Comprehensive Human and Animal Gas Exchange: Structures, Processes, and Control

What is the primary purpose of gas exchange in animals?

To bring oxygen to cells and remove carbon dioxide.

What two systems work together for gas exchange?

The respiratory system and the cardiovascular system.

What are the three phases of gas exchange in humans?

Breathing (ventilation), transport of gases in blood, and exchange of gases with body cells.

What must respiratory surfaces have to facilitate gas exchange?

High surface area, moisture, and thinness.

Which animals primarily use their skin for gas exchange?

Earthworms, flatworms, and hydra.

What specialized structures do most animals have for gas exchange?

Gills, tracheal systems, or lungs.

What is the limitation of gas exchange in water?

Water holds only about 3% of the oxygen that air does.

What enhances gas exchange in fish gills?

High surface area, ventilation of gills, and countercurrent flow of water and blood.

What are the advantages of air for breathing compared to water?

Air contains higher concentrations of O2 and is lighter and easier to move.

What are insect tracheal systems designed for?

Direct exchange of gases between air and body cells.

What are alveoli and where are they located?

Alveoli are small sacs at the end of bronchioles where gas exchange occurs.

How many alveoli are typically found in a human lung?

Approximately 300 million.

What is the role of surfactants in the lungs?

To keep alveoli lubricated and prevent them from sticking shut.

What causes air to move into the lungs during inhalation?

An increase in chest cavity volume, resulting in decreased air pressure.

What happens during exhalation?

Muscles relax, decreasing chest cavity volume and expelling air.

What can damage the elasticity of alveoli?

Air pollutants, particularly tobacco smoke.

What serious condition can result from smoking?

Emphysema, which involves the breakdown of elastin in alveolar walls.

How is breathing controlled in the body?

By the autonomic nervous system, which can also be under voluntary control.

What do breathing control centers in the brain respond to?

CO2 levels and blood pH.

What is the role of hemoglobin in the blood?

To bind oxygen for transport from the lungs to body tissues.

What is the solubility of oxygen in water?

Oxygen is not very soluble in water.

How does a human fetus exchange gases?

Through the placenta with maternal blood, without breathing with its lungs.

What happens to maternal and fetal blood in the placenta?

They run next to each other without mixing.

What is the effect of a drop in blood pH on breathing?

It increases the rate and depth of breathing.

What is the function of the cardiovascular system in gas exchange?

To transport gases in the blood.

What does the right side of the heart do?

Pumps oxygen-poor blood to the lungs.

What does the left side of the heart do?

Pumps oxygen-rich blood to the body.

How do gases move during diffusion?

From areas of higher concentration to areas of lower concentration.

What is the role of the alveoli in gas exchange?

O2 diffuses into the blood, and CO2 diffuses out of the blood.