Posterior Pituitary Gland and Pineal Gland By: Bailey Smith, Lindsey Swearingen, Jacob Thomason

Where is it? The Posterior lobe of the Pituitary gland is in the back of the forebrain and is inferior to the hypothalamus The Pineal gland is on the midline of the posterior end of the third ventricle above the Thalamus.

What hormone does it secrete? Posterior lobe of the Pituitary Gland - Releases Oxytocin (OT) and Anti-Duretic Hormones (ADH) also known as Vasopressin. The Pineal Gland - secretes the hormone melatonin.

What do those hormones do? The posterior lobe of the Pituitary Gland -Anti-Duretic Hormones (ADH) cause retainment of water. It prevents a superfluous amount of water to be in urine. This helps the body conserve water Oxytocin (OT) allows contractions of the uterus to begin childbirth. It also causes milk ejection from the breasts. The Pineal gland - Melatonin promotes sleep and affects moods.

Why are these hormones important for the maintenance of homeostasis? Posterior Pituitary-If the amounts of oxytocin, vasopressin, or other hormones are inadequate, the body is out of homeostasis. For example, a lack of oxytocin is linked to depression. Pineal Gland- the hormones present in the pineal gland play a major role in maintaining the body’s homeostasis. If the body lacks, or has an abundance of melatonin, a person’s circadian rhythm and process of sexual maturation are altered

Identify Feedback Mechanisms and Antagonistic Hormones Melatonin (Pineal)- Melatonin receptors are present on neurons of the suprachiasmatic nuclei of most species, which suggests that melatonin is regulated by a negative feedback loop. Oxytocin (Posterior Pituitary)- Oxytocin is controlled by a positive feedback loop where release of the hormone causes an action which stimulates more of its own release. For example, when the uterus begins to contract, oxytocin is released Antagonistic Hormones- The tocolytic agent atosiban (Tractocile) acts as an antagonist of oxytocin A potential antagonist of melatonin is thyroxine

Identify Releasing Hormones and Glands, and Release-Inhibiting Hormones and Glands Pineal Gland- Synthesizes and releases melatonin Posterior Pituitary- stores and releases oxytocin, vasopressin, and more

What happens when the gland improperly functions? Pineal ● Sexual dysfunction ● Hypertension ● Epilepsy ● Payets disease(causes abnormal bone destruction and regrowth resulting in deformity) posterior pituitary ●SIADH (excessive levels of antidiuretic hormones, causing the body to retain water and deplete itself of electrolytes such as sodium.) ●Diabetes Insipidus (an insufficient production of antidiuretic hormone, causing excessive dilution in the urine, dehydration, and constant thirst for water.

What can be done to counteract improper function? Pineal ● Melatonin (promotes sleep) ● Pain killers Post Pituitary ●Growth Hormone ●Increase salt intake (SIAHD) ●Synthetic hormone called Desmopressin