Neurology Pharma Flashcards
(38 cards)
What is the function of a dendrite?
To receive inputs from other neurons + convey graded electrical signals passively into the soma
What is the function of a neuron’s soma?
Integrates incoming signals that are conducted passively to the axon hillock
What is the function of the axon hillock?
Initiates ‘all or nothing’ APs
What is the function of the axon?
Conducts output signals as APs to other neurons.
Mediates transport between soma and presynaptic terminal (both ways)
Give an example of a unipolar neuron
Peripheral autonomic neuron
Give an example of a pseudounipolar neuron
Dorsal root ganglion neuron
Give an example of a bipolar neuron
Retinal bipolar neuron
Give an example of a multipolar neuron
LMN
What 4 functional regions do most neurons have?
Input
Integrative
Conductile
Output
What 2 types of axons can take part in the conductile region of the neuron?
Short = Golgi type 2 Long = Golgi type 1
Nerve cell membranes are leaky - what does this mean in terms of passive signals produced?
They do not spread far from original source.
The current leaks back into the EC space across membrane resistance (Rm) generating a potential change (deltaVm).
For any given current, if Rm increases, what happens to DeltaVm?
Increases linearly with Rm
In passive conduction what happens to deltaVm over distance?
Decays exponentially
In passive signalling, what determines the distance through which current will spread?
Rm and axial resistance of the axoplasm (Ri)
For distance traveled by a passive signal to increase what must happen to the Rm/Ri ratio?
Increase also
How does passive conduction in a nerve cell help with propegation of APs?
Longer distance traveled = greater local current spread = Increased AP conduction velocity
What 2 strategies can be put in place to increase passive current spread and therefore the AP velocity?
Decrease Ri - increase axon diameter
Increase Rm - add insulation to nerve fibre
What is the significance of the Nodes of Ranvier with regards to AP conduction?
APs ‘jump’ from one node to the next.
APs activate the voltage-activated Na+ channel clusters within the nodes thus aiding further conduction.
What is an axodendritic synapse?
Presynaptic terminal synapses onto a dendrite of the receiving cell. Very common
What is an axosomatic synapse?
Presynaptic terminal synapses onto the cell body of the receiving cell. Common
What is an axoaxonic synapse?
Presynaptic terminal synapses onto an axon of another neurone. Uncommon.
In an excitatory synapse in the CNS, what is the most common transmitter?
Glutamate
What effect does glutamate have on an excitatory synapse?
Activates postsynaptic, cation selective, ionotropic, glutamate receptors generating a local, graded, excitatory response.
what is an e.p.s.p?
excitatory postsynatic potential
