Biopsychology: neurons and synaptic transmission Flashcards
what is a neuron?
Neurons are nerve cells that process and transmit messages through electrical and chemical signals.
what are the three types of neurons?
Sensory neurons
relay neurons
motor neurons
what is the role of sensory neurons?
They carry messages from the PNS to the CNS.They have long dendrites and short axons.
what is the role of relay neurons?
They connect the sensory neurons to the motor or other relay neurons. They have short dendrites and short axons.
what is the role of motor neurons?
They connect the CNS to effectors such as muscles or glands. They have short dendrites and long axons.
what is a dendrite?
carry nerve impulses from neighbouring neurons to
the cell body
what is an axon?
carries the impulse away from the cell body down the length of the neuron.
what is a myelin sheath?
fatty layer which covers the axon. It insulate and protects the axon from external influences that might effect the transmission of the nerve impulse down the axon.
what are the nodes of ranvier?
these speed up the transmission of the impulse by forcing it to jump across the gaps along the axon.
what are terminal buttons?
communicates with the next neuron in the chain across a gap known as the synapse.
Is the inside of the cell negatively charged or positively charged when the neuron is at resting state?
negatively charged
what happens to the inside of the cell when a neuron is activated by a stimulus?
The inside of the cell becomes positively charged for a split second causing an action potential to occur. This creates an electrical impulse that travels down the axon towards the end of the neuron.
what is synaptic transmission?
The process by which neighbouring neurons communicate with each other by sending chemical messages across the synapse that separates them.
what is a neurotransmitter?
they are chemicals released from the synaptic vesicle into the synapse by neurons. They affect the transfer of an impulse to another nerve
neurotransmitters are taken back up into the terminal buttons of neurons.
what is the process of synaptic transmission?
- nerve impule travels down and axon and reaches synaptic terminal
- this triggers the release of neurotransmitters
- the neurotransmitters are fired into the synaptic gap
- neurotransmitters binds with the receptors on the dendrite of the adjacent neuron
- if successfully transmitted the neurotransmitter is taken up by the post synaptic neuron
- this message will continue to be passed in this way via electrical impulse.
where are neurotransmitters released from and received by ?
released from presynaptic neuron
received by post synaptic neuron
reflex arc
Stimulus
Receptor- ( sensory organs in the PNS conveys message along sensory neuron)
Sensory - sensory neuron sends the message to CNS where it connects with the relay neuron
Relay
Motor
Effector
Response
what is excitation?
when a neurotransmitter such as adrenaline increases the positive charge of the postsynaptic neuron. This increases the likelihood that the postsynaptic neuron will pass on the impulse.
what is inhibition?
when a neurotransmitter such as serotonin increases the negative charge on a postsynaptic neuron. This decreases the likelihood that a post synaptic neuron will pass on the electrical impulse.
define summation
Summation is the addition of positive and negative post-synaptic potentials. A nerve cell can receive both positive and negative potentials simultaneously.
