Brain & Behaviour - Neurons etc. Flashcards
Describe the structure of a neuron
> dendrites receive info
axon sends signals
synapses = where neurons communicate
Neuron signalling is ___?
electrical [ions] and chemical [neurotransmitters]
How does the cell maintain resting potential?
regylated by ion channels + pumps - creates an EC gradient
Describe what happens at the synapse
Neurotransmitters bind to the postsynaptic ion channels.
- chemical change opens ion channels
- changes the electrical potential of the cell
Define summation
- multiple axons sending information to add up
- creates a large influx of +ve ions
Describe the 4 stages in forming an action potential
- resting potential: inside of membrane is -ve
- depolarisation: Na+ channels open, positive ions enter
- repolarisation: Na+ channels close, K+ channels open.
- Na+ pumped out
What is the ‘all-or-nothing’ principle?
Means that the action potential must exceed the threshold otherwise no AP is generated.
How do drugs + toxins alter neurotransmitter action?
Agonists: ENHANCE
Antagonists: INHIBIT
Example of an agonist
morphine @ opiod receptors
Example of antagonist
curare blocking Ach at neuromuscular junctions
What 2 ways are neurotransmitters controlled in synapses?
REPUTAKE: NT effects stopped by recycling the NT into presynaptic neurons
ENZYME DEACTIVATION: enzymes destroy NT
Where is GLUTAMATE found?
all over the brain
What type of NT is GLUTAMATE?
EXCITATORY
What can GLUTAMATE cause?
ischemic strokes
- blockage of blood vessels
- no oxygen = glutamate blocks synaptic cleft
- causes neurotoxicity
Why is GLUTAMATE useful?
enhances taste of food
MSG > Stimulates neurons so food flavour increases
large doses = HEADACHES
