Lesson Notes By Weeks and Term - Senior Secondary 2

The Central Nervous System (CNS)

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  4. The Central Nervous System (CNS)

TERM – 3RD TERM

WEEK FOUR

Class: Senior Secondary School 2

Age: 16 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Biology

Topic: THE CENTRAL NERVOUS SYSTEM (CNS)

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

  1. Describe the structure and position of the brain
  2. Identify the functions of the brain

iii. Describe the structure and functions of the Spinal cord

  1. Identify the functions of the Spinal cord

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

PRESENTATION

TEACHER’S ACTIVITY

STUDENT’S

ACTIVITY

STEP 1

INTRODUCTION

The teacher describe the structure and position of the brain using diagram provided

Students pay

attention

STEP 2

EXPLANATION

Teacher discusses the functions of the brain.

Students pay

attention and

participate

STEP 3

DEMONSTRATIO

N

Teacher describe the structure,  position and function of the Spinal cord.

Students pay

attention and

participate

STEP 4

NOTE TAKING

The teacher writes a summarized

note on the board

 

The students

copy the note in

their books

 

NOTE

THE CENTRAL NERVOUS SYSTEM

The brain

The brain is the central and most complex organ of the human body, forming the core of the nervous system. It is located in the cranial cavity of the skull and consists of various interconnected regions with distinct functions. The brain is primarily composed of neurons, glial cells, blood vessels, and supporting structures.

 The brain is located within the cranial cavity of the skull at the top part of the central nervous system (CNS).

Structure of the Brain:

- The brain is divided into several main regions, including:

  1. Cerebrum: Largest part, responsible for voluntary actions, sensory perception, and language.
  2. Cerebellum: Located at the back, it controls balance and coordination.
  3. Brainstem: Connects the brain to the spinal cord and includes the medulla oblongata, pons, and midbrain. It regulates basic life functions like breathing and heart rate.
  4. Diencephalon: Contains structures like the thalamus and hypothalamus, involved in sensory relay and various homeostatic functions.

Functions of the Brain:

  1. Cognition: The brain processes thoughts, memories, and problem-solving.
  2. Motor Control: Coordinates voluntary movements through the cerebrum and cerebellum.
  3. Sensory Processing: Interprets information received from sensory organs.
  4. Emotional Regulation: The limbic system influences emotions and behavior.
  5. Autonomic Functions: The brainstem regulates vital functions like heartbeat, breathing, and blood pressure.
  6. Homeostasis: The hypothalamus helps maintain internal balance.
  7. Speech and Language: Typically localized in the left hemisphere.
  8. Consciousness and Sleep: The reticular formation influences wakefulness and sleep.

The spinal cord

The spinal cord is a crucial part of the central nervous system, running from the base of the brain down the vertebral column. It facilitates communication between the brain and the rest of the body, transmitting sensory and motor signals.

The spinal cord is situated within the vertebral column, extending from the base of the brain (medulla oblongata) to the lumbar region. It occupies the spinal canal, which is formed by the vertebrae.

Structure of the Spinal cord

- The spinal cord is cylindrical and composed of nervous tissue.

- It consists of gray and white matter. Gray matter, shaped like a butterfly, contains cell bodies and synapses. White matter surrounds the gray matter and contains nerve fibers (axons).

- The cord is divided into segments, each corresponding to a pair of spinal nerves. Regions include cervical, thoracic, lumbar, sacral, and coccygeal.

Functions of the spinal cord

  1. Transmission of Signals: The spinal cord serves as a pathway for sensory information (afferent signals) traveling to the brain and motor commands (efferent signals) returning from the brain.
  2. Reflexes: It plays a crucial role in reflex actions, quick and involuntary responses to stimuli, which don't involve the brain directly.
  3. Coordination: The spinal cord is involved in coordinating simple motor responses and some basic rhythmic activities, like walking.
  4. Conduction: Nerve impulses travel up and down the spinal cord, allowing communication between different parts of the body and the brain.

EVALUATION: 1. Identify 3 functions of the brain

  1. Identify 3 functions of the spinal cord

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively