Neurons And Neural Teansmission Flashcards
Name the two types of cells that communicate
Muscle fibers and neurons (excitable cells)
What is an action potential?
The ability to move an electrical signal down a membrane
What are the sections of an action potential?
Depolarizing, re polarizing, hyper polarizing, threshold
What is the path for sodum?
Sodium rushes in which causes depolarization and it’s channels are closed at the peak of depolarization.
What is the path for potassium
Has a slow respond and slow recovery. Potassium moves out of the cell..
Describe the molecular mechanism of an action potential
See your notes..
What happens at threshold to sodium?
There is a influx of sodium that continues to build as more channels open (positive feedback cycle)
Describe activation gates and inactivation gates
Activation gates open rapidly at threshold also at threshold the inactivation Gates start closing slowly.. Membrane repolarizes (while inactivation gate is closed) once membrane is repolarized the gate resets.
Describe the 4 zones of a neuron
Input zone
Output zone
Conducting zone
Trigger zone
What is the point of the myelin sheath
Produces faster conduction.
What do glial cells do?
Support neurons
What is an afferent neuron?
Sensory towards the Cns
What is a efferent neuron?
From Cns towards muscles and glands
What are the events at the synapse?
See notes if you have forgotten
What are neutotransmitters?
Chemical messengers that bridge the gap between the presynaptic cleft and post synaptic membrane
What are graded potentials? Name the two types
Signals coming from receptors on the membrane that add together to create an action potential (some are for an action potential some are against)
Spatial summation
-when Two different neurons fire at the same time
Temporal summation
When a neuron fires rapidly twice it more times in a row.
What are epsps and ipsps
Graded potentials
Excitatory post synaptic potentials
Inhibitory post synaptic potentials
Describe how action potentials are propagated across a membrane
See book for details
What is the difference between an absolute refractory period and a relative refractory period.
Absolute is immediately following the action potential
Relative follows the absolute refractory period
Describe saltatory conduction
See notes for more details
How do activation/ inactivation gates help with the refractory period?
During action potential activation gate/ inactivation gates are active.. In activation gate is closed until reaching resting membrane potential and isn’t reset until then.
What are Neurotransmitters?
Chemicals that are released by synaptic vesicles to send chemical messages from cell to cell through synaptic clefts
Name the four examples of Neurotransmitters
Acetylcholine
Biogenetic amines
Amino acids
Neuropeptides
What are acetylcholines receptors
Nicotinic receptors and muscarinic
What are the two types of biogenetic amines receptors (also known as adrenergic receptors)?
Alpha and beta receptors
What are Neurotransmitters and what do they do?
They are chemical messengers that send information from one membrane to another
What are the receptors on the post synaptic membrane?
Acetylcholine -Nicotinic receptors and muscarinic
Norepinephrine- beta 1, alpha one or alpha 2
Epinephrine - beta 2
What are ligand gated channels?
Channels that require an ion or molecule to attach to it for it to open
Please describe in detail the molecular mechanism of a single action potential
Sodium channels open allowing sodium to rush into the cell causing it to reach threshold which causes more sodium channels to open
While the sodium channels are opening and the cell membrane begins to depolarize to +30 mV potassium channels begin opening aswell but they open slowly.. This allows potassium to escape out.
Once the membrane is sufficiently depolarized the sodium channels should be in an inactivation state (closed) meanwhile potassium gates are closing slowly.. The membrane begins to hyper polarize and the sodium potassium pump restores the resting membrane potential
Please explain the events that occur at the synapse..
When an action potential reaches a presynaptic button calcium is released into that button which causes vesicles of Neurotransmitters to move towards the membrane for Exocytosis.. The contents are then released into the synaptic cleft.
How is an action potential propagated down a nerve cell axon
Described in book if you must check
