Central nervous-system
Transcript of Central nervous-system
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