Gaseous Exchange { 5 }

To support ___, cells take in oxygen and give out carbon dioxide by a process called ___ .

Gaseous exchange -the exchange of gases between an organism and its environment- takes place by..

Highlight the factors that determine the rate of diffusion in living things.

The shorter the diffusion path, the lower the rate of diffusion -so the respiratory surface must be as thin as possible.

Many multicellular animals have very many of their cells too far away from the body surface to receive enough oxygen by diffusion alone.

Active organisms have an ___ metabolic rate and so require more___ in their cells; mammals have specialised organs for gaseous exchange.

In mammals the respiratory surface consists of..

Since the lungs are in a protective position inside the ___, air must be brought to the respiratory surface and so the lungs must be ___ .

A ventilation system is..

The lungs are housed in the thorax, an ___ formed by the ___ and its ___ with a domed floor, the ___ .

The internal surfaces of the thorax are lined by the..

This membrane secretes ___ which is a lubricating liquid derived from ___ and protects the lungs from friction during breathing movements.

The ___ work together to prevent food from entering the __ which which connects the lungs to the ___ at the rear of the mouth and runs beside the ___ .

Air is drawn into the alveoli when the air pressure is lower in the lungs than in the atmosphere; it is then forced out when the situation reverses.

The volume of the thorax is decreased when the ribs move up and out an the diaphragm dome is lowered.

The volume of the thorax is decreased by the diaphragm muscles relaxing and becoming more dome shaped by pressure from below; the ribs now move in and down as the intercostal muscles relax.

The lung tissue consists of the alveoli, arranged in clusters and served by a bronchiole. They have ____ and a ___ system wraps around the clusters of them and is connected to the ___ and is drained by a branch of the ___ .

Highlight the advantageous features of alveoli.