Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Respiration is the process of breaking down food (glucose) using oxygen to release energy. The overall chemical reaction can be represented as: .
Breathing is a physical process consisting of two steps: Inhalation (taking in air rich in ) and Exhalation (giving out air rich in ).
The Diaphragm is a muscular sheet below the lungs that controls the breathing mechanism. During inhalation, it moves down (contracts), and during exhalation, it moves up (relaxes).
Inhaled air contains approximately Oxygen () and Carbon Dioxide (), while exhaled air contains approximately Oxygen () and Carbon Dioxide ().
Gas exchange occurs in the Alveoli, which are tiny air sacs in the lungs surrounded by blood vessels.
Exhaled air contains more moisture ( vapor) than inhaled air, which can be seen as fog when breathing onto a cold glass surface.
📐Formulae
💡Examples
Problem 1:
Why does the percentage of increase in exhaled air compared to inhaled air?
Solution:
The percentage of increases from to approximately .
Explanation:
Inside the body cells, oxygen is used to burn food to produce energy. This process, called cellular respiration, produces as a waste product, which is then transported to the lungs and expelled during exhalation.
Problem 2:
Describe the movement of the ribs and diaphragm when you breathe in ( intake).
Solution:
Ribs move outwards and upwards; Diaphragm moves downwards.
Explanation:
During inhalation, the diaphragm contracts and moves down while the rib muscles pull the ribs up and out. This increases the space in the chest cavity, lowering air pressure and allowing air rich in to rush into the lungs.
Problem 3:
If a student breathes times in minutes while resting, calculate the breathing rate per minute.
Solution:
Explanation:
Using the formula , we get . The average resting breathing rate for a human is usually between to breaths per minute.