Biology 2601A/B Lecture Notes - Lecture 20: Pericardial Sinus, Carolina Anole, Pulmonary Circulation
10 Dec 2016
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William harvey (1628) wrote a manuscript about how blood moves around the. When the body is cut, it bleeds oozes and spurts body in a circuit (cid:523)circulates(cid:524) but capillaries weren"t seen. We have a closed circulatory system aorta system connected to vena cava system. Mechanical view: pressure (heart), fluid (blood), tubes (vessels) & or spaces. Functional view: rapid transportation, o2/co2/nutrients/wastes/hormones/heat, source of hydraulic pressure (for kidney) You could have no system (sponges), an open system (lobster), or a closed (us) Tunicates and amphioxus only have a single layer of contracting vessels. Lamprey, zebrafish, medaka, freshpuffer and pufferfish evolved to have two chambered hearts. Clawed frog and green anole evolved to have three chambered hearts. Chicken, opossum, mouse and human have four chambered. Once you get beyond 1mm, you need another way besides diffusion to get: diffusion surfaces must be thin for oxygen to be delivered quickly. Breathing pulmonary o2 diffusion circulatory o2 delivery tissue.
