nervous system -structure and function of sensory, motor and relay nuerons Flashcards
what is a synaptic transmission
allows neurons to communicate by passing chemical signals/messages between them
what are the 2 types of nuerontransmitters
Excitation
Inhibition
Excitation meaning
signal sent to the nect nerve which
increase the likelihood of a new action forming in the postsynaptic cell (recieving nerve)
the electrical charge inside becomes more positive and likely to fire, known as depolarization
(more EXits)
Inhibition meaning
decrease the likelihood of a new action forming the postsynaptic cell
When the receptors are detected, the electrical charge inside becomes more negative and less likely to fire, known as Hyperpolarization
(more likely to stay IN)
Process of synaptic transmission (5)
The action potential travels down the axon of the presynaptic neuron
This forces vesicles containing neurotransmitters to merge with the cell membrane and release the neurotransmitter into the synaptic cleft
Receptors on the postsynaptic neuron’s dendrite membrane detect the presence of neurotransmitters, changing the chemistry of the postsynaptic neuron
If the change inside the postsynaptic neuron passes a threshold, a new action potential is triggered and the message is passed on
The neurotransmitters detach from the receptors and return to the presynaptic cell via transport proteins, (known as reuptake)
for a neuron
What are dendrites
Dendrites are the tree-root-shaped part of the neuron. They receive information from other neurons and transmit electrical signals to the cell body
Dendrites are covered in synapses, which allow them to receive signals from other neurons
Cell body aka soma function
the core of a neuron, responsible for maintaining the cell and keeping the neuron functioning efficiently
Nucleus function
Contains genetic information- chromosomes
nodes of ranvier function
The Nodes of Ranvier are small gaps in the myelin sheath that surrounds and insulates the axon of a neuron. They are important for the efficient transmission of electrical signals along the axon
axon function
The axon is a tail-like structure of the neuron that carries signals away from the cell body to the terminal buttons to transmit electrical signals to other neurons
myelin sheath function
the protective layer that wraps around the axons of neurons to aid in insulating the neurons and to increase the number of electrical signals being transferred.
axon terminal/ terminal buttons function
transmitting signals to other neurons through synapses
house synaptic vesticles (store various neurotransmitters that are released at the synapse)
transmission at a synapse
When an electrical impulse arrives at the end of the axon on the presynaptic neurone (also called the synaptic knob), chemical messengers called neurotransmitters are released from vesicles at the presynaptic
membrane
The neurotransmitters diffuse across the synaptic cleft and temporarily bind with receptor molecules on the postsynaptic membrane
This stimulates the postsynaptic neurone to generate an electrical impulse that then travels down the axon of the postsynaptic neurone
The neurotransmitters are then destroyed or recycled to prevent continued stimulation of the second neurone, which could cause repeated impulses to be sent
moving onto synapses
synaptic vesticle function
They store neurotransmitters and aid in their release from the presynaptic axon’s terminal
synaptic cleft function
small gap between neurons at a synapse. allows for the transmission of chemical signals, in the form of neurotransmitters, from the axon terminal of one neuron to the dendrite or cell body of another
