The Idea of an Essay, Volume 2

129 sudden narrowing that occurs in the arterial lumen about two to four centimeters below the knee. (Ostergaard et al., 2011, p. 693) This is the G-suit-like structure that giraffes contain in order to withstand the effects of hypertension. As found by dissecting the tibial arteries, Ostergaard et al. (2011) determined that the narrowing of the arterial lumen was found in the fetal giraffe as well. Indicating the giraffe is born with this feature, from the moment they stand up, they are able to adapt to the high blood pressure. The skin of the giraffe also thickens at the legs, preventing the capillaries from rupturing into the leg (Mitchel & Skinner, 2009). Without the drastic morphology of the arteries in the legs of giraffes and the increase in the thickness of the skin, the arterial pressure would be too great due to gravity, and the capillaries would burst causing blood to puddle in the hoofs (Ostergaard et al., 2011). The third and fourth mechanisms that the giraffe possesses, in order to adjust to high blood pressure, are the rete mirabile and a special, complex series of mechanisms that restore the blood in the brain after the head is lifted (Pittman, 2011). These two mechanisms prevent the opposing problems of too much blood flow to the head and too little blood flow to the head. As the giraffe bends its long neck down to get a drink of water, the amount of blood flow to the