The primary function of the respiratory system is to exchange oxygen and carbon dioxide. Inhaled oxygen enters the lungs and reaches the alveoli. The layers of cells lining the alveoli and the surrounding capillaries are each only one cell thick and are in very close contact with each other. This barrier between air and blood averages about 1 micron (1/10,000 of a centimeter) in thickness. Oxygen passes quickly through this air-blood barrier into the blood in the capillaries. Similarly, carbon dioxide passes from the blood into the alveoli and is then exhaled.
Diffusion
gas exchange
Gas exchange occurs across the respiratory membrane of the alveoli; however, the short answer is simply alveoli
no
A bilayer of phospholipids regulates cell traffic. There are five methods of transport across the membrane; diffusion, facilitated diffusion, active transport, co transport and endocytosis/exocytosis.
the lungs
Blood releases carbon dioxide and acquires oxygen, in the lungs. The opposite exchange takes place throughout the body on a cellular level, as each cell consumes oxygen from the blood and releases carbon dioxide into the blood.
Gas exchange takes place at a respiratory surface-a boundary between the external environment and the interior of the organism. For unicellular organisms the respiratory surface is governed by Fick's law, which determines that respiratory surfaces must have:a large surface areaa thin permeable surfacea moist exchange surface.
osmosis
Both have a high surface area for exchange: In the respiratory system the exchange of oxygen an carbon dioxide takes place between the alveoli and blood capillaries (both provide a high surface area for exchange) and in the digestive system, exchange of nutrients and waste takes place between the villi and blood capillaries (also both provide a high surface area for exchange) In both systems, transported materials pass through the membranes by a process called diffusion.
The membrane of the alveolus, the air sacs in the lungs where this process takes place, is only one cell thick. The wall of the capillary running adjacent to the alveolus is also one cell thick, so the gases are exchanged between the alveolus and the capillary cell membranes.
Gas exchange takes place at a respiratory surface-a boundary between the external environment and the interior of the organism. For unicellular organisms the respiratory surface is governed by Fick's law, which determines that respiratory surfaces must have:a large surface areaa thin permeable surfacea moist exchange surface.Read more: How_does_gas_exchange_take_place
Placenta