WEEK 1: Neurophysio [Doc Dee lecture vid] Flashcards
based on the nernst equation the equilibrium potential is primarily influenced by
concentration gradient
the nernst potential is the potential insdie/outside the membrane
inside
negativity of the RMP is primarily determined by? secondarily by?
K permeability
sodium (secondarily)
all the cells of the body has RMP T or F
T
what causes the RMP?
unequal distribution of uncharged particles
predominant ions in the ECF?
sodium and chloride
predominant ions in the ICF
potassium
ratio of sodium ions from inside to outside?
1 is to 10
ratio of potassium from inside to outside
35 to 1
the membrane is more permeable to sodium/potassium?
potassium. 100 x as great
sodium influx is greatest during this phase of the action potential of a neuron
depolarization
stages of action potential?
DORA! depolarization overshoot (reversal of polarity) repolarization (returning to RMP) After hyperpolarization (more negative than the RMP)
lowest intensity of a stimulus that will trigger an action potential
threshold stimulus
least intensity that will elicit the highest visible response?
maximal stimulus
increasing the stimulus above threshold levels does not cause the devt of larger action potential. T or F
T
absolute refractory period is from where to where in the action potential?
depolarization to 2/3 of the repolarization
the direction of impulse conduction if a stimulus is applied at the middle of the axon is
bidirectionally pero walang action potential na magaganap
increading the diameter of the axon will lead to increase/decrease of the impulse transmission?
increase. because when you increase the diameter of the axon -> decrease axoplasmic resistance -> increased space constant
what is the charge of sodium? chloride?
sodium is positive, chloride is negative
2 subthreshold stimuli applied at the same time resulted to a visible response. the property of synpase exhibited is?
spatial summation
junction between 2 cells at which the electrical activity in one cell influences the electrical or metabolic activity of a second cell.
synapse
most synpases in the body are chemical/electrical?
chemical esp in the brain
major neurotransmitter in PNS at NMJ and brain
Ach
example of biogenic amines?
catecholamines such as epi and nor epi, serotonin, histamine
most prevalent neurotransmitter in the CNS are?
excitatory: glutamate and aspartate
inhibitory: GABA; glycine - released by spinal cord
Somata of preganglionic neuron in sympa is found in?
Para?
sympa: T1 to L4
para: CN 10, 9, 7, 3 and S1 to S4
length of preganglionic fibers in contrast to postgang fibers in sympa is? para is?
sympa: the pregang is shorter
parasympa: the pregang is longer
fibers that release Ach are considered to be?
cholinergic
fibers that release norepinephrine are considered?
adrenergic
all pre ganglionic neurons are considered? cholinergic or adrenergic?
cholinergic
almost all post gang fibers of the parasympa are choli/adrenergic?
cholinergic
most of post gang sympathetic neurons are choli/adre?
adrenergic EXCEPT: sweat glands and peripheral blood vessels which are cholinergic.
what gland is singly innervated by the sympa nervous system?
sweat glands; however they are cholinergic in nature
how is a current generated?
because there is a difference in
charge between these two points and therefore you call that
a potential.
The greater the potential or the difference the lesser will be
the current or the flow of ions. T or F?
F. the greater
movement of ions depends particularly on 2 things?
concentration and electrical gradient
ions move from an
area of greater concentration to an area of lesser
concentration. T or F
T.
T or F? The electrical charges of the ions cause them to move
through the membrane even though no concentration
difference exists to cause movement.
T
When the two effects are EQUAL and opposite in direction therefore there is A NET MOVEMENT of the ion. And the ions will be in the state of electrochemical equilibrium.
F. NO net movement
Equilibrium potential can be computed using the?
Nernst Equation
based on the nernst equation, The sign of the potential is POSITIVE if the ion diffusing from inside to outside is a negative ion and it is NEGATIVE if the ion is positive. T or F?
T
range of the RMP in neurons?
-40 to -90 mV
They play the most important role in generating the resting membrane potential.
Na and Cl
When a membrane is permeable to several different ions, like Na, K, and Cl, you can calculate the potentials using the
Goldman equation
When you use the Goldman equation it considers three things:
-polarity or electrical charge of each ion
o permeability of the membrane to each ion
o concentration of respective ion in the inside and outside of the membrane.
lowest intensity of a stimulus that will trigger an action potential. It is usually 15 mV less negative than the resting membrane potential.
Threshold stimulus
it is the intensity of a stimulus that will not trigger an action potential.
subthreshold stimulus
ntensity of a stimulus between threshold and maximal stimulus
Submaximal stimulus
least intensity that will elicit the highest visible response
Maximal Stimulus
the intensity of stimulus above maximum.
supramaximal stimulus
When the membrane potential reaches threshold then an action potential is generated. T or F?
T
Increasing the stimulus strength above threshold levels CAUSE LARGER ACTION POTENTIAL. T or F
F. Does not cause
what response to a stimuli would not be enough to cause a change in a membrane potential, but it is not enough to trigger an action potential.
subthreshold response
developed when a stimulus is strong enough for a depolarizing graded potential to reach threshold that would subsequently result into an action potential
threshold response
is elicited maximal stimulus in which all motor units are recruited producing the greatest force of contraction.
maximal response
seen when the intensity increases from threshold to maximal recruiting more and more motor units resulting in a escalation in the force of contraction
submaximal response
is elicited with an intensity above the maximal response with no further increase in the force of contraction
supramaximal response
identify if this refers to an action potential or to a graded potential: amplitude varies with size of initiating event?
graded potential
identify if this refers to an action potential or to a graded potential: cannot be summed?
action potential
identify if this refers to an action potential or to a graded potential: has no threshold?
graded potential
identify if this refers to an action potential or to a graded potential: has no refractory period?
graded potential
identify if this refers to an action potential or to a graded potential: conducted without decrement?
action potential
identify if this refers to an action potential or to a graded potential: mechanism depend on ligand gated channels or chemical or physical changes?>
graded potential
absolute refractory period occurs from where to where?
from the resting membrane, start to include the area of depolarization to the overshoot, until 2/3 of repolarization.
when you increase the diameter of the axon, 2 things will happen?
axoplasmic resistance decreases and space constant increases.
what protein cause the vesicles that contain the neurotransmitters to dock at the segment of the presynaptic neuron
snare proteins
_________then enters the axon terminal and will cause the fusing of the vesicles that contain your neurotransmitters through the process or the help of your snare proteins
calcium
acts as a sensor for calcium?
synaptotagmin
2 types of post synaptic potential?
Excitatory and Inhibitory
in Eexcitatory Post Synaptic Potential what channels opens? how about in Inhibitory PSP?
calcium in EPSP
chloride in IPSP
what summation is possible if the input signals from the presynaptic cell arrive at different times but in a very short interval.
temporal summation (kumbaga different time at the same place.
what type of summation is possible if the signals from different presynaptic cells arrive at the same location simultaneously—which will cause a greater number of ion channels to be stimulated and it opens and therefore will change the membrane potential and the change will be greater.
spatial summation (sabay sabay dumating sa iisang location)
identify if electrical or chemical synapse: plasma membrane of pre and post synaptic cells are joined by gap junction?
electrical; sa chemical kase separated sila ng synaptic cells.
identify if electrical or chemical synapse: speed of communication is slow
Chemical synapse. rapid sa electrical.
identify if electrical or chemical synapse: density in the human brain is rare?
electrical; common ang chemical synapse sa brain.
how does the inihibitory neurotransmitter in the brain, GABA, operate?
they operate by opening the chloride channels. chloride channels diba ay negatively charged, so because of that mas negative ung inside ng cell kaya walang action potential na nagaganap.
example of a miscellaneous neurotransmitter?
nitric oxide (important in long term potentiation) purines (ATP and adenosine)
identify if para or sympa: have a paravertebral and prevertebral ganglia?
sympathetic; pag sa para kasi, located siya near or nasa each na innervated organ.
identify if para or sympa? the post gang fiber is longer
sympa
difference in nicotinic vs muscarinic receptors?
parehas silang cholinergic receptor, pero yung nicotinic ay channel protien na pag nagbind ang ach, magoopen. pag naman muscarinic, G coupled protein receptor siya so mayroon second messengers.
most of the postganglionic sympathetic neurons are ___________ except to the _________________ which are _____________.
adrenergic;
sweat glands and peripheral blood vessels;
Cholinergic
T or F? acetylcholine, when it is released, circulate in the blood, therefore, the effects are localized and of short duration
F. does not circulate in the blood.
may ach esterase pa kaya nadedegrade immediately.
in the adrenergic system, the neurotransmitters, like dopamine, epinephrine, and norepinephrine, are released into the circulation and spreads further and more prolonged. T or F?
T. That’s why almost all portions of the sympathetic nervous system discharge simultaneously to provide the fight or flight effects or mechanism that are involved in the activation of the adrenergic system.
