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32 Cards in this Set
- Front
- Back
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Neuronal Communciation
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-Rapid
-Direct -Specific |
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Hormonal Communication
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-Slower
-Spread thru/out body -Affect many cells & tissues in many diff ways |
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Local medicators are released by variety of cells into the? and act on?
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-Interstistial fluid (fluid b/w the cells)
-act on: neighboring cells a few millimeters away. |
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Local Medicators may be what?
other explanins? |
-Proteins, other AA derivatives, or even Fatty Acids.
-Growth Facotrs & lymphokines!! |
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What are Prostaglandins?
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fatty acid derivative local medicators.
- they affect Smooth Muscle contractions, platelet, inflammation & other rxns. |
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Ex:
Aspirin inhibits prostaglandins and therefore is? |
An Anti-inflammatory!!
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Neuron
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-functional unit of Nervous system.
-highly specialized cell capable of transmitting electrical signals from 1 cell to another by electrical or chem means! |
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So highly specialized that it has lost the capacity to what?
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DIVIDE
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Although neuron uses FACILTATED transport to move glucose from blood into cytosol, unlike most cells, it is?
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Not dependent upon INSULIN for this transport
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Neuron depends heavily on?
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Efficiency of AEROBIC respiration
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Dendrities?
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receive a signal to be transmitted.
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Typically, cytosol of cell body is highly conductive and any electrical stimulus creates?
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a disturbance in the electric field that is transferred immediately to the------ AXON HILLOCK!!
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The membrane of cell body usually deosn not contain enough what?
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enough ION channels to substain an Action Potential
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However what is carries the Action Potential to a synapse, which passes the signal to another cell?
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AXON
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Unipolar ?
Bipolar ? Multipolar ? |
Unipolar= sensory ONLY
Bipolar= retina, inner ear, olfactory area of brain Multipolar= most neurons of the brain |
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How does the signal travel?
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From Dendrites-->axon hillock
where AP is generated & moves down--> AXON--> to Synapase!! |
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Neurons do not depend upon insulin to obtain what?
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Glucose
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Action Potiental originates at the what?
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axon hillock
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Action Potiental
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disturbance in the electic field across a membrane of a neuron
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Since the Na+ concentration moves toward equilibrium, and the K+ concentration remains (lower or Higher) (inside or outside)inside the cell?
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K+ [ ] remains HIGHER INSIDE teh cell!
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The Membrane Potential actually reverses polarity so that it is _____ on the inside, and ______ on the outside
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Positve on inside!
Neg --> outside |
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And this process is called what?
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Depolarization
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K+ channels are ____ sensitive to voltage change so they take ____ to open?
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-->Less sensitive
--->LONGER to Open |
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Now K+ flows _____ of the cell making the _____ more (+ or _) ?
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K+ flows--> OUT of cell
Making ---> INSIDE More---> Negative |
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This Process is known as what?
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REPOLARIZATION
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What is Hyerpolarization and when does it happen?
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Bc K+ channels are so SLOW to close that, for fraction of sec, inside membrane becomes even more NEGATIVE than --> resting potential!
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What type of diffusion returns the membrane to its resting potential
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PASSIVE DIFFUSION!1
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1. Membrane is at rest
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Sodium and potassium channels are closed
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Sodium channels open and the cell ... ?
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cell DEPOLARIZES!
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Potassium channels OPEN as?
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Sodium channels begin to INACTIVATE
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4. Sodium Channels are____?
____ Potassium channels ___________ the membrane? |
Na+ channels ==> INACTIVE ;
Open K+--> Repolarize memb. |
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Potassium channels _____ and the membrane ______ to its ______?
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K+ channels --> close ;
the membrane EQUILIBRATES to its--> RESTING POTENTIAL!! |
