237 蛇的血压
P1: gravity places special demands on the cardiovascular. Terrestrial snake exhibit adaptation
P2: sea snake: regardless of the orientation in space, the distribution of the blood throughout the body remains the same. Removed from the water and heads up, blood pressure at midpoint drops significantly, brain level drop to 0. Terrestrial snakes 没有这种情况 so there has been certain adaptations
P3: Terrestrial snake’s heart is close to its head. Sea snake’s heart located in the middle of the body. 陆栖蛇尾巴血液离心脏太远的问题也被另一个adaptation解决了:when climbing, pause momentarily to wiggle their bodies, compressing the veins and forcing blood forward.