Posterior Pit Hormones Flashcards
Function of Oxytocin (2)
- milk letdown
2. uterine contraction
ADH (AVP) works on _____ cells of the the distal tubule to ________.
- principle cells
- increase water absorption
ADH induces _______ of _______ to protect against severe volume depletion
- contraction
- vascular smooth mm
ADH is released in response to _____
- increased serum osmolality
ADH increases expression of _____ on the ____side of principle cells.
- aquaporin 2
- luminal
ADH ____ urine flow and ____ urine osmolality
- decreases
- increases
In diabetes insipidus, individuals are unable to _______ normally and excrete _______. This causes an _____.
- concentrate urine
- a large volume of urine
- increase in thirst
Primary or Central Neurogenic Diabetes Insipidus is due to ____.
- the failure of the posterior pituitary to secrete ADH
Symptoms of Central Neurogenic DI (4)
- Low levels of circulating ADH
- decreased permeability of collecting ducts
- dilute urine / concentrated serum
- no effect of water restriciton
In Secondary Nephrogenic DI, the _____ is normal, there is a defect in the _____.
- posterior pituitary
- Target Tissue (V2 receptor or aquaporin 2)
Symptoms of Secondary Nephrogenic DI
- High serum ADH
- dilute urine/ concentrated serum
Common cause of secondary (nephrogenic) DI ?
Lithium toxicity - Li interferes with V2 receptors
DI urine characteristics
- hypotonic/ dilute
- tasteless
Diabetes Mellitus urine Characteristics
- hypertonic
- sweet
DI is diagnosed by a _____ stimulus followed by the _____.
- dehydration
- inability to concentrate urine
Changes for Neurogenic DI:
- Plasma Osmolality
- Plasma Osmolality
- Urine Osmolality
- Plasma ADH
- Water deprivation; urine osmolality
- water deprivation; plasma ADH
- urine osmolality after ADH administration
- normal/high
- low
- low
- no change
- no change
- increase
Changes for Nephrogenic DI:
- Plasma Osmolality
- Plasma Osmolality
- Urine Osmolality
- Plasma ADH
- Water deprivation; urine osmolality
- water deprivation; plasma ADH
- urine osmolality after ADH administration
- normal/high
- low
- normal/high
- no change
- increase
- no change
SIADH stands for
Syndrome of Inappropriate ADH
In SIADH, ADH secretion is not linked to _____-
Normal regulatory mechanisms
Primary Hyponatremia in SIADH is do to:
increased water resorption
Secondary Hyponatremia in SIADH is do to:
ANP (atrial natriuretic peptide) triggered by increased blood volume (water follows salt)
Lab values of SIADH 3
- low Na
- Low serum osmolality
- high urine osmolality
SIADH is corrected upon ____
- water restriction