Urinary System

Question 1

What factors are involved in GFR increase?

Answer 1

Afferent arteriole dilation:

• Prostaglandins
• Kinins
• Dopamine (low dose)
• ANP (atrial natriuretic peptide)
• NO (nitric oxide)

Efferent arteriole constriction:

• Angiotensin 2 (low dose)

Question 2

What factors are involved in GFR decrease?

Answer 2

Afferent arteriole constriction:

• Angiotensin 2 (high dose)
• Noradrenalin or NE (SNS)
• Endothelin
• Adenosine
• Vasopressin (ADH)
• PG blockade

Efferent arteriole dilation:

• Angiotensine 2 blockade

Question 3

Renal blood flow (RBF)

Answer 3

1200 ml/min (20-25% of CO)

Question 4

Renal plasma flow (RPF)

Answer 4

600 ml/min

Equals the clearance of PAH (C_PAH)

Question 5

Glomerular filteration rate (GFR)

Answer 5

120 ml/min (20% of RPF)

Equals C_inulin or C_creatinine

Question 6

Filtration fraction (FF)

Answer 6

GFR/RPF = 20%

Question 7

Glomerular capillary hydrostatic pressure

Answer 7

Afferent end: 53 mmHg

Efferent end: 51

Question 8

Glomerular capillary oncotic prssure

Answer 8

Afferent end: 26

Efferent end: 33

Question 9

Bowman’s capsule hydrostatic pressure

Answer 9

Afferent end: 12

Efferent end: 12

Question 10

Bowman’s capsule oncotic pressure

Answer 10

Afferent end: 0

Efferent end: 0

Question 11

Net ultrafilteration pressure

Answer 11

Afferent end: 15

Efferent end: 6

Question 12

Effective filtration pressure (average)

Answer 12

13 mmHg

Question 13

Osmotic pressure in the proximal tubule

Answer 13

300 mOsm

Question 14

Osmotic pressure of the interstitium in the cortex

Answer 14

300 mOsm

Question 15

Urine osmolarity (maximal concentration)

Answer 15

1200 mOsm

Question 16

Urine osmolarity (maximal dilution)

Answer 16

30 mOsm

Question 17

Osmotic pressure and composition of the interstitium in the inner medulla during maximal concentration

Answer 17

600 NaCl + 600 Urea = 1200 mOsm

Question 18

[Glucose]

Answer 18

4-5 mM

Question 19

Transport maximum of tubular glucose (maximum glucose reabsorption)

Answer 19

375 mg/min

Question 20

Blood pH

Answer 20

7.35-7.45

Question 21

PCO₂

Answer 21

40 (38-42) mmHg

Question 22

Buffer base (BB)

Answer 22

44-49 mEq/L

Question 23

Base excess (BE)

Answer 23

+/- 2.5 mEq/L

Question 24

[HCO₃^-]

Answer 24

Standard = 24 (22-26) mmol/L

Actual = 24 (22-26) mmol/L

Question 25

[H⁺] of blood

Answer 25

40 nM

200 nano moles or 2 µ moles in 5 liters of blood

Question 26

Intracellular pH

Answer 26

7.2

Question 27

Urine pH

Answer 27

5-7 (acidic)

Question 28

Daily production of acids

Answer 28

1 mmol/kg

70 mmol in a 70 kg man

Question 29

[Hb] in blood

Answer 29

[Hb] in males: 160-170 g/liter
[Hb] in females: 135-145 g/liter

[Hb] in general: 2-2.8 mM or 120-180 g/liter

These are the concentrations of whole hemoglobin (consisting of four monomers).

Question 30

[Albumin] in blood

Answer 30

35–50 g/L

Question 31

Total [protein] in blood

Answer 31

60-80 g/L (not sure)