Ferritin and hemosiderin are necessary because:

Physical activity raises heart rate, which in turn:

Erythropoiesis is stimulated by:

Action potentials conducted through the atrial wall lead to:

B-cells and T-cells:

In order to coagulate blood:

Vasodilation will:

Action potentials conducted through Purkinje fibers cause:

Transferrin is necessary because:

How does increased respiratory membrane thickness affect gas exchange?