The Pathway of ADHThe Effect of SIADH

Larry Li

SIADH

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

ADH

ADH

ADH

ADH

ADH

ADH

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.

Secretion of ADH

ADH

ADH

ADH

ADH

ADH

ADH

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

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

End of Production of ADH

ADH

ADH

ADHADH

ADH

ADH

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

ADHADH

ADH

ADH

ADH

ADH

ADH

SIADH makes the sodium in the bloodstream extremely low. This condition causes

hyponatreima. Sodium levels in urine extremely

high.

Implications of SIADH