Physiology 4

• 1. Resting: the All Na and K channels are closed mince leaky gates of course.in -70
• 2. depolorizing phase: the Na channels open but the K gates are still closed. getting positive
• 3. repolorizing phase: Na channels and K channels are open. getting more negative
• 4. hyperpolorization phase: Na is blocked out but K is kept flowing making it super negative

Both Na nonactivation gates and activation gates are open and you couldnt get action potential again no matter what.

If theres a high enough level you could get it to action potential again but it has to be big enough

A change in this starts a signal

travel only short distances because it uses defussion like sound (him wispering lol) ex. dendrites to soma

travel much greater distance (him saying a message then the next person says it like telephone) ex. axon hillock to axon terminals

unmyelinated fibers is very slow 1 m/s

mylinated neurons much faster and overall less energy is consumed.

• largest diameters
• velocity= 268 MPH
• myelinated

• smaller diameter
• velocity= 40 MPH
• myelinated

• smallest diameter
• velocity= 2 MPH
• unmyelinated

axons that release the ACh or acetalcholine neurotransmitter

axons that release the neurotransmitter norepinephrine

• 2 different types of receptores that recieve a specific neurotransmitter
• nicotinic- skeletal muscle many different types ACh stimulatory
• muscarinic- found in the parasympathetic that slows down the hearts heart rate. AcH stimulatory and inhibitory.

• 2 types of different receptors that are stimulated by different neurotransmitters
• Alpha- stimulated by norepinephrine and epinephrine
• Beta- also the epinephrines 3 different types can be found on the cell membrane. sympathetic nervous system with heart makes the heart rate higher.

fight or flight response and maintains blood pressure