Blood Composition and Functions: A Comprehensive Look

Blood Composition and Functions

Cells live immersed in a medium that provides them with all the nutrients they need. They also secrete the waste products released during metabolism into this medium. In multicellular organisms like humans, this medium is called the internal milieu and is made up of the interstitial plasma, a fluid found in the space between the cells. The interstitial plasma is renewed thanks to the blood, which continuously circulates around the whole body, providing nutrients and taking away waste products.

What is Blood?

Blood is a viscous fluid with a salty taste that flows inside the vessels that make up the circulatory system.

Blood Components

Blood is made up of cells suspended in a liquid called blood plasma.

• Blood plasma is a yellowish substance made up of water containing various dissolved molecules: mineral salts, nutrients, waste products, proteins, and hormones.

Types of Blood Cells

1. Erythrocytes or red blood cells:
   • Most common type of blood cell.
   • Disk-shaped and have no nucleus.
   • Contain hemoglobin, a red pigment responsible for the blood's red color, which transports oxygen from the alveoli of the lungs to the rest of the body's cells.
2. Leukocytes or white blood cells:
   • Different types exist.
   • Help to protect the body from infection and eliminate cell debris.
3. Thrombocytes or platelets:
   • These fragments contain substances that allow the blood to clot, preventing hemorrhage.

Blood Cell Production

Blood cells are produced in the bone marrow, which is found inside certain bones. Some leukocytes mature in the lymph nodes.

Functions of Blood

1. Transports nutrients and oxygen to all cells.
2. Collects waste products released during cell metabolism.
3. Transports hormones that control body functions.
4. Helps to regulate body temperature.
5. Plays an essential role in protecting the body from infections.
6. The body uses a number of mechanisms to prevent blood loss when a blood vessel is broken.

Blood Groups

People have different types of blood. The membranes of red blood cells contain different proteins. These are responsible for different blood types. The most well-known blood group system is the ABO system. This is made up of four blood groups: A, B, AB, and O. Because each blood group contains different proteins, mixing blood groups needs to be done very carefully.