Blood is a body fluid that contains plasma, cells and other nutrients that circulate through the body.
Blood is transported through the body by the circulatory system.
Blood is made up of plasma, white blood cells, red blood cells and platelets
Plasma: Plasma is made up of arround 55% of blood fluid, and is 92% water. The remaining 8% contains:
- proteins
- hormones
- glucose
- fats mineral salts
- vitamins.
Red and white blood cells and platelets mainly consist of the remaining 45%.
Red blood cells: They are the most common component of blood cells. They contains hemoglobin which is a protein that contains iron. They transport oxygen to the body tissues. They have a life span of 4 months, and the body replaces them regularly.
White blood cells: Less than 1% of blood content is made up of white blood cells. They form vital defenses against infection and disease.
Platelets(thrombocytes): They are made in our bone marrow along with white and red blood cells. They help the body to form clots to stop bleeding.
A normal platelet count is 150,000 to 450,000 platelets per microliter of blood.
Functions of blood
Blood performs various functions that are central to our survival
- Suppling oxygen to vital cells and tissues
- Protecting the body against diseases and infections
- Removing waste from the body such as urea, carbon dioxide, and lactic acid
- Regulating body temperature
Blood group
There are 4 main types of blood group (A, B, AB and O)
The antibodies and antigens in the blood determined your blood group.
- Blood group A - contains A antigens on the red blood cells with anti-B antibodies in the plasma
- Blood group B -contains B antigens with anti-A antibodies in the plasma
- Blood group O -has no antigens, but contains both anti-A and anti-B antibodies in the plasma
- Blood group AB - contains both A and B antigens, but no antibodies
The Rh System
A protein known as the RhD antigens can sometimes be present in the red blood cells. RhD positive means your red blood cells have the RhD antigen and Rhd negative means the the RhD antigen is absent in your red blood cells.
The Rh blood group system
A person can belong to 1 of the 8 blood groups according to the presence or absence of the Rh antigen.(Rh factor)
- A Rhd positive (A+)
- A RhD negative (A-)
- B RhD positive (B+)
- B RhD negative (B-)
- O RhD positive (O+)
- O RhD negative (O-)
- AB RhD positive (AB+)
- AB RhD negative (AB-)
Blood Disorders
Disorders and diseases of the blood can affect your total health.
some common blood disorders include:
- Anaemia:
- Blood clotting:
- Blood cancers
- Hemophilia
- Sickle cell disease
- Thalassemia
