Lecture 2 notes - Neuroscience & behaviour states of consciousness

Lecture 2 notes - Neuroscience & behaviour states of consciousness

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Lecture 2 Neuroscience and behaviour. States of Consciousness Modules 4 – The Neural and hormonal system 4.2 Neural communication – bodies information system is billions of interconnected cells called neurons Biological psychologist: a branch of psychology concerned with the links between biology and behaviour. 4.3 Neurons – a never cell; basic building blocks of the nervous system. Dendrite: (listener) fibres receive information and conduct it towards the cell body Axon: (speaker) fibres pass the message along to the other neurons or to muscles or glands Myelin sheath: a layer of fatty tissue insulates the axons of some neurons and helps speed their impulse. -Myelin sheath: each neuron’s axon is wrapped by this fatty insulation. Supplied by surrounding Glial cells – the nutrient providers -At each node of Ranvier, not insulated section, the electrical pulse has to jump and pulse loses strength. -Fatty insulation of myelin helps the impulse gain str. Multiple Sclerosis (MS) -immune system turns on the body, causes hardening of the myelin insulation (creates a plack) -environmental and genetic factors are contributors: positive correlation btw risk and distance from equator -identical twins have 33% chance of developing MS if one twin has it -Symptoms typically develop btw 20-40years old (women 3x more likely to get MS) -visual, sensory, motor symptoms include: -Optic Neuritis – painful vision loss -reduced balance and fine motor control -constant state of tiredness -numbness or tingling in the extremities -symptoms exacerbated in high temp and high humidity (perhaps cause a further slowing in neuronal transmission) -No cure : only treatment of symptoms such as: - Corticosteroids – decrease intensity of body’s reaction to the myelin in the CNS -Interferon – substances produced by the body to regulate the immune system -injected either subcutaneously or intramuscularly
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Action Potential – message is fired from one neuron to another via brief electrical charge that travels down the axon Resting Potential- inside of the neuron is more negative charged During the action potential channels open and close causing this balance to shift. The fluid interior of resting axon has an excess of negative charged ions, while the fluid outside the axon membrane has more positively charged ions. This positive outside/negative inside state is called the resting potential. The resting axon membrane blocks positive sodium ions from entering. When a neuron fires: the first bit of the axon opens it gates, and then positively charged sodium ion s flood through the membrane. This depolarizes that part of the axon, causing the axon’s next channel to open then the next (domino effect) During a resting pause the refractory period the neuron pumps the positively charged sodium ion back outside. Then it can fire again, the myelinated neurons speed up the potentials by hopping from on myelin to the next. Threshold: the level of stimulation required to trigger a neural impulse – excitatory are signals that push –
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This note was uploaded on 04/14/2009 for the course PSYCHOLOGY PSYCH 101 taught by Professor R.ennis during the Spring '09 term at Waterloo.

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Lecture 2 notes - Neuroscience & behaviour states of consciousness

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