Nervous System: Components, Nerves, Neurons and Neural Transmissions YouTube Lecture Handouts for Arunachal Pradesh PSC

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Nervous System: 2 Components and Neurons

Components of Nervous System

Image of Components of Nervous System

Image of Components of Nervous System

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Peripheral Nervous System

  • Somatic: Message to & from sense organs & skeletal muscles – Striated Muscles

  • Autonomic (self-governing): Message to & from internal organs & glands – Smooth Muscles

Image of Peripheral Nervous System

Image of Peripheral Nervous System

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Image of Parasympathetic And Sympathetic

Image of Parasympathetic and Sympathetic

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Image of Cranial Nerve Name

Image of Cranial Nerve Name

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Neurons

  • Sensory Neurons – input from sense organs

  • Motor Neurons – Stimulate muscles & movements

  • Interneurons – b/w sensory & motor & interconnections

  • Glial Cells – Care & feeding of neurons & connection among neurons, these are 10 times that of neurons

Structure of Neuron

Image of Dendrites, Cell Body And Myelin Sheath

Image of Dendrites, Cell Body and Myelin Sheath

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Image of Synaptic Cleft And Synapse

Image of Synaptic Cleft and Synapse

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Neuron

Image of Neuron

Image of Neuron

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How Information Moves?

  • Nerve Impulse - Primarily Electrical

  • Communication b/w neurons – Chemical – Neurotransmitters

  • Neurotransmitters – Either excite or inhibit

Nerve Impulse

  • Electrically charges molecules – Ions inside neurons

Will be discussed in separate tutorial

Neurotransmitters

Exitatory input greater than inhibitory input

Exitatory Input Greater Than Inhibitory Input

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Table of Neurotransmitters

Neurotransmitter

Mode of Action

Deficiency

Excess

Acetylcholine (blocked by drug curare)

Excitatory

Alzheimer’s

Violent muscle contractions

Dopamine (drug cocaine behaves similarly)

Excitatory

Parkinson’s

Schizophrenia

Glutamate

Excitatory

Tiredness

Neuron Death & Autism

Norepinephrine

Excitatory

Depression

Anxiety

Serotonin

Inhibitory

Anxiety, Mood Disorder, Insomnia

Autism

GABA

Inhibitory

Anxiety

Sleeping & Eating Disorders

Endorphin

Inhibitory

Experience Pain

No information on Pain

Neuropeptides

  • Don’t carry message directly

  • Brain chemicals that regulate activity of other neurons

  • Enkephalins – Opiate like regulators to relieve pain & stress

  • Endorphins – by Pituitary Glands to relive pain & stress

Neural Networks

  • Interlinked collection of neurons

  • A reflex arc – stimulus provokes automatic response

  • One neuron may weigh hundred of inputs to outward message

  • Each neuron is a tiny computer – billions of neurons & trillions of synapse

Image of Neural Networks

Image of Neural Networks

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Reflex Arc

Image of Sensory Neuron, Connector Neuron And Motor Neuron

Image of Sensory Neuron, Connector Neuron and Motor Neuron

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Neuroplasticity & Neurogenesis

Neuroplasticity – Capacity of brain to change in response to experience

  • Hebb’s rule: Repeated activation of synapse b/w 2 neuron strengthen connection between them

  • If in complex situation – longer dendrites & more synapse (eg. rat)

  • Human brain is neuron-plastic – patience & persistence

Neurogenesis – Growth of new neurons & production of new brain cells

  • Constraint Induced Movement Therapy – Constraint right arm so that impaired left arm becomes active