Nervous system Flashcards
organization of NS
central NS and peripheral NS
what is the central NS
the brain and spinal cord
peripheral NS
afferent (sensory) and efferent (motor division) with the somatic and autonomic NS
somatic NS
involved with the skeletal system and movement
autonomic NS
generally things that are not thought about, affects smooth muscle, cardiac muscle, glands
- parasympathetic NS and sympathetic NS
what is resting membrane potential
the negative charge that is inside of cells at rest
- normally -40 to -75 mv in neurons
how does different substances affect resting membrane potential
- drugs can make it more sensitive by bringing the RMP up
- anesthetics or lidocaine can bring the RMP down to make it harder to initiate a response
what is RMP determiend by
the permeability of the plasam membrane to ions and the charge difference that is present within the system
what are the different ions that play a role in RMP
sodium, potassium, chloride, calcium
how is the RMP maintained
the sodium-potassium ion pump
what is the sodium-potassium ion pump
- concentration gradients cause the cell to be leaky so K+ often leaks out
- moves 2 K+ in and 3 Na+ in out of the cell
- since going against their concentration gradients the pump required ATP
- helps to correct ion concentration differences post AP
what are the concnetration differences of the ions at RMP
greater [K+] within the cell
greater [Cl-] and [Na+] outside of the cell
what does the nernst equation tell us
relationship between cell potentials to standard potentials
what are the ion concentration differences in different muscle types
slow twitch has lower [K+] and higher [Na+] than fast twitch
what is the RMP for type I muscles
-70
what is the RMP for type II muscles
-90
why do the two muscle types have different RMP
bc of ordered recruitment or specificity in movement
action potential
charge that travels the membrane due to changes in resting membrane potential
how do APs spread
through the opening of ion channels along the membrane = sequential spreading of AP
- the ion channel will only open if there is a change within the cell
depolarization
when membrane potential goes toward zerorepo
repolarization
when the membrane potential goes towards negative
hyperpolarization
an increase in membrane potential (more differences)
hypopolarization
decrease in membrane potential
absolute refractory period
the period after AP/contraction occurs where another contraction cant occur
- allows for no tetanus or summation to occur
