Respiratory System - The Need for Oxygen

Science, Grade 6


Table Of Contents: Respiratory System - The Need for Oxygen

1. Functions of the Respiratory Tract
In order to function, the human body needs a constant supply of oxygen and a process for removal of carbon dioxide waste. The respiratory tract is made up of a system of conducting tubes that connect the atmospheric air with the lungs. In the lungs, the inhaled oxygen-rich air is exchanged for carbon-dioxide rich air that is exhaled from the body.
2. The Need for Oxygen
Every cell in the human body needs oxygen. A steady supply of oxygen is critical to supporting highly active tissues and cells, which have a constant need for energy. This energy can only be produced in high quantities by cells when oxygen is present. For example, nerve cells of the brain will begin to break down and die if they are without oxygen for four minutes!
3. Organs of the Respiratory Tract – From Mouth to Lungs
Air enters through the nose and mouth, and then travels through the throat known as the pharynx. Air then passes along the area of the vocal cords, the larynx, before entering the main air tube known as the trachea. From there, air goes through separate tube connections, called bronchi, into the right and left lung. Most of the sounds we make in speaking happen when we exhale air across our vocal cords, which are muscular tissues.
4. Lung Structure
Within the lungs, the two main bronchi each branch into many smaller tubules (bronchioles). The bronchioles branch into even smaller air sacs known as alveoli.
5. Organs of the Respiratory Tract – The Lungs
The exchange of oxygen for carbon dioxide in the lungs occurs across the air sacs called alveoli that have walls rich in capillaries. These sacs provide surfaces where gases can diffuse back and forth between the bloodstream and the air space. Specifically, oxygen in newly inhaled air within the alveolar air space will diffuse into the bloodstream; while carbon dioxide, rich in the blood coming into the lungs, will diffuse from the bloodstream into the air space to be exhaled from the body.
6. Process of Respiration – How You Breathe
The process of respiration is driven by your breathing. When you inhale, your ribcage moves up and out and the diaphragm contracts to create a vacuum. Air rushes through your nose and mouth, through your conducting tubes, and into your lungs as inspiration. When you exhale, the diaphragm relaxes and air is forced out of the lungs as expiration.
7. Smoking and Health
Smoking or breathing in other pollutants can cause a breakdown in the elastic nature of the lungs and the trapping of air. This can lead to a dangerous condition of chronic bronchitis and emphysema. These conditions, including asthma, for which the cause is mainly unknown, are labeled as chronic obstructive pulmonary diseases (COPD).
8. Emphysema
In emphysema, air gets trapped over time. The air spaces get bigger and bigger, causing the air space walls to break down and cease to function. When these walls of tissue stop working, the respiratory process is interrupted or incomplete.
9. Lung Cancer
Lung cancer is common in smokers. Cancer occurs when pollutants cause a mutation, or change, in the lining of the bronchi. This change leads to an uncontrolled growth of abnormal cells, which can spread over many parts of the body and disrupt body functions.