Blood is a specialized body fluid that circulates through the veins, arteries, and capillaries of humans and other vertebrates. It is composed of four main components: plasma, red blood cells, white blood cells, and platelets. Plasma makes up about 55% of blood and is mostly water containing proteins, nutrients, hormones, and waste products. The remaining 45% consists of blood cells, primarily red blood cells which carry oxygen, white blood cells which fight infections, and platelets which help with blood clotting
. Blood serves several vital functions in the body:
- Transporting oxygen from the lungs to tissues and carrying carbon dioxide back to the lungs for exhalation.
- Delivering nutrients, hormones, and other essential substances to cells.
- Removing waste products to organs like the kidneys and liver for filtration.
- Regulating body temperature and maintaining pH balance.
- Protecting the body by forming clots to prevent excessive bleeding and by supporting the immune system to fight infections
Overall, blood is essential for sustaining life by ensuring cells receive what they need and by maintaining the body's internal environment
