Action potential steps
: 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.
relative refractory period
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.
Type A fibers (axons)
velocity= 268 MPH
type B fibers Axon
velocity= 40 MPH
Type C fiber (axon)
velocity= 2 MPH
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.
sympathetic nervous system
fight or flight response and maintains blood pressure
Lecture 4 with moffat at shoreline