72: Solute Handling

Question 1

Sodium (Na+) is a major cation of the …….. compartment and it determines …….volume

Answer 1

ECF

Question 2

ECF volume affects:

Answer 2

Plasma Volume
Blood Volume
Blood Pressure

Question 3

……….. maintain normal body Na+ content/balance so that Na+ intake= Na+ excretion

Answer 3

Kidneys

Question 4

If there is a positive Na+ balance where Na+ excretion < Na+ intake ………

Answer 4

Na+ retained in ECF which leads to:
Volume expansion
Increase blood volume
Increase in blood pressure

Question 5

If there is a negative Na+ balance where Na+ excretion > Na+ intake ……….

Answer 5

Na+ lost from ECF which leads to:  Volume contraction
Decrease blood volume
Decrease blood pressure

Question 6

67% of Na+ and K+ is reabsorbed from the ……..

Answer 6

Proximal Convoluted Tubule

Question 7

100% of Na+ and K+ is filtrated by the……..

Answer 7

Glomerulus

Question 8

25% of Na+ is reabsorbed from the……..

Answer 8

Thick ascending limb of the Loop of Henle

Question 9

5% of Na+ is reabsorbed from the…….

Answer 9

Distal Convoluted Tubule

Question 10

3% of Na+ is reabsorbed from the……

Answer 10

Collecting Duct

Question 11

Around……% of Na+ is excreted from the body

Answer 11

1%

Question 12

What happens to the following levels when Na+ intake decreases?

• Sympathetic Activity
• ANP (Atrial Natriuretic Peptide)
• Oncotic Pressure of the Capillary
• Renin-Angiotensin Aldosterone

Answer 12

• Sympathetic Activity- INCREASED
• ANP(Atrial Natriuretic Peptide)-DECREASED
• Oncotic Press. of the Capillary- INCREASED
• Renin-Angiotensin Aldosterone-INCREASED

Question 13

What happens to the following levels when Na+ intake increases?

• Sympathetic Activity
• ANP (Atrial Natriuretic Peptide)
• Oncotic Pressure of the Capillary
• Renin-Angiotensin Aldosterone

Answer 13

• Sympathetic Activity- DECREASED
• ANP (Atrial Natriuretic Peptide)- INCREASED
• Oncotic PresS. of the Capillary-DECREASED
• Renin-Angiotensin Aldosterone-DECREASE

Question 14

Atrial natriuretic peptide (ANP) is secreted by atria in response to …….. in ECF volume

Answer 14

Increase

Question 15

Atrial natriuretic peptide (ANP) ………. GFR and ………. reabsorptive mechanisms along tubule that results in increase in Na+ and H20 excretion.

Answer 15

Increases GFR (dilate afferent / constrict efferent arterioles) 
Inhibits Reabsorptive Mechanisms

Question 16

……….. Blood Pressure in Right Atrium leads to ……….. ANH (Atrial Natriuretic Hormone) that leads to an ……… Na+ and H20 excretion.

Answer 16

Increased Blood Pressure
Increased ANH (Atrial Natriuretic Hormone)
Increased excretion of NA+ and H20

Question 17

The increase in the excretion of Na+ and H20 leads to water loss and ………… blood pressure

Answer 17

Decreased Blood Pressure

Question 18

…………. is required for tissues that use action potentials and is found is more abundance in the ICF.

Answer 18

Potassium K+

98% in ICF, 2% in ECF

Question 19

Small shifts across the membranes causes large changes in plasma and …… concentrations

Answer 19

ECF

Question 20

K+ Shift into the cells=

Answer 20

Hypokalemia

Question 21

K+ Shift Out of Cells=

Answer 21

Hyperkalemia

Question 22

Causes of K+ Shift into Cells: Hypokalemia

Answer 22

• Insulin
• β2-Adrenergic agonists
• α-Adrenergic antagonists
• Alkalemia
• Hyposmolarity

Question 23

How does insulin and insulin deficiency cause a K+ shift?

Answer 23

Insulin, b-agonists (albuterol), and a-antagonists all stimulate Na+-K+ ATPase activity.- K+ Shift INTO Cells

Insulin deficiency;,b-Antagonists (propranolol), a- agonists, all reduce Na+-K+ ATPase activity- K+ Shift OUT of Cells

Question 24

Causes of K+ Shift out of Cells: Hyperkalemia

Answer 24

• Insulin deficiency (Type I Diabetes)
• β2-Adrenergic antagonists
• α-Adrenergic agonists
• Acidemia
• Hyperosmolarity
• Cell lysis
• Exercise

Question 25

How does alkalemia and acidemia cause a K+ shift?

Answer 25

- Alkelemia: [H+] is decreased so H+ moves into blood/K+ exchanges into cells - Acidemia: [H+] is increased so H+ leaves blood/ K+ exchanges into blood (Out of cells)

Question 26

How does cell lysis, hyperosmolarity, and exercise cause K+ shift out of cells?

Answer 26

- Cell lysis (breakdown of cell membranes - burns, rhabdomyolysis, chemotherapy): Releases K+ from ICF into blood - Hyperosmolarity in ECF: H2O shifts from ICF to ECF dragging K+ - Exercise: Depletion of ATP stores opens K+ channels in muscle cells - shifts into blood

Question 27

If there is a positive K+ balance where K+ excretion < K+ intake .........

Answer 27

Hyperkalemia

Question 28

If there is a negative K+ balance where K+ excretion > K+ intake .........

Answer 28

Hypokalemia

Question 29

20% of K+ is reabsorbed from the........

Answer 29

Thick ascending limb

Question 30

K+ Reabsorption in the late distal tubule and collecting duct occurs with......

Answer 30

A low K+ diet

Question 31

K+ secretion determines the K+ .......... in the collecting duct

Answer 31

K+ Excretion

Question 32

With a normal or high K+ diet, K+ secretion .......... as a function of Na+ delivery to collecting duct; aldosterone/K+-sparing diuretic

Answer 32

Increases

Question 33

Normal Serum Concentration of Phosphate:

Answer 33

2.5 – 4.5 mg/dL

Question 34

Phosphate is a constituent of ..... and urinary buffer for H+

Answer 34

Bone (85%)

Question 35

Phosphate is a constituent of ..... and urinary buffer for H+

Answer 35

Bone (85%)

Question 36

90% of ........ is filtrated by the Glomerulus

Answer 36

Phosphate

Question 37

85% of Phosphate reabsorbed in the ....

Answer 37

Proximal Convoluted Tubule

Question 38

....... inhibits phosphate reabsorption

Answer 38

PTH (Parathyroid Hormone)

Question 39

15% of phosphate is excreted and serves as ........... (urinary buffer for H+)

Answer 39

Titratable acid

Question 40

......... binds to the type 1 PTH (PTH1R) basolateral receptor in PCT cells which is coupled to adenylyl cyclase via a Gs protein

Answer 40

PTH (Parathyroid Hormone)

Question 41

Parathyroid Hormone (PTH) inhibits Na+-phosphate cotransport and therefore inhibits..........

Answer 41

Inhibits Reabsorption. Leads to Phosphaturia (Phosphate in Urine) and Hypophophatemia (Low Phosphate in Blood

Question 42

........... catalyzes conversion of ATP to cAMP to activate protein kinaseA (PKA) and protein kinase C which stimulate the internalization and degradation of sodium-phosphate cotransporters

Answer 42

Adenylyl cyclase

Question 43

30% of Magnesium reabsorbed from the ....

Answer 43

Proximal Convoluted Tubules

Question 44

80% of ........ is filtrated by the Glomerulus

Answer 44

Magnesium

Question 45

Normal serum concentration of Magnesium:

Answer 45

1.5-2.0 mg/dl

Question 46

........ is required for enzymatic reactions (Nerve, muscle, CV, GIT) & maintain PTH function

Answer 46

Magnesium

Question 47

60% of magnesium is reabsorbed in........

Answer 47

Thick Ascending Limb of Loop of Henle

Question 48

........ inhibit reabsorption and increase excretion and leads to hypomagnesemia

Answer 48

Loop diuretics

Question 49

5% of Magnesium reabsorbed from.... and another 5% is ...........

Answer 49

Distal Convoluted Tubule | Excreted

Question 50

Normal serum value of Calcium

Answer 50

8.4 – 10.2 mg/dL

Question 51

60% of calcium in filtered by the ......

Answer 51

Glomerulus

Question 52

67% of .......... is reabsorbed in the Proximal Convoluted Tubule

Answer 52

Calcium

Question 53

25% of Calcium reabsorbed in ...........

Answer 53

Thick Ascending Limb

Question 54

.......... inhibits cotransporter and reabsorptive driving force - treats hypercalcemia

Answer 54

Loop diuretics (Furosemide)

Question 55

8% Reabsorption of Calcium in ...............

Answer 55

Distal Convoluted Tubule

Question 56

.......... increase Ca+2 reabsorption treat idiopathic hypercalciuria (decrease excretion and Ca+2 stone formation)

Answer 56

Thiazide diuretics

Question 57

Decreased Plasma Ca2+ leads to:

Answer 57

- PTH secretion: Increase - Bone reabsorption: Increase - Phosphate reabsorption: Decrease - Calcium Reabsorption: Increase - Urinary cAMP: Increase