Resources | Subject Notes | Biology
Blood is a fluid connective tissue that transports various substances throughout the human body. It is composed of several key components, each with specific functions.
Blood can be divided into four main components:
Red blood cells are the most abundant cells in blood. They are responsible for transporting oxygen from the lungs to the body's tissues and carrying carbon dioxide back to the lungs.
| Characteristic | Value |
|---|---|
| Shape | Biconcave disc |
| Nucleus | Absent (in mature cells) |
| Function | Oxygen and carbon dioxide transport |
| Contain | Haemoglobin (for oxygen binding) |
White blood cells are part of the immune system and defend the body against infection and disease. There are different types of white blood cells, each with a specific role.
Types of white blood cells include:
Platelets are small, cell fragments produced by the bone marrow. They play a crucial role in blood clotting, helping to stop bleeding.
| Characteristic | Value |
|---|---|
| Origin | Bone marrow (from megakaryocytes) |
| Function | Blood clotting |
| Shape | Small, irregular fragments |
Plasma is the liquid component of blood, making up about 55% of its volume. It is a yellowish fluid that contains water, proteins, salts, glucose, amino acids, urea, and hormones. Plasma transports blood cells, nutrients, and waste products.
| Component | Main Function |
|---|---|
| Red Blood Cells | Oxygen and carbon dioxide transport |
| White Blood Cells | Immune defence |
| Platelets | Blood clotting |
| Plasma | Transport of blood cells, nutrients, and waste products |