RAAS

Question 1

5 actions of angiotensin II

Answer 1

1. Potent vasoconstriction → ↑ blood pressure
2. ↑ Na/H exchange and HCO3- reabsorption in proximal tubules
3. ↑ release of aldosterone → ↑ intravascular volume
4. ↑ release of ADH → ↑ intravascular volume
5. Stimulates hypothalamus to ↑ thirst sensation

Question 2

How does an increase in plasma protein affect:

• GFR (glomerular filtration rate)?
• RPF (renal plasma flow)?
• FF (filtration fraction)?

Answer 2

Decrease
No change
Decrease

Question 3

A patient with a ureteral stone develops oliguria. The decreased glomerular filtration in this individual is the result of:

Answer 3

Increased bowman’s space hydrostatic pressure

Question 4

How does chronic renal failure result in anemia?

Answer 4

decreased erythropoietin production by renal interstitial fibroblasts.

Question 5

Kidney produces prostaglandins which preferentially XXXXXX afferent arterioles.

Answer 5

vasodilates

Question 6

Kidneys XXXX prostaglandin synthesis during ischemia

Answer 6

upregulate

Question 7

Effect of NSAIDs on kidney

Answer 7

NSAIDs (e.g., ibuprofen), which inhibit prostaglandin synthesis, will vasoconstrict afferent arterioles and thereby ↓ GFR.

Question 8

RBF is related to RPF (Renal Plasma Flow) by the expression

Answer 8

RBF = [ RPF / (1-Hematocrit) ]

Question 9

In what pH range are buffers most effective?

Answer 9

Most effective within 1.0 pH unit of the pKa

Question 10

The unfiltered blood that exits the glomerulus is drained into _______________.

Answer 10

Unlike most other capillary beds, the glomerulus drains into an efferent arteriole rather than a venule.

Question 11

Provide the equation for Free Water Clearance (CH2O).

Answer 11

Free Water Clearance (CH2O) = V – Cosm

Question 12

Describe the 3 physiological/physical barriers established by the glomerular filtration barrier

Answer 12

1) Fenestrated glomerular epithelium (< RBC size)
2) Fused negatively charged GBM
3) Podocytes form tight NW of foot processes (pedicles) that control UF of proteins into BS.

Question 13

Types of renal tubular acidosis

Answer 13

type 1
type 2
type 4

Question 14

type 1 renal tubular acidosis is caused by

Answer 14

(↓ distal tubule H+ secretion) –> hypokalemia, urine pH>5.5

Question 15

type 2 renal tubular acidosis is caused by

Answer 15

(↓ proximal tubule HCO3- reabsorption): hypokalemia, urine pH<5.5

Question 16

type 4 renal tubular acidosis

Answer 16

(aldosterone deficiency or resistance): hyperkalemia, urine pH<5.5.

Question 17

OPgc decreases by decreases in capillary protein concentration, such as in cirrhosis or nephrotic syndrome –>

Answer 17

increased GFR.

Question 18

How do ACE inhibitors decrease GFR?

Answer 18

Angiotensin II preferentially constricts the efferent aterioles. Thus, ACE inhibitors (e.g., lisinopril) will dilate efferent arterioles and thereby ↓ GFR.

Question 19

Myogenic mechanisms of RBF autoregulation:

Answer 19

afferent arterioles contract in response to stretch caused by increased arterial pressure

Question 20

Serum anion gap =

Answer 20

[Na+] – ([HCO3-] + [Cl-])

Question 21

Which structure supplies blood to the glomerulus?

Answer 21

The afferent arteriole that supplies the glomerulus is a branch of an interlobular artery in the cortex

Question 22

In the absence of ADH, is CH2O (free water clearance) greater, less than, or equal to zero?

Answer 22

Without ADH: CH2O > 0 (excretion of free water)

Question 23

What regulates glucose reabsorption in the proximal convoluted tubule?

Answer 23

limited number of these Na-glucose carriers.

Question 24

Which types of solutes have a C(x) < GFR?

Answer 24

If C(x) < GFR, then there is a net tubular reabsorption of X (example: Na, glucose, amino acids, HCO3-, Cl-)

Question 25

Use of what class of diuretic leads to CH2O = 0?

Answer 25

Loop!

Question 26

What is Free Water Clearance (CH2O)?

Answer 26

the ability to dilute urine

Question 27

The filtered load of glucose is in direct proportion to what?

Answer 27

Plasma glucose concentration

Question 28

Give the equation used to calculate the pH of arterial blood.

Answer 28

pH = pKa + log ([HCO3-] / 0.03 x PaCO2) where PaCO2 is the partial pressure of CO2 in arterial blood

Question 29

Tubuloglomerular feedback:

Answer 29

reased renal arterial pressure leads to ↑ delivery of fluid to the macula densa. The macula densa secretes paracrine signals that lead to constriction of the nearby afferent arteriole.

Question 30

In the presence of ADH, is CH2O (free water clearance) greater, less than, or equal to zero?

Answer 30

With ADH: CH2O < 0 (retention of free water)