Nervous System: 2 Components And Neurons YouTube Lecture Handouts

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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

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

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

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

Reflex Arc

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