Giraffe have unusually high heart rates for their size, at 150 beats per minute. When the animal lowers its head the blood rushes down fairly unopposed and a rete mirabile in the upper neck, with its large cross sectional area, prevents excess blood flow to the brain. When it raises again, the blood vessels constrict and direct blood into the brain so the animal does not faint. The jugular veins contain several (most commonly seven) valves to prevent blood flowing back into the head from the inferior vena cava and right atrium while the head is lowered. Conversely, the blood vessels
The Blood Line to the Blessing- causing it to disperse immortality to the whole human race as a 'defence' to a perceived 'attack'-, and furthermore is simply the first part in a larger plan to assert control of the world. By stopping death and destabilizing the economy, the Families are now poised to take control of the banks, thereby influencing the world governments, eventually leading to a fascist oligarchy which can "decide who lives, how long, where, and why." When Jack moves to open his veins and release his blood into the Blessing (reasoning that his now-mortal blood would 'prompt' the Blessing to