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45 Cards in this Set
- Front
- Back
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what is a synapse?
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connection between two things; its the place where the cells communicate
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where does communication on a synapse occur?
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at the terminal end called the telodendria
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what type of communication is involved in a synapse?
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intercellular communication- can be neuron to neuron OR neuron to muscle OR neuron to gland
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what two types of cells are involved in intercellular communication in a synapse?
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a presynaptic cell and a postsynaptic cell
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what is a presynaptic cell?
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its always a neuron
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what is a postsynaptic cell?
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its either a neuron or another type of cell
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what direction is the communication in a synapse?
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its unidirectional
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what signals the receptors in a synapse?
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neurotransmitters
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where do neurotransmitters signal the receptors?
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in the synaptic cleft
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what is the synaptic cleft?
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a small space between two cells
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what is the perikaryon?
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the cell body
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how do the terminals receive continuous supply of neurotransmitters in the cell body?
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axoplasmic transportation
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what two types of directionality does axoplasmic transportation involve?
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anterograde (cell body to terminal end) and retrograde (from terminal end to cell body)
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what does axoplasmic transport show?
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it shoes directionality
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what is an example of retrograde and how?
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rabies virus- it enters the neuron through axon to cell body and kills it
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what is the resting membrane potential?
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its the difference in the charge of excitable cells across the membrane
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what type of cells does the resting membrane potential involve?
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excitable cells
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what is the charge of the inside of a cell at rest?
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slightly negative
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what is the charge of the outside of a cell at rest?
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slightly positive
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what is potential different?
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potential energy; its the difference between the charges inside and outside the cell at rest
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what causes the difference in voltage among a cell at rest?
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ionic composition differences inside and outside (different charges)
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what is the usual voltage of a cell in an isotonic colution?
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-70mV at rest
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what is a physiological saline?
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isotonic solution
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what does the intracellular fluid consist of?
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-high concentration of K+
-negatively charged proteins- give net negative charge |
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what does the extracellular fluid consist of?
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high concentrations of Na+ and Cl- (balance each other)
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what does the maintenance of RMP (resting membrane potential) do?
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it maintains our ability to be excited by changing the type of energy in order to use it
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how are the differences of the RMP maintained?
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by selective permeable membranes
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what are the two different ways at RMP that ion movement occurs?
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through leak channels and active transport mechnisms
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what are the two different leak channels?
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(passive)
1. K+ leak channels 2. Na+ leak channels |
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what are K+ channels?
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potassium channels; 75% more than Na+ leak channels
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what are Na+ leak channels?
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sodium leak channels; slow channels
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what are the two active transport mechanisms?
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1. sodium potassium pump
2. Na+/K+ ATPase |
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what is the sodium potassium pump's function and what does it use?
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it uses energy to maintain -70mV
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what are the four different types of channels?
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1. voltage gated
2. mechanically gated 3. chemically gated 4. leak channels |
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what are voltage gated channels?
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they open and close by a change in the potential voltage across the membrane; voltage regulated
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what are mechanically gated channels?
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regulated by pressure changes (push and forces to open)
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what are chemically gated channels?
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ligand comes down and hooks onto the protein and then opens the channel
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what type of gradients exist for Na+ and K+?
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chemical gradients
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what ion is more abundance on the outside? inside?
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outside- Na+
inside- K+ |
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what do the chemical gradients for Na+ and K+ follow?
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follow concentration gradients so Na+ moves in while K+ moves out
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what direction do the concentration gradients of Na+ and K+ follow?
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sodium moves in and potassium moves out
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what else besides concentration gradients affect the flow of K+ and Na+ ions?
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electrical charge/electrical difference
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what are the primary factors affecting RMP?
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electrochemical gradients of Na+ and K+
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what is the function of the Na+/K+ exchange pump?
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-at RMP cell removes Na+ and recaptures K+
-3Na+:2K+ -exactly balances diffusion rate |
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which gradient is larger for sodium and potassium?
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the electrochemical gradient is larger than the chemical gradient
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