Class: Senior Secondary School 2 (SS2 / SSS 2)
Term: 1st Term
Week: 11
Age: 16 years
Duration: 45 minutes
Subject: Physical Education
Curriculum Theme: Human Body Systems
Previous Lesson: Nervous System: Meaning, Brain and Spinal Cord Functions.
Topic: Nervous System Continues
Subject Matter: Function of the nerves, reflex action

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:

Explain the importance of the brain in body coordination.
List at least three functions of the nerves.
Define reflex action.
Describe the sensory and motor pathways of nerve messages.

Affective Domain:

Appreciate the role of the nervous system in maintaining body functions.
Value the protective nature of reflex actions.

Psychomotor Domain:

Draw and label a simple diagram of a reflex arc.
Identify the components of a reflex arc.

Participate actively in discussions about the nervous system.

Reference Materials

The following resources were used in planning this lesson:

Senior Secondary Schools Education Curriculum
State Unified Scheme of Work
Physical and Health Education for Senior Secondary Schools, Book 2

Instructional Materials

The teacher will teach this lesson with the aid of:

Textbooks
Diagrams of the nervous system and reflex arc
CD-ROMs/projectors (if available)
A chart showing the reflex pathway

Rationale for the Lesson

This lesson helps pupils understand how their body coordinates movements and responds to stimuli, especially involuntary actions. Understanding the nervous system is important for appreciating how the body functions and reacts to its environment.

Prerequisite/Previous Knowledge

Pupils have prior knowledge of the basic structure and general function of the nervous system from previous lessons.

Lesson Content/Board Summary

The Nervous System: Functions of Nerves and Reflex Action

Functions of the Nerves

Nerves are essential for transmitting information throughout the body. The following are key functions of the nerves:

Transmission of Impulses: Nerves carry electrical signals (nerve impulses) between the brain, spinal cord, and all other parts of the body.
Coordination: They coordinate voluntary and involuntary actions, ensuring different body parts work together smoothly.
Sensation: Sensory nerves detect stimuli from the environment and inside the body (e.g., touch, pain, temperature, sight, sound).
Movement: Motor nerves transmit signals from the brain and spinal cord to muscles, causing them to contract and produce movement.
Homeostasis: They help maintain the body’s internal balance by regulating various physiological processes.

Reflex Action

A reflex action is a rapid, involuntary, and automatic response to a stimulus that does not involve conscious thought. Reflex actions are protective mechanisms of the body.

Examples:
- Withdrawing a hand from a hot object.
- Blinking when an object approaches the eye.
- Sneezing, coughing, or yawning.
- Knee-jerk reflex.

The Reflex Arc

The reflex arc is the neural pathway that mediates a reflex action. It typically consists of five main components:

Receptor: Detects the stimulus (e.g., pain receptors in the skin).
Sensory Neuron (Afferent Neuron): Transmits the nerve impulse from the receptor towards the central nervous system (spinal cord).
Relay Neuron (Interneuron): Located within the central nervous system (spinal cord), it connects the sensory neuron to the motor neuron.
Motor Neuron (Efferent Neuron): Transmits the nerve impulse from the central nervous system to the effector organ.
Effector: A muscle or gland that responds to the nerve impulse (e.g., a muscle contracting to withdraw the hand).

Pathways of Messages to and from the Central Nervous System

Nerve impulses travel along specific pathways:

Sensory Pathway (Afferent Pathway): This pathway carries sensory information from receptors in the body towards the central nervous system (brain and spinal cord). Sensory neurons are responsible for this.
Motor Pathway (Efferent Pathway): This pathway carries motor commands from the central nervous system to effector organs (muscles and glands) to produce a response. Motor neurons are responsible for this.

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 3 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils and reminds them about the previous lesson on the nervous system. The teacher then asks pupils what happens when they accidentally touch a hot object.
Pupils’ Activity: Pupils respond to the greeting and share their experiences or knowledge about quick reactions to danger.
Learning Point: Pupils are engaged and connect to the topic through real-life scenarios.

Step 2: Functions of the Nerves

Time: 7 minutes
Teaching Skill: Explanation/Discussion
Teacher’s Activity: The teacher discusses the importance of the brain in coordinating the body and explains the various functions of the nerves, using examples.
Pupils’ Activity: Pupils listen attentively, ask questions, and list the functions of the nerves in their notebooks.
Learning Point: Pupils understand the diverse roles nerves play in the body.

Step 3: Reflex Action

Time: 7 minutes
Teaching Skill: Explanation/Illustration
Teacher’s Activity: The teacher defines reflex action, giving clear examples such as withdrawing a hand from a hot object or blinking. The teacher emphasizes that these actions are involuntary and rapid.
Pupils’ Activity: Pupils define reflex action and provide additional examples.
Learning Point: Pupils grasp the concept of involuntary, protective responses.

Step 4: Components of the Reflex Arc

Time: 8 minutes
Teaching Skill: Explanation/Visualisation
Teacher’s Activity: The teacher explains the components of a reflex arc (receptor, sensory neuron, relay neuron, motor neuron, effector) using a diagram or chart of a reflex pathway.
Pupils’ Activity: Pupils identify and name the components of the reflex arc as explained by the teacher.
Learning Point: Pupils understand the pathway of nerve impulses in a reflex action.

Step 5: Sensory and Motor Pathways

Time: 7 minutes
Teaching Skill: Explanation/Comparison
Teacher’s Activity: The teacher explains the pathways of messages to and from the central nervous system, differentiating between sensory (afferent) and motor (efferent) pathways.
Pupils’ Activity: Pupils listen and ask questions to clarify their understanding of sensory and motor pathways.
Learning Point: Pupils distinguish between the different directions of nerve impulse transmission.

Step 6: Drawing and Labeling the Reflex Arc

Time: 5 minutes
Teaching Skill: Demonstration/Practical Activity
Teacher’s Activity: The teacher guides pupils on how to draw and label a simple diagram of a reflex arc, emphasizing clear labels for each component.
Pupils’ Activity: Pupils draw and label the reflex pathway in their notebooks.
Learning Point: Pupils develop psychomotor skills and reinforce their understanding of the reflex arc.

Step 7: Evaluation/Review

Time: 4 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

State two functions of the nerves.
What is a reflex action?
List the five components of a reflex arc.
Differentiate between sensory and motor pathways.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 4 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the key points of the lesson, reinforcing the importance of nerves, reflex actions, and their pathways. The teacher then gives pupils an assignment.
Pupils’ Activity: Pupils listen to the summary, ask any final questions, and copy the assignment.
Learning Point: Pupils consolidate their understanding of the nervous system, functions of nerves, and reflex actions.

Lesson Keywords

Nerves – Bundles of nerve fibres that transmit impulses.
Reflex action – A rapid, involuntary response to a stimulus.
Reflex arc – The neural pathway followed by a nerve impulse during a reflex action.
Sensory neuron – A nerve cell that transmits impulses from a receptor to the central nervous system.
Motor neuron – A nerve cell that transmits impulses from the central nervous system to an effector (muscle or gland).
Interneuron – A neuron that connects sensory and motor neurons, typically found in the central nervous system.
Central nervous system – Comprises the brain and spinal cord.

Differentiation

For struggling learners, the teacher will provide simplified diagrams and allow more time for drawing and labeling. Advanced learners will be encouraged to research specific types of reflexes and their physiological importance.

Note for teachers using this lesson plan

Ensure the diagrams used are clear and easy for pupils to copy. Encourage pupils to relate the concepts to everyday experiences to enhance understanding. Emphasize the protective role of reflex actions.