Physiology & Behavior

Neurotransmission

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USING ONE OR MORE EXAMPLES, EXPLAIN THE EFFECTS OF NEUROTRANSMISSION ON HUMAN BEHAVIORDEFINE THE COMMAND TERM

Standard/Learning Outcome B6

Jette Hannibal - Inthinking

Jette Hannibal - Inthinking

The nervous system

NS: gathers and processes information, produces responses to stimuli, coordinates the workings of different cells

CNS (brain + spinal cord): receives, processes, interprets, and stores incoming sensory information (e.g. Taste, state of internal organs)

PNS: deals with input and output of CNS through sensory and motor neurons.

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The nervous system

Neurons: basic structural unit of NS

Communication between neurons: electric conduction chemical transmission

A large concentration of neurons in the brain and the spinal cord. 80% are found in the brain’s Cerebral cortex

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Structure of neurons

Cell body or nucleus (contains DNA) Dendrites:

information transmission Axons:

the cell body. Terminal buttons:

storage of neurotransmitters. Synaptic gap:

between dendrites and terminal buttons. Where neurotransmitters “pass” information from neuron to

neuron.

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Neuron

http://learn.genetics.utah.edu/content/addiction/reward/neurontalk.html

Jette Hannibal - Inthinking

Jette Hannibal - Inthinking

Neuronal communication

Within neurons: Action potential Between neurons: Synaptic transmission

of neurotransmitters

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Action potential

Electro-chemical messages AP occurs when a neuron sends

information down an axon AP caused by an exchange of Sodium and

Potassium ions across the neural membrane

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Neurotransmitters

Chemical messengers from neuron to neuron.

Messages may also travel from neurons to to muscles and organs in the body, such as lungs or the intestines.

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Synaptic gap

Synaptic vesicles with neurotransmitters at one side of the gap (terminal buttons): pre-synaptic gap. Like “keys”

Receptor sites for neurotransmitters (like locks) at the other side of the gap: post-synaptic gap

1/10000 of a second to travel across the synaptic gap

Neurotransmitters

Jette Hannibal - Inthinking

Jette Hannibal - Inthinking

Brief intro to principles of neurotransmission

Intro to Neurotransmission

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Neurotransmitter processes

Excitatory: increases the frequency of action potential

Inhibitory: decreases the frequency of action potential

De-activation: effect of neurotransmitter stopped (destroyed by special enzyme)

Re-uptake: reabsorbed by the terminal buttons. Drugs can inhibit re-uptake so that the

neurotransmitter remains longer in the synaptic gap

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Examples of neurotransmitters

Dopamine: (inhibitory) Controls arousal levels in the brain; vital for physical motivation (e.g. associated with craving in addiction)

Serotonin: (inhibitory) Controls mood and anxiety levels High levels of serotonin are associated with optimism.

Acetylcholine (ACh): (excitatory) Controls activity in the brain connected with attention, learning and memory

Noradrenaline: (excitatory) involved in mental arousal and elevated mood

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Dopamine and serotonin

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The reward pathway - dopamine

Stimulation of the reward center is linked to release of dopamine

Rats will continuously press a lever that gives a small electrical stimulation to the pleasure center

A Song to Help

http://www.youtube.com/watch?v=XP9IEoCw5W4&safe=active

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