Nervous System Functions
Lesson Transcript:
In this lesson, we'll discuss the nervous system and its function. You'll learn about the main parts of the nervous system - the central and peripheral nervous systems - and how they function in the body.
Your Nervous System
How do your lungs remember to breathe when you're asleep? How does your big toe know to wiggle when a fly lands on it? How does your nose tell you that cookies are baking in the kitchen? These things are all handled by your nervous system, which is a network of organs and nerves that sends signals throughout the body. Your nervous system controls everything you do, including breathing, moving, and smelling.
There are two main parts that make up the nervous system: the central and the peripheral nervous systems. While the two have their own particular functions, they work together to send messages throughout the body. Let's explore a little bit further.
Central Nervous System
The central nervous system is made up of your brain and spinal cord. Your brain is your body's control center, overseeing all the functions of the body by sending and receiving messages. It receives messages from your body and the world around you and then figures out how to react to the information.
Peripheral Nervous System
The peripheral nervous system is the part responsible for actually carrying those messages to and from the central nervous system. It's made up of nerves that connect to the spinal cord. You also have some peripheral nerves that come directly off your brain, and these are called cranial nerves. Nerves act as information highways, carrying messages to and from your brain.
This peripheral nervous system can be further separated into two parts, which we'll look at in some more detail right now.
Autonomic Nervous System
The autonomic nervous system makes sure your body keeps working even when you're not paying attention. For example, it tells your stomach to digest dinner and your lungs to breathe. Do you see how the word 'autonomic' looks like the word 'automatic?' When something is automatic, it happens without you having to think about it.
Somatic Nervous System
The somatic nervous system lets you control your muscles through motor nerves, which carry messages away from your brain and send those instructions to your muscles and organs. Let's say your brain receives a sensory nerve message that a fly has landed on your big toe. Your brain sends a message down a motor nerve to your foot, so you can wiggle it off! This system is also responsible for connecting your senses (which you know as taste, sight, touch, smell, and hearing) to your brain. It does this through sensory nerves, which tell the brain what's going on outside of your body. When you eat a chocolate chip cookie, the taste buds on your tongue send taste information to the sensory nerves. Those sensory nerves carry the message to your brain. You wouldn't know how good a cookie tastes if it weren't for your somatic system!
Sometimes, you don't even have to tell your motor nerves when to move your muscles. Have you ever touched a hot stove and, as soon as your hand sensed heat, it pulled away instantly? This quick action is called a reflex. Reflexes protect you from things that might hurt you. In the case of touching a hot stove, the sensory nerves are activated, sending a message to the spinal cord, which then sends a message directly to the motor nerves, forcing your hand away before you get burned. Your nervous system is pretty smart!
Lesson Summary
Okay, let's take a couple of moments to review what we've learned. Your nervous system a network of organs and nerves that sends signals throughout the body, and it controls everything you do - from breathing to tasting. It's made up of two main parts: the central nervous system, which is made up of your brain and spinal cord, and the peripheral nervous system, which is the part responsible for actually carrying those messages to and from the central nervous system. The peripheral nervous system is further divided into the autonomic system, which makes sure your body keeps working even when you're not paying attention, and somatic system, which lets you control your muscles through motor nerves which carry messages away from your brain and send those instructions to your muscles and organs.
Now, you should understand the different systems that let your body do all the amazing things it can do on its own. Think about which different systems are at work the next time you're eating or running, or really doing anything active.
Quiz Questions:
Directions Choose the the correct answer for each question based on the reading selection above.
1. Your _____ receives messages from your body and the world around you and then figures out how to react to the information.
• Brain
• Motor nerves
• Sensory nerves
• Spinal cord
2. The central nervous system is made up of _____.
• Your brain and spinal cord
• Only your brain • All of your nerves
• Only your spinal cord
3. The _____ system is one of the two main parts of the peripheral nervous system. It takes care of automatic functions in your body.
• Somatic
• Organ
• Autonomic
• Voluntary
4. The _____ system is one of the two main parts of the peripheral nervous system. It lets you control your muscles and experience sensory information.
• Autonomic
• Brain
• Spine
• Somatic
5. _____ nerves carry messages toward the brain. They tell the brain what's going on inside and outside your body.
• Central
• Spinal
• Motor
• Sensory