Nervous System

Nervous System

Middle School

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Learning Objectives

• Describe the main function and parts of the nervous system.

• Identify the three main parts of the brain and explain their specific roles.

• Differentiate between the Central and Peripheral Nervous Systems.

• Explain the functions of sensory, motor, and mixed nerves.

Key Vocabulary

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Neuron

The basic cell of the nervous system that transmits electrical and chemical signals.

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Cerebrum

The largest part of the brain that controls your ability to think and learn.

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Part of the brain that controls and coordinates all of your voluntary movements.

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Medulla

Connects the brain to the spinal cord and controls all involuntary actions.

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Reflex Action

A quick and automatic response to a stimulus without involving the brain.

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Nervous System

The network of nerve cells and fibers that transmits impulses around the body.

Cerebellum

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The Nervous System: An Overview

• The nervous system is the control center for your entire body.

• It manages your breathing, walking, thoughts, and feelings.

• It consists of the brain, spinal cord, and a network of nerves.

• Nerves carry signals between the brain and the rest of the body.

Multiple Choice

What are the three main parts that make up the nervous system?

• Brain, Spinal Cord, and Nerves

• Cerebrum, Cerebellum, and Medulla

• Sensory, Motor, and Mixed Nerves

• Heart, Lungs, and Kidneys

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The nervous system is divided into two major parts that work together seamlessly.

Central Nervous System

• ​This system is the primary command center for the entire body.

• ​​It consists of the brain and the spinal cord, which are well-protected.

• ​The spinal cord connects directly to the brain and runs down your back.

Peripheral Nervous System

• ​This system is made up of all the nerves branching off the spinal cord.

• ​​These nerves extend from the spinal cord to all other parts of the body.

• ​It is responsible for connecting the CNS to your limbs and organs.

Multiple Choice

The Central Nervous System (CNS) is comprised of which two parts?

• The brain and the spinal cord

• The nerves and the spinal cord

• The brain and the nerves

• The Cerebrum and the Cerebellum

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The Cerebrum: The Thinking Part of Your Brain

• The cerebrum is the largest part of your brain, resembling a wrinkly walnut.

• It controls your ability to think, learn, make decisions, and feel emotions.

• This part of the brain is also responsible for your memory and dreams.

• It helps you understand senses like sight and sound, and controls your speech.

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Multiple Choice

Which part of the brain is responsible for thinking, learning, and controlling your voice?

• Cerebrum

• Cerebellum

• Medulla

• Spinal Cord

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The Cerebellum and Medulla

• The cerebellum controls voluntary movements like walking, running, and painting.

• It also manages your muscle actions to help you maintain your balance.

• The medulla controls involuntary actions like sneezing, coughing, and swallowing.

• It works all the time, managing your heartbeat even when you are asleep.

Multiple Choice

Which part of the brain controls involuntary actions like your heartbeat, even while you are asleep?

• Medulla

• Cerebrum

• Cerebellum

• Nerves

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Nerves and Neurons

• The nervous system is made of special cells called neurons.

• A neuron has a cell body and small fibers called dendrites.

• Dendrites receive signals, and a long axon sends signals to other cells.

• Nerves are bundles of axons that send signals throughout the body.

Multiple Choice

What are the special cells that make up all parts of the nervous system called?

• Neurons

• Axons

• Dendrites

• Medullas

Types of Nerves

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Sensory Nerves

• These nerves act as the body's detectors for sensing the environment.

• They carry messages from sense organs to the brain and spinal cord.

• These nerves help you sense pressure, temperature, and even different tastes.

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Motor Nerves

• These nerves are known as the body's primary movers and action-takers.

• They carry messages from the brain and spinal cord to muscles.

• They tell your body's muscles and glands what actions to perform.

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Mixed Nerves

• These versatile nerves act as the body's efficient two-way communication highways.

• They are capable of carrying messages to and from the brain.

• Mixed nerves can function as both sensory and motor nerves combined.

Multiple Choice

If you touch a hot pan, which type of nerve sends the 'hot' message from your hand to your brain?

• Sensory Nerves

• Motor Nerves

• Mixed Nerves

• Spinal Nerves

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What Is a Reflex Action?

• A reflex is a very fast response that bypasses the brain.

• ​It is a quick, automatic reaction to a stimulus, protecting you from harm.

• Common examples are blinking your eyes, sneezing, or coughing.

• You withdraw your foot from a sharp object without thinking about it.

Multiple Choice

What is the key characteristic of a reflex action?

• It is an automatic response that occurs without the involvement of the brain.

• It is a slow, deliberate action controlled by the cerebrum.

• It only involves motor nerves.

• It is a response that you can consciously stop from happening.

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Common Misconceptions

Misconception	Correction
Your brain is not involved in any quick responses.	The brain is not in the initial reflex, but gets information after it happens.
The Cerebellum is responsible for involuntary actions like your heartbeat.	The Medulla controls involuntary actions. The Cerebellum coordinates movement and balance.
Sensory nerves are responsible for making your muscles move.	Motor nerves make muscles move. Sensory nerves carry information to the brain.

Multiple Choice

If a person suddenly has trouble with their balance and coordinating movements like walking, which part of the brain is most likely affected?

• The Cerebellum, because it controls coordination of voluntary movements and balance.

• The Cerebrum, because it is the largest part of the brain.

• The Medulla, because it connects the brain to the spinal cord.

• The Sensory Nerves, because they detect information from the environment.

Multiple Choice

How do the Central Nervous System (CNS) and Peripheral Nervous System (PNS) work together when you decide to pick up a book?

• The CNS (brain) makes the decision, and the PNS (nerves) carries the command to your arm and hand muscles.

• The PNS makes the decision, and the CNS carries out the action.

• The CNS and PNS work independently and do not communicate for this action.

• Only the PNS is involved in picking up a book.

Multiple Choice

A patient has damaged motor nerves in their arm, but their sensory nerves and CNS are fine. Which of the following would be the most likely outcome?

• They can feel things with their arm but cannot move it voluntarily.

• They can move their arm but cannot feel any sensations like touch or temperature.

• They cannot move their arm or feel anything with it.

• Their arm moves uncontrollably without any stimulus.

Multiple Choice

If a person's medulla were to stop functioning, but their cerebrum and cerebellum remained active, what would be the immediate and most critical consequence?

• Involuntary actions like breathing and heartbeat would stop, leading to a life-threatening situation.

• The person would lose their ability to think and learn.

• The person would be unable to walk or maintain their balance.

• The person would lose all their memories.

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Summary

• Your nervous system is the body’s command center, run by the brain and spinal cord.

• The cerebrum handles thoughts, the cerebellum balance, and the medulla involuntary actions.

• Sensory nerves send information to the CNS, and motor nerves carry out commands.

• Reflex actions are fast, automatic responses that protect the body from harm.

Poll

On a scale of 1-4, how confident are you about the concepts covered in today's review?

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