My advice to people today is as follows: if you take the game of life seriously, if you take your nervous system seriously, if you take your sense organs seriously, if you take the energy process seriously, you must turn on, tune in, and drop out. -Timothy Leary
FUNCTIONS of the nervous system
- Interpretive: Sensory information brought to the center of the nervous system is processed and interpreted.
- Motor: Motor nerves convey information from the centers of the nervous system to the muscles and glands of the body.
- Sensory: Sensory nerves gather information from inside the body and the outside environment. They then carry the information to the central of the nervous system.
Structures of the system
- Central nervous system: consist of the brain and spinal cord. These are protected by bone and cushioned from injury by the cerebrospinal fluid aka CNS
- Peripheral system: this part connects the central nervous system to the rest of the body.
Central nervous system
The brain is a huge tissue of soft nerves which is protected by the skull. Made of mostly grey and white matter which re cell processes. The grey part is found in the periphery of the brain and in the center of the spinal cord. The white is found deep in the brain at the periphery of the spinal cord as the peripheral nerves. The Brain divides into:
- Cerebrum: largest part of the brain. This is what gives you your five senses. It is the center of thoughts and intelligence. It is divided into the right and left hemispheres. The right of the body controls the left sides movement and the left side controls the right sides movement.
- Cerebral cortex: this is the outside of the cerebrum, in control of learning, reasoning, language and memory.
- Cerebellum: below the cerebrum and the back the skull. It is in charge of voluntary muscles, balance and muscle tone.
- Medulla: this controls heart rate, breathing, swallowing, coughing and vomiting. With this it forms the brainstem which connects the cerebrum to the spine.
The spinal cord connect to the medulla and is around 45 centimeters long. It's almost like a message pathway between the brain and the rest of the body. Motor nerves travel through the spine and down to different types of organs. When the impulses reach they leave the cord to travel to the target organ. Sensory or afferent impulses also use the spine to travel throughout the body.
- Peripheral system: Connects the central nervous system to the rest of the body.
- Autonomic nervous system: controls the heart, smooth muscles which are organs and glands. It's divided into the “fight or flight system” and the “ resting and digesting system”
- Somatic nervous system: allows us to consciously or voluntary control the skeletal muscles. It contains 12 cranial nerves and 31 spinal nerves.
- Nerves: made of cells called neurons. They are comprised of a dendrite, a cell body and axon. The impulses move through the dendrite and the axon. Special sheath called myelin in reseals the conductivity of the neurons.
- Neuron: is a special cell that make us cells quickly sending messages to the body.
Throughout our body lies a huge network of nerves or neurons. These neurons are in some cases so small that they can only be seen under a microscope. They are threadlike cells that run from the spinal cord out to every area of our body. They allow us to experience our world, to touch, taste, see, hear, smell, and move. They tell us when it is too hot or that the wind is blowing. They also tell us to cover our eyes when the sun is too bright or that the bug crawling on our arm tickles. The nerves provide us with information, but they also tell our body to respond to pain, temperature, or other sensations too.
- Nerves: a whitish fiber or bundle of fibers that transmits impulses of sensation to the brain or spinal cord, and impulses from these to the muscles and organs.
The nervous system governs all the working parts of our body — even some that we are unaware of. For example, you do not need to tell your heart to beat. We don't need to remind ourselves to breathe. These functions of the body are called involuntary reflexes. Our body does these things without our conscious effort. Sneezing, coughing and blinking are also forms of involuntary reflexes.
We also have voluntary reflexes. Voluntary reflexes tend to be learned behaviors that we do without really thinking. Kicking a soccer ball as it rolls toward your foot is something that you had to learn how to do. But the thought process involved in kicking it becomes easier and less conscious over time. The message from the brain to the nerves is often slower than an involuntary reflex because it must make two trips — one from the brain to tell the body something and then the response to actually do that thing — but it is still so fast that one wouldn't know the difference. Habits like biting your nails or popping your knuckles would be considered voluntary reflexes.
- Reflexes: The sympathetic and parasympathetic nerves are what causes a fast heart rate when you're scared or nervous.
Here ARE SOME VIDEOS ABOUT OUR NERVOUS SYSTEM (CRASH COURSE)
Frequently asked questions
1: Why are nerves so important to our body?
Nerves are important to sense what's going on around you or within you. They tell your body where you are or what's around you. They tell your heart to speed up or slow down, your stomach when it's full, and they let your bladder know when you need to go to the bathroom. They are very important for every part of our functioning.
2: What are nerves made out of?
Nerves are made out of axons like the wire that's in an electrical cord. There is an axon, or wire, that transmits the energy. The axon is covered with a coating called a myelin sheath, which protects it, and also keeps the electricity that is traveling along the axon from leaking out.
3: When you get older, will you get more nerves?
You generally don't grow more nerves. You can heal an injured nerve if the injury is not too deep. If you injure the myelin sheath, or coating, of a nerve, you can regrow the coating. That's what happens when you bruise your funny bone. If you actually injure the axon of a nerve, most of the time, it doesn't re-grow.
4: What does the nervous system look like?
If you look at the nervous system without any covering or with the naked eye, it would look whitish and a lot like firm jello. If you look at it microscopically, you would see bundles of nerves going up and bundles of nerves going down. It would look a lot like electrical cords bundled together.
5: How fast does it take for your brain to recognize that it got hurt?
The nerve fibers that sense discomfort or pain transmit messages very, very quickly in order to keep you from being hurt. If you touch a hot pan, those nerves transmit the message very quickly in order to get you to pull your hand away from the hot pan as soon as possible and avoid further injury. It would be in the range of 200 miles per hour.
6: Why do nerves respond so fast?
Nerves respond quickly in order to keep you out of danger. If you step on a tack, then the nerve that you stimulated by doing that has to travel very quickly up to your brain to keep you from stepping on it further. Then a message travels back down allowing you to quickly step off the tack. This fast response helps keep you out of danger.
7: Why does a nerve not regenerate when it gets harmed?
Some nerves do regenerate. In the peripheral nervous system, the arms and legs, if a nerve is injured, it can sometimes re-grow if it hasn't been injured too severely. Most of the time, they don't. The number we are born with is the number that we get. You have to take good care of your nerves.
8: Does the nervous system create fear?
The nervous system doesn't create fear. It responds to fear. If you are walking in the woods and a bear shows up, your eyes see the bear. A message is then sent to the rest of the brain and the brain reacts, or responds, to that stimulation.
9: What makes people ticklish?
There isn't a specific answer to that. The thought is that ticklish areas, like the bottom of your feet or under your arms, tend to be vulnerable. When they feel that something is going to happen, they withdraw for protection.
10: Why does it hurt so much when you hurt your elbow?
It's not funny even though it is called the funny bone. The ulnar nerve is a nerve that goes to the pinky finger and half of the ring finger. It travels through a bony canal in the elbow. That groove of the canal in the elbow does not have a lot of protection. If you bang it, you actually bruise or shock the nerve.
- video about peripheral nervous system w/ pictures
- Virtual heart app
- Neuroanatomy word search app