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Physio ch. 6
| Question | Answer |
|---|---|
| nervous system functions | communication and homeostasis |
| communication can be either | electrical or chemical |
| electrical communication happens through the...and chemical is between... | axon...neurons and other types of cells like effectors |
| homeostasis controls...,...,... | system coordination (turning on and off)...direct activity....regulating +/- feedback |
| neuron classes | CNS and PNS |
| cns contains the | brain and spinal cord |
| pns contains | everything outside the cns including spinal nerves |
| axons are | nerve fibers |
| nerves are | bundle of axons in PNS |
| tracts are...also called... | bundle of axons in CNS...columns |
| afferent pathway is for...reception and is the...part of the spinal... | sensory...posterior...root |
| interneurons are in the..and used for... | cns...integration |
| efferent pathway is the..spinal...and does... | anterior..root...effector activation |
| membrane potential is key for | neurons |
| resting potential is around | -70 mV |
| resting potential is the..between.. | electrical potential..inside and outside of the cell |
| inside the cell is | k+, amino acids(-) and phosphates (-) |
| outside the cell | na+, cl- |
| at the membrane: | negative charges inside attracted to positive charges outside |
| when compared, the inside membrane is | negative relative to the outside membrane |
| resting membrane potential: extracellular fluid is used for | reference and is assigned a voltage of 0 |
| resting membrane potential: intracellular fluid is compared...and voltage difference is... | extracellular fluid...membrane potential |
| electrochemical gradient is a balance between | electrical gradient (ion movement) and chemical gradient |
| electrical and chemical gradients influence | movement of ions |
| key ions and their actions | K+ leaks out and Na+ leaks in |
| which is the most important ion? | K+ |
| K+ follows... | concentration gradient but agaisnt electrical gradient |
| Na+ follows.. | concentration gradient and electrical gradient |
| ions get through the membrane via | leak channels (diffusion) |
| P is higher for...because... | K than Na+..there are more leak channels for it |
| why doesn't the concentration gradient disappear? | overall distribution of ions and na+/k+atpase pump |
| na+/k+ atpase pump helps | establish gradient |
| how many na+ are pumped out | three |
| how many k+ are pumped in | 2 |
| leak channels...gradient | increase |
| the fact that there are more K+ leak channels than na+ leak channels...on the outside | augments the + charge |
| na+/k+ atpase pump...leak channels | counteracts |
| variation in membrane potential includes | resting potential, depolarizing, overshoot, hyperpolarizing |
| if the membrane potential is disrupted then | na/k pump fixes it and uses atp |
| depolarizing takes the membrane potential towards...with means losing... | zero...charge difference |
| overshoot is the membrane potential when it is...and the inside is...relative to the... | above zero...+...outside |
| repolarizing | from depolarizing back towards resting |
| hyperpolarizing means more | negative than resting potential |
| graded potential involves | ligand and mechanical, etc gated channels |
| graded potential DOES NOT involve | voltage gated channels |
| graded potentials are | localized meaning only a small area of the neuron is affected |
| the localized area of neuron that graded potentials affect are the | cell bodies and dendrites |
| graded potentials have...channels, the charge flows...and it is not | open ion...to surrounding area...propogated |
| graded feedback have no | + feedback |
| graded potentials have a | variable magnitude or strength |
| magnitude of depolarization for graded potential depends on | strength, usually small |
| graded potentials can be | summed |
| graded potentials can either be | depolarized or hyperpolarized |
| depolarizing means that...open and they have an effect on | na channels...internal charge (more +) |
| hyperpolarizing means that...open and the effect is that | cl- channels...internal charge becomes more - |
| graded potentials can't go far because of | decremental conduction (decrease magnitude over distance) |
| action potentials are not...and have the...principle | localized...all or none |
| action potentials involve open...and they are... | voltage gated ion channels...propagated |
| propagation means that the action potentials | generate themselves |
| all or none magnitude requires a...which is usually a... | stimulus...graded potential |
| enough change in the membrane reaches the | threshold potential |
| action potentials involve three steps | depolarization, repolarization and hyperpolarization |
| action potentials are non...meaning that the conduction is as... | decremental conduction...strong at the end as at the beginning |
| voltage gated ion channels: voltage change triggers | conformational change |
| voltage gated ion channels open in response to | membrane depolarization |
| voltage gated ion channels are not | leak channels |
| na+ channels respond...are closed until...open at...and are lastly | quickly...until threshold...at threshold...inactivated |
| open na+ channels allow na+ to | follow gradient |
| na channels remain open until | equilibrium is almost met |
| k+ channels respond...then are...and then they... | more slowly...closed to keep most k+ in the cell...open to allow k+ to follow gradient |
| 3 positions of na+ channels | closed, open and inactivated |
| 2 positions of k+ channels | closed, open |
| action potential mechanism 1: resting membrane potential =...only..are open..and the..is active | -70 mV..leak channels..na+k+ atpase pump |
| mechanism 2: threshold potential =...and is usually... | -55 mV...ligand gated |
| threshold potential is an... | excitatory graded potential stimulus |
| how does the potential get to threshold? | depolarization |
| mechanism 3: rapid depolarization | voltage gated na+ channels open and reach overshoot |
| mechanism 4: near na+ equilibrium | voltage gated na+ channels inactivate and voltage gated k+ channels open |
| mechanism 5: repolarization | k+ moves out of the cells |
| mechanism 6: hyperpolarization | na+ channels close, k+ channels still open |
| mechanism 7: resting membrane potential | near k+ equilibrium, k+ channels close and potential returns to normal |
| na+ movement: ...until... | positive feedback...na+ nears equilibrium (reinforcement) |
| after the na+ nears equilibrium the channels become | inactivated |
| k+ movement: K+ channels can't open in | -ly charged situations |
| k+ movement leads to | neg feedback as membrane repolarizes |
| after cell is repolarized | k+ channels close |
| all or none response | subthreshold or threshold |
| subthreshold would be | graded potentials or stimuli |
| threshold occur because of | strong enough stimuli or all or none action potential |
| all or none action potential requires the | opening of voltage gated na+ channels |
| all or none action potential: some anesthetics | block na+ channels (novacain, lidocain, tetrodotoxin) |
| refractory periods limits | # of action potentials |
| there is a ...of signals | one way propagation of signals |
| absolute refractory period means no.. | additional action potentials can occur because na+ channels open or inactivated |
| relative refractory period requires... | stronger stimulus |
| relative refractory peiod allows neuron to | carry potential in only one direction |
| during relative refractory period | na channels close and k channels are still active |
| action potentials are generated via | graded potentials |
| 3 types of potentials that produce APs | receptor potential, synaptic potential, pacemaker potential |
| afferent neurons produce | receptor potentials |
| interneurons and efferent neurons produce | synaptic potential (stimulus) and pacemaker potentials |
| pacemaker potentials are called...meaning they are...like in the... | spontaneous...self generated by neuron or tissue...cardio, digestive systems |
| action potentials are initiated at | initial segemtn by voltage gated Na+ channels |
| action potential propagation: initial segment: the...are opened by... | voltage gated na channels...changed membrane potential |
| initial segment is...which...area | depolarized...stimulates the adjacent |
| adjacent area: | voltage gated na channels, depolarization, nondecremental, stimulation of adjacent area |
| previous area undergoes the...and produces a | refractory period...one directional flow |
| rates of condution for action potential if it is a small unmyelinated neuron | .5m/s |
| rate of conduction for ap on a large myelinated neuron | 100m/s (instantaneous) |
| rate of conduction is affected by | diameter and myelination |
| diameter: larger axons = | less resistance |
| myelination provides | insulance, less leakage |
| what types of cells produce lipid insulation? | oligodendrocytes or schwann cells |
| lipid insulation has...and... | poor conduction...less leak |
| oligodendrocytes or schwann cells have less...compared to graded potentials | decrementation |
| nodes of ranvier have a high concentration of...and allow for... | voltage gated na channels...saltatory conduction |
| saltatory conduction is...because it doesnt have to... | faster...go entire length of axon |
| efficiency of myelin: saves...saves...and is...efficient | time...space...metabolically (fewer ions to move back) |
| demyelination | heavy metal poisoning, multiple sclerosis (difficulty moving bec impulses aren't sent) and active herpes |
| 3 types of synapses | convergent, divergent and reverberating |
| convergent synapses have info from...and mean | autonomic and somatic...many presynaptic neurons come together to effect a single postsynaptic neuron |
| divergent synapses start with...-> | a small number of neurons...synapse on many (one message/many receptors) |
| divergent means there are multiple | motor units |
| reverberating synapses are...meaning... | cyclic....rhythmic activities |
| examples of reverberating synapses | breathing and staying awake (reticular) |
| synapses can either be...which both are | excitatory or inhibitory...graded potentials |
| excitatory synapses lead to... | EPSP and depolarization |
| EPSP tells what is happening to | next cell |
| excitatory synapses do not guarantee | an action potential to occur |
| inhibitory synapses create...and...the membrane | IPSP...hyperpolarize |
| inhibitory synapses do not | lead to action potentials |
| electrical synapses: neurons are connected via..which allows... | gap junctions...direct transfer of action potential |
| electrical synapses are...meaning there is one... | bidirectional...point of origin but two different directions for the action potential (just not backwards) |
| electrical synapses can be found | in cardiac and smooth muscle |
| electrical synapses are extremely | fast |
| chemical synapses contain | presynaptic cell, synaptic cleft, post synaptic cell |
| chemical synapsdes...transfer action potentials via... | indirectly...neurotransmitters that diffuse across the cleft |
| chemical synapses flow in...down the.. | one direction..axon hillock |
| most of the nervous system is connected via | chemical synapses |
| in the presynaptic cell during chemical synapsing there is the...which has.... | axon terminal...active zone and voltage gated ca channels |
| active zone contains...that contain... | docked synaptic vesicles...neurotransmitters |
| voltage gated ca channels are opened via...and causes | depolarization...ca++ influx |
| ca++ influx allows...to... | neurotransmitters...fuse with cell membrane and be diffused across the cleft |
| neurotransmitters undergo...and the amount at which this occurs depends on... | exocytosis...amount of Ca++ |
| synaptic cleft is where | the neurot diffuses |
| postsynaptic cell contains the...which is a... | postsynaptic density...dense collection of neurotransmitter receptors |
| postsynaptic acivity involves 2 steps | neurotransmitter binding and removal |
| neurotransmitter binding opens | ligan (chemical) gated channels |
| removal of neurotransmitter involes...or... | reuptake by axon termical or diffusion away from cleft...chemically inactivated (enzymes change shape) |
| neurotransmitter binding and removal occur at the | postsynaptic density |
| excitatory postsynaptic potential: ...allow...ions into the cell (usually...) | ligand or chemical gated channels...+...(na) |
| the ligand is the | neurotransmitter |
| the depolarization of the excitatory postsynaptic potential = | graded potential |
| IPSP: ...allows...ions into cell (...) and...ions out of the cell (...) | ligand or chemical gated channels...-...(cl-)...+...(k+) |
| IPSP...the cell membrane and cause a... | hyperpolarize..graded potential |
| stabilization means...and makes it.. | cell remains at resting membrane potential...harder for stimulus to cause E/IPSP |
| synaptic integration means that | graded potentials can sum |
| temporal summation means that 1 | presynaptic neuron sends multiple APs, neurotransmitters and graded potentials |
| temporal summation must be | close enough together in time |
| spatial summation is different | presynaptic neurons sending out at the same time |
| spatial summation must be | close enough togehter in space |
| graded potentials can last | longer than an AP |
| one epsp can result in | multiple aps |
| presynaptic factors affecting synaptic strength includ | intracellular ca, axo axonic synapses, other presynaptic factors, neurotransmitters, reuptake and breakdown |
| amount of intracellular ca++..to presynaptic cell promotes... | influx...release of neurotramitters |
| amount of intracellular ca++ removed from presynaptic cell determines the | amount of neurotransmitter released |
| axoaxonic synapses are responsible for...and they send neurotransmitter from... | modifying instructions...other axon and presynaptic receptors |
| axoaxonic synapses are common for | pain |
| axoaxonic synapses alter...and create | neurotransmitter release...presynaptic inhibition or facilitation |
| other presynaptic receptors include | reeptors to other chemicals (hormones) and autoreceptors |
| autoreceptors detect...and result in... | neurotransmitter...neg feedback mechanism |
| postsynaptic factors affecting synaptic strength | receptor variability |
| receptor variability includes altering...and also can be... | # of receptors (up/down regulating), receptor activity (signal transduction and second messenger systems)...desensitized |
| second messenger systems produce...effect from altering... | domino...one part of membrane to effect the next part |
| overall actions of drugs and diseases- they...with any step... | interfere...in pathway of synaptic transmission and reception |
| agonists...and antagonists... | promote...work against |
| clostridium tetani block..to..and result in.. | neurotransmitter release...inhibitory neurons..severe muscle contractions |
| clostridium botulinum blocks..to..and ...muscle contractions | neurotransmitters release...excitatory neurons...decrease |
| black widow spider venom...neurotransmitter relase to...and results in... | increases...excitatory neurons...increase muscle contractions |
| curare is used in...and binds to...but doesn't...and results in... | poison darts...ACh receptors...ion channels...decrease muscle action |
| nerve gas (sarin) inactivates...and the continued presence of...causes... | acetylcholinesterase...ACh...continued depolarization of postsynaptic neuron and voltage gated na channels inactivated |
| nerve gas ultimately results in | desensitization of ACh receptors |
| neuromodulators ...the synapse not... | impact...drive |
| neuromodulates alter... | action of synapse (presynaptic cell action and postsynaptic cell response) |
| neuromodulators have many...such as... | sources...hormones, paracrine, immune system, presynaptic cell |
| neurotransmitters affect...of the... | ion channels...postsynaptic cell |
| neurotransmitters can have an...or...effect | excitatory or inhibitory |
| ACh is found in the...and is received by... | somatic ns, para and symp...nicotinic receptors and muscarinic receptors |
| nicotinic receptors are refered to as...which causes | ionotropic receptors...opening of both na and k channels |
| na electrochemical gradient is | greater than k electrochemical gradient |
| which ion will have the greater movement in nicotinic receptors? will this result in depo or hypo? | na+...depo (EPSP) |
| nicotinic receptors are found at...and also...and are responsible for... | neuromuscular junctions...reward pathways in the brain (tobacco)...cognition, learning and memory |
| what disease is associated with a loss of ACh neurons | alzheimers |
| muscarinic receptors function with...occur in the...and... | g protines...brain and organs/glands |
| muscarinic receptors are considered...meaning they interfere with... | metabotropic...metabolism |
| in the heart ACh muscarinic receptors... | inhibit pacemaker (parasympathetic division) |
| antagonist to ACh muscarinic receptors that increases heart rate | atropine |
| biogenic amines | major cns neurotransmitters and modulators (some pns) |
| categories of biogenic amines | catecholamines and serotonin |
| catecholamines include | dopamine, NE, E and monoamine oxidase |
| catecholamines are the amine group attached to a...formed from the...and are... | catechol ring...synthesis of tyrosine (amino acid)...metabotropic (funciton via g proteins) |
| dopamine is a precursor to...which is a precursor to... | NE...E |
| dopamine in the...leads to... | CNS...parkinson's (reduced motor control) and cocain addiction (blocks re-uptake) |
| NE is in the...and is considered... | CNS and PNS...adrenergic neurons and receptors |
| adrenergic means neurons and receptors... | release and respond to NE |
| E is in the...is also considered....and is most commonly produced as a... | CNS & PNS...adrenergic neurons and receptors...hormone (adrenal medulla) |
| E=...and is also called...which is a... | neurotransmitter...adrenaline...hormone |
| monoamine oxidase breaks down...in order to... | catecholaimes in synaptic cleft...keep neurotransmitter in cleft |
| MAO inhibitors reduce...which is used as a treatment for...and there is an increased presence of | rate of breakdown...depression...dopamine and norepinephrine |
| serotonin is a...and is formed from | neuromodulator...synthesis from essential amino acid tryptophan |
| serotonin is...for...and...for... | excitatory...muscle control..inhibitory...senses |
| increased activity of serotonergic neurons when | awake |
| serotonin specific...treat...and leaves... | reuptake blockers...depression...serotonin in synaptic cleft |
Created by:
handrzej
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