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 Awkward Yeti of "The Awkward Yeti". "Heart and Brain" features Lars' anthropomorphized heart and brain as the two main characters. In the webcomic, the heart follows its feelings and emotions, chasing down butterflies and getting excited about kittens, while the brain is concerned about adult responsibility. While the heart skips to emotional need, the brain brings in reason and logic for why the heart's action are ill-advised. Lindsey Holmes described "Heart and Brain" as "the internal tennis match we often face between our romantic hearts and our realistic brains." The characters of "Heart and Brain" are considered very relatable, as they cover