Blood Types

Blood types are how doctors figure out what kind of blood you have. There are four main blood types: A, B, AB, and O. Each type can be either positive (+) or negative (-). The "+" or "-" tells if your blood has something called Rh factor, a special protein. For example, if your blood type is A+, it means you have type A blood and also the Rh protein. If it's A-, you have type A blood, but no Rh protein. People with type O- blood are called "universal donors" because their blood can be given to anyone. Type AB+ blood is called the "universal receiver" because people with AB+ blood can get blood from any type. Knowing your blood type is important, especially if you ever need a blood transfusion.

Blood Cells

Blood is made up of three main types of cells: red blood cells, white blood cells, and platelets. Red blood cells make up most of the blood, about 45%. These cells carry oxygen from your lungs to the rest of your body. White blood cells are much fewer, around 1%, but they help protect you from infections by fighting germs. Platelets are even smaller, making up less than 1%, and they help your blood clot when you get a cut, so you don’t bleed too much. The most important blood cells depend on what your body needs. Red blood cells are really important because they give your body energy by carrying oxygen, while white blood cells are important for keeping you healthy by fighting off sickness.

Circulatory System

The circulatory system is the system in your body that moves blood around. It includes your heart, blood vessels, and blood. The heart is like a pump that sends blood through your body. Arteries carry oxygen-rich blood away from the heart to your body, and veins bring oxygen-poor blood back to the heart. Tiny blood vessels called capillaries connect arteries and veins and allow oxygen and nutrients to pass to your cells. Blood flows in a circle, starting at the heart, moving to the lungs to get oxygen, and then traveling to the rest of the body. This system helps keep your body working by delivering oxygen and nutrients and getting rid of waste.