Week Four
Subject: Basic Science
Class: Primary Four
Week of the Second Term: 4th Week
Topic: The Salivary Glands and Saliva
Subtopics:
- Functions of the salivary glands
- Role of saliva in digestion
Instructional Objectives
At the end of the lesson, pupils should be able to:
- Identify the salivary glands and explain their location in the mouth.
- Describe the main functions of the salivary glands.
- Explain the role of saliva in the digestion of food.
Entry Behavior
Pupils should have basic knowledge of the human mouth and its role in the feeding system.
Instructional Materials
- Charts showing the location of the salivary glands.
- Video clips on how saliva helps in digestion.
- Flashcards illustrating the functions of saliva.
Reference Materials
Ijiyemi, C. (2016). Foundations of Sci. & Tech for Primary School Book 4. Metropolitan Publishers, Lagos.
Oyinlola, M., Rahaman, B., & Ezeume, I. (2015). Basic Science and Technology for Primary School Book 4 (BEC Edition). Spectrum Book Limited, Lagos.
Content
The Salivary Glands and Saliva
Functions of the Salivary Glands
Production of Saliva:
The primary function of the salivary glands is to produce and secrete saliva into the mouth. Saliva is a watery fluid that helps in moistening food, making it easier to chew and swallow.
Initiating Digestion:
The salivary glands release enzymes like amylase, which begin the process of breaking down carbohydrates (starches) in food. This is the first step in digestion, starting even before food reaches the stomach.
Lubricating the Mouth:
Saliva helps keep the mouth moist, which aids in speaking, chewing, and swallowing. It also helps protect the delicate tissues of the mouth fm damage and drying out.
Maintaining Oral Health:
The salivary glands play a crucial role in keeping the mouth clean. Saliva helps wash away food particles and bacteria, reducing the risk of tooth decay and gum disease.
Role of Saliva in Digestion
Moistening Food:
Saliva moistens food, making it easier to chew and form into a bolus (a soft, easy-to-swallow mass). This allows the food to pass smoothly through the esophagus to the stomach.
Breaking Down Starch:
One of the key roles of saliva in digestion is the enzyme amylase, which starts breaking down complex carbohydrates (like bread or rice) into simpler sugars. This process helps prepare the food for further digestion in the stomach and intestines.
Facilitating Swallowing:
Saliva makes food slippery and easier to swallow, reducing friction as it passes through the throat and esophagus. This ensures that food reaches the stomach more easily.
Cleansing and Protecting the Mouth:
Although not directly linked to digestion, saliva helps cleanse the mouth by washing away food particles and neutralizing acids produced by bacteria, which can harm teeth and gums. This also prevents infections that might interfere with proper digestion.
Step 1: Introduction
Lesson Presentation (Step-by-Step Procedure)
Others removed.
