RAAS Flashcards
5 actions of angiotensin II
- Potent vasoconstriction → ↑ blood pressure
- ↑ Na/H exchange and HCO3- reabsorption in proximal tubules
- ↑ release of aldosterone → ↑ intravascular volume
- ↑ release of ADH → ↑ intravascular volume
- Stimulates hypothalamus to ↑ thirst sensation
How does an increase in plasma protein affect:
- GFR (glomerular filtration rate)?
- RPF (renal plasma flow)?
- FF (filtration fraction)?
Decrease
No change
Decrease
A patient with a ureteral stone develops oliguria. The decreased glomerular filtration in this individual is the result of:
Increased bowman’s space hydrostatic pressure
How does chronic renal failure result in anemia?
decreased erythropoietin production by renal interstitial fibroblasts.
Kidney produces prostaglandins which preferentially XXXXXX afferent arterioles.
vasodilates
Kidneys XXXX prostaglandin synthesis during ischemia
upregulate
Effect of NSAIDs on kidney
NSAIDs (e.g., ibuprofen), which inhibit prostaglandin synthesis, will vasoconstrict afferent arterioles and thereby ↓ GFR.
RBF is related to RPF (Renal Plasma Flow) by the expression
RBF = [ RPF / (1-Hematocrit) ]
In what pH range are buffers most effective?
Most effective within 1.0 pH unit of the pKa
The unfiltered blood that exits the glomerulus is drained into _______________.
Unlike most other capillary beds, the glomerulus drains into an efferent arteriole rather than a venule.
Provide the equation for Free Water Clearance (CH2O).
Free Water Clearance (CH2O) = V – Cosm
Describe the 3 physiological/physical barriers established by the glomerular filtration barrier
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.
Types of renal tubular acidosis
type 1
type 2
type 4
type 1 renal tubular acidosis is caused by
(↓ distal tubule H+ secretion) –> hypokalemia, urine pH>5.5
type 2 renal tubular acidosis is caused by
(↓ proximal tubule HCO3- reabsorption): hypokalemia, urine pH<5.5
type 4 renal tubular acidosis
(aldosterone deficiency or resistance): hyperkalemia, urine pH<5.5.
OPgc decreases by decreases in capillary protein concentration, such as in cirrhosis or nephrotic syndrome –>
increased GFR.
How do ACE inhibitors decrease GFR?
Angiotensin II preferentially constricts the efferent aterioles. Thus, ACE inhibitors (e.g., lisinopril) will dilate efferent arterioles and thereby ↓ GFR.
Myogenic mechanisms of RBF autoregulation:
afferent arterioles contract in response to stretch caused by increased arterial pressure
Serum anion gap =
[Na+] – ([HCO3-] + [Cl-])
Which structure supplies blood to the glomerulus?
The afferent arteriole that supplies the glomerulus is a branch of an interlobular artery in the cortex
In the absence of ADH, is CH2O (free water clearance) greater, less than, or equal to zero?
Without ADH: CH2O > 0 (excretion of free water)
What regulates glucose reabsorption in the proximal convoluted tubule?
limited number of these Na-glucose carriers.
Which types of solutes have a C(x) < GFR?
If C(x) < GFR, then there is a net tubular reabsorption of X (example: Na, glucose, amino acids, HCO3-, Cl-)
