What is Blood?

Blood is a bodily fluid that circulates through the body’s cardiovascular system, carrying oxygen and nutrients to the body’s cells and removing waste products. It is composed of various cell types suspended in a fluid called plasma.

The blood’s primary cell types are:

• Red blood cells (erythrocytes): These cells contain a protein called haemoglobin, which binds to oxygen and carries it to the body’s cells.
• White blood cells (leukocytes): These cells aid in the body’s defence against sickness and the battle against infections. White blood cells come in a variety of forms, such as neutrophils, lymphocytes, and monocytes.
• Platelets (thrombocytes): These cells help to stop bleeding by forming clots.

Blood also contains plasma, which is a yellowish liquid that carries nutrients, hormones, and proteins throughout the body. Plasma is made up of water, proteins, minerals, and other substances.

Blood performs many important functions in the body, including:

• Delivering nutrition and oxygen to the body’s cells
• Removing waste products, such as carbon dioxide and urea
• Regulating body temperature
• Maintaining pH balance
• Protecting against infection and disease

A person’s blood type is defined by whether or not specific proteins are present on the surface of their red blood cells. There are various different blood types. The four most prevalent blood types—A, B, AB, and O—can all be positive or negative.

In humans, blood is a freely circulating, opaque red liquid that is denser and more viscous than water. The peculiar colour is due to a unique iron-containing protein called haemoglobin.