HPA and Growth Hormone Quiz

See The Posterior Pituitary. Option E is correct because the posterior pituitary releases just two hormones, oxytocin and antidiuretic hormone (ADH), also called vasopressin. Both are made by neurosecretory cells (nerve cells that release hormones into the blood) in the supraoptic and paraventricular nuclei of the hypothalamus. They travel down the cell axons (the long nerve fibres) through the pituitary stalk to the posterior pituitary, where they are stored until the nerve cells are stimulated, and then they enter the general circulation. Oxytocin is involved in the milk let-down reflex during breastfeeding and in uterine contractions during birth. ADH acts on the nephron of the kidney to promote water reabsorption, so the urine becomes more concentrated and less water is lost. A memory aid: the posterior pituitary is a store, not a factory, and it holds only two hormones, one for the breast and uterus and one for the kidney.

• Hormones: the posterior pituitary releases only two, oxytocin and antidiuretic hormone (vasopressin).
• Origin: both are made in the supraoptic and paraventricular nuclei of the hypothalamus and stored in the posterior pituitary.
• Oxytocin: it drives the milk let-down reflex and uterine contractions during birth.
• ADH: it promotes water reabsorption in the nephron, so the urine becomes more concentrated.

Learning the posterior pair as a fixed list of two means that any other pituitary hormone is made in the anterior lobe.