S: The Nervous System
BC: Made by: Kayla Guerrero | I hope you liked it!
FC: By Kayla Guerrero Period 3 | The | Nervous | System
1: The Nervous System
2: The | Nervous | System | The nervous system is a very important thing in our bodies. You defiantly could not survive with out it. It can be compared to a telephone communication system. I will also tell you about the different parts of the brain that controls some of this. Like the cerebrum, cerebellum, and the medulla oblongata. Reflexes are a very important thing in the nervous system too. The nervous system is very essential to all of us.
4: How it | Works | The Nervous System is made up of 'wires' that are our nerves. Neurons are nerve cells that have many fibers that connect to it. Just like a control center, the cell body has the nucleus (center) that is in cytoplasm. Dendrites are the thread fibers that carry the messages. The axon is a large nerve fiber that carries messages away from the cell body. Messages can only travel in one direction at a time from the dendrites, then the cell body and finally to the axon to the end plate.
6: Different Types of Neurons | Neurons vary from 3 differnt types: sensory, motor and association. Carrying messages from skin, eyes, ears, nose and tongue, is the sensory neuron, towards the brain and spinal cord. Motor neurons send messages to the brain and spinal cord to muscles, to make a movement, or to glands making a serecetion. Lastly, association neurons are in the brain and spinal cord. They just connect the motor and sensory neurons to each other. These neurons let the brain know what's going on everywhere else. Also, they can carry messages starting at the brain/spinal cord.
8: Reflexes | Reflexes means to "turn back" So, when a doctor strikes you in the knee with a tool (see images to right) your leg should jerk up if your reflexes are good. This works when the nerve message is being carried by a sensory neuron to the spinal cord; then, an association neuron sends the nerve message to a motor neuron. A reflex arc is what a round trip is and all of this is involuntary. Involuntary means you can't control whether you want to do it or not. The brain does not have a part with reflexes. Reflexes can be very important to you and life saving.
10: The | Central | Nervous | System | The human body has a main 'switch board' that controls everything. It is the brain and the spinal cord. If one of these two things get injured, you could lose senses (brain) and you may be paralyzed below your injury (spinal cord). The cerebrum, cerebellum, and the medulla oblongata are all parts of the brain essential to the nervous system. The cerebrum is on the top of the brain and gets sensory messages from the body; it operates muscles, and it lets you think. The cerebellum, behind and below the cerebrum, coordinates the muscles. The lower part of the brain, the medulla oblongata, connects to the spinal cord and controls respiration, heartbeat and digestion.
12: The | Cerebrum | The cerebrum is the biggest part of the brain. It's made up of grey and white matter. The fissure is a deep groove that separates the cerebrum into two hemispheres. The cortex, surface area, is folded into convolutions, ridges. Every part of the cerebral cortex has something to do. The motor area, that's two inches wide, of the cerebral cortex, controls muscles. The left side of your brain controls the right side of your body and vice-versa because the neurons of the motor area criss-cross and connect to the other sides. When you touch something, the message is sent behind the motor area. In the back of the cerebrum, is sight. Speech, hearing, taste, and smell come from the lower parts of the cerebrum. Consciousness is the interpretation and awareness of all of the senses. The cerebral medulla is the second layer of the cerebrum that connections are also made by. Also, they connect by many different parts of the cerebral cortex.
14: The Cerebellum, Medulla, and Spinal Cord | Behind and below the cerebrum lies the cerebellum that is split into two halves and has layers of grey and white matter. It controls balance and coordination. Movements might become jerky and involuntary if this gets injured. Also, it is folded. The medulla oblongata is the lowest part of the brain that is connected to the spinal cord and is also made up of grey and white matter. White matter is on the outside and it's a passage for nerve messages originating from the central nervous system and for motor messages. In the medulla oblongata, the grey matter controls important functions (rate of breathing, heart beat, and digestion). Lots of nerves and vertebrae is what the spinal cords is made of. There are 31 pairs of nerves that stretch out to the rest of the body. Even some nerves are sent to the brain or muscles and glands.
16: Connecting to your central nervous system to your body, is the peripheral nervous system. 43 pairs of big nerves made from smaller ones that are messengers. Cranial nerves connect to the brain are 12 pairs of the 43 pairs of peripheral nerves. This includes some of the senses and balance. The vagus nerve is the longest nerve that gives nerves to your internal organs. The rest of the pairs of nerves are the spinal nerves that connect to the spinal cord to other external parts of the body. The autonomic nervous system is what some peripheral nerves are and it controls essential internal actions. We do not have to think about about these to make them happen. There are two parts to the autonomic nervous system.The parasympathetic part slows down actions; while the sympathetic part is faster and has more speed/acceleration. | The | Peripheral | Nervous | System
18: The End | The nervous system is a very essential part of our lives. With out it, you would never survive. It is made up of many different, complex things that many people don't know about, but now you know all about it.