[6] Loop of Henle and Distal Convoluted Tube

Question 1

What occurs in the descending loop?

Answer 1

Descending: Dry

Water diffuses out

Question 2

What occurs int he thick ascending loop?

Answer 2

Ascending: Asin

Na+ diffuses down electrical gradient

Question 3

Osmolarity at the top of nephron

Osmolarity at the bottom of nephron

Answer 3

300 milliosmoles

1200 milliosmoles

Question 4

Why does the interstitium have to be concentrated?

Answer 4

Otherwise you’ll urinate to death

Question 5

Main Function: Countercurrent Multiplier

Answer 5

Create a hyperosmotic medullary interstitium

Have an osmotic equilibrium of water in the medulllary collecting tubules and medullary interstitium

Question 6

[Red Slide]

What clinical conditions will produce a concentrated urine?

A dilute output?

Answer 6

Do research, send me answers. =))

Question 7

[Descending Limb of Henle]

What is it permeable to?
What is it impermeable to?

Answer 7

P: Water
I: Na and Cl

Question 8

[Descending Limb of Henle]

How does water pass?

Answer 8

Aquaporin 1

Question 9

[Thin Ascending Limb of Henle]

What is it permeable to?
What is it impermeable to?

Answer 9

Highly impermeable to water

Permeable to Na, Cl and Urea

Question 10

What’ll happen to Potassium levels if the Na K 2Cl pump gets deactivated?

Answer 10

Research

Question 11

[Red Slide]

What happens if a drug inhibits the area of the thick ascending limb of the Loop of Henle?

Answer 11

Research

Question 12

[Major Problem of the Loop of Henle]

How does NaCl get out of the thin ascending loop?

Answer 12

Urea concentration gradient helps move sodium out of the loop

Question 13

[Red Slide]

What happens in persons with Marasmus in terms of the concentration gradient

Answer 13

They are frequently urinating because they have no urea. Since they have Marasmus, which has a lack of protein, and urea is a byproduct of protein breakdown, they cannot create a very concentrated urine.

Question 14

Kidney receives what % of CO?

Answer 14

20%

Question 15

How many liters/day of glomerular filtrate?

Answer 15

180 liters

Question 16

What keeps NaCl from leaving the medulla?

Answer 16

Vasa Recta

Question 17

Origin of the Vasa Recta

Answer 17

Efferent Arterioles

Question 18

[Red Slide]

How does Mannitol, an osmotic diuretic, increase urine output?

Answer 18

Increases renal blood flow in the vasa recta, allowing less time to concentrate your urine.

Question 19

Active pumping out of NaCl occurs where?

Answer 19

Thick Ascending Loop

Question 20

CCD: Principal Cells

Effect of Aldosterone and Vasopressin

Answer 20

Opens water and sodium channels

Question 21

Ammonia Secretion

Answer 21

Glutamine -> NH3 + H -> NH4 + Cl -> NH4Cl

Question 22

Where is Glutamine secreted?

Answer 22

Proximal Tubule

Question 23

OMCD has which Aquaporins?

Answer 23

2 and 3

Question 24

IMCD mainly Water Absorption/Secretion?

What about Urea?

Answer 24

Absorption for both

Question 25

Intercalated cells increase/decrease in number as collecting duct descends?

Answer 25

Decrease

Question 26

Is the collecting duct permeable/impermeable to water?

Answer 26

Impermeable

Question 27

Function: Macula Densa

Answer 27

Na-K-Cl Reabsorption | Adenosine Secretion

Question 28

Function: DCT1

Answer 28

Na and MG Reabsorption

Question 29

Function: DCT2

Answer 29

H and K Secretion | CA Reabsorption

Question 30

Function: CNT

Answer 30

Na, K, Ca reabsorption | K Secretion

Question 31

Function: CCD

Answer 31

H AND HCO3 SECRETION | Water and Na Reabsorption

Question 32

Function: OMCD

Answer 32

H and NH3 Secretion | Water Reabsorption

Question 33

Function: IMCD

Answer 33

Water and UREA Reabsorption

Question 34

Gitelman Syndrome

Answer 34

NCCT

Question 35

Classic Bartter Variant

Answer 35

Cl-CK2b

Question 36

Clinical Presentation of Patient with Gitelman Syndrome

Answer 36

Hyponatremia because there is a lot of salt loss | Primarily hypovolemic then dehydration because of the salt loss

Question 37

Do you treat a dehydrated person immediately? | What about a hypovolemic person?

Answer 37

Slowly to get the system accustomed to it | Immediately

Question 38

What electrolyte problems do you foresee in patients with Gitelman Syndrome?

Answer 38

Research

Question 39

What electrolyte problems do you foresee in patients with AE1 Mutations?

Answer 39

Research AE1: Cl-HCO3 Antiport AE1: Distal Renal Tubular Acidosis Hyperchloremic metabolic acidosis

Question 40

Type 1 Pseudohypoaldosteronism (PHA) Liddle Syndrome What symptoms do you expect in patients with Liddle Syndrome?

Answer 40

WNK1 | 4-Type II PHA

Question 41

Nephrogenic Diabetes Insipidus AQP2- Autosomal Nephrogenic Diabetes Insipidus What electrolyte problems do you foresee in patients with AQP2 defects?

Answer 41

Hypernatremia due to the closed aquaporins that are a result from the lack of ADH

Question 42

What does Thiazide block?

Answer 42

Na-Cl Symporter

Question 43

What do Lactones Block?

Answer 43

Aldosterone Receptors

Question 44

[Red Slide] How do thiazides prevent kidney stone formation?

Answer 44

Research

Question 45

[Red Slide] How do K-sparing diuretics help in patients with Gitelman syndrome?

Answer 45

Research

Question 46

Memorize that Chart with Values of Substances Related to Loop Areas

Answer 46

Go look for it =))

Question 47

Potassium is primarily taken up by the A. H-K ATPase B. K-Cl Co-Transporter C. Na-K-ATPase Pump D. ROMK Channels

Answer 47

Don't know yet, wanna tell me?

Question 48

What is the major intracellular ion?

Answer 48

Potassium

Question 49

How does K exit cells?

Answer 49

Mostly via K Channels Some via K-H Exchange

Question 50

Majority of Potassium is found in?

Answer 50

Muscles

Question 51

Least Potassium found in which organs?

Answer 51

Plasma

Question 52

Which of the following conditions causes more hypokalemia? A. Anuria B. Polyuria C. Constipation D. Diarrhea

Answer 52

B Because more potassium is excreted via urine

Question 53

Majority of K is excreted via?

Answer 53

Urine 90meq/day | Feces 10meq/day

Question 54

Aldosterone affects which pumps?

Answer 54

Na-K Pump

Question 55

Changes in K concentration have marked effects on?

Answer 55

Cell Excitability

Question 56

Potassium is a major intracellular?

Answer 56

Osmotically Active Cation

Question 57

Potassium is critical for what activities?

Answer 57

Enzyme Cell Division Growth

Question 58

Intracellular K participates in?

Answer 58

Acid Base regulation

Question 59

Which phase of the propagation of the action potential permits potassium ions to exit the cell? A. Resting Potential B. Action Potential C. Repolarization D. Hyperpolarization

Answer 59

C

Question 60

Action Potential

Answer 60

Na moves inside the membrane

Question 61

Repolarization

Answer 61

K move outside and sodium stays inside the cell

Question 62

Hyperpolarization

Answer 62

More K on the outside than Na on the inside

Question 63

Refractory

Answer 63

K returns inside | Na returns outside

Question 64

Buffering of ECF K through cell K uptake is impaired in the absence of?

Answer 64

Aldosterone Insulin Catecholamines

Question 65

Characteristics: Renal Outer Medulla K, SK/ROMK

Answer 65

Low Conductance | pH Sensitive

Question 66

Characteristics: Ca++-Acitvated (BK/Maxi-K)

Answer 66

High Conductance | Flow Stimulated

Question 67

Characteristics: H-HK ATPase

Answer 67

Colonic: Resorption Gastric: Secretion

Question 68

Majority of K Secretion Occurs in: A. PCT B. TAL C. DCT D. CD

Answer 68

Don't know, wanna tell me?

Question 69

Fate of Potassium

Answer 69

65% in PCT: Passive Diffusion 25% in TAL: Na-K-2Cl Pump 3% DCT 10% OMCD 1% IMCD

Question 70

Secretion of Potassium

Answer 70

10-50% DCT 5-30% CCD 15-80% IMCD

Question 71

What factors are needed to facilitate renal K secretion A. ANP B. Distal delivery of NA C. ECFV Contraction D. All of the Above

Answer 71

TIP: Usually not All of the Above for Dr. Anacleto Don't know, wanna tell me?

Question 72

What is the most important regulation for management of potassium problems?

Answer 72

Dietary K

Question 73

What happens in Hyperkalemia

Answer 73

Stimulates secretion of K via principal cells in DT/CCD

Question 74

High K Intake

Answer 74

Stimulates Aldosterone and SK/ROMK, BK/maxi-K channels

Question 75

Low K Intake

Answer 75

Enhance colonic H-K-ATPase

Question 76

Effect on Exercise on K Levels

Answer 76

Release of K from muscles | Opening of K channels

Question 77

What counterbalances the increase of K from exercise?

Answer 77

Catecholamines which decrease extracellular K

Question 78

Luminal Flow Rate

Answer 78

High Flow Rate -> High K Secretion in DT/CCD

Question 79

If you urinate too much what kind of potassium problems will you have? If you don't urinate at all what kind of potassium problems will you have?

Answer 79

Hypokalemia Hyperkalemia

Question 80

Alkalosis leads to? | Acidosis leads to?

Answer 80

Alk: Hypokalemic, increased K secretion Aci: Hyperkalemic, decreased K secretion

Question 81

Effect of Acidosis on Na pump

Answer 81

Lowers cellular potassium levels

Question 82

Effect: Increased luminal bicarbonate levels?

Answer 82

Increased potassium secretion