Divisions of the Divisions of the Nervous SystemNervous System

Describe the structures and functions of Describe the structures and functions of the CNS and PNSthe CNS and PNS

Explain what a reflex isExplain what a reflex isID 2 ways in which the NS can be ID 2 ways in which the NS can be

injuredinjured

Divisions of the NSDivisions of the NS

►Central Nervous System- consists of Central Nervous System- consists of the brain and spinal cordthe brain and spinal cord

►Peripheral Nervous System- all nerves Peripheral Nervous System- all nerves outside of the CNSoutside of the CNS

Central Nervous SystemCentral Nervous System

►The control center of the body, The control center of the body, including the brain and spinal cordincluding the brain and spinal cord

►Brain- located in the skull, controls Brain- located in the skull, controls most functions of the bodymost functions of the body

►Spinal cord- the thick column of Spinal cord- the thick column of nervous tissue that links the brain to nervous tissue that links the brain to most nerves in the PNSmost nerves in the PNS

Central Nervous SystemCentral Nervous System

►Three main regions of the brain that Three main regions of the brain that receive and process inforeceive and process info CerebrumCerebrum Cerebellum Cerebellum Brain StemBrain Stem

Central Nervous SystemCentral Nervous System

►Cerebrum- largest part of the brainCerebrum- largest part of the brain Interprets input from senses, controls Interprets input from senses, controls

movements, and carries out complex movements, and carries out complex mental processes mental processes

Divided into right and left halvesDivided into right and left halves The right- sends impulses to skeletal The right- sends impulses to skeletal

muscle on the left side of the bodymuscle on the left side of the body The left-sends impulses to skeletal muscle The left-sends impulses to skeletal muscle

on the right side of the bodyon the right side of the body

Central Nervous SystemCentral Nervous System

►Cerebrum- Cerebrum- The right- Creativity, artistic abilityThe right- Creativity, artistic ability The left- math skills, logical thinkingThe left- math skills, logical thinking Certain area are associated with smell, Certain area are associated with smell,

touch, taste, hearing, and vision as shown touch, taste, hearing, and vision as shown on pg 185on pg 185

Central Nervous SystemCentral Nervous System

►Cerebellum- 2Cerebellum- 2ndnd largest part of the largest part of the brainbrain Coordinates actions of your muscles and Coordinates actions of your muscles and

helps keep balancehelps keep balance

Central Nervous SystemCentral Nervous System

►Brain stem- btwn the cerebellum and Brain stem- btwn the cerebellum and spinal cordspinal cord Controls body’s involuntary actionsControls body’s involuntary actions

Central Nervous SystemCentral Nervous System

►Spinal cordSpinal cord The link btwn your brain and the PNSThe link btwn your brain and the PNS Protected by connective tissue and watery Protected by connective tissue and watery

fluidfluid

Peripheral Nervous SystemPeripheral Nervous System

►Consists of a network of nerves that Consists of a network of nerves that branch from the CNS and connect to branch from the CNS and connect to the rest of the bodythe rest of the body

► Involved in both involuntary and Involved in both involuntary and voluntary actionsvoluntary actions

►43 pairs of nerves43 pairs of nerves

Peripheral Nervous SystemPeripheral Nervous System

►How spinal nerves functionHow spinal nerves function Like a two lane highwayLike a two lane highway Impulses travel both to and from the CNSImpulses travel both to and from the CNS Sensory n. carry impulses from the body Sensory n. carry impulses from the body

to the CNSto the CNS Motor n. carry impulses from CNS to bodyMotor n. carry impulses from CNS to body

Peripheral Nervous SystemPeripheral Nervous System

►Nerves of PNS are divided into 2 Nerves of PNS are divided into 2 groupsgroups SomaticSomatic

►Controls voluntary actions (tying your shoes)Controls voluntary actions (tying your shoes)

AutonomicAutonomic►Controls involuntary actionsControls involuntary actions►Regulates contractions of smooth muscles Regulates contractions of smooth muscles

ReflexesReflexes

►An automatic response that occurs An automatic response that occurs very rapidly and without conscious very rapidly and without conscious controlcontrol

►Help protect the bodyHelp protect the body

ReflexesReflexes

►Reflex pathwayReflex pathway Sometimes skeletal muscles contract with Sometimes skeletal muscles contract with

involvement of spinal cord only, not braininvolvement of spinal cord only, not brain Touch a sharp object- message to spinal Touch a sharp object- message to spinal

cord, impulse moves to motor n. in arm cord, impulse moves to motor n. in arm and hand causing muscles to contractand hand causing muscles to contract

ReflexesReflexes

►Signaling the brainSignaling the brain At the same time, nerve impulses make At the same time, nerve impulses make

your arm muscles contract, other nerve your arm muscles contract, other nerve impulses travel to the brainimpulses travel to the brain

The impulse reaches the brain, and you The impulse reaches the brain, and you feel painfeel pain

By the time you feel pain, your hand is By the time you feel pain, your hand is already removedalready removed

Nervous System InjuriesNervous System Injuries

►Two waysTwo ways ConcussionsConcussions Spinal cord injuriesSpinal cord injuries

Nervous System InjuriesNervous System Injuries

►ConcussionsConcussions A bruise-like injury of the brainA bruise-like injury of the brain Occurs when soft tissue of the brain collides Occurs when soft tissue of the brain collides

against the skullagainst the skull May occur when your bump your headMay occur when your bump your head Most of the time- you have a headache, Most of the time- you have a headache,

injured tissue heals itselfinjured tissue heals itself More serious concussions- may lose More serious concussions- may lose

consciousness, feel confused, or feel drowsyconsciousness, feel confused, or feel drowsy

Nervous System InjuriesNervous System Injuries

►Spinal cord injuriesSpinal cord injuries Occur when the spinal cord is cut or Occur when the spinal cord is cut or

crushedcrushed Axons in the injured area are damaged, Axons in the injured area are damaged,

impulses cannot pass through themimpulses cannot pass through them Usually results in paralysis (loss of Usually results in paralysis (loss of

movement)movement)