Kidney 2 Flashcards
Which factor increases renin release?
a. positive end-expiratory pressure
b. hypervolemia
c. angiotensinogen
d. increased chloride delivery to the macula densa
a. positive end-expiratory pressure
____________________ located in the distal tubule, monitors renal perfusion, and solute concentration.
The juxtaglomerular apparatus
the juxtaglomerular apparatus maintains GFR by
modulating renal vascular resistance and renin release
The RAAS plays an integral role in regulating
systemic vascular resistance and the composition of the extracellular volume
Conditions that increase renin release include
decreased renal perfusion pressure
SNS activation
tubuloglomerlar feedback
Antidiuretic hormone controls serum osmolarity because it
increases reabsorption of water but not sodium
______________ is a steroid hormone that’s produced by the zona glomerulosa of the adrenal gland
Aldosterone
Aldosterone facilitates the
reabsorption of Na+ and water
excretion of K+ & H+
Unlike renal blood flow, __________ is not auto-regulated
urine output- instead there’s a linear relationship between UO & MAP
Urine output typically comes to a halt when MAP is
less than 50 mmHg
Angiotensinogen is produced in the
liver
Describe the RAAS system.
Renin released by the juxtaglomerular cells converts angiotensinogen into angiotensin 1
ACE release by the lungs converts angiotensin 1 to angiotensin 2
Angiotensin 2 leads to
vasoconstriction of peripheral vessels & efferent arteriole
release of aldosterone
release of ADH
Na+ reabsorption
thirst
Causes of tubuloglomerular feedback that lead to increased renin release are
decreased sodium and chloride in distal tubule
Causes of decreased renal perfusion pressure that lead to increased renin release include
hemorrhage
PEEP
CHF
liver failure with ascites
sepsis
diuresis
In addition to RAAS stimulation, aldosterone release is increased by
hyperkalemia
hyponatremia
Disorders of aldosterone release include
Conn’s disease- excess aldosterone production
Addison’s disease- destruction of cortical zones
Antidiuretic hormone
a. upregulates aquaporin-2 channels
b. is produced in the posterior pituitary gland
c. increases sodium reabsorption in the proximal tubule
d. agonizes the V1 receptor to decrease cAMP
a. upregulates aquaporin-2 channels
______________ is the principal determinant of osmolarity
Sodium concentration
Normal serum osmolarity is
280-290 mOsm/L
Antidiuretic hormone is released into the systemic circulation from the
posterior pituitary gland
When is ADH released?
blood volume is decreased
osmolarity of the ECF is increased
Perioperative factors that increase ADH release include
PEEP
positive pressure ventilation
hypotension
hemorrhage
ADH restores blood pressure in two ways:
- V1 receptor stimulation causes vasoconstriction in the vasculature (increased SVR)
- V2 receptor stimulation in the collecting ducts causes water retention
ADH is produced in the
supraoptic and paraventricular nuclei of the hypothalamus
The half-life of ADH is
5-15 minutes
ADH leads to what effect on cAMP?
increased cAMP in the collecting ducts
All of the following enhance renal perfusion EXCEPT:
a. fenoldopam
b. PGE2
c. natriuretic peptide
d. thromboxane A2
d. thromboxane A2
_________ pathways promote renal vasodilation
Three
What are the pathways that promote renal vasodilation?
vasodilating prostaglandins
natriuretic peptides
dopamine receptors
Discuss the use of dopamine in prevention or treatment of AKI.
does increase UO but no solid evidence to support the notion that renal-dose dopamine either prevents or treats AKI
Vasodilating prostaglandins antagonize
the effects of RAAS
Natriuretic peptides inhibit
RAAS and stimulate sodium and water excretion
DA1 dopamine receptors lead to
vasodilation, increased renal blood flow, increased GFR, diuresis, and sodium excretion
DA2 dopamine receptors lead to
decreased NE release from the presynaptic SNS nerve terminal
_______________ is liberated from the cell membrane in response to ischemia, hypotension, norepinephrine, and angiotensin 2
Arachidonic acid
______________ inhibit cyclooxygenase. These drugs can reduce renal blood flow by inhibiting the production of vasodilating prostaglandins
NSAIDs
How do DA1 & DA2 receptors affect cAMP?
DA1- increased cAMP–> vasodilation
DA2- decreased cAMP–> decreased NE release
Does fenoldopam decrease AKI?
selective DA1 receptor agonist that increases renal blood flow, GFR, and facilitates Na+ excretion without affecting arterial blood pressure
List three compounds that promote renal vasodilation.
dopamine
natriuretic peptide
prostaglandins
Which condition increases the glomerular filtration rate?
a. increased plasma protein
b. afferent arteriolar constriction
c. cyclooxygenase inhibition
d. increased efferent arteriolar resistance
d. increased efferent arteriolar resistance
The normal glomerular filtration rate is
125 mL/min.
What is freely filtered in the glomerulus?
water, electrolytes, and glucose
What is not filtered in the glomerulus?
plasma proteins (i.e. albumin)
The most important determinant of GFR is
glomerular hydrostatic pressure
How is GFR determined?
by arterial blood pressure
afferent arteriole resistance
efferent arteriole resistance
_________ is the process where a substance is transferred from the tubule to the peritubular capillaries
Reabsorption
______________- is the process where a substance is transferred from the peritubular capillaries into the tubule
Secretion
______________ is the process where a substance is removed from the body in the urine
Excretion
Kidney disease destroys the _______________ which allows the filtration of ___________ into the tubules
basement membrane; proteins
