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106 Cards in this Set
- Front
- Back
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what are the two types of Calcium transporters
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intracellular > extracellular
intracellular > organelles |
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what is the major difference between secondary active transport and normal active transport
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secondary active transport doesn't require immediate energy
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where does the energy for the secondary active transport come from
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sodium pump
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what occurs in cotransport
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the primary molecule goes down its gradient while the secondary molecule hitching a ride is going against its gradient, but both molecules are headed in the same direction
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antiport
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counter transport
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where do the molecules bind in cotransport
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at the same side
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where do both molecules bind in counter transport
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the bind at opposite ends and the secondary molecule the one hitching a ride is going against its electrochemical gradient
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cell in nervous system that has the unique ability to generate electricity
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neuron
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another name for cell body
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perikaryon
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what is the most important and largest part of the neuron
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cell body
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hair on cell body
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dendrites
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where does axon originate
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axon hillock
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cytoskeleton of neuron cell
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neurofilaments and neurotubules
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what are all neurons composed of
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axon, axon hillock, dendrites, cell body, neurofillaments/neurotubules, synaptic terminals (CNS), Vericosities (PNS)
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why can't neurons in CNS divide
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due to lack of stem cells
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what cell can replicate in the CNS
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neuroglial cells (oligodendrocytes/astrocytes)
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what are the functions of neurotubules/neurofilaments
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give cell body mechanical strength (cytoskeleton)
involved in regeneration of injured axons involved in transport of material w/ in the cell |
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what are the two forms of transport in nerve cells
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slow axonal and rapid transport
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what is used in slow axonal transport
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microfilaments
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at what rate does transport occur in slow axonal transprot
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6mm a day
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what is used in rapid axonal transport
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microtubules and motor proteins
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what are microtubules composed of
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9 microfilaments
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at what rate does transport occur in rapid axonal transport
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2.6m a day
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what are the motor proteins used in rapid axonal transport
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kinesin and dynein
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kinesin
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anterograde transport
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dynein
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retrograde transport
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non myelinated portion of axon
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node of ranvier
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what is myelination used for
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increase speed of conduction and protection
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CNS glial cells
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oligodendrocytes/astrocytes
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PNS glial cells
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schwann cells
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myelin is loss
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demyelination
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patchy demyelination
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multiple sclerosis
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demyelination is confined
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Lou Gehrig's disease (ALS)
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involves loss of sensation and paralysis
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multiple sclerosis
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disseminated sclerosis is another name for
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multiple sclerosis
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what are the characteristics of MS
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occurs in country side more than city
occurs in people under age of 50 occurs in women more than men PNS not effected at ALL occurs in cold'/temperate climates |
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dysmyelination
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error of metabolism for enzymes responsible for compacting the myelin
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CNS myelin diseases
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Dysmyelination and Demyelination
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PNS protection of fine axon fibers
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schwann cells hug multiple small fibers, but these fibers are still exposed to the extracellular fluid
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CNS protection of fine axon fibers
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astrocytes send their feet to partially protect some of the thin axon fibers
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why is myelination of small fibers not important
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w/ or w/o the myelination the small fibers have such a high electric resistance that the rate of conduction will notchange
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how does resting membrane potential develop
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membrane contains electrogenic pump
membrane more permeable to K than Na at rest inside cytoplasm large amount of negatively charged ions (proteins and phosphorous) permeability of membrane to Cl at rest is 0 |
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major reasons for development of resting membrane potential
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Na/K pump
equilibrium potential of Na/K |
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Na Pump does:
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throws 3 Na out
takes 2 K in *generates a difference of -5mV therefore creating electricity keeps Na out Keeps K in |
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current is
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movement of charged particles in response to potential differences
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what is action potential
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the abrupt self propogating change in resting membrane potential
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what are the two gates to the sodium channel
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activation gate and inactivation mechanism
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what is the outside gate in the sodium channel
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activation gate
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what is the charge of the activation gate
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positive
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at rest is the activation gate open or close
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closed
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what two forces drive Na rushing into the channel
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electrical gradient and chemical gradient
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what is the inside gate in the sodium channel
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inactivation mechanism
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at rest what state is the inactivation mechanism
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open
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when does the inactivation mechanism close
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when the inside of the cell becomes too positive
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when does the cells permeability to Na increase
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at the onset of an action potential
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what is the positive feed back look for Na
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stimulus occurs > Na enters cell > cell depolarizes > more Na channels open> more Na enters cell etc
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what is the reversal potential
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0 - the top of the peak
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what is the delayed rectifier
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the K channels
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what does the delayed rectifier do
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K channels open in response to the cells loss of negative charge and allows K to exit the cell to rectify the resting membrane potential
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what determines resting membrane potential
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K
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how does K determine the membrane potential
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at rest the cell is still permeable to K
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at hyper-polarization what occurs
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the nerve has become more negative than at rest (resting membrane potential)
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what causes hyper-polarization
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K leaving the cell
Na/K pump being too active |
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depolarization
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membrane goes from a negative charge to a positive charge
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re-polarization
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the membrane goes from a positive charge back to the resting membrane potential
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absulute refractory period
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during this time the cell can't be stimulated regardless of the magnitude of the stimulus
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relative refractory period
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during this time the cell can be stimulated again but due to hyperpolarization the stimulus will have to be greater
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at rest the activation sodium gate is
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closed
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during the refractory period what is the state of the Na channel
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the inactivation mechanism is closed and the activation gate eventually closes
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when is the sodium channel inactivated
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when the inactivation mechanism is closed
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what are the major players in repolarization
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Delayed rectifier, Na/K pump, and Na inactivation mechanism
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what AP only use Ca
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action potentials for the heart
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what are the important factors for understanding AP
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squid giant axon, tetrodotoxin (TTX), tetraethylammonium (TEA), and oscilloscope
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what is a Na channel blocker
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tetrodotoxin
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what is a K channel blocker
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tetraethylammonium
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what is the latent period
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time required for current to give a action potential
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when do K channels close
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once the resting membrane potential is restored
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when do Na channels return to normal
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once the charge in the cell goes back to threshold
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hyperpolarization is due to
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too much K going out and Na/K pump being over active
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excitable tissue are
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tissue that can generate electricity
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saltatory conduction occurs in what kind of axons
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myelinated axons
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myelin advantages
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speed up rate of conduction and save the neuron E since pump will only be at node of ranvier won't have to be throughout cell
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orthodromic conduction
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happens in nature and AP goes away from cell body
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antidromic conductions
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happens artificially (against nature) and the AP travels towards the cell body
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what does no AP occur during the absolute refractory period
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due to the Na inactivation gates being closed
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if you double the strength of stimulus what happens to the AP
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it remains the same
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what are the characteristics needed in order to be a oscillator
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RMP has to be low (-50)
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what order does rhythmic AP occur
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prepotential > Ca channels open (AP) > delayed rectifier
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what are the two types of oscillators
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intrinsic and conditional
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what are intrinsic oscillators
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they have the ability to generate an AP by themselves
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what are conditional oscillators
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they require a neurotransmitter in order to generate an AP
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Muscle RMP
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-90
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Nerve RMP
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-70
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which one has a longer duration of AP, muscle or nerve
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muscle
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which one has a faster speed of conduction muscle or nerve
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nerve
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increase Na outside
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RMP - no change
Rate of rise of AP - sharper due to more Na going in Amplitude - no change |
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decrease Na outside
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RMP - no change
Rate of rise of AP - slows b/c not as much Na to go inside Amplitude - lower due to less Na being available to come in therefore less current |
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increase K outside
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RMP - Depolarization occurs due to less K being pumped out (being able to leave the cell)
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decrease K outside
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RMP would become hyper polarized due to more K leaving the cell down its gradient
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what effect does Ca have on RMP
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none
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what does inceasing Ca outside do
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the Na gate will be hard to open making Na less permeable therefore decreasing excitability
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what does decreasing Ca outside do
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Na gate will be a lot easier to open therefore the amount of excitability would increase as well as Na permeability
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what is the point of communication between two excitable tissues
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synapse
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what is the communication of two cells via gap junctions
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electrical synapse
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what type of synapse predominates in the body
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chemical synapse
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what are the characteristics of electrical synapse
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fast conduction due to no synaptic delay
BIDIRECTIONAL hard to manipulate w/ drugs/ don't respond to drugs/inhibitors |
