What is a nerve? What is a neruron?
- a nerve: is a bundle of fibers that receive and send messages between the body and the brain
l - Neuron = “ building block” of nervous system because the entire system is made of neurons
3 types of neurons
- Sensory neurons
- Interneurons ( rtelay neurons)
- motor neurons
- Sensory neurons
Pick up info from your senses to send to your brain
Sensory
Recepter—–> CNS
- Interneurons ( relay neurons)
- only found in CNS
Relay
CNS —> CNS
- Motor neurons
- Move your muscles/ organs/glands
Directly attached to muscle/glands to move them
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Dendrite
Receives info from other neurons and transmits it to the soma.
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Soma
Also known as the cell body. This contains the nucleus and maintains the neuron and keeps it functioning.
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Axon
This thin tube- like extension that transmits information from the soma to the axon terminal.
The space between two neurons.
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Axon terminal
Found at the end of axons, this small structure stores and secretes NEUROTRANSMITTERS.
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Myelin
- A white fatty substance that coats the axon
- This insulates the axon and allows the message to pass faster along the axon.
vesicles:
- carry neurotransmitters across synaptic gap
- Made out of same substances as cell membrane to be able to merge together.
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Synaptic gap
the space between tow neurons
trannsmitions from one neuron to another
Labke the synapotic gap
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What direction is the electrical impulse ?
Neurotransmitters
and their types
Are chemicals that neurons used to communicate with each other
Types:
- Adrenaline ( FFF)
- dopamine ( pleasure)
- Serotonin ( mood)
How does neurotransmission work?
- an electrical pulse causes ACTION POTENTIAL ( ions moving along axon & releases electricity )
- Neurotransmitters ( in vesicles) merge with axon terminal and release neurotransmitters into synaptic gap.
- neurotransmitters bind to the receptors of post - synaps and spark another action potential
re-uptake
neurotransmitters return to pre-synaps and wait until a new message comes along, is reused
How are excitatory and inhibitory neurotransmitters different?
Excitatory: “ gas pedal”
- Increase likelihood that a neuron will fire and electrical signal
- leading to actions or reactions in the body
Inhibitory: “brake” “slow down”
- decrease likelhood that a neuron will fire
- helps to calm brain and reduce activity
Why are neuron messages referred to as electrochemical?
Electrochemical = Neuron messages involve both electrical & chemical proccesses.
- Inside neuron the message is Electrical (IMPLUSE)
- and outside the neuron ( through synaps ) message is in chemical form ( neurotransmiiters)
