9.1 Gas Exchange Flashcards
The human gas exchange system links the
circulatory system with the atmosphere
The human gas exchange system is adapted to
-clean and warm air that enters during breathing
How is human gas exchange system adapted for its function
-maximized surface area for diffusion oxygen ad carbon dioxide between the blood and the atmosphere
-minimized distance for diffusion
-maintain adequate gradients for diffusion
Why is a supply of oxygen needed
for respiration in order to obtain energy
How do single celled organisms get oxygen
the oxygen diffuses from the fluid outside the cell through cell surface membrane and into the cytoplasm
What is gas exchange surface?
any part of an organism that allows the movement of gases between the surroundings and the body.
Gas exchange occurs across the body surface of some organisms that have
large surface area : volume ratios
Organisms with small surface area : volume ratio have
specialized gas exchange surfaces because most of the cells are a considerable distance away from the external environment from which the oxygen is obtained which makes diffusion a very slow and inefficient process for it
Give two examples of specialized gas exchange surfaces
lungs and gills
What is the specialized gas exchange surface in humans
Alveoli in the lungs
What is the collective surface area of the alveoli in an adult human
70-75m^2
What is another reason why a large surface area required
Oxygen is not very soluble in water
What is an alveolus
A small air sac in the lungs composed of a single layer of squamous epithelium and some elastic fibers
Each alveolus is surrounded by capillaries that transport blood from
pulmonary artery to pulmonary vein
