diffusion
The bird's respiratory system consists of paired lungs, which contain static structures with surfaces for gas exchange, and connected air sacs, which expand and contract causing air to move through the static lungs.
The primary system to get rid of CO2 is the respiratory system. But it is aided by the circulatory system which delivers CO2 to the aveoli, where hemoglobin on Red blood cells then picks up O2 to take back to the cells.
The respiratory system and the circulatory system work together to move oxygen throughout the body. The respiratory system takes in oxygen from the air and delivers it to the bloodstream, while the circulatory system transports oxygen-rich blood to all the cells in the body.
The main functional cell of the respiratory system is the alveolar cell, specifically the type I alveolar cell. These cells are responsible for gas exchange in the lungs by allowing oxygen to enter the bloodstream and carbon dioxide to be removed. Another key cell in the respiratory system is the ciliated epithelial cell, which help to filter and move mucus and other particles out of the respiratory tract.
Material moves from the respiratory system to the circulatory system by diffusing across a membrane in the air sacks called alveoli.
In the alveoli
Carbon dioxide moves from the circulatory system to the respiratory system primarily in the lungs, specifically at the alveoli. In the alveoli, carbon dioxide diffuses from the blood in the capillaries into the air sacs due to the concentration gradient, where it is then exhaled. This exchange occurs as oxygen from the inhaled air moves in the opposite direction, entering the bloodstream.
Three (of many) are: * the muscular system and the skeletal system. All muscles move bones. * the circulatory system and the respiratory system meet in the lungs for the exchange of gases * the circulatory system and the urinary system meet in the kidneys where wastes are removed
The changing epithelial cells along the respiratory tree are specialized to perform different functions. For example, the ciliated pseudostratified columnar epithelium in the trachea and bronchi helps to move mucus and trapped particles out of the airways, while the simple squamous epithelium in the alveoli facilitates gas exchange. This specialization allows the respiratory system to efficiently carry out its functions of breathing and gas exchange.
Friction in a system can be increased by increasing the roughness of the surfaces in contact, increasing the force pressing the surfaces together, or by increasing the speed at which the surfaces move against each other.
Diffusion occurs in the respiratory system, where oxygen and carbon dioxide exchange happens in the lungs. It also occurs in the digestive system, where nutrients pass through the walls of the small intestine into the bloodstream. Additionally, diffusion takes place in the circulatory system, where gases and nutrients move between blood and tissues at the capillaries.
Echinoderms do not have a respiratory system similar to a person's. Instead, they have a water vascular (otherwise known as "ambulacral") system, made up of a network of canals to move water. This method accounts for the creature's gas exchange, feeding, and locomotion. Because of this characteristic, echinoderms lack gill slits.