Neuronal signalling 2 Flashcards
Different types of patch clamping?
Whole cell, outside in, inside out
What is impalement ab?
Change in electrical activity
Which type of synapse is direct?
Electrical
Which type of synapse has a delay?
Chemical
Delay of a chemical synapse?
0.3-0.5ms
Difference in direction between electrical and chemical synapses?
Electrical–> bidirectional
Chemical–> unidirectional
Gap in a chemical synapse?
20-40nm
Stages of chemical synapse?
AP invades
Ca2+ influx
Depolarisation–> NT release
NT diffusion
Ligand binding
DEpolarization
Transmitter recycling
Vesicular membrane recycling
Where does calcium responsible for NT release come from?
Outside the Pre N as well as intracellular stores
What does the AP at the pre N immediately cause?
Change in potential, causing the VG Ca2+ and Na+ channels to open
What happens as a result of increased intracellular Ca2+ conc?
Exocytosis of the NT into the synaptic cleft
What are the first channels to be opened on the Post N membrane?
Ligand gated
Ionotropic receptors?
Open the channel directly as a result of NT binding
Two diff types of chemical synapses?
Fast and slow
Fast chemical transmission?
NT released directly into cleft
Ligand binding directly stimulates opening of Na+ channels
What does the ACh receptor have built in?
A Na+ channel
Slowchemical transmission?
NT binds to receptor
Receptor then causes signalling via G proteins which eventually cause an ion channel to open
Which type of chemical synapse doesnt have to release its NT directly into the synapse?
Slow
Which type of chemical synapse has larger vesicles?
Slow
What type of synapse is the motor end plate?
Fast
What is the threshold?
the membrane potential that results in the neuron generating the AP
What is the membrane potential equal to?
The movement of the current * the resistance of the movement
Current*resistance
IR
What causes resistance to the movement of ions (current)?
Closed ion channels
Why are cell membranes called “leaky”?
Some ions can move across the membrane w/o channels, but not many
What is a quanta?
The units of NT molecule released from a pre n
Consequence of NT binding to the receptor?
Ion channel opens, allows ions to enter the cell
What happens as a result of opening of ion channels?
Change in potential due to a charge movement
What are nongated ion channels?
Channels that are open all the time
How is a membranes permeability to an ion changed?
Opening/closing the ion channels for that ion
What can ion channels be gated by?
Binding of a chemical (NT) or electrical activity
