Liberal Arts Blog — The Pituitary (the “Master Gland”)
By: John Muresianu
Tags: Liberal Arts Blog, Brain, Medicine, Biology, Anatomy

Liberal Arts Blog — Wednesday is the Joy of Science, Engineering, and Technology Day

Today’s Topic — The Pituitary (the “master gland”) — What should every 8th grader know? 12th grader? college graduate?

Last week, the brain. Today, a tiny structure of out-sized importance and a strange history. Half of it grew upward out of the mouth (the anterior pituitary), the other half grew downward out of the brain (the posterior pituitary). But both ended up linked to the hypothalamus (but not to each other). Experts — please chime in. Correct, elaborate, elucidate.

A PEA-SIZED ORGAN THAT PACKS A LOT OF PUNCH

1. Located under the hypothalamus which controls it.

2. The hypothalamus is the bridge between the nervous (electrical) system and the endocrine (chemical system). This is a rough generalization. The nervous system also uses chemicals (eg neurotransmitters).

3. The pituitary sits in the “Turkish saddle” (sella turcica), a “bony hollow in the base of the skull …behind the bridge of the nose.”

THE ANTERIOR AND THE POSTERIOR: the division of labor

Anterior pituitary makes hormones (eg. growth hormone). The posterior just stories them (eg oxytocin and vasopressin which are actually produced in the hypothalamus.) Anterior hormones: ACTH regulates metabolism through its control of the cortisol-producing adrenal cortex, GH (growth hormone) stimulates growth of bone and muscle, TSH (thyroid stimulating hormone) manages the iodine-dependent thyroid which regulates the body’s metabolic rate, controlling “heart, muscle and digestive function, brain development and bone maintenance,” the gonadotropins drive the production of sex hormones in the ovaries and testes as well as egg and sperm maturity. Posterior: oxytocin stimulates uterine contraction during labor, milk secretion during breastfeeding, and is responsible for both sexual pleasure during and after sex. It also promotes bonding between mother and baby as well as trust, generosity, and romantic love more generally. Vasopressin is an “anti-diuretic” meaning it tells the kidney to retain water, impacting blood pressure. (Alcohol suppresses vasopressin production which results in excess urination which results in dehydration which causes

hangovers.

NB: The anterior pituitary is linked to the brain by a vein-to-vein delivery (“portal”) system analogous to the hepatic portal system linking the digestive system to the liver. The posterior is connected to the brain via the “pituitary stalk” also called the “infundibulum” a combination of axons and vascular tissue.

DAVID AND GOLIATH — the consequences of a pituitary adenoma or not?

1.How did David take down Goliath? Well, some scientists now say it may have been Goliath’s poor peripheral vision. Goliath probably suffered from acromegaly, a disease of the pituitary that causes gigantism.

2. With acromegaly, an expanding pituitary puts pressure on the optical chiasm which sits above it. This pressure causes shrinkage of peripheral vision.

3. David took advantage of Goliath’s tunnel vision and whacked him at his most most vulnerable point — his temporal lobe.

NB: In his book, “David and Goliath,” Malcolm Gladwell told this “scientific” version of the ancient story and was accused of practicing pseudo-science and anachronistic “now-ism.”

Pituitary gland | You and Your Hormones from the Society for Endocrinology

Development and Anatomy of the Pituitary Gland

Thyroid gland | You and Your Hormones from the Society for Endocrinology

Oxytocin

Pituitary Adenoma

Pituitary Adenomas: Definition, Symptoms, Treatment & Diagnosis

http://israelbehindthenews.com/faulty-peripheral-vision-of-goliath-may-have-aided-david-in-his-historic-battle-in-the-elah-valley/3205/

Slaying a biblically bad idea

A LINK TO THE LAST THREE YEARS OF POSTS ORGANIZED BY THEME:

PDF with headlines — Google Drive

YOUR TURN

Please share the coolest thing you learned this week related to science, engineering, or technology. Or, even better, the coolest or most important thing you learned in your life related to science and engineering.

This is your chance to make someone else’s day. Or to cement in your mind something that you might otherwise forget. Or to think more deeply about something dear to your heart. Continuity is key to depth of thought.