Module 3: Lecture 6 Flashcards
True or False
The synapses can be inhibitory or excitatory?
True
What is an ionotropic receptor?
- the ion channels that use receptors to activate them in order for ions the freely pass through
- DIRECTLY affecting the cell membrane because they are directly an ion channel that opens up
ie. neurotransmitter’s bind to the channels to allows ions through
What are metaoblotrophic receptors?
- these receptors respond to a neurotransmitter binding to them, although do different tasks
- Act INdirectly on an ion channel, because it can alter its excitability
- 2nd messangers or G protein
Where can we find the ionotropic and metabotropic receptors?
on the sub synaptic membrane
What is EPSP?
excitatory post-synaptic potential (graded potential)
What is responsible for an EPSP?
sodium bringing more positive charge into the cell to get closer to the threshold potential
One single EPSP from a single neuron is only going depolarize the cell by how much?
0.5 mV
What is an IPSP
inhibitory post-synaptic potential
What ions contribute to thE IPSP?
Potassium K+ and Chloride Cl-
What is Chlorides rest concentration Intracellularly and Extracellularly?
Intracellularly = 7
Extracellularly = 100
Which direction chemically would chloride want to move?
intracellularly, down the concentration gradient
What is chlorides resting membrane potential?
-70 mV or so
What are 2 ways the cell uses to transport chloride?
- Active transport of Cl- into or out of the cell (requires ATP)
- Into the cell means more “-“ charge causing a hyper polarization
- Out of the cell mean more
“+” charge causing a depolarization
*ONLY IN CELLS THAT CAN ACTIVELY TRANSPORT CHLORIDE
- Passive transport of Cl-
- only moving depending on its equilibrium potential relative to membrane potential
What is the point of chloride?
stabilizes membrane potential, to counter other ions channels
What is 3 causes for synaptic delay?
- Presynaptic neuron
- electrical signal - Chemical conversion
- neurotransmitter receptor combination - Post-synaptic neuron
- electrical signal
How long is a synaptic delay?
0.5 - 1 milisec for 1 synapse
What are the 3 mechanism that nerves use to remove neurotransmitters from the synaptic cleft?
- Actively uptake back to axon terminal (endocytosis and recycled)
- Diffuse away from the receptors site and the synaptic cleft
- Enzymatically degraded
(enzymes from postsynaptic neuron that will physically degrade the neurotransmitters, then retaken to presynaptic neuron to be recycled)
What does GPSP stand for?
Grand Post-Synaptic potential
What is the Grand Post-Synaptic potential?
The sum of thousands of inputs to the post synaptic cell being either EPSP or IPSP
What is temporal summation?
When the same neuron is activated twice, sending their EXCITATORY “signal” in a close enough time frame that they summate their EPSP’s on top of one another
ie. A+A
What is spatial summation?
Having two different neurons firing their EXCITATORY “signals” in a close time frame
ie. A and B
What is spatiotemporal summation?
the sum of temporal summation and spatial summation will dictate weather the threshold is met
*This can be excitatory and inhibitory signals together as well
What is presynaptic inhibition/facilitation?
This is when there are pre synaptic neurons acting on other pre synaptic neurons not allowing for it’s signals to pass to the postsynaptic neuron
ie. GOAL TO ACTIVATE NEURON “C”
- neuron “A” and “D” are excitatory and are pre synaptic neurons trying to pass the signal along
- neuron “B” attached to neuron “A” rather than neuron “C”
- neuron “B” has inhibitory response therefore when attached to “A” counteracts it’s effects
True or False
Presynaptic inhibition/facilitation will effect the amount of neurotransmitter that are released either increasing or decreasing them BEFORE the synapse occurs?
True
