Lesson Notes By Weeks and Term v4 - SHS 3
ANATOMY AND PHYSIOLOGY
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ANATOMY AND PHYSIOLOGY
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Subject: Biomedical Science
Class: SHS 3
Term: 1st Term
Week: 4
Grade code: 1.2.1.LI.2
Strand code: 2
Sub-strand code: 1
Content standard code: 1.2.1.CS.1
Indicator code: 1.2.1.LI.2
Theme: HUMAN BODY SYSTEMS
Subtheme: ANATOMY AND PHYSIOLOGY
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This lesson explores one of the most fundamental concepts in biology: how the different systems in our body, from the heart that pumps our blood to the stomach that digests our food, are not isolated units but are part of a highly coordinated team. We will learn how this team works together to maintain a stable internal environment, a state known as homeostasis. Understanding this is crucial for our own health. When you feel thirsty after playing football in the hot sun, or when you shiver on a cool night in the Kwahu mountains, that is your body's systems working together to keep you alive and well.
A. What is Homeostasis?
Homeostasis is the body's ability to maintain a stable, relatively constant internal environment despite changes in the external world. Think of it like the thermostat in an air conditioner. If you set the temperature to 20°C, the AC will turn on when the room gets hotter and turn off when it reaches the set temperature. It constantly makes adjustments to maintain stability.
Our body does the same for many variables, including: Body Temperature: Kept around 37°C. Blood Glucose (Sugar) Level: Kept within a narrow range. Blood pH: Kept around 7.4. Water and Salt Balance: Regulated to prevent cells from shrinking or bursting. Blood Pressure: Maintained within a healthy range.
If these variables stray too far from their normal range (the "set point"), it can lead to disease (like diabetes from high blood sugar) or even death. B. The Mechanism of Homeostasis: Feedback Loops