cells that hardens as it dries, forming a clot.
A scab is an external blood clot that we can easily see, but there are also internal blood clots. A bruise, or black-and-blue mark, is the result of a blood clot. Both scabs and bruises are clots that lead to healing.
Some clots however can be extremely dangerous.
A blood clot that forms inside of a blood vessel can be deadly because it blocks the flow of blood, cutting off the supply of oxygen.
A stroke is the result of a clot in an artery of the brain. Without a steady supply of oxygen, the brain cannot function normally. If the oxygen flow is broken, paralysis, brain damage, loss of sensory perceptions, or even death may occur.
Without platelets we would bleed to death when we got a paper cut!
Red blood cells: as the name would suggest these are red coloured cells. Their red colour comes from the hemoglobin within them. They are doughnut shaped because this gives them a larger surface area, which enables them to carry more oxygen and to bend when necessary. Their hemoglobin makes blood red.
White blood cells: these cells come in different shapes and colours depending on how they go about their “job”. Some white blood cells produce antibodies and so are marginally smaller than those that eat the offending germs.