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
My Heart Bleeds the Darkest Blood gonna be gray. And it's gonna last you for the rest of your life." in Groundhog Day. (1993) The lyric, "A rock feels no pain," is inspired by Simon & Garfunkel's 1965 song, "I Am A Rock." A music video was made for the song in 1997. Brian Fair of Overcast & Shadows Fall and Jerry Villarroel of Morning Again made an appearance in the video. My Heart Bleeds the Darkest Blood "My Heart Bleeds the Darkest Blood" is a song from the hardcore punk band Shai Hulud from their debut album "Hearts Once Nourished with Hope and Compassion". It