Nervous System: Components, Nerves, Neurons and Neural Transmissions YouTube Lecture Handouts for Tripura PSC Exam

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Nervous System: 2 Components and Neurons

Components of Nervous System

Components of Nervous System

Peripheral Nervous System

  • Somatic: Message to & from sense organs & skeletal muscles – Striated Muscles
  • Autonomic (self-governing) : Message to & from internal organs & glands – Smooth Muscles
Peripheral Nervous System
Parasympathetic and Sympathetic
Cranial Nerve Name

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

Dendrites, Cell Body and Myelin Sheath
Synaptic Cleft and Synapse

Neuron

Neuron

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 > Inhibitory Input
Table of Neurotransmitters
NeurotransmitterMode of ActionDeficiencyExcess
Acetylcholine (blocked by drug curare)ExcitatoryAlzheimer՚sViolent muscle contractions
Dopamine (drug cocaine behaves similarly)ExcitatoryParkinson՚sSchizophrenia
GlutamateExcitatoryTirednessNeuron Death & Autism
NorepinephrineExcitatoryDepressionAnxiety
SerotoninInhibitoryAnxiety, Mood Disorder, InsomniaAutism
GABAInhibitoryAnxietySleeping & Eating Disorders
EndorphinInhibitoryExperience PainNo 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
Neural Networks

Reflex Arc

Sensory Neuron, Connector Neuron and Motor Neuron

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

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