neuronal membrane Flashcards
chapter 3
key ingredient in intra/extra cellular fluid
water!!!
water
-polar solvent
-covaelent bonds between h and o
polar
charges are unevenly distributed
ions
atoms or molecules with a net electrical charge
spheres of hydration
clouds of water that surround ions
phospholipid bilayer/ membrane
polar head- hydrophilic
nonpolar tail- hydrophobic (containing hydrocarbon)
hydrophilic
dissolve in water due to uneven electrical charge (eg ions, water)
hydrophobic
does not dissolve in water due to even electrical charge (eg lipid bilayer)
four levels of protein structure
primary, secondary, tertiary, quaternary
sodium potassium pump
enzyme- breaks down atp when na present
calcium pump
actively transports ca2+ out of cytosol
diffusion
the movement of ions from a region of high concentration to low concentration
diffusion happens when:
-selective channels that are permeable to that ion exists
-concentration gradient across the membrane exists
(without channels there can be no movement of ions!!! + they cant get through bc they are hydrophilic and the inside of the membrane is phobic)
electrical current
(I)
the movement of electrical charge
electrical conductance
(g)
relative ability of a charge to migrate from one point to another
Resistance
R = 1/g
opposite of conductance- the relative inability of a charge to mograte rom one point to another
electrical potential
(voltage; V)
reflects the difference in charge between anode and cathode
membrane potential
voltage across the neuronal membrane
resting membrane potential
-60/-80 mV in most neurons
voltage is measured with
a voltmeter
equilibrium potential
-electrical potential difference that exactly balances the ionic concentration gradient
-there is no net movement of ions when separated by a phospholipid membrane
electrical driving force
electrical driving force (electrical force) equal and opposite to chemical driving force (diffusion)
