BIO 121 Lecture Notes - Lecture 20: Surface Tension, Venule, Fetal Hemoglobin
24 Jul 2020
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Document Summary
Internal circulatory system distributes blood throughout gill & body. Gills made of discs (lamellae: in lamellae network of capillaries that are v. close to the surface + increases. Staggered closing b/n mouth & operculum acts as a pump to move water uni- directional flow of water. Have specialised accessory breathing organs that they use in addition to/instead of gills when breathing air. Ventilation sys req to move air in/out of lungs. Invaginated internalised extension of body surface highly folded increase tsa for gas exchange. Trachea bronchi bronchioles alveoli. Arterioles coming in from heart are poor in o2 ; arterioles leaving from pulmonary venule rich in o2. Alveolar wall is v. thin small diffusion distance that gases can pass across (increase efficiency) Some epithelial cells prod sticky mucus that captures foreign particles. Other cells have cilia (hair-like projection) constantly beating & pushes mucus back up to throat/mouth.
