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The Human Nervous System By: Nick Jara, Matt Alden, Chris Kurnat, Rachael Mueller and Cecilia Weir **1.** The Central Nervous System consists of the brain and the spinal chord. There are five functions of the Nervous System The peripheral nervous system lies outside the nervous system and is made up of nerves and ganglia. There are two divisions. First is the sensory division and conducts action potentials from the sensory receptor to the central nervous system. The second division is the motor division and this conducts the action potentials from the central nervous system to effect organs and muscles and glands to cause body movement.
 * Sensory Input - Actions from the sensory receptors get carried along nerves to the spinal chord and the brain and then are intercepted.
 * Integration - Input produces a response and it can be stored as memory or it can just be ignored.
 * Homeostasis - Detect, interpret, and respond to changes on the inside and outside of the body. The nervous system stimulates other systems so everything goes well.
 * Mental Activity - The brain is the center of consciousness, memory, and thinking.
 * Control of muscles and glands - Muscles contract when stimulated by the nervous system. The nervous system controls movements of the body. It also controls the cardiac muscles, smooth muscles, and many glands.



Central Nervous System. **2.** The structure of a neuron consists of axons and dendrites. Axons produce action potentials (movements) away from the cell body. Dendrites receive these actions potentials. The axon terminal is the basic structure of the neuron. It is the point where information is passed and connected in the neuron. All of these structural parts of a neuron are protected by myelin. The myelin sheath protects the axons from one another. All of these structures support the function of the neuron which is to transmit information, store information, and check or judge the data that is being transported.

**3.** The brain is a jelly-like substance with three main parts; the brain stem, the forebrain, and the cerebellum. The brain stem is an extension of the spinal cord. The spinal cord consists of thirty-one pairs of spinal nerves. These nerves link the brain to the parts of the body so they can feel touches. Neurons are nerve cells in the brain that send information to one another to learn new skills.

Parts of the Brain:


 * 1) Cerebrum: Largest part of the brain that accounts for thought and action.
 * 2) Frontal Lobe: Associated with reasoning, planning, parts of speech, movement, and emotion.
 * 3) Temporal Lobe: Associated with perception, memory, and speech.
 * 4) Parietal Lobe: Controls movement, orientation, and recognition.
 * 5) Occipital Lobe: Accounts for visual processing.
 * 6) Thalamus: Deep in the forebrain and has sensory and motor functions.
 * 7) Hypothalamus: Involved in homeostasis, emotion, thirst, and hunger.
 * 8) Cerebellum: Associated with posture and balance.
 * 9) Limbic System: Contains the thalamus, hypothalamus, amygdaba, and hippocampus and is buried in the cerebellum.
 * 10) Medulla Oblongata: Controls vital body functions.

**4.** Neurons are a key part of the nervous system because they send electrical "messages" throughout our brain. The way neurons send electricity to each other is simple. First, the neuron sends the message through an axon (axons are what connect neurons to each other). Then, when the message reaches the axon terminal, the terminal sends electric impulses to neurotransmitters (chemicals made of proteins). Then the neurotransmitters send the message through the synapse (space between neurons) and the message finally ends up in the the dendrites (structure that receives electrical messages) of the neuron that the message is going to.

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 * 5. ** CVA is a sudden loss of consicousness resulting when the rupture of a blood vessel leads to a lack of oxygen or when there is a blockage. There are two main types of CVA: Ischemic (a blockage) and Hemorrahoagic (rupture of a blood vessel). Some risk factors consist of old age, hypertension, high cholestrol, smoking, and diabetes.

**6.** Did you know?
 * An average adult male brain weighs 1375 grams and adult female's brain weighs 1275 grams.
 * The human brain is about 85% water.
 * There are 45 miles of nerves in the skin of a human being.
 * At any given point of time only 4 percent of the cells in the brain are active and the rest in reserve.