Term
| Factors that determine permeability of a molecule |
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Definition
| Electrochemical gradient, presence of molecule-specific channels, size, and polariy |
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Term
| Active, passive, and carrier mediated transport |
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Definition
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Term
| how are ions, water, O2,Co2, and glucose transported across the membrane |
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Definition
ions - passive or active diffusion
water - passive diffusion
O2, Co2 - simple diffusion
glucose - passive diffusion |
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Term
| How are membrane channels specific |
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Definition
| Size of the molecule, and through a "filtration" system which involves certain amino acids within the channel which interact with the molecules |
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Term
| How are membrane carriers specific to certain molecules? |
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Definition
| The carrier protein will not produce a conformational change unless it interacts with a specific molecule which it will transport |
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Term
| What is the purpose of the sodium/potassium pump? |
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Definition
| To maintain the resting membrane potential of the neuron |
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Term
| how does the sodium/potassium pump function |
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Definition
the pump transports 3 sodium ions out of the cell and transports 2 potassium ions back into the cell
(uses ATP to make conformational change)
"Active Transport" |
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Term
| What are the factors that contribute to the resting membrane potential |
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Definition
| Large protein anions, net loss of charge due to Na/K pumps, K voltage gated pumps are more "leaky" than the Na voltage gated pumps |
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Term
| What are I, E, and G -PSPs |
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Definition
Inhibitory, Excitatory, and Grand Post Synaptic Potentials
IPSPs have an inhibitory affect on the production of an action potential
EPSPs have an excitatory affect on the production of an action potential
A GPSP is the net effect of the summations of both the IPSPs and EPSPs |
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Term
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Definition
| The leaping of an action potential between the nodes of rainvier on an axon. Uses fast electrotonic conduction to travel the length of the myelinated sections, depolarizing the node sections just enough to reach threshold, which causes the influx of Na and propogates the process all the way down the axon |
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Term
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Definition
| Hormone or chemical messenger signaling of nearby cells |
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Term
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Definition
| The release of hormones or chemical transmitters that affect changes on the same cell they were released from |
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Term
| Electrotonic or Graded Potential |
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Definition
| The fast moving effect of diffusion of ions within the membrane of a neuron, dissipates over distance |
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Term
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Definition
| Relatively slow moving electic signal transmission, positive feedback system that ensures signal strength remains strong over distance |
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Term
| Steps of an action potential |
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Definition
| stimulus is recieved, threshold is attained, voltage-gated Na channels open, cell rapidly depolarizes, K channels open, Na channels close, cell begins to repolarize, K channels begin to close, cell hyperpolarizes as the last K channels close, Na/K pumps restore resting membrane potential |
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Term
| Absolute / Relative refractory periods |
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Definition
Absolute - time in which another action potential cannot be induced no matter how strong the incoming stimulus, due to open or inactive Na channels
Relative - Time when resting membrane potential is being re-established where another action potential could be induced with a strong enough stimulus, stimulus would need to be stronger than normal during this period due to inhibitory effect of K channels remaining open |
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Term
| Factors influencing rate of impulse conduction |
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Definition
| axon diameter, myelination |
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Term
| Describe how neurotransmitters are released |
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Definition
| Action potential reaches terminal bouton, voltage gated Ca channels open, Ca binds to neurotransmitter secretion apparatus, stimulates NT vesicles to undergo exocytosis into synaptic cleft |
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Term
| How do NT affect the post-synaptic cell |
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Definition
| NTs (ligands) bind to ligand-gated channels, channels open releasing either + or - ions into the cell, resulting in an increase of excitatory or inhibitory post synaptic potential |
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Term
| Temporal vs. Spacial summation |
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Definition
Temporal - summation of repeated action potentials from the same neuron
Spacial - summation of the effect of action potentials from multiple synapses on the same post synaptic cell
(this is considered convergence) |
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Term
| How is the NT removed from the synaptic cleft |
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Definition
In the case of Acetylcholine, acetylcholinesterase hydrolyzes ACh into acetate and choline which are taken back into the presynaptic cell for reuse.
Other ways include
Re-uptake - i.e. seratonin
and diffusion |
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Term
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Definition
Agonists - drugs that stimulate a receptor
Antagonists - drugs that inhibit a receptor |
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Term
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Definition
| Molecules that relay signals recieved by receptors on the cell membrane |
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Term
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Definition
| Made up of Actin (thin) myofilaments, Myosin (thick) myofilaments, titin, troponin, and tropomyosin |
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Term
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Definition
Z line - outer borders of sarcomere
M line - midline of sarcomere, made up of creatine kinase
H zone- area between the actin (myosin only)
I zone - Area between myosin ends (actin only)
A zone - encompasses all of the myosin, some actin |
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Term
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Definition
| Made up of a motor neuron and the group of skeletal muscle fibers that it innervates, the finer the movement the smaller the number of muscle fibers innervated by one nerve |
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Term
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Definition
| Formed when Myosin head binds to its receptor site on the Actin filament |
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Term
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Definition
| The conversion of electrical stimulus to mechanical response, fundamental to muscle action |
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Term
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Definition
| Specialized organelle within the muscle cell responsible for storing and releasing Calcium ions necessary for muscle contraction and relaxation |
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Term
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Definition
| deep invaginations within the plasma membrane of a skeletal muscle cell, allows for depolarization of the membrane to quickly penetrate to the interior of the myofiber, this allows speedy communication from the motor neuron |
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Term
| Elements responsible for muscle fatigue |
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Definition
Accumulation of potassium
depletion of stored glycogen
reduced SR calcium release
lactic acid accumulation and lower pH
lack of ATP
buildup of ADP
increased PO4
fatigue of upper motor neurons |
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Term
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Definition
Receptors "having to do with ACh"
2 types
Nicotinic and Muscarinic receptors |
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Term
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Definition
| Muscles use myoglobin (stores O2) to respond to demand until consumption is able to compensate, after exertion the body must repay that debt by restocking myoglobin stores |
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Term
| Organization of skeletal muscle and its coverings |
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Definition
Muscle body - wrapped with epimysium or fascia
Fascicles - subunit of muscle body containing many myofibers, surrounded by perimysium
Myofiber - muscle cell, surrounded by endomysium
Myofilaments- thick and thin filaments within myofiber |
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Term
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Definition
| thick double stranded myofibril, with heads for interaction with actin |
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Term
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Definition
| Helical thin filament, wrapped with a tropomyosin filament which is held to the actin by troponin |
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Term
| Cross-bridge forming "sliding filament" theory |
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Definition
| When ATP binds to myosin head it releases its attachment to actin, then it hydrolyzes ATP into ADP and Pi, the energy obtained from this reaction "cocks" the myosin head forward, the cross bridge is formed, phosphate group is released strengthening the cross bridge, the ADP is released activating the "power stroke" ratcheting the myosin head, ATP binds repeating the process |
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Term
| Role of myosin ATP-ase in muscle contraction |
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Definition
| hydrolyzes ATP, causing energized state of myosin head |
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Term
| Role of Calcium in skeletal muscle contraction |
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Definition
During periods of low Ca concentration in the cell, tropomyosin blocks the myosin cross bridge sites
High Ca concentration causes Ca to bind to troponin and produce a conformational change that moves tropomyosin out of the way, revealing the myosin cross bridge active sites, allowing the sliding filament contraction to occur
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