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107 Cards in this Set
- Front
- Back
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The capillary network of the nephon, called the ________.
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Glomerulus
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In mammals each Glomerulus is supplied with blood from an arteriole called the _________ .
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afferent arteriole.
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What are the general transport processes of urine formation?
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filtration
resorption secretion |
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What are the 4 steps of urine formation?
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filtration
bulk resorption dilution/concentration Final adjustment |
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Where does the filtration step of urine formation occur?
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glomerulus
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What gets filtered in the Glomerulus?
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All but proteins & cells
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Where does the bulk resorption step of urine formation occur?
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Proximal tubule
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What type of resorption occurs in the proximal tubule?
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Iso-osmotic resorption (moves w/ the gradient)
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What is an example of what gets resorbed in the proximal tubules?
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2/3 NaCl, H2O
100% amino acids, glucose |
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Where does the dilution/concentration step of urine formation occur?
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Loop of Henle
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Low tubular & high interstitial osmotic pressure are preconditons for which step of urine formation?
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final adjustment
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Low tubular & high interstitial osmotic pressure occur in which step of urine formation?
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dilution/concentration
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Where in the nephron does the final adjustment step of urine formation occur?
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distal tubules & collecting duct
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What occurs in the final adjustment step of urine formation?
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Urine volume & concentration is adjusted.
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tubular fluid refers to _______ & interstitium refers to ________ in the process of urine formation.
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dilution
concentration |
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The loops of Henle of cortical nephrons remain in the ___________
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outer medulla
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Only loops of ________ the descend into the inner medulla.
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juxtamedullary nephrons
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Most of the valuable solutes like Na+, K+, Ca2+, Mg2+, Cl-, glucose, amino acids, lactate & sulfate are already resorbed in the _______.
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proximal tubule
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Waste products like ___, ______, _______ & _______ are secreted into the proximal tubule.
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H+, organic acids and bases, antibiotica (!)
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_______ is resorbed by osmosis in the proximal tubule of the nephron.
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water
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Driving forces for these transports in the proximal tubule are _________ & _________.
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electro-chemical gradients and active transport
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The resorption of high amounts of Na+/Cl- from the ascending loop and water from the descending loop results in __________, ___________ & __________.
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1.A decrease in total volume
2.A decrease in osmolarity of the tubular fluid 3. Increase in osmotic pressure in the interstitium |
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A low osmolarity of the tubular fluid is an important _________ of urine in the distal tubule and collecting duct
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precondition to the final adjustment
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The transport of key solutes like Na+ and water in the distal tubule & collecting duct is regulated by _______.
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hormones
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Why is the nephron regulated by hormones in the distal tubule & collecting duct?
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To adjust urine volume and concentration as needed.
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The __________ regulates the filtration into the Bowman’s capsule
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Macula Densa
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The Macula Densa regulates the ________ in the tubular system.
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flow speed
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In the macula densa, if filtration & flow speed decreased, what would happen to resorption?
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more time for resorption to increase
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The ________ in the nephron generates high osmotic pressure in the Cortex & Medulla.
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loop of Henle
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A ___________ in the medullary interstitium is precondition of concentrating the tubular fluid in the collecting duct which finally leaves the duct as urine
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high osmotic pressure
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Only the ________ limb of the Loop of Henle is permeable to water. The ________ limb is not.
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descending, ascending
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Approximately 2/3 of ________ and ______ entering the descending loop get resorbed.
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water, NaCl
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Only the ________ is equipped with Na/K pumps. The _______ is not.
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ascending limb, descending limb
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The osmolality of the ________ entering the loop equals the osmolality of _________ (=290 mOsm), but it leaves the loop with a much lower osmolality (220 mOsm)
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tubular fluid, blood plasma
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The loop of Henle generates ________ osmotic pressures in the medulla which are essential for the resorption of water from the collecting duct.
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high interstitial
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The sodium conc. of the tubular fluid entering the loop equals the _______ concnetration.
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blood sodium concentration
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In the ascending limb, _______ is transported from the tubular fluid into the ________.
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sodium, interstitium
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The ______ fluid leaves the ascending limb with an oncotic pressure ______ than blood.
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tubular, lower
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Because of higher interstitial pressure _____ diffuses out of descending limb.
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water (water-permeable descending limb)
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As Na+ can't follow its concentration in the tubular fluid, it ______ along the descending limb, reaching a max at the turning point.
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increases
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The increase in NA+ in the descending limb triggers a _______ in the ascending limb.
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positve feedback cycle
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NaCl resorption happens in the ______ limb of the loop of Henle.
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ascending
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High interstital _____ concentration drives water resorption.
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NaCl
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hormonal control of water & NaCl resorption happen in the ______ & ______ of the nephron.
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DCT & collecting duct
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______ equals return of blood
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resorption
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Iso-osmotic resorption happens in the ______ of the nephron.
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proximal tubule
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High interstitial ______ concentration drives water resorption.
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NaCl
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________ & _______ hormones increase the NaCL resorption in the ascending limb.
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aldosterone, angiotensin
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_______ hormones decrease the NaCL resorption in the ascending limb.
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ANF
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Most (~2/3)_____ of the filtered into the Bowman’s capsule is immediately resorbed from the ________.
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Na+, proximal tubule
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Na+ filtered into the Bowman’s capsule is immediately resorbed from the proximal tubule which is also called _________ resorption!.
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isotonic
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The main source of Cl- (and of Na+!) is ______ in the diet.
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cooking salt (NaCl)
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_________ hormone is found in the distal tubule & collecting duct
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Aldosterone
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Aldosterone can increase ____ & _____ resorption but decrease _____ resorption.
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NaCl & H20
K+ |
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________ hormone is found in the prox. tubule, thick ascending loop of Henle & dist Tubule
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Angiotensin II
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Angiotensin II can increase ____ & ____ resorption while decreasing _____ resorption.
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NaCl & H2O
K+ resorption |
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_________ hormone is found in the distal tubule & collecting tubule. It also decreasing NaCl resorption & increases Na excretion.
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Atrial natriuretic factor
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_________ hormone is found in the distal tubule & collecting tubule. It also increases H20 resorption.
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ADH-Antidiuretic hormone
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Blood volume must decrease for ______ hormone to be released.
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ADH
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________ hormone is found in the prox. tubule, thick ascending loop of Henle & dist Tubule. It also causes an increase in CA2+ resorption & decrease in phosphate resorption
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Parathyroid hormone
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Total Body water is divided into ___% (ECF) & ____ (ICF)
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37%, 63%
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How is the ECF distributed through out the body?
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Total ECF in body- 37%
Interstitial fluid- 27% Blood plasma- 7% Transcellular Fluid- 3% |
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What one mechanism above all others dominates the control of blood volume and extracellular fluid volume?
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the effect of blood volume on arterial pressure, &
the effect of arterial pressure on the urinary excretion of sodium and water. |
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There is an intensive continuous exchange of water and electrolytes between ________ & _________.
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blood and extracellular fluid
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In order to control blood volume to any given level what must also be controlled at the same time?
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extracellular fluid volume
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What are the main organic constituents of the body fluids?
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Water
Sodium (NaCl) Potassium Calcium and phosphate Magnesium |
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_________ controls the ECF volume
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Aldosterone
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_________ hormone controls the ECF osmolarity
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Antidiuretic
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Aldosterone controls the excretion of ______ & _____.
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Na+ and Cl-.
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An increase in salt intake increases water intake and the plasma volume _______ . This decreases the Aldosterone blood level and more NaCl and water is excreted. The ________ gets reduced to normal levels.
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increases
plasma volume |
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ADH controls _______.
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the excretion of water
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If osmolarity deviates more than 1% then less ___ is released and the blood level ______ . This increases excretion of water until the normal osmolarity is achieved again.
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ADH, decreases
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What happens during high plasma osmolarity?
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Preformed water channels allow the resorption of water from the tubular fluid. As a result water excretion decreases.
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What happens during low plasma osmolarity?
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W/O ADH the Collecting Duct cells are watertight & water is not resorbed & gets excreted.
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When the ECF rises more than 30 – 50% above normal, almost all of this excess fluid fills the interstitial spaces and causes _______.
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edema
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The ________ acts as an important “overflow release valve”, preventing over-filling of the circulatory system
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interstitium
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Any increase or decrease of
_______ results in increase or decrease of the ECF. |
sodium
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______ is the most important extracellular cation for the control of the volume of the ECF
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Na
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70% of sodium is reabsorbed in the _______ & 20-25% is resorbed in the ______.
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proximal tubule
loop of Henle |
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________ controls final reabsorption in the distal tubule and collecting duct.
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Aldosterone
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There is a positive correlation of NaCl intake and _______.
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hypertension
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Any increase in sodium causes increase in ______ volume.
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blood
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Potassium homeostasis is maintained by ________, _________ & ________.
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-Na/K pump
-K+ permeability of the cell membrane -Na/K antiport |
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If K+ homeostasis is disturbed it can cause __________ shifts of K+ bt. intracellular & extracellular space.
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life-threatening
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_______ ion is the main contributor to the membrane potential.
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K+
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Changes in extracellular K+ concentration can cause ________, ________ & _______.
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bradycardia, arrythmia & even heart arrest
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The kidney regulate ____ ion metabolism.
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K+
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What are the most important factors regulating the rate of potassium excretion?
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Extracellular K+ concentration &
plasma aldosterone concentration |
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Only 2% of the K+ are in the ________ space.
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extracellular
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Disturbance of the________ or ________ results in major changes in the extracellular K+ concentration.
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Na+-K+ pump or the membrane permeability
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1% decrease in intracellular K+ would cause _____ %increase in extracellular K+.
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50%
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How does low intracellular pH effect the activity of Na+/K+ pump?
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decreases activity
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How does high intracellular pH effect the activity of Na+/K+ pump?
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increases activity
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How does Intracellular acidosis effect K+ in the ECF?
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K+ accumulates in the ECF
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How does Intracellular alkalosis effect K+ in the ECF?
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K+ depletes in the ECF
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How does low intracellular pH effect K+, H+ & Cl- in the ECF?
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K+-up
H+-up Cl-up |
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How does high intracellular pH effect K+, H+ & Cl- in the ECF?
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K+-down
H+-down Cl-down |
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How does Na/K pump effect urine formation?
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It provides the chemical, osmotic & electrical gradients for transport processes.
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The distal tubule & proximal collecting duct are impermeable to ______, but are not to water.
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urea
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The resorption of water causes a high concentration of ______.
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urea
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Recycling of urea saves _____.
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NaCl
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The resorption capacity of glucose is _______.
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limited
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If the glucose conc. in plasma rises too high, the resorption system becomes _______ and glucose appears in the final urine causing _______.
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saturated, diabetes mellitus
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H+ ions are mainly exchanged for _____ ions.
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Na+
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In the distal tubule and the collecting duct, _______ cells excrete H+ ions by active transport.
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type A
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In ______ type A cells change to type B cells and reverse the transport of H+ ions from the lumen back into blood.
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alkalosis
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90% of bicarbonate are resorbed in the _________.
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proximal tubule
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