2.2 Neurophysiology Flashcards
Neurons are highly
irritable
Plasma membranes are peppered with a variety of
ion channels
two types of channels
- passive or leakage channel (always open)
- active or gated channel
two types of gated channel
- chemically gated channels
- voltage gated channel
Body is electrically _____. But there are small differences in electrical charge between inside and outside of cell membranes due to differences in __________ on inside and outside of cell membrane.
neutral;
+ and – ions
differences in charge = _________
potential (stored energy)
resting cells (all cells in body) have potential difference (-50 to -200 mV)
membrane potential
average muscle and nerve cells membrane potential
-70 mv
Resting Membrane Potential is in _______ state
polarized state
3 major processes of Resting Membrane Potential
- Different kinds concentration of ions inside and outside the cell membranes
- The differential permeability of the plasma membrane to Na+ and K+ ions
- The operation of the sodium-potassium pump
There are different kinds and concentrations of ions inside and outside cell membranes: there are more ________ ions inside cell (especially ________)
negative ions, especially proteins
Both Na+ and K+ can diffuse across cell membrane by ________ via leakage channels
facilitated diffusion
In resting membrane potential, ___+ is more permeable than ___+
K+ > Na+
a change in resting membrane potential can be produced by anything that changes _________
membrane ion permeability (opens or closes ion gates)
Two kinds of potential changes
- Graded potentials
- Action Potential
- local phenomenon, signal over short distances
- small to large changes in membrane potential due to opening and closing of chemical gates
Graded potential
membrane potential decreases
- Depolarization
membrane potential increases
- Hyperpolarization
true or false
Graded potentials are given different names depending on where they occur and the functions they perform
True
What do you call the graded potential in receptor region of dendrites and cell bodies of neurons? What are the two types?
Postsynaptic potentials
- Excitatory postsynaptic potential (EPSP)
- Inhibitory postsynaptic potential (IPSP)
- local depolarization occurs and response stimulatory
- depolarization might reach threshold producing an action potential and cell response
Excitatory postsynaptic potential (EPSP)
- local hyperpolarization and response inhibitory
- decrease action potentials by moving membrane potential farther from threshold
Inhibitory postsynaptic potential (IPSP)
True or False
The EPSP is an all-or-none response.
False
The EPSP is not an all-or-none response but is proportionate in size to the strength of the afferent stimulus
Two types of summation of post-synaptic potentials
Temporal and Spatial Summation
summation of EPSP’s or IPSP’s due to repeated stimulation by one neuron
Temporal Summation
summation of EPSP’s or IPSP’s due to stimulation by more than one neuron simultaneously
Spatial Summation
- long-distance signals
- a rapid, all-or-none change in the membrane potential, followed by a return to the resting membrane potential
Action potential