What is Blood?
Read about red blood cells, white blood cells, platelets, and plasma.
What Color is Blood
Human blood is always red. The only difference is that when it is oxygenated, it is a bright red, and when it is depleted of oxygen, it is a darker red.
What is in blood?
Circulatory Path
How Our Circulatory System and Respiratory System Work Together
Video
Blood Flow through the Heart in 2 MINUTES
Blood Flow through the Heart in 2 MINUTES