Renal Lec 4

Question 1

4 different types of renal handling

Answer 1

• filtration only
• filtration + partial reabsorption
• filtration + complete reabsorption
• filtration + secretion

Question 2

harmful/not useful substance undergo what type of renal handling

Answer 2

-filtration + secretion

Question 3

useful substances undergo what type of renal handling

Answer 3

-filtration + complete reabsorption

Question 4

inulin, creatine (type of renal handling)

Answer 4

-filtration only

Question 5

electrolytes (type of renal handling)

Answer 5

-filtration + partial reabsorption

Question 6

glucose, amino acids (type of renal handling)

Answer 6

-filtration + complete reabsorption

Question 7

organic acids (PAH-para-aminohippuric acid) and bases

Answer 7

-filtration + secretion

Question 8

urea (mostly excreted or reabsorbed?)

Answer 8

slightly excreted and reabsorbed)

Question 9

water, sodium (mostly excreted or reabsorbed?)

Answer 9

mostly reabsorbed

Question 10

glucose (mostly excreted or reabsorbed?)

Answer 10

all reabsorbed

Question 11

is neurohormonal input involved in glucose reabsorption

Answer 11

no

Question 12

is neurohormonal input involved in water,sodium reabsorption

Answer 12

yes

Question 13

reabsorption from tubular lumen through tubular epithelial cell into peritubular capillaries is mediated by (2 methods- major/minor)

Answer 13

• mediated transport (transepithelial) - major

- diffusion across tight junction (paracellular) - minor

Question 14

reabsorption of Na+

Answer 14

• passive diffusion across luminal/apical side into tubular epithelial cells
• active transport on basolateral membrane by Na+/K+ ATPase into interstitial fluid (to peritubular capillaries)

Question 15

Na+ movement depends on

Answer 15

type of channel/ transport protein

cotransport in PCT (proximal tubule)

Question 16

filtrate is similar to (Na+ conc.)

Answer 16

interstitial fluid

Question 17

filtrate —-> interstitial fluid (Na+ reabsorption mechanism)

Answer 17

mediated transport

Question 18

interstitial fluid —-> blood plasma (Na+ reabsorption mechanism)

Answer 18

diffusion and bulk transport

Question 19

high or low Na+ conc in tubule lumen and interstitial fluid

Answer 19

high

Question 20

high or low Na+ conc in tubule epithelial cell

Answer 20

low

Question 21

at normal plasma glucose concentration, amount of filtered glucose reabsorbed

Answer 21

all of it

Question 22

in proximal tubule, glucose is reabsorbed by

Answer 22

• secondary active transport on luminal side by SGLT (sodium linked co-transport)
• facilitated diffusion on basolateral side by GLUT (diffusion)

Question 23

renal threshold

Answer 23

the concentration level up to which a substance (as glucose) in the blood is prevented from passing through the kidneys into the urine.

Question 24

glucosuria

Answer 24

glucose in urine

Question 25

glucose conc in tubule lumen

Answer 25

low

Question 26

glucose conc in tubule epithelial cell

Answer 26

high

Question 27

glucose conc in tubinterstial fluid

Answer 27

low

Question 28

transport maximum

Answer 28

the point at which increase in concentration of a substance does not result in an increase in movement of a substance across a cell membrane

Question 29

renal threshold glucose

Answer 29

300 mg/100ml

Question 30

transport maximum glucose

Answer 30

375 mg/min

Question 31

diabetes mellitus (pathophysiological reason)

Answer 31

capacity to reabsorb glucose is normal, but filtered load is greatly increased and is beyond the threshold level to reabsorb glucose by the tubules

Question 32

renal glucosuria (pathophysiological reason)

Answer 32

• genetic mutation of the Na+/glucose cotransporter, that normally mediates active reabsorption of glucose in the proximal tubules

Question 33

renal glucosuria (other names)

Answer 33

- benign glucosuria | - familial renal glucosuria

Question 34

reabsorption of urea by diffusion

Answer 34

-water is reabsorbed in proximal tubule and concentration urea increases inside tubule lumen so urea diffuses down the concentration gradient into interstial fluid

Question 35

urea reabsorption depends on

Answer 35

water reabsorption

Question 36

substances secreted

Answer 36

* mostly H+ and K+ | * choline, creatinine and penicillin

Question 37

tubular secretion is coupled to

Answer 37

reabsorption of Na+

Question 38

tubular secretion requires

Answer 38

active transport

Question 39

renal clearance is a way of

Answer 39

quantifying kidney function in removing substances from plasma

Question 40

renal clearance is a measure of

Answer 40

the volume of plasma from which a substance is completely removed by kidney/unit time

Question 41

unit for clearance

Answer 41

ml/min or L/h

Question 42

clearance values are specific to

Answer 42

each substances

Question 43

Clearance of S (equation)

Answer 43

``` S= Us *V/Ps Us= conc of S in urine V= volume of urine passed (ml/min) Ps= conc. of S in plasma ```

Question 44

inulin is

Answer 44

a polysaccharide not found in body but in plants + vegetables

Question 45

inulin is (type of renal handling?)

Answer 45

readily filtered but not reabsorbed, secreted, or metabolized by tubule

Question 46

clearance of inulin equals the

Answer 46

glomerular filtration rate

Question 47

clearance of inulin (equation)

Answer 47

Cin= Uin *V/Pin

Question 48

creatinine is a product of

Answer 48

muscle metabolism

Question 49

creatinine is (type of renal handling?)

Answer 49

filtered not reabsorbed, but undergo slight secretion

Question 50

clearance of creatinine slightly overestimates

Answer 50

GFR but can be used to determine GFR clinically

Question 51

clearance of X > GFR + example

Answer 51

secretion occurred | ex. PAH

Question 52

clearance of X < GFR + example

Answer 52

reabsorption occurred | ex. glucose

Question 53

Ion transport in nephron summary (Na+, Cl-, K+)

Answer 53

• Na+ is actively reabsorbed • Cl- is transported passively when Na+ is pumped out of the cell • K+ is secreted into the tubules mainly by cells of the distal tubule and collecting ducts (CD)

Question 54

proximal convoluted tubule reabsorbs

Answer 54

most of the water and non-waste plasma solutes

Question 55

PCT is a major site of

Answer 55

solute secretion expect K+

Question 56

loop of henle creates

Answer 56

osmotic gradient + reabsorbs large amounts of ions and less amounts of water

Question 57

distal convoluted tubule is the site for

Answer 57

major homeostatic mechanisms of fine control of water and solute to produce urine (hormonal control)

Question 58

proximal tubules (percent of renal handling?)

Answer 58

80% reabsorptive + secretory activates

Question 59

loop of henle (renal handling)

Answer 59

little of water, large amount of ions reabsorbed

Question 60

distal tubules (percent of renal handling?)

Answer 60

12% --15% reabsorption occurs here