JAMES VALLEY VOCATIONAL TECHNICAL CENTER

Neuron: Nerve Neuron: Nerve CellCell

Basic structural unit Basic structural unit nervous systemnervous system

Consists of:Consists of:–nucleusnucleus–nerve fibers /dentritesnerve fibers /dentrites–axonaxon

NervesNerves

Sensory Nerves:Sensory Nerves:–carry messages carry messages toto brain brain and spinal cord and spinal cord fromfrom body body

Motor Nerves:Motor Nerves:–carry messages carry messages fromfrom brain and spinal cord brain and spinal cord toto bodybody

Connecting or Mixed Connecting or Mixed Nerves:Nerves:–Carry both sensory and Carry both sensory and motor messagesmotor messages

Divisions of CNSDivisions of CNS

CNS - central nervous CNS - central nervous system:system:–consists of brain and consists of brain and spinal cordspinal cord

Peripheral Nervous Peripheral Nervous SystemSystem–a. any nerves outside a. any nerves outside the brain and spinal cordthe brain and spinal cord

–b. Autonomic nervous b. Autonomic nervous system: controls system: controls involuntary body involuntary body functionsfunctions

Central Nervous Central Nervous SystemSystem

1. Brain:1. Brain:–a. Mass of nerve tissuea. Mass of nerve tissue–b. Protected by b. Protected by membranes & the membranes & the cranium or skullcranium or skull

C. CerebrumC. CerebrumLargest section of the Largest section of the brainbrain

Responsible for:Responsible for:–reasoning, thought, reasoning, thought, memory, speaking, memory, speaking, sensstion, sight, hearing, sensstion, sight, hearing, voluntary body movementvoluntary body movement

D. CerebellumD. CerebellumResponsible for:Responsible for:

–coordination of coordination of muscles, balance, muscles, balance, posture, & muscle toneposture, & muscle tone

E. MidbrainE. MidbrainResponsible for:Responsible for:

–conducting impulses conducting impulses between brain parts between brain parts

–certain eye reflexescertain eye reflexes

PonsPons

Responsible for:Responsible for:–conducting messages to conducting messages to other parts of the brainother parts of the brain

–Reflex actions such as Reflex actions such as chewing, production of chewing, production of salivasaliva

G. Medulla G. Medulla OblongataOblongata

Lowest part of brain Lowest part of brain stemstem

Connects to the spinal Connects to the spinal cordcord

Responsible for:Responsible for:–regulating heart beat, regulating heart beat, respirations, swallowing, respirations, swallowing, coughing, b/pcoughing, b/p

2. Spinal Cord2. Spinal CordGoes down back of body from Goes down back of body from Medulla OblongataMedulla Oblongata

Surrounded and protected by Surrounded and protected by vertebraevertebrae

Responsible for reflex actionsResponsible for reflex actionsCarries sensory and motor Carries sensory and motor messagesmessages

3. Meninges3. Meninges

Consists of 3 Consists of 3 membranesmembranes

Covers and protects Covers and protects the brain and spinal the brain and spinal cordcord

Three MembranesThree MembranesC. Dura materC. Dura mater

–thick, tough outer layerthick, tough outer layerD. Arachnoid membraneD. Arachnoid membrane

–middle delicate weblike layermiddle delicate weblike layerE. Pia materE. Pia mater

–inner most layer with blood inner most layer with blood vessels to nourish the nerves vessels to nourish the nerves

4. Ventricles4. Ventricles

Four hallow spaces located Four hallow spaces located in the middle of the brain.in the middle of the brain.

Connected to each otherConnected to each otherFilled with fluid called Filled with fluid called cerebrospinal fluidcerebrospinal fluid

Cerebrospinal FluidCerebrospinal Fluid

Circulates continuouslyCirculates continuouslyServes as shock Serves as shock absorber to protect absorber to protect brain and spinal cordbrain and spinal cord

Carries nurients to parts Carries nurients to parts of brain and spinal cordof brain and spinal cord

helps remove metabolic helps remove metabolic products & wastesproducts & wastes

after circulation, after circulation, absorbed into the blood absorbed into the blood vessels of the dura vessels of the dura mater.mater.

Peripheral Nervous Peripheral Nervous SystemSystem

Made of all nerves Made of all nerves outside the brain and outside the brain and spinal cordspinal cord

Consists of cranial and Consists of cranial and spinal nervesspinal nerves

A. Cranial NervesA. Cranial Nerves12 pairs & their branches12 pairs & their branchesSome responsible for Some responsible for special senses: sight, special senses: sight, hearing, taste, smellhearing, taste, smell

Others receive sensations: Others receive sensations: touch, pressure, pain, touch, pressure, pain, temperaturetemperature

B. Spinal NervesB. Spinal Nerves

31 pairs & their branches31 pairs & their branchescarries messages to & carries messages to & from the spinal cordfrom the spinal cord

Both sensory and motor Both sensory and motor nervesnerves

31 spinal nerves:31 spinal nerves:–8 cervical8 cervical–12 thoracic12 thoracic–5 lumbar5 lumbar–5 sacral5 sacral–1 coccygeal1 coccygeal

3. Autonomic 3. Autonomic Nervous SystemNervous System

Helps maintain a balance Helps maintain a balance in involuntary functions in involuntary functions of the body. But allows of the body. But allows the body to react in the body to react in times of emergency.times of emergency.

2 divisions of ANS2 divisions of ANS Sympathetic Sympathetic

nervous nervous systemsystem–acts in acts in emergencyemergency

ParasympatheParasympathetictic–counter acts counter acts the the sympathetic sympathetic ns after the ns after the emergencyemergency

SNSSNS– increase heart increase heart raterate

– increase resp. increase resp. raterate

– increase b/pincrease b/p–decrease decrease digestive digestive system activitysystem activity

PNSPNS–decrease heart decrease heart raterate

–decrease resp. decrease resp. raterate

–decrease b/pdecrease b/p– increase increase digestive digestive system activitysystem activity