Hi Natasha,

1. ADH and Aldosterone are both involved in the regulation of blood pressure and volume. They also both act at the level of the kidney tubules. In response to increased blood osmolarity or decreased blood volume, ADH is released from the posterior pituitary which causes water resorption from the kidney tubules into the capillaries which lowers blood osmolarity. Aldosterone is released from the adrenal cortex in response to decreased osmolarity or blood volume and acts on the kidney tubules to increase sodium reabsorption which leads to an increase in blood osmolarity.

(You will learn more about this during BioBiochem 7)

So for those thinking questions on page 93:
1. This person probably has increased blood osmolarity ...triggering ADH.
2. This person has elevated blood volume...so your body would decrease levels of ADH.
3. Low blood volume would trigger Aldosterone to increase Na+ levels which would increase water reabsorption (via ADH)
4. You may have heard that our bodies can't survive long without water. So your body will do anything to save water so ADH will be working to reabsorb any water in the kidney tubules.

Remember that ADH and Aldosterone don't work independently of each other but work together to regulate our bodies.

2. Teratogens are agents that affect the development of an embryo/fetus. This isn't high yield. I personally did not come across that terminology during my MCAT.

I hope this helped :)

- Shin