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32 Cards in this Set
- Front
- Back
net filtration rate (NRT)
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blood hydostatic pressures- colloid osmotic pressure - capsular hydrostatic pressure
(~ 10mm Hg) |
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decrease in blood pressure
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decrease glomerular hydrostatic pressure and GFR
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homeostatic mechanism for blood pressure
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arteries of the body at balloons...when containing less fluid, the pressure is lower...decreased GFR and urine output will prevent further fluid loss and catastrophic loss of blood pressure
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renal autoregulation of GFR
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helps ensure that wastes are removed despite variation in blood pressure...keeps GFR relatively constant in face of small changes in MAP
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afferent arterioles and autoregulation
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respond to changes in blood pressure to control GFR
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arterial pressure increases
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afferent arterioles constrict to reduce GFR
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arterial pressure decreases
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afferent arterioles relax to increase GFR
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vasocontriction
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decrease blood flow into glomerulus
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vasodilation
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increases blood flow into the glomerulus
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myogenic response (renal autoregulation)
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1. all stretched arteries constrict in response to strech
2. when afferent arterioles are stretched from increased MAP -> they constrict to reduce GFR |
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tubuloglomerular feedback
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1. local sensors that assess flow of fluid through the tubules
2.if flow is too low, changes are made to increase flow and vice versa. 3. sensors are in the macula densa cells of the distal tubule |
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macula densa cells
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regulate vasoconstriction/dilation of special cells in the afferent arteriole called JUXTAGLOMERULAR cells
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if flow is too low, macula densa cells...
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release nitric oxide to cause afferent arteriole dilation
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if flow is too high, macula densa cells...
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release ATP and prostaglandins, which cause juxtaglomerular cell constriction
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sympathetic nervous system regulation of GFR
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1. stimulated during exercise or blood loss
2. causes constriction of afferent arterioles 3. decreases GFR |
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exercise
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reduction of GFR diverts blood from kidneys to working muscles
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blood loss
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reduces filtration to keep blood volume up
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hormonal regulation of GFR
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1. epinephrine is secreted by the adrenal medulla in response to stress, exercise, or blood loss
2. epinephrine binds to G-protein link receptos in the afferent arteriole -> vasoconstriction of the arteriole and decreased GFR |
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hormone released from the heart in response to high blood pressure
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atrial natriuretic hormone
-increases GFR by vasodilating afferent arterioles and constricting the efferent arteriole |
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if a drug raises levels of prostoglandins around the juxtaglomerular cells it will...
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decrease GFR
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blocking a pathway that causes a function to increase it'll...
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cause a decrease
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drugs that block the sympathetic nervous system
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decrease heart rate
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drugs that block the parasympathetic nervous system
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increases heart rate
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how do ions like Na+ move through a lipid bilayer?
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A channel
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how do polar organic molecules like glucose and amino acids move through the cell membrane?
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transporter
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channel
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: membrane protein that allows high rates of movement of an ion through a hole. It does not saturate, and the higher the electrochemical gradient the faster the transport
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transporter
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membrane protein with binding sites for molecules that flip over in response to the electrochemical gradient for all binding molecules. They saturate because at some point all binding sites are filled.
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passive transport
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movement of a molecule down an electrochemical gradient
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active transport
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movement of a molecule against an electrochemical gradient, powered by energy from the cell (ATP)
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NaCl and water reabsorption
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1. Na+/K+ ATPase are located on the basolateral side and pumps Na+ to ECF, Na+ is absorbed into blood
2. Na+ is absorbed across apical membrane 3. Cl- moves between cells due to electrical gradient across epithelia 4. water follows salt between cells because of osmotic gradient 5. water crosses the membranes through aquaporins. |
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transport of water driven by Na+ transport
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1. Na+ is pumped out by Na+/K+ pump using active transport
2. produces low Na+ concentration inside the cell 3. Na+ diffuses from filtrate into cell through Na+ channels in luminal side 4. K+ diffuses out of channels in basolateral side of cell and is recycled 5. water follows salt |
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paracellular transport
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important for reabsorption of salts, water and nutrients in the proximal tubule
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