Neuronal physiology: Membrane and Action Potentials and Synapse Flashcards
What are the two gates in Na++ voltage gated channels?
A fast gate and a slow gate.
What gates are closed during activation?
The fast and the slow gate are open but the slow gate will close after a while.
What happens when the membrane is trying to reach the resting potential?
Hyperpolarization, the membrane goes to negative values even below the resting potential.
When is the absolute refractory period?
From the opening of the fast gate to the closing of the slow.
The values higher than the threshold (-60mV).
Impossible to fire up a new action potential (as the Na++ channels are not closed).
When is harder than normal to fire a new action potential?
During the hyperpolarization (Na+ gates closed and K+ gates opened). Relative Refractory Period.
Where are sodium and potassium channels located in neurons?
In the trigger zone, in the axon hillock.
Which type of muscle presents a longer hill in the action potential because of Ca++?
The Smooth Muscle.
What type of conduction allows myelin?
Saltatory Conduction
Faster.
What property of myelin makes the lenght constant higher?
The increase in the membrane resistance.
Where is in myelinated axons the action potential generated?
No me refiero al axon hillock, que también.
In the Nodes of Ranvier
Parts that are unmyelinated.
Why is better to have an axon with a greater diameter?
Greater diameter means less intermembrane resistance
Myelination reduces or increases Capacitance?
Reduces Capacitance.
This ONLY affects the time constant (is lower).
What type of temperature increases conduction?
High Temperatures
Cold Temperature make the conduction slower.
Which type of synapses are unidirectional?
Chemical Synapses
Which type of synapses have a minimal intracellular space?
Electrical Synapses
