Oxygen & Breathing
Why do we need oxygen?
To release energy from food.
What pipe carries air into the lungs?
The trachea (windpipe).
Which gas makes up 78% of the air?
Nitrogen.
What happens to the diaphragm when you breath in?
It contracts and moves down.
About how many times do we breathe in a lifetime?
Around 600 million times.
What waste gas tells your brain to breathe?
Carbon dioxide.
What are the tiny air sacs at the end of the lungs called?
Alveoli
What percentage of the air is oxygen?
About 21%
What happens to the ribs when you breathe in?
They move upward and outward.
How many drink bottles of air do we need every minute?
About three bottles.
Why can’t we store oxygen?
Because our body uses it constantly, we must keep breathing.
Which muscle moves down to help us breathe in?
The diaphragm.
Name one gas found in the air in very small (trace) amounts.
Helium or other trace gases.
Why do the lungs expand when we breathe in?
Because the chest cavity becomes larger, creating space for air.
Who discovered that some diseases are carried in the air (11th century)?
Ibn Sina (Avicenna).
What happens if oxygen is missing in your body?
You cannot release energy from food, and you may die.
Explain how alveoli exchange gases with blood.
Oxygen moves into the blood, and carbon dioxide moves out into the alveoli.
Why is it better to be a nose-breather than a mouth-breather?
Because nose hairs trap dirt and germs.
Describe what happens during breathing out.
The diaphragm relaxes and moves up, ribs move down and in, lungs shrink, and air is pushed out.
Name one disease that spreads through the air.
Flu, tuberculosis, or COVID-19.
Why do you feel the urge to breathe after holding your breath?
Because carbon dioxide builds up in the blood and signals the brain.
What happens to the blood after it collects oxygen in the alveoli?
It carries oxygen to the rest of the body.
Which gas makes up only 0.04% of the air?
Carbon dioxide.
Why do the lungs need the diaphragm and ribs to help them work?
Lungs have no muscles of their own to expand or contract them.
How long can whales hold their breath?
Around half an hour.