Blood and the circulatory system
Be careful with your health
Observing human blood and blood vessels
Human blood appears to be a red liquid to the naked eye, but under a microscope we can see that it contains four distinct elements: plasma, red blood cells, white blood cells and platelets.
We have learning also what are the differences between arteries and veins based on the observations under the optical microscope and the main characteristics of the capillaries in organs like the lungs or kidneys.