Biopsychology- Neurons & Synaptic transmission Flashcards
What are neurons?
The cells making up the nervous system, which conduct electrical impulses
What do dendrites do?
Receive signals from other neurons or sensory receptors
What is the cell body?
Control centre of the neuron
What does the axon do?
Conducts nerve impulses away from cell body and towards other neurons
What structure do sensory neurons have?
Mostly unipolar- have a cell body, with two stems on either side
What do sensory neurons do?
Carry sensory information from the body’s sensory receptors to the brain
What are the 3 main types of neurons?
1) Sensory neurons
2) Motor neurons
3) Relay neurons
What is the structure of motor neurons?
Mostly multipolar neurons- single axon & many dendrites
What is the function of motor neurons?
Carry motor commands from CNS to skeletal muscles or glands, allowing control of movement and responses of internal systems
What structure do relay neurons have?
Mostly multipolar-have a cell body surrounded entirely by dendrites
What do relay neurons do?
Pass messages to other neurons within the CNS and allow sensory and motor neurons to communicate with each other
What are nerve impulses also known as?
Action potential
Where do neurons transmit information?
Within the neuron and from one neuron to another
What parts of neurons receive info and where from?
Dendrites from sensory receptors
What does information travel across the body in the form of?
Nerve impulse/ action potential
What does the process of synaptic transmission refer to?
The process by which a nerve impulse passes across the synaptic cleft from one neuron (presynaptic neuron) to another (postsynaptic neuron)
What is the synapse?
Small gap between neurons- end of one & dendrite/cell body of another in which neurotransmitters are released, permitting nerve impulses to travel between them
What is included in the synapse region?
1) End of pre-synaptic
2) Membrane of post-synaptic neuron
3) Synaptic gap
What are neurotransmitters?
Chemical substance that transmits nerve impulses across a synapse
What is the synaptic transmission?
Transmission of nerve impulses across the synapse
How long does a synaptic transmission take?
A fraction of a second
What is the first step in synaptic transmission?
Synaptic vesicles that store neurotransmitters move to the end of the axon
What is the second step in synaptic transmission?
As the nerve impulse goes down the axon, it stimulates the vesicles to release the neurotransmitter molecules into the synapse
What is the third step in synaptic transmission?
The neurotransmitter molecules diffuse across the synaptic cleft to the post-synaptic membrane of the next neuron & bind to specialised receptors activated by that particular neurotransmitter
What does the process of synaptic transmission produce?
Excitatory or inhibitory effects of on the postsynaptic neuron
How many receptors can most neurotransmitters bind to?
Various types e.g. serotonin can bind to at least 10 types
What happens after synaptic transmission?
The neurotransmitter is released back into the synaptic space, then it is cleared from the synaptic cleft
What processes clear the neurotransmitter from the synaptic cleft after synaptic transmission?
1) Diffusion- some of it drifts away
2) Break-down- some of it is broken down by enzymes
3) Re-uptake-some of it is taken back up into the presynaptic neuron, repackaged & stored for later
What are two types of neurotransmitter?
1) Excitatory
2) Inhibitory
What does an excitatory neurotransmitter do?
Binds with postsynaptic receptor, causing an electrical change in the cell membrane- resulting in an excitatory postsynaptic potential (EPSP) making the postsynaptic cell more likely to fire
What does an inhibitory neurotransmitter do?
Binds with a postsynaptic receptor, resulting in an inhibitory postsynaptic potential (IPSP) making the postsynaptic cell less likely to fire
Can a nerve cell receive excitatory and inhibitory neurotransmitters at the same time?
Yes
What determines whether a neuron fires or not?
Sum of all the excitatory and inhibitory synaptic input for the postsynaptic cell
