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 Book Books," which would give insight into the minds of two characters from his Circle Series, presumably Thomas Hunter and an enemy. As time went on, the two books merged into a single book. In 2009, Ted released "Immanuel's Veins", in which a Blood Book plays a significant role. On his Facebook page, Ted Dekker posted suggesting that he would not publish "The Blood Book", but after much protest from his fans, he consented. In 2011, in an effort to promote his newest thriller novel, "The Priest's Graveyard", Ted began a campaign entitled "Share the Love". Participants had to pre-order at