Lecture Notes Flashcards
Total osmolality will change but tonicity will not with large changes in
BUN
What is the normal range of serum osmolality?
285-295 mOsm/kg
The ONLY place filtration occurs
Glomerulus
The minimum GFR we like to see is
60
In a healthy adult, steady state creatinine should be less than
1.5 mg/dL
What is the relationship between GFR and creatinine levels?
They are inversely related (i.e. as GFR goes up, creatinine goes down)
What is impeded if GFR is either too low or too high?
Reabsorption
The distal nephron can communicate with the glomerulus via the
Macula densa
An increase in NaCl tells the macula densa what?
That GFR is too high
Works in cohort with SNS to maintain BP
RAAS
What does AN-II do?
- ) Good vasoconstrictor (especially of efferent arteriole)
- ) Promotes aldosterone secretion
- ) Inhibits Renin
- ) promotes Na+ and H2O reabsorption
Upregulated by low BP or high Na+
AVP
What does AVP do?
- ) Promotes H2O reabsorption
2. ) Potent vasoconstrictor
What does Aldosterone do?
- ) Very active in Na+ reabsorption
2. ) Excess will cause K+ excretion
Extrarenal event caused by reduced renal perfusion
Azotemia
Moves K+ into forming urine to help drive NKCC
ROMK-2
What does furosemide do?
Blocks NKCC and promotes K+ and Ca2+ wasting
Which hormone is the major hormone responsible for Na+ reabsorption?
-also important for acid-base status
Aldosterone
When we see “presser” response, we are talking about
AVP
Stimulates a change in gene transcription which causes an increase in the secretion of K+ by aldosterone
Hyperkalemia
Mineralocorticoid hypertension is caused by
Hyperaldosteronism
What are the possible effects of hyperaldosteronism?
Possible hypokalemia and metabolic alkalosis
What are the possible symptoms of hypoaldosteronism?
Hyponatremia, Hyperkalemia, Metabolic acidosis, and increased HR
If blood and urine Na+ are not following the same trend we should suspect
AVP problem
Urine osmolality is
- ) Maximally dilute at values below
- ) Maximally concentrated at values above
- ) 100
2. ) 600
Acute alcohol consumption suppresses
AVP
Can cause AVP secretion
Nausea
ANP is secreted in response to
Increased BP and RAP
ANP inhibits
Renin secretion
Characterized as an AVP insensitivity or loss of AVP
Diabetes Insipidus (DI)
What are the effects of DI?
Mass diuresis
- dilute urine
- constant thirst
A mismatch between blood osmolality and water retention can signify
DI
What are the symptoms of SIADH?
Hyponatremia, increased SG of urine, potential hypertension
In SIADH, patients body’s are holding too much
Water
A patient presents with hypernatriemia, but is NOT antidiuresing. This suggests?
DI
A patient presents with hyponatremia, but is NOT diuresing. This suggests
SIADH
How can we characterize a type 2 RTA?
General proximal tubule defec leading to a normal AG metabolic acidosis
Glucose in urine, PO4 wasting, and vitamin D deficiency are all symptoms of a
Type 2 RTA
A UAG that is greater than 0 suggests
Type 1 RTA
A patient with a kalemic and acid base disorder likely has a disorder with
Aldosterone
Sulfonylureas set up gradients that favor
Insulin secretion
Are patients with type 1 DM typically overweight or thin?
Thin
Defects with insulin can cause problems with
Callular K+ uptake, FFA uptake, and peripheral glucose uptake
DKA is very common with
Type 1 DM
An autoimmune disease characterized by a destruction of B cells
Type 1 DM
ST elevations and depressions suggest a problem with
K+
QT elongations or shortening suggests a problem with
Ca2+
Calcitriol has a negative feedback effect on
PTH secretion
The point of regulation for calcitriol formation
1a-hydroxylase (CYP27B1)
Under normal conditions, which effects will win, PTH or Calcitriol?
PTH
In a very sick kidney, Ca2+ reabsorption will not occur and we will not be able to make calcitriol. This leads to
Secondary hyperparathyroidism
-eventually leads to osteoporosis
Long QT syndrome is caused by
Hypocalcemia
