1

2

Nervous System (NS)

Peripheral NS Central NS

Autonomic NS Somatic NS Brain Spinal 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

DendritesAxon 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

12

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

18

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

20

• 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

22

• 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 seizure23

• 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