Lesson Notes By Weeks and Term v4 - SHS 1

Lesson Video

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Performance objectives

• Describe the structure and function of the respiratory system.
• Identify common disorders of the respiratory system.
• Explain the effects of smoking on lung health.
• Discuss the process of aerobic respiration.

Lesson summary

This lesson explores common disorders that affect our respiratory system—the very system that allows us to breathe and live. In Ghana, we are exposed to various factors that can harm our lungs, from the dusty Harmattan winds and fumes from "trotros" and burning rubbish, to indoor smoke from charcoal stoves. Understanding these diseases is not just for examinations; it is crucial for our personal health, the health of our families, and our community. By learning about the causes, symptoms, and prevention of respiratory disorders, we can make informed choices to protect ourselves and others.

Lesson notes

A. Quick Recap: The Healthy Respiratory System Before we discuss what goes wrong, let's remember how a healthy system works. Air enters through the nose/mouth, goes down the trachea (windpipe), which branches into two bronchi (one for each lung). These bronchi branch further into smaller tubes called bronchioles, ending in tiny air sacs called alveoli. In the alveoli, oxygen enters the blood, and carbon dioxide leaves it. This entire pathway is lined with tiny hairs called cilia and a layer of mucus, which trap dust and germs to keep the lungs clean. B. Common Respiratory Disorders

We will discuss four major disorders: Asthma, Bronchitis, Tuberculosis (TB), and Lung Cancer. Asthma What it is: Asthma is a chronic (long-term) condition where the airways (bronchioles) become inflamed, narrow, and swell, and produce extra mucus. This makes it very difficult to breathe. Causes: The exact cause is not known, but it is linked to a combination of genetic and environmental factors. Breathing is made difficult by "triggers." Common Triggers in Ghana: Allergens: Dust mites (in mattresses and carpets), pollen from plants, mould spores (in damp rooms). Irritants: Harmattan dust, smoke from burning rubbish or wood/charcoal fires, strong perfumes, vehicle exhaust fumes. Other: Cold air, strenuous exercise, respiratory infections like the common cold. Symptoms (often come as an "attack"): Wheezing: A whistling sound when breathing. Coughing: Especially at night or early in the morning. Shortness of breath: Feeling like you can't get enough air. Chest tightness: A feeling of pressure or squeezing in the chest. How it affects the lungs: During an asthma attack, the muscles around the bronchioles tighten (bronchoconstriction), the lining of the airways swells, and thick mucus is produced. This severely narrows the passage for air, making it hard to breathe out. Bronchitis What it is: Bronchitis is the inflammation of the lining of the bronchial tubes (the bronchi). There are two types: Acute Bronchitis: This is a short-term illness, often developing after a cold or other respiratory infection. It usually clears up within a week or two. Chronic Bronchitis: This is a serious, long-term condition. It is defined as having a cough with mucus on most days for at least three months a year, for two years in a row. Causes: Acute: Usually caused by viruses (the same ones that cause colds and flu). Chronic: The most common cause is cigarette smoking. Long-term exposure to air pollution, dust, and toxic gases can also cause it. Symptoms: Persistent cough, which may produce clear, white, yellow, or greenish mucus. Shortness of breath. Wheezing. Chest discomfort. How it affects the lungs: The irritants (like smoke) damage the cilia, the tiny hairs that sweep debris out of the lungs. When the cilia stop working, mucus builds up, clogging the airways and leading to a persistent cough and increased risk of infection. Tuberculosis (TB) What it is: TB is a serious infectious disease that mainly affects the lungs. It is caused by a type of bacteria called *Mycobacterium tuberculosis*. Causes and Transmission: Caused by bacteria. It spreads through the air when an infected person coughs, sneezes, or spits. A healthy person can get infected by inhaling these airborne droplets. It spreads easily in crowded and poorly ventilated places (e.g., some crowded homes, prisons, packed "trotros"). Symptoms: A bad cough that lasts three weeks or longer. Coughing up blood or mucus. Chest pain. Weakness or fatigue. Weight loss and loss of appetite. Fever and night sweats. How it affects the lungs: The bacteria attack the lung tissue, causing it to be destroyed. The body's immune system tries to wall off the bacteria, forming small lumps or nodules called tubercles. If not treated, the bacteria can destroy large parts of the lung and spread to other parts of the body. Lung Cancer What it is: Lung cancer is the uncontrolled growth of abnormal cells in one or both lungs. These cells do not carry out the functions of normal lung cells and grow to form tumours. Causes: Smoking: This is the number one cause. Cigarette smoke contains over 70 cancer-causing chemicals (carcinogens) like tar. The more you smoke and the longer you smoke, the higher your risk. Second-hand Smoke: Inhaling smoke from other people's cigarettes. Exposure to certain substances: Asbestos, radon gas, and heavy air pollution. Symptoms (often do not appear until the disease is advanced): A new cough that doesn't go away. Changes in a chronic cough ("smoker's cough"). Coughing up blood. Shortness of breath. Chest pain. Unexplained weight loss. How it affects the lungs: The carcinogens in smoke damage the DNA of the cells lining the airways. This damage causes the cells to grow uncontrollably, forming a tumour. The tumour can block airways, interfere with breathing, and spread (metastasize) to other parts of the body, making it deadly.

Guided Practice (With Solutions)

Question 1: Ama is a 12-year-old girl who lives near a dusty, untarred road in Accra. During the Harmattan season, she often starts coughing, wheezing, and complains that her chest feels tight. Her parents rush her to the clinic where the doctor gives her an inhaler, which helps her breathe easily again. Which respiratory disorder does Ama most likely have, and what is the likely trigger? Solution and Commentary: Disorder: Asthma. Explanation: Ama's symptoms – coughing, wheezing, and chest tightness – are classic signs of an asthma attack. The fact that an inhaler (which opens up the airways) provides relief further confirms this. Trigger: The Harmattan dust from the untarred road is the most likely environmental trigger. Dust and other airborne particles are common irritants that can cause asthma attacks in sensitive individuals.

Evaluation guide

• Discuss disorders associated with the respiratory system .
• Initiating Talk for Learning and Group work/collaborative Learning:
•  Put learners in differentiated learning groups to review the structure of the lungs after
• viewing videos/models or pictures of the human lungs with various disorders.