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Central Nervous System . Peripheral Nervous System. The Nervous System . Major division - Central vs. Peripheral Central or CNS- brain and spinal cord Peripheral- nerves connecting CNS to muscles and organs. Brain. Spinal Cord. Nerves. Peripheral Nervous System.

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The nervous system l.jpg

Central Nervous System

Peripheral Nervous System

The Nervous System

  • Major division - Central vs. Peripheral

  • Central or CNS- brain and spinal cord

  • Peripheral- nerves connecting CNS to muscles and organs


Peripheral nervous system l.jpg

Brain

Spinal

Cord

Nerves

Peripheral Nervous System

  • 3 kinds of neurons connect CNS to the body

    • sensory

    • motor

    • interneurons

  • Motor - CNS to muscles and organs

  • Sensory - sensory receptors to CNS

  • Interneurons: Connections Within CNS


Peripheral nervous system3 l.jpg

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Peripheral Nervous System


Somatic system l.jpg

Brain

Sensory

Neuron

Motor

Neuron

Skin receptors

Interneuron

Muscle

Somatic System

  • Nerves to/from spinal cord

    • control muscle movements

    • somatosensory inputs

  • Both Voluntary and reflex movements

  • Skeletal Reflexes

    • simplest is spinal reflex arc


Autonomic system l.jpg
Autonomic System

  • Two divisions:

    • sympathetic

    • Parasympatheitic

  • Control involuntary functions

    • heartbeat

    • blood pressure

    • respiration

    • perspiration

    • digestion

  • Can be influenced by thought and emotion


Sympathetic l.jpg

CENTRAL NERVOUS SYSTEM

SYMPATHETIC

Brain

Dilates pupil

Stimulates salivation

Salivary

glands

Relaxes bronchi

Spinal

cord

Lungs

Accelerates heartbeat

Heart

Inhibits activity

Stomach

Pancreas

Stimulates glucose

Liver

Adrenal

gland

Secretion of adrenaline,

nonadrenaline

Kidney

Relaxes bladder

Sympathetic

ganglia

Stimulates ejaculation

in male

Sympathetic

  • “ Fight or flight” response

  • Release adrenaline and noradrenaline

  • Increases heart rate and blood pressure

  • Increases blood flow to skeletal muscles

  • Inhibits digestive functions


Parasympathetic l.jpg

CENTRAL NERVOUS SYSTEM

PARASYMPATHETIC

Brain

Contracts pupil

Stimulates salivation

Constricts bronchi

Spinal

cord

Slows heartbeat

Stimulates activity

Stimulates gallbladder

Gallbladder

Contracts bladder

Stimulates erection

of sex organs

Parasympathetic

  • “ Rest and digest ” system

  • Calms body to conserve and maintain energy

  • Lowers heartbeat, breathing rate, blood pressure


Summary of autonomic differences l.jpg

Autonomic nervous system controls physiological arousal

Sympathetic

division (arousing)

Parasympathetic

division (calming)

Pupils dilate EYES Pupils contract

Decreases SALVATION Increases

Perspires SKIN Dries

Increases RESPERATION Decreases

Accelerates HEART Slows

Inhibits DIGESTION Activates

Secrete stress

hormones

ADRENAL

GLANDS

Decrease secretion

of stress hormones

Summary of autonomic differences


Central nervous system l.jpg

Brain

Spinal

Cord

Central Nervous System

  • Brain and Spinal Cord


Brain has 2 hemispheres l.jpg

Corpus Callosum

Right

Hemisphere

Left

Hemisphere

Brain has 2 Hemispheres

  • Left & Right sides are separate

  • Corpus Callosum : major pathway between hemispheres

  • Some functions are ‘lateralized’

    • language on left

    • math, music on right

  • Lateralization is never 100%


Each hemisphere is divided into 4 lobes l.jpg

Frontal

Parietal

Occipital

Temporal

Each hemisphere is divided into 4 lobes


Sensory information sent to opposite hemisphere l.jpg

Left visual

field

Right visual

field

Optic

nerves

Left Visual

Cortex

Corpus

Callosum

Right Visual

Cortex

Sensory Information sent to opposite hemisphere

  • Principle is Contralateral Organization

  • Sensory data crosses over in pathways leading to the cortex

  • Visual Crossover

    • left visual field to right hemisphere

    • right field to left

  • Other senses similar


Contralateral motor control l.jpg

Motor Cortex

Somatosensory Cortex

Contralateral Motor Control

  • Movements controled by motor area

  • Right hemisphere controls left side of body

  • Left hemisphere controls right side

  • Motor nerves cross sides in spinal cord


Corpus callosum l.jpg

Medial surface of right hemisphere

Corpus Callosum

Corpus Callosum

  • Major ( but not only) pathway between sides

  • Connects comparable structures on each side

  • Permits data received on one side to be processed in both hemispheres

  • Aids motor coordination of left and right side


Corpus callosum15 l.jpg
Corpus Callosum

  • What happens when the corpus callosum is cut?

  • Sensory inputs are still crossed

  • Motor outputs are still crossed

  • Hemispheres can’t exchange data


The split brain studies l.jpg

Verbal

left

hemisphere

Nonverbal

right

hemisphere

The ‘Split Brain’ studies

  • Surgery for epilepsy : cut the corpus callosum

  • Roger Sperry, 1960’s

  • Special apparatus

    • picture input to just one side of brain

    • screen blocks objects on table from view


The split brain studies17 l.jpg

“What did

you see?”

“Using your left hand,

Pick up what you saw.”

“What did

you see?”

??

I saw an

apple.

Verbal

left

hemisphere

Nonverbal

right

hemisphere

Verbal

left

hemisphere

Nonverbal

right

hemisphere

The ‘Split Brain’ studies

  • Picture to left brain

    • can name the object

    • left hand cannot identify by touch

  • Picture to right brain

    • can’t name the object

  • left hand can identify by touch


Localization of function l.jpg

Frontal

Parietal

Occipital

Temporal

Localization of function


Occipital lobe l.jpg
Occipital Lobe

  • Input from Optic nerve

  • Contains primary visual cortex

    • most is on surface inside central fissure

  • Outputs to parietal and temporal lobes

Occipital

Lobe

Visual

Lobe


Temporal lobe l.jpg

Auditory

Cortex

Temporal

Lobe

Temporal

Lobe

Temporal Lobe

  • Contains primary auditory cortex

  • Inputs are auditory, visual patterns

    • speech recognition

    • face recognition

    • word recognition

    • memory formation

  • Outputs to limbic System, basal Ganglia, and brainstem


Parietal lobe l.jpg

Somatosensory

Cortex

Parietal

Lobe

Parietal Lobe

  • Inputs from multiple senses

  • contains primary somatosensory cortex

  • borders visual & auditory cortex

  • Outputs to Frontal lobe

    • hand-eye coordination

    • eye movements

    • attention


Frontal lobe l.jpg

Frontal

Lobe

Working

Memory

Motor

Cortex

Motor

Cortex

Motor

Cortex

Broca’s

Area

Frontal Lobe

  • Contains primary motor cortex

  • No direct sensory input

  • Important planning and sequencing areas

  • Broca’s area for speech

  • Prefrontal area for working memory


Frontal lobe disorders l.jpg
Frontal Lobe Disorders

  • Broca’s area

    • productive aphasia

  • Prefrontal area

    • lose track of ongoing context

    • fail to inhibit inappropriate responses

  • Often measured with the Wisconsin Card Sorting Task


Wisconsin card sorting task l.jpg
Wisconsin Card Sorting Task

  • Row of 4 example cards set out

  • Patient is given a deck of 64 different cards

  • Told to place each card under the one it best matches

  • Told correct or incorrect after each card

Correct!

  • Must deduce what the underlying rule is.


The nervous system summary l.jpg

Central Nervous System

Peripheral Nervous System

The Nervous System: Summary

  • Major structures of the nervous

    • CNS, Somatic, Autonomic

    • Two hemispheres & 4 lobes

  • Organization

    • contralateral input & output

    • primary sensory areas

    • motor areas

    • Commissure

  • Localization of functions


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