Nervous Physiology Flashcards
How negative is the intracellular environment of a neuron?
-70mV
What maintains the charge balance of the membrane?
Na+/K+ pump
What is the Na+/K+ pump?
Active transport that requires ATP to move positively charged ions around to increase or decrease the charge of an area
What is a local potential change?
Membrane potential in the region of the membrane exposed to stimuli is changed
What are the two responses to stimuli in the membrane?
Depolarize
Hyperpolarize
What does a graded potential mean?
Degree of change is proportional to instensity of stimulation
What is the threshold potential to initiate AP?
-55mV
What is a refractory period?
A time during which a second AP cannot occur
What is the absolute refractory period?
During a current AP, no more additional AP can cause anything
What is the relative refractory period?
Immediately following an AP, the membrane is hyperpolarized and a stronger AP can initiate a new one
What is a common impulse/sec in the body?
100 impulses/sec
How does the refractory period help with directing a message?
Ensures AP only goes in one direction, since the area upstream is in refractory period
What is saltatory conduction?
The action of AP jumping over myelin sheaths, much faster than unmyelinated neurons
What role does calcium play in synaptic transfer?
Tells the synaptic vesicles to release their neurotransmitters into the synaptic cleft
What is acetylcholinesterase?
AChE, removes ACh from the synaptic cleft by breaking it down