Other

Question 1

What are the two rules for compensation?

Answer 1

Compensation by the other system will never return our system back to normal

Question 2

Why is the DCT and the CD important for respiratory alkalosis and acidosis?

Answer 2

Cells here can secrete HCO3- or H- on demand.

Question 3

If acidotic, what will the DCT and CD do?

Answer 3

Move H+ ion to urine and take HCO3 and move it back to the blood, compensating for respiratory acidosis (plasma HCO3 levels will increase)

Question 4

If respiratory alkalosis the DCT/CD cells will do what?

Answer 4

HCO3 will go to the urine and the H+ will go to the blood, so the HCO3 plasma levels will be lower and the pH will become more acidic

-Type B intercalated cells-

Question 5

Osmolarity of blood can be measured how?

Remember normal osmolarity is 290mOsmoles/L

Answer 5

Osmolarity = (2xserumNa) + (BUN/2.8) + (glucose/18)

Question 6

What is the difference between acute respiratory acidosis and chronic respiratory acidosis?

Answer 6

ARA–> Changes in HCO3- will cause a large change in your pH

CRA–> Large changes in HCO3- will cause small changes in your pH because your kidneys are compensating acidosis by increasing your bicarb to help you maintain a more normal PH

Question 7

We do not need to know the equation for acute and chronic respiratory acidosis/alkalosis. How do we figure it out just by looking?

Answer 7

For respiratory acidosis/alkalosis, if the HCO3 is close to normal, it is acute. If it is far away, it is chronic.

Question 8

What are type B intercalated cells important for?

Answer 8

Cl- reabsorption

Question 9

How can we tell if something is Cl- responsive?

Answer 9

It urine chloride levels are low compared to serum, the body is trying to hang onto chloride, meaning that they are chloride responsive.

Question 10

In the PT, how does volume contraction affect HCO3-

Answer 10

Increase the reabsorption.

Question 11

Diarrhea

Answer 11

Lose HCO3- in the stool and it leads to metabolic acidosis.

Question 12

What increases out anion gap? (metabolic acidosis)

Answer 12

1. DKA
2. ASN
3. Ischemic tissue with a build up of lactate
4. Ingestion of EtOH

Question 13

What happens if we OD on opiates?

Answer 13

Respitory acidosis becaue opiates shut down our breathing.

Question 14

Urea recycling depends on ADH. Thus, reabsorption of urea will increase the osmolarity of the ISF. which will promote water to be reabsorbed from the descending loop.

Thus, if we have enough water, how will urea be affected?

Answer 14

No ADH= no reabsorption of urea.

Thus, if we do not need to reabsorb water, then we do not reabsorb urea.

Question 15

When is the osmolarity of the ISF greater?

W/ ADH or w/o ADH?

Answer 15

WITH ADH because then we are reabsorbing urea–> increases concentration gradieint

Question 16

A high amount of urea in the medulla means that we have made the inner medullary CD permeable to urea, meaning that?

Answer 16

we have released ADH, which is also reabsorbing water.

This means that we are secreting a small amount of concentrated urine.

Question 17

what is a antidiuresis

Answer 17

produced by high adh levels

secrete a small amount of concentrated urine

Question 18

_____ is great in acidic conditions. It will promote the secretion of H+ ions via the H+ ATPase in the intercalated cells.

Answer 18

Aldosterone

Question 19

ADH responses to changes in

1. Plasma osmolarity
2. BP/BV
3. Angiotensin II
4. Nausea
5. ANP

Aldosterone is released in response to

1. Indirectly via angiotensin II
2. Directly via high plasma K+ levels

Question 20

hyponatremia usually occurs during

Answer 20

high ADH. very rearely a consequence of not eating enough Na+ or polydipsia

Question 21

hypenatremia is often due to

Answer 21

1. impaired thirst

2 decreased water consumption

Question 22

polyuria is often assx with _______

Answer 22

polydipsia (too much water consumption)

Question 23

where is most water reabsorbed

Question 24

Obligatory urine volume is the amount of urine a person must excrete in a given day based on their weight. If the kidney can concentrate up to 1200 mOsm, how do we calculate obligatory urine volume?

Answer 24

____mOsm of solute a person of a certain weight must excrete/1200mOsm

Question 25

Free water clearance is the amount of solute free water that is cleared from the kidneez.

how do we calculate it?

Answer 25

Free water clearance (CH2O )= [urine flow rate - osmolar clearance]

Cosm= Uosm*V/Posm

• if +, excess water is being excreted from the kidneys.
• If -, excess solutes are being removed from the blood by the kidneys and water is being conserved.

Question 26

What happens in cases where ADH is not secreted?

Answer 26

1. TAL: NaCl is being reabsorbed, diluting the tubular fluid and creating a hypoosmotic tubular fluid.
2. DCT and CCD: Tubular fluid will become even more hypoomotic because NaCl is being moved out without water.
3. Medullary CD: NaCl is being actively reabsorbed without water, making it more hyposmotic.

Result: a urine osmolality as low as 50 mOsm and a urine volume up to 18 L/day.

Question 27

When a person ingests alot of water, what happens to urea?

Answer 27

Ingests a lot of water= no ADH= no reabsorption of urea, causing less urea to be in the medulla

Question 28

What happens in cases where ADH levels are high (when we are dehydrated)?

Answer 28

High ADH= insertion of AQP channels on the principal cells of the late DT and the CD

1. ​H20 will be reabsorbed; increasing the osmolarity of the tubular fluid and decreasing the osmolarity of the medulla.
2. TAL, DT and CCD will reabsorb NaCl–> medulla–> to balance the medulla
3. As fluid flows down the CD, it continues to become more concentrated.

As a result, we can produce urine with osmolality of 1200 mOsm and a volume of a small as .5 L. This a small volume of concentrated urine

Question 29

Aldosterone is called the salt retaining hormon and is released during 2 situations

-indirectly by stimulation from Angiotensin II or directly by high plasma K+ levels.

How does it continue to remove K+?

Answer 29

Aldosterone will add ENac channels on the apical membrane so that we can continue to uptake Na+ and remove K+ from our plasma.

Question 30

Fluid that leaves the descending LoH will have a osmolarity of what?

Answer 30

With ADH: 1200 mOsm

Without ADH: 600 mOsm.

The difference here is due to the increased amount of urea in the medullary interstitial space, increasing the osmotic pressure–> which will affect water reabsorption.

Question 31

What will the osmolarity fluid leaving the TAL be?

Answer 31

Around 100, with or without ADH

Question 32

What is the osmolarity of fluid in the DCT and CD?

Answer 32

Without ADH, it will become more hypoosmotic because NaCl is still being reabsorbed without water.

Question 33

Inner medullary CD is permeable to water without ADH. What is the osmolarity of the fluid leaving the MCD?

Answer 33

With ADH: 1200mOsm

Without ADH: 50mOsm

Question 34

What do diuretics do?

Answer 34

Diuretics impair our ability to concentrate urine by inhibiting the NKCC2 in the TAL, which creates an osmotic gradient but it has an increased ability to dilute the urine.

-Diuretics do NOT impair ADH.

Question 35

When would a diuretic be useful?

Answer 35

Incases where we need to release more water than we normally can. For example, when we have edema.

Question 36

In SIADH: the following happens

1. Increase ADH
2. Increase water reabsorption
3. Increase in ECF volume
4. Increase in BP will lead to 4 situations
   
   1. Decrease in plasma osmolarity
   2. Increase in GFR
   3. Hyponatremia
   4. ….

Finish the rest.

Answer 36

SIADH will also lead to a decrease in aldosterone secretion because the RAAS system is inactivated –?

D/t the high ECF volume–> water will move from the ECF to the ICF, causing cells to swell.

Thus, we are reabsorbing too much H20 and secreting too much Na+–>

Small, concentrated urine –>

We are overhydrated, but thirsty to respond to bodies constant needs to reabsorb water.