That's what makes the nervous system the body's master communicator. Updated by: David C. Editorial team. Nerve conduction. What's this? Overview The nervous system is made up of two parts. Let's examine an individual neuron up close. Related MedlinePlus Health Topics. A beginner's guide to the brain and nervous system. For Educators Log in.
Core Concepts. Neurons communicate using both electrical and chemical signals. Sensory stimuli are converted to electrical signals. If our hearing neurons are activated over and over again, it takes a stronger electrical message to continue to activate them. As a result, ear hair cells in people with hearing problems need to feel a louder sound in order to pass on the message to the neurons that travel to the brain [ 5 ].
In cases of blindness, light receptor synapse problems can cause light-sensitive cells to disappear completely [ 6 ]. Thus, light cannot be turned into electrical signals, and the information is not carried into the brain. Finally, problems with the plasticity of brain synapses can cause thinking disabilities and autism [ 1 , 2 ].
Perhaps you know someone with autism spectrum disorder? Autism causes a reduced social interaction and decreased ability to communicate with friends and family. It appears that autism may be caused by problems with plasticity—synapses do not change as much as they should when they are used [ 1 , 2 ]. Also, new synapses do not form as well as usual and therefore communication between neurons is weakened.
Although the causes of autism are still being determined, we know that it is related to our genes. So many functions of your body are carried out based on communication between cells that happens at synapses! Right now, as you are reading this, literally trillions of synapses are sending signals whizzing around your brain and into the rest of your body.
Neurons are driving movement in your muscles through neuromuscular junction synapses, allowing your eyes to move and your fingers to tap! Your brain synapses are receiving sensory information from your eyes, your ears, and your other senses, and you are using this blizzard of information to make the best decisions about what you should do next. Your synapses are changing to allow you to learn and to remember what you learn. Hopefully, your synapses will help the information in this article to stay in your brain as a long-term memory!
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Campbell Biology. Glenview, IL: Pearson Education. Synaptic signaling in learning and memory. Cold Spring Harbor Perspect. The structure of human neuromuscular junctions: some unanswered molecular questions. Muscular dystrophies: a novel player. The skull , which is made of bone, like the vertebral column, forms the first and toughest layer of protection for the brain.
Between the skull and the brain are three layers of membranes called meninges. Think of each membrane as a pillow case surrounding the brain. Finally, to prevent the brain from moving around violently inside the skull there is a fluid called cerebrospinal fluid.
As the child grows, new connections are constantly made between these nerve cells. The more we learn and make memories, the more connections formed between nerve cells.
There are two types of cells making up the brain: the neurons and the glial cells. The glial cells, also called neuroglia, are support cells that provide the neurons with nutrition and help them function well. Like the spinal cord, the brain has both myelinated neurons and unmyelinated neurons. The neurons with the myelin sheath are found deep in the middle of the brain and appear white.
The unmyelinated neurons located on the outer surface of the brain appear grey in color. The brain is made of three main parts: the brainstem, cerebellum, and the cerebrum. Use the diagram to locate each of these three sections. The brainstem connects the spinal cord to the cerebellum and cerebrum. It contains the control centers for body functions that are automatically controlled. Examples of these functions include breathing, swallowing, blinking and vomiting. The cerebellum found just above the brainstem controls muscle movements, maintains posture and balance.
The cerebrum is the largest part of the brain and is divided into two sections: the left and right hemispheres. The cerebrum controls all higher thought processes. This includes forming memories, interpreting signals received from the five senses and emotions. Neurons form pathways that relay information from the sensory organs to the brain or spinal cord.
Interestingly, none of the neurons forming this pathway touch each other. Between the dendrites of one neuron and the axon of another neuron is a small gap called the synaptic gap. When a nerve cell is activated, the signal passes through the cell as an electrical signal. Think of this signal as an electrical current passing through a wire.
Once the electrical signal arrives at the axon, it turns into a chemical signal so that it can pass through the synaptic gap and into the next neuron. Neurotransmitters are chemical substances produced at the ends of axons that carry the message through the synaptic gap.
Some common examples of neurotransmitters are dopamine, serotonin and epinephrine. Add these resources for a more complete lesson plan!
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