Respiration and Photosynthesis by Donna Latham

Learn about the major environmental problems facing our planet and what can be done about them!

Saving Earth Britannica Presents Earth’s To-Do List for the 21st Century.

100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.

COVID-19 Portal While this global health crisis continues to evolve, it can be useful to look to past pandemics to better understand how to respond today.

Student Portal Britannica is the ultimate student resource for key school subjects like history, government, literature, and more.

This Time in History In these videos, find out what happened this month (or any month!) in history.

#WTFact Videos In #WTFact Britannica shares some of the most bizarre facts we can find.

Demystified Videos In Demystified, Britannica has all the answers to your burning questions.

Britannica Classics Check out these retro videos from Encyclopedia Britannica’s archives.

Britannica Explains In these videos, Britannica explains a variety of topics and answers frequently asked questions.

Some insects forcefully blow air from the air sacs and out the spiracles when threatened, making a noise loud enough to startle a potential predator or curious person. Insects in dry climates may also store air and keep their spiracles closed, to prevent water in their bodies from evaporating. They simply store air until they surface again. In aquatic insects, the air sacs enable them to 'hold their breath' while under water. In some areas, however, there are no taenidia, and the tube functions as an air sac capable of storing air. Most of the tracheal tubes are reinforced by taenidia, ridges that run spirally around the tubes to keep them from collapsing. Carbon dioxide released from the cell follows the same pathway back to the spiracles and out of the body. The tubes continue to divide, creating a branching network that reaches each cell in the body. Once entering through the spiracle, oxygen travels through the tracheal trunk (8), which divides into smaller tracheal tubes.

When the muscles controlling the valves relax, the valves open and the insect takes a breath.

Small flaps or valves keep the spiracle closed until there is a need for oxygen uptake and carbon dioxide discharge. Most insects have one pair of spiracles per body segment. Along the sides of the thorax and abdomen, a row of small openings called spiracles (8) allow the intake of oxygen from the air. Oxygen is delivered to the cells directly through respiration, and not carried by blood as in vertebrates. Insect Respiratory System Insects require oxygen just as we do, and must 'exhale' carbon dioxide, a waste product of cellular respiration.

Respiration and Photosynthesis by Donna Latham