Gas Exchange Surfaces, Ventilation, and Mammalian Lung Adaptations

What is a gas exchange surface?

The surface tissue or membrane where gas exchange occurs in an organism.

Give an example of a gas exchange surface in mammals.

Alveoli and surrounding capillaries in the lungs.

Why must gas exchange surfaces be permeable?

To allow gases to diffuse across while preventing loss of essential fluids.

Why is tissue thickness important for gas exchange surfaces?

Thin tissues reduce diffusion distance and increase diffusion rate.

How thick is the diffusion barrier between alveoli and blood?

Two cells thick, one alveolar cell and one capillary cell.

Why must gas exchange surfaces be moist?

Gases dissolve more easily in moisture and diffuse faster.

How does large surface area increase gas exchange efficiency?

More gas molecules can be exchanged simultaneously.

Why are concentration gradients needed for gas exchange?

Gas exchange is passive and requires a gradient to continue.

How do dense blood vessel networks maintain concentration gradients?

They remove diffused gases and replenish the gradient.

How does continuous blood flow help gas exchange?

It removes gases that have diffused and maintains gradients.

What is ventilation?

The movement of air across a gas exchange surface.

How does ventilation maintain concentration gradients in lungs?

By continuously supplying oxygen-rich air and removing carbon dioxide.

How is water movement used in fish gas exchange?

Water flows over gills to maintain dissolved oxygen gradients.

What is countercurrent exchange?

Water and blood flow in opposite directions to maximize oxygen uptake.

Name two adaptations of mammalian lungs for gas exchange.

High surface area and thin respiratory membrane.

What is the function of surfactant in the lungs?

It reduces surface tension and makes diffusion easier.

How do the diaphragm and intercostal muscles aid ventilation?

They change chest volume to create pressure gradients.

What is tidal volume?

The volume of air moved in or out with each breath.

What is ventilation rate?

The number of breaths taken per minute.

What is vital capacity?

The maximum amount of air that can be inhaled and exhaled in one breath.

What is residual volume?

The air that remains in the lungs and cannot be exhaled.

What happens to ventilation during exercise?

Ventilation rate and tidal volume increase.