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gas exchange redo - Coggle Diagram
gas exchange redo
surfaces
short diffusion distance
thin membrane asllows oxygen and co2 to diffuse through the cells faster as travel distance from the cells and external environment is shorter
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large surface area
so that more oxygen can diffuse into the cells and co2 out of the cells per unit of time. more space for diffusion
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mammals
when a mammal inhales air, the air can only enter the cells through the nose and mouth. the nose contains noise hairs that filter out foreign particles that may block gas exchange surfaces. the mouth does not contain filters so only air that enters the nose can be filtered.
the air will then travel down the trachea (the windpipe). this is a structural adaptation that allows the air to travel down to a mammal's gas exchange surface: the lungs. the trachea contains a ring shaped cartilage that prevents the tube from collapsing
then it will travel to the left and right bronchi (called the primary bronchi). the bronchi will then divert into smaller tubes. once these smaller tubes divert to 1mm, they are called bronchioles. the branching out of these tubes help maximise surface area for diffusion. this allows for more space for air to travel and for oxygen to be transported from the air into the blood stream . this increases the rate of gas exchange.
after this, the bronchioles will divide into smaller tubes known as alveolar ducts. these lead to clusters/ grapelike structures known as alveoli. each lung contains millions of alveoli. these are thin-walled sac where the exchange of oxygen and co2 from the air and the bloodstream takes place. due to the large amounts of alveoli per lung, the combines surface area is large and ensures an efficient gas exchange surface
as the alveoli contain the exchange of CO2 and oxygen between the bloodstream, it is enveloped by a network of blood vessels known as capillaries. in these, red blood cells are found. haemoglobin is a protein that gives these red blood cells the red pigment. it is a physiological adaptation that binds to oxygen and allows it to be transported throughout the whole body. it amplifies the body's ability to carry large amounts of oxygen
alveoli are also coated by a chemical substance known as surfactant. this keeps the gas exchange surface moist and prevents the lungs from collapsing during ventilation (a behavioural adaptation that enables the mammal to intake deep breaths of air allowing for larger diffusion of oxygen into the cells)