Exhange Flashcards
Why do larger organisms require specialist exchange mechanisms
Their Sa:v ratio is too low
What is the difference between breathing and ventilation
Ventilation is the movement of air in and out of the lungs and breathing is the mechanisms that change thoracic pressure to bring about ventilation
What happens in inspiration
The external intercostal muscles contract pulling ribs up and out and diaphragm contracts and is pulled down and flat. This increases thoracic volume which decreases pressure in the thorax. Therefore air moves in along a pressure gradient
What brings about expiration
The internal intercostal muscles contract to move ribs in and down and diaphragm relaxes and pulls up into an arch. This decreases thoracic volume which increases thoracic pressure. Therefore air moves out along a pressure gradient
What is held open by a c shaped section of cartilage
Trachea
What is the job of ciliated epithelial cells
To trap unwanted molecules like bacteria and dust in mucus and then waft it up to throat using hair like structure that work together
What do macrophages do
Engulf and destroy dust and bacteria that enter the lungs
What is tidal volume
The volume of air inspired and expired in one breath at rest
What is inspiratory reserve volume
The additional amount of air that can be breathed in excluding tidal volume
What is expiratory reserve volume
The maximal volume of air that can be breathed out excluding tidal bolume
What is residual volume
The amount of air that always remains in the lungs after expiration to prevent the lungs from collapsing
What is the role of elsatin on the lungs
Imparts elasticity on tissues allowing them to stretch during inspiration and recoil during expiration. Also decrease surface tension to prevent collapse of lungs
What is surfactant
It is a liquid secreted in the lungs that prevents alveoli from sticking together (due to water and h bonds) which prevents them collapsing under surface tension
What are the factors that effect exchange
Surface area, diffusion distance,availability of gasses, conc gradient, temperature
How does a close supply of blood increase roe
Removes oxygenated blood to maintain conc gradient
How do alveoli increase roe
Increases sa
Does moisture help roe
Gassed can dissolve into tissues
Where does air enter insects from
Spiracles
What is the mouth of a fish called
Buccal cavity
