Lesson Notes By Weeks and Term v4 - SHS 3
DISEASES AND DISORDERS
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DISEASES AND DISORDERS
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Subject: Biomedical Science
Class: SHS 3
Term: 2nd Term
Week: 16
Grade code: 3.2.2.LI.4
Strand code: 2
Sub-strand code: 2
Content standard code: 3.2.2.CS.1
Indicator code: 3.2.2.LI.4
Theme: HUMAN BODY SYSTEMS
Subtheme: DISEASES AND DISORDERS
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This lesson explores one of the most significant health challenges facing Ghana and the world today: heart disease. As our lifestyles change, with more processed foods and less physical activity, conditions like hypertension ("pressure") and high cholesterol are becoming more common in our communities, affecting our parents, grandparents, and even younger adults. We will investigate a powerful medical tool, the angiogram, used by doctors to see inside our blood vessels and find problems. We will also critically examine the risk factors—the habits and conditions—that lead to heart disease, empowering us to make healthier choices for ourselves and our families.
This section provides the core content needed for the lesson. Part 1: The Problem - Blocked Arteries (Atherosclerosis)
Before we can understand the solution (angiogram), we must understand the problem. The most common type of heart disease is Coronary Artery Disease (CAD). Coronary Arteries: These are the special blood vessels that sit on the surface of the heart muscle. Their only job is to supply the heart muscle itself with oxygen-rich blood so it can keep pumping. Atherosclerosis: This is the process where the coronary arteries become narrowed or blocked. It's often called "hardening of the arteries." How it happens: It starts when the inner lining of an artery is damaged (e.g., by high blood pressure or smoking). The body tries to repair this damage, but this process can go wrong. Plaque Formation: Fatty substances, cholesterol, cellular waste products, calcium, and fibrin (a clotting material) build up at the site of the injury. This buildup is called plaque. Analogy: Think of the plumbing in a house. Over time, grease, hair, and other debris can build up inside the pipes, making the opening smaller and smaller. Eventually, water can barely pass through. Plaque does the same thing to our arteries. Consequences: When an artery is narrowed, less blood can get to the heart muscle. Angina: This is chest pain or discomfort that occurs when the heart isn't getting enough oxygen, especially during physical activity. Heart Attack (Myocardial Infarction): If a plaque ruptures, a blood clot can form on its surface and completely block the artery. The part of the heart muscle supplied by that artery begins to die from lack of oxygen. This is a medical emergency. Part 2: The Diagnostic Tool - The Angiogram
How do doctors find out if a person's coronary arteries are blocked? They can't see them from the outside. They use a special X-ray test called a coronary angiogram. Definition: An angiogram is a medical imaging procedure that uses X-rays and a special contrast dye to visualise the inside, or lumen, of blood vessels. When used to check the heart's arteries, it is called a coronary angiogram. The Purpose: The main function is to identify the exact location and severity of any blockages or narrowing (stenosis) in the coronary arteries. How it Works (Step-by-Step): Preparation: The patient is awake but may be given a mild sedative to relax. The area where the catheter will be inserted (usually the groin/femoral artery or the wrist/radial artery) is numbed with a local anaesthetic. Catheter Insertion: A thin, flexible, hollow tube called a catheter is inserted into the artery. Guidance to the Heart: The doctor carefully guides the catheter through the body's arterial system, watching its progress on a live X-ray screen (fluoroscopy), until the tip reaches the opening of the coronary arteries at the heart. Contrast Dye Injection: A special iodine-based liquid, called a contrast agent or dye, is injected through the catheter directly into the coronary arteries. This dye is opaque to X-rays. X-ray Imaging (Fluoroscopy): As the dye flows through the arteries, it makes the blood inside them visible on the X-ray. A series of rapid X-ray images (like a video) are taken. Interpretation: The resulting images, called angiograms, show a clear map of the arteries. Healthy Artery: Appears as a smooth, wide, uniformly dark channel. Blocked Artery: Appears narrowed, pinched, or may show a complete break in the flow of the dye where the blockage is total.
*(Teacher can draw this on the board or project a similar image)* Part 3: The Causes - Risk Factors for Heart Disease