What is in blood?

Blood is a complex fluid that contains many different components, including:

* Plasma: The liquid part of blood, which makes up about 55% of its volume. Plasma contains water, electrolytes, proteins, hormones, and waste products.

* Red blood cells: These cells carry oxygen from the lungs to the rest of the body. They make up about 45% of blood volume.

* White blood cells: These cells fight infection. They make up about 1% of blood volume.

* Platelets: These cells help to stop bleeding. They make up less than 1% of blood volume.

Blood also contains small amounts of other substances, such as lipids and gases.

The composition of blood can vary depending on a person's age, sex, health, and environment. For example, the blood of a healthy adult male will typically have a higher concentration of red blood cells than the blood of a healthy adult female.

Blood is essential for life. It provides oxygen to the body's cells, removes waste products, and helps to fight infection.