Lesson Notes By Weeks and Term v4 - SHS 3
DISEASES AND DISORDERS
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
DISEASES AND DISORDERS
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Subject: Biomedical Science
Class: SHS 3
Term: 2nd Term
Week: 14
Grade code: 3.2.2.LI.3
Strand code: 2
Sub-strand code: 2
Content standard code: 3.2.2.CS.1
Indicator code: 3.2.2.LI.3
Theme: HUMAN BODY SYSTEMS
Subtheme: DISEASES AND DISORDERS
This page supports the lesson note with a companion video and a short classroom-ready summary.
For class groups and homework, share this lesson page so learners also get the summary, objectives, and full lesson context.
In Ghana, we are seeing a rise in lifestyle-related diseases such as hypertension, stroke, and heart attacks, even among younger adults. Many of these conditions are linked to what is happening silently inside our blood vessels. A key factor is cholesterol. While our bodies need cholesterol to function, having too much of the "bad" type and not enough of the "good" type can lead to serious health problems. This lesson will demystify the terms HDL and LDL, which you may have heard at the clinic or on health programmes. We will explore what they are, how they work, and most importantly, how their levels in our blood can predict our risk for heart disease.
Starter Activity (Initiating Talk for Learning) Begin the class by asking: "Have you ever heard an older relative talk about their 'cholesterol levels' after visiting the hospital? What do you think they mean? Why is it something doctors check?" (This discussion serves as a bridge to the main topic, drawing on learners' prior exposure.) A. What is Cholesterol? Cholesterol is a waxy, fat-like substance that is found in all the cells in your body. It is not inherently bad. In fact, your body needs cholesterol to perform important jobs, such as: Building the structure of cell membranes. Producing essential hormones like oestrogen, testosterone, and cortisol. Making vitamin D. Producing bile acids, which help you digest fat.
Your liver produces all the cholesterol your body needs. However, you also get cholesterol from the food you eat, especially animal products like meat, poultry, and full-fat dairy products. B. The Transport Problem: Introducing Lipoproteins Cholesterol is a lipid (fat), and our blood is mostly water. As you know from basic chemistry, oil (fat) and water do not mix. So, for cholesterol to travel through the bloodstream to where it is needed, it must be packaged into special carrier particles called lipoproteins.
Think of lipoproteins as "transport taxis" for cholesterol and other fats. A lipoprotein is a particle made of fat (lipid) on the inside and protein on the outside. The protein coating allows it to move through the watery blood.
There are several types of lipoproteins, but we will focus on the two most important ones related to heart disease: LDL and HDL. C. LDL (Low-Density Lipoprotein) - The "Bad" Cholesterol Function: LDL's main job is to be a delivery truck. It transports cholesterol from the liver to cells throughout the body. When a cell needs cholesterol for repair or to make hormones, it takes it from an LDL particle. Why is it "Bad"? The problem arises when there is too much LDL in the blood. If the cells already have enough cholesterol, they stop taking it up. The excess LDL particles continue to circulate in the bloodstream. These excess particles, especially when they become damaged (oxidized), can get stuck in the walls of your arteries. The Link to Disease: This build-up of LDL cholesterol in the artery walls is the starting point for a condition called atherosclerosis. D. HDL (High-Density Lipoprotein) - The "Good" Cholesterol Function: HDL's main job is to be a garbage collector or a recycling truck. It moves through the bloodstream and collects excess cholesterol from the cells and, importantly, from the artery walls. It then transports this excess cholesterol back to the liver. The liver then removes it from the body or reprocesses it. Why is it "Good"? By removing excess cholesterol from the arteries, HDL helps to prevent or even reverse the build-up of plaque. A high level of HDL is therefore protective against heart disease. E. The Process of Atherosclerosis (How Plaque Forms)