what is the role of a neuron?
Neurons work in unison with one another to produce functions
role of dendrites/cell body?
Receive information from other neurons
what is the post-synaptic site?
the dendrites and cell body
what is the pre-synaptic site?
axon terminals
what does post-synaptic site mean?
- Receiving end of the synapse
- Contains receptors to bind neurotransmitter
what does pre-synaptic site mean?
- Sending end of the synapse
- Filled with neurotransmitter
what is the role of the axon?
to carry the message from the input zone to the output zone
what is the role of the axon terminals?
Sends the message on to other cells
what is the threshold of excitation?
- Change in voltage at hillock (depolarization)
- Change opens voltage-gated Na+ channels
- Change is around 5m (-70mV to -65 mV)
step one of the action potential
- Voltage-gated Na+ channels open
- Na+ rushes in
- Cell rapidly depolarizes
step two of the action potential
- Voltage-gated K+ channels open
- K+ starts to leave the cell
- Contributes to the cell hyperpolarizing (Not immediately noticeable because of Na+)
step three of the action potential
- Na+ channels close at Na+ equilibrium (+ 50mV)
- Cell begins to hyperpolarize
- Na+ isn’t rushing in
- Na+/K+ pumps are pushing Na+ out
- K+ is still leaving via its open channels
step four of the action potential
- K+ channels finally close slowly
- Cell hyperpolarizes: overshoots the resting potential
- Eventually cell comes to the resting potential
what is the synapse?
Two cells communicate with one another via a chemical messenger
what is the goal of the pre-synaptic cell?
get neurotransmitter into the synaptic gap
what is the goal of the post-synaptic cell?
cause a ‘yes’ or ‘no’ signal
Glutamate (Glut)
- Major excitatory neurotransmitter
- MDMA receptors
- involved in learning and memory
- Involved in excitotoxicity
- Can happen in injury or stroke
GABA
- Major inhibitory neurotransmitter
- Contains many binding sites for depressants (Alcohol, Xanax, Barbituates)
Acetylcholine (ACh)
- Neurotransmitter of the neuromuscular junction
- Role in learning and memory
- Loss of ACh in the basal forebrain is associated with Alzheimer’s disease and dementia
Dopamine (DA)
-Involved in movement (Basal Ganglia)
-Loss of DA in Parkinson’s disease is associated with movement dysfunction
-Reward and pleasure (Limbic System)
-Increased DA is associated with addiction
Planning and Cognition (Cortex)
-Increased DA is associated with schizophrenia
Norepinephrine (NE)
- Involved in arousal and vigilance
- Involved in emotion
- Increases in NE associated with the stress response
- Decreases in NE associated with depression
Serotonin (5-HT)
- Involved in sleep, appetite, sexual function, and mood
- Decreased 5-HT is associated with anxiety and depression
what structures make up the central nervous system?
brain and spinal chord
what is the spinal chord?
- ‘Superhighway’
- Dorsal portion=sensory info (Body to brain)
- Ventral portion=Motor info (Brain to body)
- Spinal reflexes can act independently of the brain
