PH2113 - Neuropharmacology 2 Flashcards
What is the function of the white matter?
Communicating neurones
- myelinated axons
What are the four lobes of the brain?
Parietal
Frontal
Occipital
Temporal
What is a gyrus and a sulcus?
A gyrus is a prominent rounded elevation - “folds” of brain tissue that form the cerebral hemisphere
Gyri are separated by sulci, which are the grooves or furrows on the surface of the cerebrum - these are the areas between the gyri
What are the two hemispheres of the brain called?
Left and right hemispheres
What are the four steps to the transmission of an electrical impulse?
Depolarisation to threshold Activation of sodium channels - rapid depolarisation - more positive inside Inactivation of sodium channels and activation of potassium channels - membrane potential rectified Return to normal permeability and resting state - leak channels
What happens to sodium channels in the membrane of a neurone when the threshold membrane potential is reached?
Sodium channels are sensitive to voltage and open when threshold membrane potential is reached
What happens when sodium channels open in an axon?
More sodium channels open
Sodium channels behind the action potential become inactive
Action potential can only move in one direction
What is saltatory conduction?
The propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials
What is neurotransmission?
Process of sending signals from nerve to nerve across a synapse
- membrane depolarisation opens voltage gated calcium channels
- calcium influx triggers vesicles to move to the pre-synaptic membrane
- vesicles fuse with the membrane and release their content into the synapse
- transmitters diffuse across the synaptic cleft
- transmitter binds to receptors on the post-synaptic membrane
- may also bind receptors at pre-synaptic neurone to affect release
Give examples of two receptors that neurotransmitter can bind to
Ligand-gated ion channel receptors
G-protein linked receptors
What factors are all defined by the receptor’s structure?
Ligand binding site Antagonist binding sites Ion channel domains Recognition sites for extra- and intra-cellular modulators Sites of contact for regulatory proteins
What are the three units that make up the sodium channel?
alpha unit - forms the pore in the membrane channel beta-1 unit - regulatory - transmembrane beta-2 unit - regulatory - on extracellular side
What is the role of the voltage-gated sodium channel?
Rising phase of the action potential
- voltage dependent gating
- depolarisation
How many subtypes are there of the voltage-gated sodium channel?
9 functional members of the family
Why are there different subtypes of voltage-gated sodium channel?
Tissue specific
