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112 Cards in this Set
- Front
- Back
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What type of system is the urinary system? |
an excretion system (elimination of metabolic waste) |
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What are the four types of excretion systems? |
*urinary (urine) *respiratory (breathing) *digestive (feces) *integumentary (sweat) |
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What are the 7 functions of the urinary system? |
*excretion of metabolic wastes *regulation of fluid and electrolyte balance *regulation of blood acidity-alkalinity (pH) *regulation of blood volume and pressure *production of erythropoietin hormone *activation of Vit D to calcitriol *gluconeogenesis |
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What does erythropoietin do? |
It is a hormone that stimulates RBC formation in the bone marrow. |
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What does calcitriol do? |
Activation of Vit D to calcitriol stimulates intestinal absorption of calcium |
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What do the kidneys do? |
they filter blood and produce urine |
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What do the ureters transport? Where does it transport it to? |
Ureters transport urine to the urinary bladder |
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What does the urinary bladder do? |
It stores urine until it is eliminated |
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What is the urethra? |
It is a tube for the elimination of urine |
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What is the sheath of the kidney called? |
Renal capsule |
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What is the renal cortex of the kidney? |
It is the outer region |
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What is the renal medulla of the kidney? |
It is the inner region with 8 to 18 renal pyramids |
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What is the apex or tip of the renal pyramid called? |
Renal papilla--this is where the urine comes out |
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What are renal columns made of? Where are they located? |
The are made of cortical tissue and are between the pyramids in the kidney |
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What part of the kidney receives urine? Where does the urine come from? |
The minor calyx receives urine. The urine comes from the renal papilla. |
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What does the major calyx do? |
It collects urine from 2 or more minor calyces. |
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What is the function of the renal pelvis of the kidney? |
It collects urine from all major calyces |
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What is the function of the ureter in the kidneys? |
It carries urine from the renal pelvis to the bladder |
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What are nephrons? |
*They are microscopic filtering units of the kidneys composed of renal tubules and a blood supply. *called functional units that make urine *about 1 million per kidney *mostly found in renal cortex with some tubules extending into renal pyramids of medulla |
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What are the two parts of a nephron? |
*renal corpuscle *renal tubules |
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What does the renal corpuscle consist of? |
*loops of capillaries called glomerulus *double layered Bowman's capsule surrounds glomerulus |
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What are the renal tubules made of? |
*proximal convoluted tubules (PCT) connects to Bowman's capsule *Loop of Henle with descending and ascending limbs *distal convoluted tubule (DCT) is the last part of the nephron *DCT of several nephrons connect to a collecting duct (CD) |
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What are the four types of tubules found in the nephron? |
*PCT--proximal convoluted tubule *DCT--distal convoluted tubule *CD--collecting duct *Loop of Henle |
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If you have 6 liters of blood in your body, how often does it all pass through the kidneys? |
every 5 minutes |
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What is the route of blood supply to the kidney? |
aorta --> renal a. --> segmental a. --> interlobar a. --> arcuate a. --> interlobular a. --> afferent arteriole --> glomerulus --> efferent arteriole --> peritubular capillaries and vasa recta --> interlobular v. --> arcuate v. --> interlobular v. --> renal v. --> inferior vena cava |
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What are afferent and efferent arterioles? |
Afferent arterioles go into the nephron to form the glomerulus capillary bed--when it is formed and comes out of the nephron, it is then called efferent arterioles. |
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What is the blood supply route of a nephron? |
afferent arteriole --> glomerulus --> efferent arteriole --> peritubular capillaries --> vasa recta *this capillary network is important for urine formation |
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What four processes are required for urine formation? |
*filtration from the glomerulus blood into Bowman's capsule *tubular reabsorption from renal tubules to blood *tubular secretion from blood into the renal tubules *excretion of the final product (urine) |
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What happens during filtration? |
High glomerular capillary hydrostatic pressure of about 60 mmHg forces water and solutes through the filtration membrane which is formed by the glomerular capillary wall and visceral layer of the Bowman's capsule. |
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What filtration pressures are present? |
*blood hydrostatic pressure (BHP)=60mmHg out *colloid osmotic pressure (COP) = -32mmHg in *capsular pressure (CP) = -18 mmHg in *net filtration pressure (NFP) = 10 mmHg out |
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What solutes pass through the glomerulus during filtration? Where do they go? |
*water and many different solutes pass from glomerulus blood *it goes into the Bowman's capsule |
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What is filtrate? What does it contain? |
*The resulting fluid in capsular space during filtration. It contains: *wastes (urea, uric acid) that must be eliminated in the urine *useful substances like water, organic nutrients, and electrolytes that must be kept |
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What is renal blood flow (RBF)?
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The amount of blood flow through kidneys in one minutes (about 1200 mL/minute) |
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What is glomerular filtration rate (GFR)? |
The amount of filtrate formed in one minutes (about 120 mL/minute) |
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How much RBF becomes a filtrate? |
about 10% of RBFs |
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Regulation of glomerular filtration rate (GFR) is done by... |
...controlling glomerular blood flow by dilation or constriction. |
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What will increase GFR? |
Dilation of afferent arteriole and constriction of efferent arterioles increases GFR. |
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What will decrease GFR? |
Constriction of afferent arteriole and dilation of efferent arterioles decreases GFR. |
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What are the three types of regulation of GFR? |
*autoregulation *neural regulation *hormonal regulation |
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Describe auto regulation of GFR. |
regulation by the juxtaglomerular or macula dense apparatus |
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Describe neural regulation. Does it increase or decrease GFR? |
Sympathetic nervous system stimulation during exercise or in circulatory shock that decreases GFR. |
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Describe hormonal regulation. |
It is by renin, angiotensin, and aldosterone system. |
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What is renin? |
An enzyme produced by the kidneys
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What does Angiotensin II do? How long is it? |
*stimulates hypothalamus to make you thirsty *vasoconstriction *stimulates adrenal cortex to produce aldosterone which causes the kidneys to retain water and sodium *8 amino acids long |
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What is the route of the feedback system? |
*High GFR *Rapid flow of filtrate in renal tubules *Sensed by macula dense *Paracrine secretion *Constriction of afferent arteriole *Reduced GFR |
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What is the route of renin angiotensin aldosterone? |
*Drop in blood pressure is sensed by the kidneys *The liver produces angiotensinogen *Renin from the kidney changes angiotensinogen into angiotensin I *The lungs produce ACE (angiotensin converting enzyme *ACE converts angiotensin I to angiotensin II *elevated blood pressure occurs |
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Describe the effects of angiotensin. |
*angiotensin II is secreted *constricts afferent and efferent arterioles *reduces glomerular blood pressure and filtration *reduces blood pressure in peritubular capillaries *reduces resistance to tubular reabsorption *tubular reabsorption increases *urine volume is less but concentration is high |
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What is tubular secretion? |
Some solutes move from the blood of the peritubular capillaries back into the filtrate |
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What is secreted into the filtrate during tubular secretion? |
*bile acids *ammonia *urea *uric acid *creatinine |
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What drugs are cleared by tubular secretion? |
*blood pollutants *morphine *penicillin *aspirin |
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What does tubular secretion balance? |
Tubular secretion of hydrogen and bicarbonate ions helps to regulate acid-base balance and fluids pH |
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What can diffuse through the paracellular route? |
Water, Na+, K+, Mg2+, Cl-, Pi, urea, uric acid |
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What can diffuse through the transcellular route? |
Active transport: sodium and glucose, amino acids, lactate, chloride, and phosphorous are cotransported |
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What can diffuse by pinocytosis? |
Proteins |
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What mechanisms make sure that useful products are taken in? |
*active transport *transmembrane transport *paracellular transport *endocytosis *exocytosis |
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Where does most filtrate move from and into? |
Most filtrate moves from the nephron tubules back into the peritubular capillaries blood |
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What percentage of reabsorption is in the proximal convoluted tubule? |
65% |
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What is the transcellular route? |
through the epithelial cells |
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What is paracellular route? |
between the epithelial cells |
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What is transport maximum? |
It is the amount of a substance that can be transported before the transport proteins for that substance to become fully saturated |
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How many liters of filtrate are reabsorbed each day? |
150 to 180 liters |
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How many liters of urine are reabsorbed per day? |
1 to 2 liters of urine |
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How many liters of water are reabsorbed each day? |
148 to 178 liters |
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What is the only area that doesn't reabsorb water? |
Ascending limb of Henle |
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What percentage of water in reabsorbed in each area? |
*65% in proximal convoluted tubules *15% in descending limbs of Henle *10% in distal convoluted tubules *10% in collecting ducts *NONE in ascending limb of Henle |
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Where does obligator water reabsorption happen? It is constant or intermittent? |
*Happens in proximal convoluted tubules and descending limbs of Henle *It is more constant |
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Where does facultative water reabsorption happen? Is it constant or variable? What does it depend on? What is it controlled by? |
*Happens in distal convoluted tubules and collecting ducts *variable *depends on degree of hydration *reabsorption is controlled by anti-diurretic hormone |
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What are the steps in the counter current multiplier system? |
*more salt is continually added by the PCT *the higher the osmolarity of ECF, the more water leaves the descending limb by osmosis *the more water that leaves the descending limb, the saltier the fluid that remains in the tubule *the saltier the fluid in the ascending limb, the more salt the tubule pumps into ECF *the more salt that is pumped out of the ascending limb, the saltier the ECF is in the renal medulla |
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There are 6 steps in the concentration of urine. What are the first three? |
1. As water loss exceeds gain, hypothalamus stimulate secretion of antidiuretic hormone (ADH) from the posterior pituitary 2. ADH makes the cells of the DCT and CD more permeable to water 3. More water leaves the DCT and CD and enters concentrated interstitial fluid and blood at the bottom of the LOH |
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There are 6 steps in the concentration of urine. What are the last three? |
4. Concentrated interstitial fluid and blood take more water out of the filtrate and concentrate the urine 5. Aldosterone from adrenal cortex increases salt and water reabsorption from filtrate and thus helps to concentrate urine 6. Results in a small volume of concentrated dark yellow urine |
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What are the 4 steps in dilution of urine? |
1. As water gain exceeds loss, hypothalamus stops secreting ADH 2. DCT and CD become less permeable to water and less water is reabsorbed 3. Adrenal cortex decreases aldosterone secretion, thus less salt and water is reabsorbed from filtrate and this helps to dilute urine 4. More water stays in filtrate resulting in a large volume of light colored dilute urine |
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What is the difference between dilution and concentration of urine? |
There is no water reabsorption, no ADH, from DCT or CD in dilution of urine. |
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What is the definition of obligatory urine volume? |
The minimum urine volume that must be excreted by the kidneys to get rid of metabolic waste and excess ions |
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How many liters per day have to be excreted no matter what? |
0.5 liters per day |
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What is the maximum concentration ability of the kidney? |
1200 to 1400 mOsm/liter |
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What is urine composed of? |
*95% water *5% solutes (solids) |
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What is included in the solid solutes in urine? |
*electrolytes *nitrogenous wastes like urea, creatinine, and uric acid |
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What is urea from? |
protein metabolism |
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What is creatinine from? |
muscle metabolism |
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What is uric acid from? |
nucleic acid metabolism |
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What are the 4 characteristics of the final product, urine? |
*color: yellowish to water clear *turbidity: clear without turbidity *specific gravity: 1.00 to 1.03 *pH: acidic, around 6 |
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What is albuminuria? |
albumin in urine |
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What is glycosuria? |
glucose in urine |
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What is hematuria? |
blood in urine |
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What is pyuria? |
pus in urine |
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What is ketonuria? |
ketones in urine from bad metabolism |
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What is bilirubinuria? |
bilirubin (dead RBCs) in urine |
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What is casts? |
dead cells in urine |
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What are renal calculi? |
kidney stones |
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What is micturition? |
The feeling of needing to urinate *a spinal cord reflex that causes the feeling of need for urination *a self regenerating reflex |
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How is micturition inhibited? |
The brain has conscious control centers that can inhibit micturition for a little bit. Facilitation is done through the pudendral nerve. |
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What is the signal route of micturition? |
*signals from sensory stretch receptors in bladder *pelvic nerve *spinal cord *back by PNS fibers *bladder *stimulation of detrusor muscle contraction |
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What is atonic bladder? |
*overflow incontinence *destruction of sensory nerve fibers abolish the micturition reflex contractions *bladder fills to capacity and overflows in drops *conscious control is still there, but not feeling *syphilis and sacral nerve injury |
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What is automatic bladder? |
*spinal cord injury above the sacral region *causes loss of conscious control of urination *usually paralyzed from the waist down *bladder empties itself automatically when it is filled |
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What is uninhibited neurogenic bladder? |
*loss of inhibitory signals to the bladder promotes frequent urination *the feeling of needing to go will never stop until the bladder is emptied |
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What are the three levels of renal failure? |
*acute *chronic *end stage renal failure |
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Describe acute renal failure. |
*pre-renal: caused by decreased renal blood supply *intra-renal: caused by kidney tissue abnormalities *post-renal: caused by any urine outflow obstruction |
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Describe chronic renal failure. |
*caused by an irreversible decrease of functional nephrons to less than 25% of normal due to blood, kidneys, or urinary tract disorders (nephrons can't regenerate, so the surviving nephrons have to work harder) |
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Describe end stage renal failure. |
*Kidney transplant *Dialysis treatment required for life |
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What is central diabetes insipidus? |
Failure of posterior pituitary to produce or release ADH |
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What is nephrogenic diabetes insipidus? |
Inability of kidney tubules to respond to ADH stimulation |
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What is azotemia/uremia? |
Retention of water, electrolytes, and waste products into the blood |
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What is nephrotic syndrome? |
Protein excretion in urine |
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What are diuretics? |
Drugs that increase water excretion by the renal tubules |
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What are diuretics prescribed for? |
Commonly used to alleviate: *vascular hypervolemia *edema *congestive heart failure *hypertension |
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What are action sites? |
They are various parts of the renal nephron tubules |
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What do thiazide diuretics do? |
Inhibit NaCl transport in the DCT (hydrochlorothiazide) |
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What do loop diuretics do? |
Inhibit NaCl transport in the thick ascending limb (furosemide) |
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What do aldosterone inhibitors do? |
Block aldosterone receptors and prevent K+ excretion (spironolactone) |
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What are osmotic diuretics? |
Inhibit absorption of water in PCT (mannitol) |
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What are carbonic anhydrase inhibitors? |
Used for glaucoma (acetazolamide and dorzolamide) |
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What is an example of ADH receptor antagonists? |
conivaptan |
