Week 3_Synaptic transmission & neurotransmitter systems Flashcards
What is Phospholid bilayer
Phosphorylation is the covalent addition of a phosphate group to a protein by a protein kinase with an alteration in the activity of the protein
What are proteins in form of pumps ?
- sodium potassiumATPase
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What are ion channels
- sodium channel
-potassium channel
Ion channel is a transmembrane pore that allows ions to flow across a membrane. It exists in at least an open and closed state and is regulated by either a change in membrane potential (voltage-gated channels) or the binding of a specific neurotransmitter or chemi- cal substance (ligand-gated or chemically activated channels)
What is a leak channel ?
That is, they’re open, and they allow ions to passively flux up and down their concentration gradients. Or they can be gated in that they are closed at the resting condition and can respond to an external stimuli, be this electricity in the form of a voltage- gated channel or a neurotransmitter, for example, in the form of a ligand-gated channel, causing this gate to open and allowing these channels to flux ions across the membrane
What is a ligand ?
Ligand is a substance that binds to a membrane receptor or ion channel. Most ligands are either neurotransmitters, hormones or drug
What is graded potential
Change in potential of the membrane around the ion channel,
which can be positive or negative.
What is Axon?
Axon is the neuronal process that originates at the axon hillock and conducts information away from the neuronal cell body to the nerve terminal and synapses. There is only one axon per neuron, although that axon may have multiple branches
What is Axon hillock?
Axon hillock is the site at which the axon originates from the neuronal cell body, and is in continuity with the initial segment of the axon. This is the most excitable part of a neuron as a result of its high density of sodium channels and is therefore the site of initia- tion of the action potential
What is the threshold which will trigger an action ?
Threshold 55 mv that will trigger a neuron to fire an action potential
What is Temporal summation?
Temporal summation is based on the
timing of triggering either by a single
presynaptic input or multiple ones.
Spatial summation
Spatial summation is performed in the postsynaptic cell and refers to the integration of all synaptic inputs at a given point in time at the trigger zone
What is AIS ( Axon initial segement) ?
Initial segment of the axon is that part of the axon, adjacent to the axon hillock, which has the highest density of sodium channels and which is the most excitable part of a neuron. It is thus the site of action potential generation
What is Excitatory postsynaptic potential (EPSP)?
Excitatory postsynaptic potential (EPSP) is the depolarisation of a postsynaptic membrane in response to a synaptic input which
increases the probability that a cell will fire an action potential
What is Inhibitory postsynaptic potential (IPSP) ?
Inhibitory postsynaptic potential (IPSP) is the hyperpolarisation of a postsynaptic membrane in response to a synaptic input which decreases the probability that a cell will fire an action potential
What is neural integration of EPSP?
Changes that happen in response to
positively charged ions (sodium and
potassium ions), which moves the membrane
potential towards the triggering threshold for
an action potential.
