Human Anatomy and Physiology

Explore the intricate structures and functions of the human body, from cells to organ systems.

Cells: The Building Blocks of LifeTissues and Organs: Teamwork in ActionThe Major Body Systems
The Nervous System: Communication HeadquartersThe Circulatory System: Keeping You PumpedThe Immune System: Your Body's Defense Force
First Aid: Helping the Body HealHealthy Habits for a Strong BodyUnderstanding Medical Tests
Making Diagrams and Mind MapsUsing Mnemonics and Stories
Cells: The Building ...Tissues and Organs: ...The Major Body Syste...The Nervous System: ...The Circulatory Syst...The Immune System: Y...First Aid: Helping t...Healthy Habits for a...Understanding Medica...Making Diagrams and ...Using Mnemonics and ...
Advanced Topics

The Nervous System: Communication Headquarters

How Does Your Body Communicate?

The nervous system is your body's information highway. It includes your brain, spinal cord, and all the nerves branching throughout your body.

Neurons: The Messengers

Neurons are special cells that carry electrical signals, or impulses. These impulses travel as fast as a race car—up to 120 meters per second!

Central and Peripheral Nervous Systems

  • Central (CNS): Brain and spinal cord, where decisions are made.
  • Peripheral (PNS): Nerves outside the CNS, carrying information to and from the brain.

Real-World Applications

When you touch something hot, nerves in your skin send a signal to your brain, which quickly tells your hand to move away. This fast response protects you from harm!

Examples

  • Blinking when something comes close to your eyes is a nerve reflex.

  • Feeling pain when you stub your toe is your nervous system at work.

In a Nutshell

The nervous system controls everything you feel, think, and do by sending fast electrical messages.

Key Terms

Neuron
A nerve cell that transmits electrical and chemical signals.
Reflex
An automatic response to a stimulus that does not require conscious thought.
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The Circulatory System: Keeping You Pumped