1. The Pathway of ADH The Effect of SIADH Larry Li

2. Production of ADH
ADH is released from the pituitary gland in response to dehydration
Produced by neurosecretory cells, ADH is put in vesicles and sent through ion channels to the hypothalmus
It then travels through the pituitary stalk to the pituitary gland
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3. Secretion of ADH
ADH is stored in the pituitary gland until the lack of water in the human body triggers it.
In the cell, ADH causes the kidney to increase in water permeability.
Results in reabsorption of water and concentrated urine excretion.
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4. A water channel, aquaporin-2, allows for the moving of water
This allows for reabsorption
With ADH, the loss of water is reduced by less urine being formed
Reabsorption of Water

5. End of Production of ADH
With the aquaporins active, the plasma osmolarity decreases and the urine osmolarity increases.
The dilution of plasma is detected by receptors
The release of ADH is then stopped
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6. SIADH makes the production of ADH not stop by the dilution of plasma
The off switch for the ADH is essentially removed, the production cannot stop
Effects of SIADH
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7. SIADH makes the sodium in the bloodstream extremely low.
This condition causes hyponatreima.
Sodium levels in urine extremely high.
Implications of SIADH