Lesson Notes By Weeks and Term v4 - SHS 1
ESSENTIALS FOR SURVIVAL
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ESSENTIALS FOR SURVIVAL
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Subject: General Science
Class: SHS 1
Term: 2nd Term
Week: 10
Grade code: 3.2.1.LI.3
Strand code: 2
Sub-strand code: 1
Content standard code: 3.2.1.CS.1
Indicator code: 3.2.1.LI.3
Theme: PROCESSES FOR LIVING
Subtheme: ESSENTIALS FOR SURVIVAL
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This lesson focuses on the Autonomic Nervous System (ANS), the "automatic" or "involuntary" part of our nervous system that controls essential bodily functions without us having to think about them. Think about your heartbeat, your breathing, or your digestion after eating a heavy meal of `banku` and tilapia. You don't consciously command your heart to beat or your stomach to digest; these processes are managed automatically to keep you alive and well. Understanding the ANS helps us appreciate how our bodies respond to stress, danger, and relaxation.
Part 1: The Building Block - The Neuron
Before we can understand the vast network of the nervous system, we must first understand its basic building block: the neuron (or nerve cell). Neurons are special cells that transmit electrical and chemical signals. They are like the electrical wires of the body.
Structure of a Typical Neuron:
A neuron has three main parts: the cell body, dendrites, and an axon. Cell Body (Soma): Description: This is the main part of the neuron, containing the nucleus (the cell's "control centre") and other organelles. Function: It maintains the health of the neuron and processes signals received from the dendrites. Dendrites: Description: These are short, branching, tree-like extensions that come off the cell body. Function: They act like antennas, receiving signals (nerve impulses) from other neurons and passing them towards the cell body. Axon: Description: This is a long, single fibre that extends away from the cell body. Think of it as a long cable. Function: It carries nerve impulses *away* from the cell body to other neurons, muscles, or glands. Myelin Sheath: Description: A fatty layer that covers the axon of many neurons. It's like the plastic insulation around an electrical wire. Function: It protects the axon and, more importantly, speeds up the transmission of the nerve impulse. Axon Terminals: Description: These are the small branches at the very end of the axon. Function: They form junctions (called synapses) with other cells to pass the signal on.