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2 Nervous System (NS) Peripheral NS Autonomic NS Somatic NS Central NS BrainSpinal Cord

3 What is the nervous system? Each day, you use verbal and nonverbal communication as a signal to others. For example, to signal a student has a question, he/she would raise his/her hand. The teacher would recognize this signal and direct his/her attention to the student. Your body works in much the same way. The nervous system is one of your body’s personalized communication systems. Signals are sent from one location to another in order to control and coordinate many bodily functions. The nervous system responds to internal and external stimuli.

4 Are cells, which transmit electrical signals or impulses Provide a pathway for messages going to and from the brain and spinal cord

5 Characteristics: –have a cell body, which is the largest part –have processes »are fiber-like extensions »increase the distance at which signals can be transmitted »two types of processes: dendrites -- carries signal to the cell body axons -- carries signal away from cell body

6 Myelin sheath Axon Nucleus Cell body Dendrites Axon terminals

7 Transmit signals toward the body Are short and branch extensively Neurons may have dozens of dendrites Are bound with axons to form a nerve pathway

8 Transmit signals away from the body Most neurons have only one very long axon Gaps between synaptic knobs are called synapses

9 Myelin sheath »cover the axon for protection »aid in delivery of impulses traveling through the axon by insulating the nerve

10 Is the location where neurons transfer impulses between cells Are gaps separating the axon terminal from dendrites of adjacent cell Have terminals containing sacs filled with neurotransmitters –are chemicals used by neurons to transmit impulses across a synapse to another cell

11 1.Central nervous system central processing system of the nervous system -- much like the main processing chip of a computer 2. Peripheral nervous system relays information received from the central nervous system to organs and glands

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13 Brain Spinal Cord

14 Is the central control unit for the body Is protected by the skull –cerebrospinal fluid (CSF) occupies space between two layers »functions as a shock absorber »allows for the exchange of nutrients and waste between blood and nervous tissue

15 Divided into: –cerebrum –cerebellum –brain stem Did you know the average adult human brain weighs about 3 lbs.?

16 Connects brain and spinal cord Is located beneath the cerebellum Has two regions, which act as a control system, regulating information between the brain and body –medulla oblongata –Pons INJURY to this can lead to COMA!!

17 Is enclosed in the vertebral column Is a continuation of the brain stem Serves as the main communication link between the brain and body Functions to: –transmit impulses to and from the brain –control several reflex actions

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19 Divided into two parts: 1.Motor Division –relays impulses from the central nervous system to muscles and glands 2.Sensory Division –relays impulses from sensory organs to the central nervous system

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Electroencephalogram: EEG, measures electrical impulses in the brain CT/ CAT: shows cross section images of the brain Myelogram: picture of spinal cord after a contrast is injected Cerebral Angiogram: picture of the brain’s blood vessels after a contrast has been injected Reflexes: involuntary muscle contractions responding to a stimulus Babinski’s : reflex on bottom of foot 21

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Concussion: injury to brain from impact Coma: abnormal deep sleep wit or no response to stimuli Brain contusion: bruise to brain Shaken baby syndrome: closed head trauma; brain hitting skull Alzheimer’s: degeneration of neurons in the brain Amnesia: loss of memory CVA: stroke, cerebrovascular accident; lack of o2 to brain Epilepsy: seizure; abnormal electrical impulse –Aura: the feeling before a seizure 23

Hydrocephalus: injury to brain from impact Tourette syndrome: neurological disorder with uncontrollable sounds and tics Paralysis: loss of feeling and movement –Hemiplegia –paraplegia Syncope: fainting 24