The lungs are intricate organs that are primarily responsible for breathing. Also known as respiration, breathing is a physical and biological process that automatically occurs without the need to think. In fact, "Kids Health" suggests that each day, you breathe about 20,000 times, and by the time you are 70 years old, you would have taken at least 600 million breaths. Breathing is vital to life; it involves taking in oxygen from the environment and expelling carbon dioxide from inside the body.
- Skill level:
Identify the structures involved in respiration. Although the lungs are the largest organs required to breathe, lesser-known parts of the body also make breathing possible. Use a diagram or image to point to and identify the diaphragm, upper respiratory tract consisting of the nose, sinuses and pharynx, and lower respiratory system made of the larynx, trachea, bronchi, bronchioles and alveoli.
Explain inspiration, also called inhalation, which is the act of taking in a breath. As you breathe in through the nose or mouth, the diaphragm contracts and flattens while the rib muscles lift the ribs, making room for the lungs to expand as air enters.
Discuss the flow of air through the respiratory system. As the lungs are expanding, the air pressure decreases, allowing air to flow through the upper and lower respiratory tract. When the air reaches the alveoli, oxygen is passed to the blood via capillaries, which are picked up by red blood cells.
Describe internal respiration. Internal respiration occurs when the haemoglobin in red blood cells carries oxygen to the body's cells and tissues by the cardiovascular system in exchange for carbon dioxide. Carbon dioxide-rich blood returns to the heart through the veins and enters the lungs, and carbon dioxide is released into the alveoli.
Talk about exhalation. Exhalation, or expiration, is the reverse process of inhalation, with carbon dioxide moving out of the lungs from the lower to the upper respiratory tract, respectively, and out through the nose or mouth. The air is able to be released from the body because the diaphragm and rib muscles relax, increasing the air pressure in the lungs, which forces the air out.
Tips and warnings
- Demonstrate with hands on the chest to show what happens as the lungs expand and contract.
- Explain the difference between aerobic and anaerobic respiration.
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