Phys: Renal Week 3

Front 1

factors that increase ADH secretion

Back 1

1. 1% increase in osmolarity
2. 10% decrease in blood volume
3. nausea
4. angiotensin II (acts directly on osmoreceptor neurons)
5. nicotine

Front 2

factors decreasing ADH secretion

Back 2

1. ANP
2. ethanol

Front 3

1. if you have a high volume of ECF what affect does this have on ADH secretion?
2. what about a low ECF volume?
3. what is the normal osmolarity of ECF?

Back 3

1. the body lets you become a little dehydrated and allows the osmolarity to rise a little above normal before it secretes AVP
2. AVP is released sooner @ an osmolarity a little below normal
3. 285, anything above this stimulates the secretion of ADH

Front 4

1. positive free water clearance is what?
2. negative free water clearance is what?

Back 4

1. excreting a dilute urine (excreting excess water)
2. excreting a conc. urine (conserving water)

Front 5

how do you calculate the free water clearance?

Back 5

Cosm = Urine osm x Urine vol. / Plasma osm

C water = Urine Volume - C osm

Front 6

what are some conditions that can result involving water?

Back 6

1. diabetes insipidus
- central type
- tubular type
2. syndrome of inappropriate ADH secretion (too much)
3. water intoxication (take in H2O faster than the kidney can get rid of it)

Front 7

1. what is the medullary gradient composed of?
2. what is the medullary gradient created by?

Back 7

1. NaCl and Urea (each 50%)
2. loop of henle and vasa recta
- countercurrent multiplying system of loop of henle
- countercurrent exchange system involving the vasa recta

Front 8

functions of the countercurrent exchange system of the vasa recta

Back 8

- supply nutrients and oxygen to the medulla
- help maintain the high conc. of NaCl and urea in the medulla
- remove reabsorbed substances (from the loop and collecting duct) and water (from collecting duct) back into blood

Front 9

why do we need to drink alot of water?

Back 9

1. able to get rid of more waste products
2. less likely to get kidney stones
3. body works better at its proper osmolarity
4. decreases risk of stroke

Front 10

what are the functions of the countercurrent multiplying system (loop)?

Back 10

- removes NaCl from the ascending loop to produce a dilute filtrate. The removed salt creates part of the high osmolarity w/i the medulla
- other functions

Front 11

why does the ascending loop separate NaCl from the water of the filtrate?

Back 11

- NaCl enters the medullary ISF producing a hypertonic medulla that is used to reabsorb enough water, from the collecting duct, to maintain the proper osmolarity of the body
- excess H2O remaining in the filtrate is excreted

Front 12

why is the countercurrent multiplying system (loop) called a multiplying system?

Back 12

b/c energy is used in the process (active transport is used to remove the NaCl)

Front 13

urea is responsible for _____ of the osmolarity w/i the medulla

Back 13

1/2

Front 14

what part of the tubule is permeable to urea?

Back 14

inner medullary collecting duct, ADH increases it's permeability. as H2O is reabsorbed, urea is also reabsorbed into the medullary ECF

Front 15

how does having urea as part of the osmolarity in the ISF of the medulla, affect the Na+ reabsorption?

Back 15

a larger Na+ gradient is available to reabsorb Na+ from the lumen of the thin ascending limb into the interstitial fluid of the medulla

Front 16

what is the affect of GFR on medullary gradient?

Back 16

- low GFR decreases gradient formation
- high GFR decreases gradient due to washout

Front 17

what is the affect of RBF on medullary gradient?

Back 17

- decreased RBF decreases gradient formation
- increased RBF decreases gradient due to washout

Front 18

1. how do you test the concentrating ability of the kidneys?
2. how do you test the diluting ability of the kidneys?

Back 18

1. withhold water and measure urine osmolarity
2. give a water load and measure urine osmolarity

Front 19

what are nitrogen comopounds?

Back 19

breakdown compounds from proteins

Front 20

is the excretion of creatinine affected by osmolarity of filtratre?

Back 20

no

Front 21

nitrogenous compounds are excreted primarily as what?

Back 21

- urea (mammals)
- ammonia (fish)
- uric acid (birds)
(urea and ammonia are both very soluble in H2O, uric acid precipitates)

Front 22

when does the BUN/creatinine ratio increase and decrease?

Back 22

- decreases w/ excretion of a dilute urine
- increases w/ excretion of a conc. urine

Front 23

the BUN/creatinine reatio reflects measurements of urea nitrogen and creatinine in the what?

Back 23

plasma - not urine

Front 24

amount of urea excreted varies w/ the what?

Back 24

osmolarity of the urine; passive reabsorption of urea increases as the filtrate is conc. (excretion of a conc. urine)

Front 25

examples of an increased BUN/creatinine ratio

Back 25

- excretion of a conc. urine (increased urea reabsorption)
- GI hemorrhage (increased urea synthesis)
- very high BMR (increased urea synthesis w/ increase in metabolic activity)
- tissue damage (increased urea synthesis)

Front 26

examples of a decreased BUN/creatinine ratio

Back 26

- excretion of a dilute urine (decreased urea reabsorption)
- low protein intake (decreased urea synthesis)
- renal patient on dialysis (urea removal by dialysis)

Front 27

Gout

Back 27

condition of abnormally high plasma uric acid causing crystallization of uric acid w/i the body (usually in lower extremeties)

Front 28

uric acid

Back 28

- catabolite of proteins
- actively reabsorbed and secreted by the proximal tubule
- plasma conc. is regulated by regulating the secretions

Front 29

azotemia

Back 29

excess nitrogen compounds in the plasma

Front 30

uremia

Back 30

azotemia w/ clinical symptoms. 3 types:
- Pre-renal (decreased BP causes decreased GFR. this decreases excretion of nitrogen compounds)
- renal (decreased excretion of nitrogen compounds caused by a condition w/i the kidneys)
- post-renal (blockage of urine from the kidneys or bladder)

Front 31

newborns have decreased ability to do what?

Back 31

- reabsorb and secrete substances
- conc. and dilute the urine

Front 32

elderly have decreased ability to what?

Back 32

- reabsorb and secrete substances
- conc. and dilute the urine
- GFR due to a decrease in # of nephrons

Front 33

1 water diuresis caused by what?
2. osmotic diuresis caused by what?

Back 33

1. excess water
2. due to excretion of an excess amount of solutes

Front 34

ADH inhibitors

Back 34

inhibit water reabsorption causing water diuresis (increased urine volume)

Front 35

thiazide-type diuretics

Back 35

inhibit the distal tubule Na+/Cl- symporter (increases NaCl excretion leading to increased urine volume)

Front 36

potassium sparing diuretic

Back 36

inhibit Na+ channels or the action of aldosterone (increase NaCl excretion leading to increased urine volume)

Front 37

loop diuretics

Back 37

inhibit the Na+/K+/2Cl- symporter (increases NaCl excretion leading to increased urine volume)

Front 38

carbonic anhydrase inhibitors

Back 38

inhibit the Na+/H+ antiporter (increases NaCl and H2CO3- excretion leading to increased urine volume)

Front 39

osmotic diuretics

Back 39

excess excretion of any solute increases urine volume (ex. NaCl, Glucose, Phosphates)