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22 Cards in this Set
- Front
- Back
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what does lidocaine do?
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it blockes voltage-gated Na+ channels and prevents the occurrence of nerve action potentials.
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what are three things voltage gated Ca2+ channels do>
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Ca2+ is a second messenger - secretion, muslce contraction, kinase activation, gene expression
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what does amiloride do?
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it blocks sodium epithelia channels which causes diuresis
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What are Epithelial Sodium Channels (ENaC)? where are they typically located in the cell?
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found in the kidney, lung, guy, allow for Na+ to travel down its concentration gradient
typically located in the apical membrane to provide a pore for Na+ to diffuse down its concentration gradient. |
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waht is liddle's syndrome?
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it is an ENaC mutation that causes hypertension
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what does alosterone do?
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it increases cell absorbtion of sodium
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what are the 2 main water channels where are they found?
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Aquaporin 1- RBCs, renal proxmial tubules, endothelia cells, choroid plexus;
Aquaporin-2: renal collecting duct - ADH |
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What is a Uniporter?
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a uniporter are found in facilitated diffusion, they transport a single substance down its concentration gradient
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What are the 2 limiting factors of facilitated diffusion?
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the Vmax of the carrier protein and the density of the carrier protein in the membrane
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Which is faster: Carrier Mediated (facilitated) or simple diffusion?
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Carrier Mediated.; the transport rate shows saturation kinetics, the membrane carrier protein show a high degree of chemical specificity for substances they will bind; structually related molecules may compete for binding sites on the carrier protein. structurally unrelated may inhibit transport by non-competitive means. this decreases the affinity of the carrier for the tranported molecule.
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What do glycosides do? What is the result of their action?
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the inhibit the Na/K ATPase pump. increase intracellular Na+, decrease Na+ gradient, which decreases the Na+/ Ca2+ counter transport. You get an Increase in intracellular Ca2+
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What is a symporter? What is another name for this?
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transports 2 or more substances in the same direction across a membrane. Also called a Cotransporter
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What is an antiporter? Another name?
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exchanges substrates in opposite directions, a countertransporter if you will.
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what does amiloride do?
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it blocks epithelial sodium channels which causes diuresis or more production of urine.
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what are 5 examples of a symporter?
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Na+/ Sugar
Na+/ amino acid Na+/Cl- Na+/K+/2Cl- Na+/H2PO4- |
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what are 3 examples of an anitporter?
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Na+/H+
Na+/Ca2+ Cl-/HCO3- |
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What kind of fluid does sweat glands produce? what happens to this fluid as it travels along the sweat duct?
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secretory cells prodcue isotonic fluid which travels down a reabsorptive duct that is impermeable to water. however, Na+ and Cl- are reabsorbed to yield a hypotonic sweat.
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what happpens in cystic fibrosis in the in the intestine? what happens bc of cystic fibrosis in the sweat glands?
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in the intestine cycstic fibrosis results in the loss of cAMP Cl- secretion and increases the salt concentration in ducts which can lead to ductile obstruction.
in sweat glands the Cl- channels are defective and result in isotonic sweat. |
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what is paracellular transport?
what is the category for this epithelia? how is this different from transcellualr transport? |
paracellular transport means the movement of water and solutes can travel between the cells of an epithelial layer.
this epithelia that has paracellular transport is considered leaky transcellular transport the water or solute travels through the apical end and out the basolateral end. |
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what is the def of tight epithelia?
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in tight epithelia the movement of solutes and ions across the apical and basolateral meembranes is very important for physiological function. such as renal collecting duct and the salivary gland ducts are examples of tight epithelia
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Simple diffusion happens how?
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used for water soluble ions, driven by electtrical and chemical gradients (downhill).
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facilitated diffusion
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are enzyme like proteins that provide passive pathways for solutes to move across membranes down their concentration gradients.
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