renal reabsorption

Question 1

how much ultra filtrate do we typically produce a day

Answer 1

180 Litters

contains a lot of water that must be modified or we would loose important substances

Question 2

what is contained in the water that we must modify

Answer 2

important minerals, bicarbonate, glucose and electrolytes

Question 3

reabsorption

Answer 3

returns substances in ultra filtrate back to circulation

Question 4

secretory mechanisms

Answer 4

remove substances from the blood and add it to the urine

Question 5

which capillary bed is responsible for secretion and reabsorption

Answer 5

pertiubular capillaries

Question 6

protein net transport

Answer 6

stays within the vasculature

Question 7

insulin net transport

Answer 7

within the vasculature and the nephron (without crossing from nephron back to vasculature )

Question 8

sodium net transport

Answer 8

within the vasculature and the nephron (crossing from nephron back to vasculature , some sodium remains in nephron)

Question 9

glucose net transport

Answer 9

within the vasculature and the nephron (crossing from nephron back to vasculature, no glucose is normally excreted in urine )

Question 10

what is PAH

Answer 10

Parahippurate an organic anion

Question 11

Parahippurate net transport

Answer 11

within the vasculature and the nephron (remaining PAH in the vasculature secreted to the the nephron to be excreted in urine )

Question 12

organic bases net transport

Answer 12

within the vasculature and the nephron (crossing from nephron back to vasculature , some organic bases are excreted in urine )

Question 13

what is the most important function of the kidneys

Answer 13

reabsorption of sodium

Question 14

wherever sodium goes

Answer 14

water follows

Question 15

amount of NA+ in the ECF determines

Answer 15

the ECF volume, which then determines plasma volume, blood volume and thus blood pressure

Question 16

how much sodium do we excrete in urine

Answer 16

less than 1%

Question 17

where are the two places in which we reabsorb the most sodium

Answer 17

the proximal convoluted tubule (67%) and the thick ascending limp of Henle (25%)

Question 18

why is the lumen of the early proximal tubule negative

Answer 18

results from the net positive charge (na +) moving into the cell of the early proximal tubule from the lumen where if leaves behind its negative charge

Question 19

why vessel forms the vasa recta

Answer 19

the efferent arterioles

Question 20

what does the proximal convoluted tubule reabsorb?

Answer 20

Na+, Cl-, K+, glucose, amino acids, urea, bicarbonate and water

Question 21

what is reabsorbed in the descending loop of Henle

Answer 21

water

Question 22

what is reabsorbed in the ascending loop of Henle

Answer 22

sodium chloride and potassium

Question 23

what does the distal convoluted tubule reabsorb?

Answer 23

sodium chloride calcium potassium magnesium and bicarbonate

Question 24

what does the collecting duct reabsorb?

Answer 24

sodium chloride urea and water

Question 25

Na + and water play a key role in

Answer 25

regulating blood pressure

Question 26

HCO3 and H play a key role in

Answer 26

acid base balance | maintaining the pH of our body

Question 27

early proximal tubule sodium channels from the lumen to the cells of early proximal tubule

Answer 27

Na+ coupled with glucose, amino acids, phosphate lactate or citrate Na+ in exchange for the positively changed H+ which id attracted to the negatively charged lumen

Question 28

early proximal tubule channels from the cells of early proximal tubule to the blood

Answer 28

``` ATPase pump, exchange Na for K glucose channel amino acid channel phosphate, lactate, or citrate channel bicarbonate channel ```

Question 29

Filtered HCO3- in lumen of early proximal tubule

Answer 29

once H enters the lumen from the cell it has the ability to chemically react with the HCO3- creating H2CO3 which can then react with the enzyme carbonic anhydrase and produce H2O and CO2 both which can diffuse across the lumen into the cell of the early proximal tubule once inside the cell, the may form H2CO3 once again and then dissociate via a chemical reaction (with the enzyme carbonic anhydrase) to create H (which can go on and repeat the cycle) and bicarbonate (HCO3-) that can now be transferred via channel across the cell membrane to the blood for circulation

Question 30

why are you acidic when you have an increase in carbon dioxide levels

Answer 30

there is a shift for more hydrogen ion production

Question 31

tubular fluid reaching the late proximal tubule has

Answer 31

a high Cl- concentration which drives the paracellular reabsorption of Cl-

Question 32

why is the lumen positive in the late proximal tubule

Answer 32

the Cl- diffusion into the blood makes the lumen positive with respect to the blood

Question 33

what are the consequences of transport of solutes into the lateral intercellular space

Answer 33

increase osmolarity | establishes driving force of H2O

Question 34

what type of channels allow for the reabsorption of H2O

Answer 34

aquaporin channels

Question 35

what is the cortical layer of the Interstitial Fluid maintained at

Answer 35

300 mOsm

Question 36

reabsorption in the Loop of Henle

Answer 36

overall the loop of Henle ill reabsorb more sodium chloride than water

Question 37

what percentage of sodium chloride does the LoH reabsorb overall

Answer 37

25%

Question 38

what percentage of water does the LoH reabsorb overall

Answer 38

10%

Question 39

what is the thin descending limb permeable to

Answer 39

passive permeability to H2O, NaCL and urea H20 will move out and the solutes will move in very permeable to water

Question 40

what is the thin ascending limb permeable to

Answer 40

passive permeability to NaCL and urea not passive permeable to water

Question 41

what is the thick ascending limb permeable to

Answer 41

uses active transport to reabsorb NaCL this is a load dependent-- the more deliver the more reabsorbed impermeable to water

Question 42

water and thin descending, thin ascending, and thick ascending

Answer 42

passively permeable not passively permeable impermeable

Question 43

lumen charge in thick lim

Answer 43

positive 7 relative to the blood, due to the back diffusion of the positively charged K+

Question 44

active transport mechanism in the thin ascending limb of Henle

Answer 44

NaCl reabsorption is mediated by a Na+/2Cl-/K+ cotransport system, present in the luminal membrane of this nephron segment. furosemide binds reversibly to carrier protein, thus reducing or abolishing NaCl reabsorption. This leads to a decrease in interstitial hypertonicity and thus to a reduced water reabsorption

Question 45

Corticopapillary Osmotic Gradient

Answer 45

osmotic gradient from the cortex to the tip of the papilla

Question 46

how is Corticopapillary Osmotic Gradient created

Answer 46

by multiplying a small local gradient by the length of the counter-current system

Question 47

where does the COG take place

Answer 47

in the long loops of Henle

Question 48

acsending limb omoslarity

Answer 48

is decreased pumps out NACl

Question 49

interstitial fluid omoslarity

Answer 49

increased because the NaCl is being pumping into it, increasing concentration at first

Question 50

decsending limb omoslarity

Answer 50

is increased because water is leaving the nephron to the interstitial fluid and increasing the concentration

Question 51

3 steps to concentrate urine

Answer 51

pump, equilibrate, shift

Question 52

tubular fluid is progressively | Descending limb

Answer 52

concentrated as if flows down the descending limb

Question 53

tubular fluid is progressively | Ascending limb

Answer 53

diluted as it flows up from the ascending limp

Question 54

fluid leaving the lop of Henle is

Answer 54

dilute

Question 55

gradient flow of _____ mosm/l is maintained across the ascending limb at every ______ level

Answer 55

200, horizontal | but the larger osmotic gradient from top to bottom

Question 56

osmolality of the interstitial fluid increases as you go

Answer 56

deeper into the medulla

Question 57

why is the gradient referred to as a multiplier

Answer 57

beast the 200 mOsm/ L established by the active transport has been multiple

Question 58

why is the gradient referred to as countercurrent

Answer 58

the flow I in opposing directions in the two limbs

Question 59

what is an essential component of the countercurrent multiplier?

Answer 59

active transport

Question 60

what is the Juxtaglomerular Apparatus composed of

Answer 60

the macula densa granular cells Extraglomerular mesangial cells

Question 61

what do granular cells secrete

Answer 61

renin

Question 62

what do Extraglomerular mesangial cells secrete

Answer 62

erythropoietin

Question 63

function of the Juxtaglomerular Apparatus

Answer 63

regulate Blood pressure, blood cell production and the rate at which kidneys filter fluid

Question 64

Macula

Answer 64

increased NaCl delivery causes the macula densa cells to swell and this leads to the release of chemical transmitters which stimulate the gradual cels and will have direct effects of the VSM Ca2+ channels