B3.1 Flashcards
Gas Exchange
What is gas exchange?
the exchange of respiratory gases (oxygen, carbon dioxide) between cells/organisms and the environment
How does the exchange of gases between an individual cell and its environment take place?
Through diffusion
Why do large organisms have specialised organs for gas exchange?
because of the surface area to volume ratio that decreases when size increases
What does diffusion require?
a concentration gradient
What are the properties of gas exchange surfaces?
permeability
thin tissue layer
moisture
large surface area
How are concentration gradients maintained?
A dense network of blood vessels
a continuous blood flow
ventilation
What is the thorax?
in mammals, the upper part of the body separated from the abdomen, in insects, the region between head nad abdomen
What is a ventilation system?
a pumping mechanism that moves air in and out of the lungs, maintaining the concentration gradient
What improves the efficiency of diffusion in mammals?
a blood circulation system
a respiratory pigment
What are intercostal muscles?
muscles between the ribs involved in ventilation
What is the diaphragm?
sheet of tissue that separates the thorax from the abdomen in mammals
What are bronchi?
tubes connecting the trachea with the lungs
What is the pleural membrane?
lines lungs and thorax cavity and secretes pleural fluid
What are the alevoli?
air sacs in the lungs
What is surfactant?
substance that lines the inner surface of the alveoli and reduces surface tension