Flashcards in Medical Phsiology Nerve Deck (18)
Anatomy of a Neuron
Nuerons are special in that they are...
Electrically charged and can change their charge to produce impulses
Inside of the cells negative with respect to the outside
Potential = voltage = push =
Ability to do electrical work
Cells are bag if sea water containing...
Na+, Cl-, K+, Ca++
The resting potential is a result of these steps:
1) Diffusion of K+ across the membrane
2)Diffusion of Na+ across the membrane passive Na+ channels
3) Na/K ATPase pump
Passive K channels
-open all the time (not voltage-gated)
-protein channels made membrane permeable to K but not to Na
- K diffuses out along concentration gradient
The diffusion of K+ out of the cell leaves behind...
Negatively charged anionic proteins [A-], creating a cloud of negative charge on inside of membrane.
Force of the fusion pushing K out equals the negative attraction that pulls K back in, resulting in a cloud of K outside the membrane but no further net movement of K.
Membrane is _______, inside ___ when potassium alone defuses out of the membrane
Na+ wants to go inside so because...
-negative charge inside membrane
Potassium leaks out _____
more than Sodium
Less negative than normal membrane potential
More negative than normal membrane potential
Movement of sodium inside depolarizes membrane slightly to…
Electrogenic pumping by Na/K ATPase pump causes ...
Polarizes membrane -4mV, bringing membrane potential back to -90mV
Neurons send nerve impulses; is an electrical signal