The Nervous System

1. The Nervous System By Emily Lopez & Nathalie Mairena

2. The Nervous System INTRODUCTION The nervous system is a organized network of specialized cells called neurons that travel through the length of the body. They work in controlling all functions of the body. They also respond to any stimuli on the inside or outside of the body. The nervous system consists of the central and peripheral nervous system.

3. Cells In the Nervous System NEURONS Neurons are the cells that basically make up the body. They are long cells that travel throughout the body. They are responsible for transferring messages to and from the brain , collecting messages from all over the body. They send back a reaction from the brain. The stimuli needs to exceed a certain level, or threshold, to trigger an impulse. A bundle of neurons is known as a nerve. Neurons are unique in that they do not repair themselves the way other cells do. Once they are damaged, they usually stay that way.

5. Cells In the Nervous System KINDS OF NEURONS There are three basic kinds of Neurons: SENSORY NEURONS: These neurons carry the impulses sent by sense organs, such as the eyes, ears and tongue to the brain and spinal cord. MOTOR NEURONS: These cells assist in sending messages from the brain to the muscles, thus helping in movement. INTERNEURONS: These do some of the most complex work of other neurons. They take the messages from the sensory neurons, process them and then help them in transporting commands to other interneurons or to the motor neurons.

7. Cells in the Nervous System Structure of Neurons While there are various kinds, they all have about the same structure. CELL BODY- That is the largest part of the neuron and contains the nucleus and most of the cytoplasm DENDRITES- These extend from the cell body and act as recipients to impulses and also help in sending them throughout the nervous system AXONS- They are the long part of the cell that extends from the cell body and helps carry impulses through the cell MYELIN SHEATH- A waxy covering of the axon that helps in insulating. If damaged, impulses do not travel properly through the cell. Without them, impulses would not travel as quickly or efficiently without them NODES-These are the gaps between the Myelin Sheath. The impulses jump from node to node.

9. Cells In the Nervous System THE SYNAPSE At the end of a neuron is a part which helps in the transfer of impulses to another neuron. They are called synapses. A cloud of chemicals that transfer the impulse from the synapse to another cell is called a neurotransmitter.

11. Cells In the Nervous System GLIAL CELLS These cells are also known as neuroglia. These cells help in maintaining the nervous system. They outnumber neurons 10 to 1. These cells do jobs such as keeping blood flowing to the neurons, supplying them with proper nourishment, recycling neurotransmitters, breaking down dead neurons and creating myelin sheaths, and protect the brain from chemicals. Without them, the nervous system would not function at all.

13. The Central Nervous System The Central Nervous System is in charge of storing and processing information. The brain and the spinal cord are the main components of the central nervous system. Several layers protect the Central Nervous system. The Dura mater, the arachnoid mater, and the pia mater. It is also protected by the cerebrospinal fluid.

15. The Brain Cerebrum: The largest part of the brain and it mainly controls conscious thinking. It is split into the left and right hemisphere. Hemisphere: are split into different lobes. Frontal Lobe: is in charge of behavior. Parietal Lobe: in charge of sensory information, like pain. Temporal lobe: in charge of hearing and smell. Occipital Lobe: in charge of vision and is where dreams take place. Cerebellum: is the second largest part of the brain. It mainly works in controlling muscle movement and balance. Brain Stem: in charge of involuntary actions, such as your heartbeat and it is what connects the brain with the spinal cord, thus with the cost of the body.

17. The Spinal Cord The Spinal Cord is the connection for the brain to the rest of the body. The main functions are to transfer information to and from the brain and in processing reflexes.

19. Peripheral Nervous System The Peripheral Nervous System are all the nerves not a part of the brain or spinal cord. The Peripheral nervous System consists of two divisions, the sensory division and the motor division. The Sensory Division The Sensory Division of the Peripheral Nervous System is what impulses from the sensory organs, like the eyes, use to get to the brain. The Motor Division The Motor Division sends impulses from the central nervous system to the muscle that needs to be moved. There are two systems under the Motor Division: the Somatic Nervous System and the Automatic Nervous System.

21. Peripheral Nervous System Nerves of the Peripheral Nervous System There are two kinds of nerves in the Peripheral Nervous System: the spinal nerve and the cranial nerve. Spinal Nerves are in charge of motor and sensory impulses. They are located off of segments of the spinal cord. Cranial nerves also control senses and movement but go from the skull to the rest of the body.

22. Peripheral Nervous System The Somatic Nervous System When you consciously control something that is the work of the somatic nervous system. When you think about moving something, your motor neurons send impulses to move the muscle. Reflexes also take place here. The Automatic Nervous System Unconscious movements are made here. Like your heart beat or breathing. Under the automatic nervous system there are two systems, the sympathetic and parasympathetic nervous system. The sympathetic nervous system heightens the sense and makes you more alert and heightens blood pressure. On the other hand, the parasympathetic nervous system relaxes the body and lowers blood pressure.

23. Stem Cells and the Nervous System Nerve Cells unlike other cells do not repair themselves. As a result many people have looked into stem cell research, or the using of undifferentiated cells to make new nerve cells or repair them. Early research has already shown improvements in patients. One woman, once paralyzed, managed to begin walking using braces.

25. Most Common Diseases of the Nervous System Cerebral Palsy Infantile Paralysis Tumors Cerebral Thrombosis Amnesia Parkinson’s Disease Brain Cancer Peripheral Neuropathy Multiple Sclerosis Meningitis

27. Thank You Resources http://en.wikipedia.org Biology Book http://www.google.com/images http://www.brainpop.com/