the structure and function of neurons Flashcards
what are the 3 different types of neurons ?
- motor neuron
- sensory neuron
- relay neuron
draw and label a motor neuron
- dendrite
- cell body
- myelin sheath
- axon
- neurofibril node ( node of ranvier)
draw and label a sensory neuron
- receptor cell
- axon
- myelin sheath
- cell body
draw and label a relay neuron
- dendrite
- cell body
- axon
- pre-synaptic terminal
what does a cell body contain ?
a nucleus
what is the function of the nucleus in the cell body ?
it contains genetic material of the cell
what is the function of dendrites ?
they carry nerve impulses from neighbouring neurons towards the cell body
what is the function of the axon ?
the axon carries the impulse away from the cell body down the length of the neuron
function of the myelin sheath ?
protects the axon an speeds up electrical transmission of the impulse
what do the nodes of ranvier do ?
these speed up the transmission of the impulse by forcing it to jump across the gap along the axon
what is the function of the pre-synaptic terminals ?
they communicate with the next neuron in the chain across a gap known as the synapse
sensory neurons
- send info from senses to the brain
- tell the rest of the brain about the external and internal environment by processing info taken from one of the sense organs
relay neurons
- connects with other neurons
- carry messages from one part of the CNS to another
- connects motor and sensory neurons
motor neurons
- send messages via long axons from the brain to the muscles / effectors
- carry signals from the CNS, which helps both organs including glands and muscles to function
what is involved in synpatic transmission ?
- synaptic vesicle
- neurotransmitters
- pre-synaptic ending / axon terminulus
- synaptic gap
- post-synaptic neuron or dendrite
- receptor sites
what are synaptic vesicles ?
- small sacs that develop in the axon terminals and contain neurotransmitters specific to that neuron
what are neurotransmitters ?
these ae the chemical messengers that are transmitted from the pre to post synaptic neuron
what is the pre-synaptic ending ?
- the end of a neurons axon where an electrical impulse is turned into a chemical message
what us the function of a synaptic gap ?
gap that the chemical messages passes across
what is the post-synaptic neuron / dendrite ?
- if enough excitory neurotransmitters are received , the chemical message is turned into an electrical signal to transmit along the dendrite of the next neuron
what is the function of receptor sites ?
- neurotransmitters are received by their counter part receptors on the post synaptic membrane based on the level of excitors and inhibitors received
- summation determines whether the post synaptic neuron will fire
