(Zhao Kouwu) The following figure is a schematic diagram of human blood circulation, in which 1234 represents each ventricle of the heart. Please answer the questions according to the pictures: (5 poi

(Zhao Kouwu) The following figure is a schematic diagram of human blood circulation, in which 1234 represents each ventricle of the heart. Please answer the questions according to the pictures: (5 points) ( (1) glomerular filtration? Renal tubular reabsorption? (2) ③? 2? (3) There are many alveoli; Extraalveolar bread is surrounded by abundant capillaries; The alveolar wall and capillary wall are very thin, and only one layer of epithelial cells is formed.

The process of urine formation includes glomerular filtration and renal tubular reabsorption. Intravenous drugs first reach the right atrium of the heart through systemic circulation, then the right ventricle, and then reach the left atrium of the heart through pulmonary circulation, so they reach the heart twice. The basic structure of the lung is alveoli, with a large number of alveoli and abundant capillaries around it. The walls of alveoli and capillaries are very thin, forming only one layer of epithelial cells. These structural features are beneficial to gas exchange.