Lots of different endocrine related illnesses like diabetes or hyperthyroidism tend to be the result of either hyper too much or hypo too little secretion of certain hormones which throw your homeostasis off balance but there are lots of more common and less obvious ways your hormones can get out of balance not because of some disorder but because these signaling chemicals are just caught up in a chain reaction which can take a while to subside, some hormones just exist to control other hormones which in turn control still more hormones so as soon as one starts to trickle out, you can pretty quickly wind up with a cascade on your hands, you got a few different hormone cascades going on at any given moment but one of the big ones, one that’s really worth understanding is the hypothalamic pituitary adrenal axis or the hpa axis because you don’t want to have to say that every time this is a complex series of interactions between three glands that ultimately regulates lots of your body’s daily processes like digestion, sexuality immune response and how you handle stress and it’s complex not just because of all the glands involved, it’s also one of the more crucial instances of your endocrine system coordinating with your nervous system specifically. It’s behind that fight-or-flight response that everybody keeps talking about, the hpa axis is essentially the endocrine system’s companion to the sympathetic nervous system, the sympathetic system in times of high stress does things like speed up your heart rate and direct blood away from your digestive organs into the muscles but many of the other effects of the stress response are carried out by your endocrine system and getting your nervous and endocrine systems to work together. In times of crisis is where the hypothalamus comes in, it’s the hub of where the two systems meet, it keeps tabs on what’s going on all over your body, analyzing your blood for signs that something might be off so let’s revisit our fight or flight scene from a few lessons ago, the old burning house scenario, so you’re sleeping, you’re dreaming about patting pandas with emma watson or whatever, when the smoke alarm goes off, well action potentials in your brain trigger neurons in your hypothalamus to release the peptide hormone crh or corticotropin releasing hormone, the crh makes the very short trip through the bloodstream to the anterior pituitary gland where because it is water-soluble it binds to receptors on the outside of its target cells, there it triggers the release of adrenocorticotropic hormone or acth, the acth travels again through the bloodstream to the adrenal cortices of the adrenal glands on top of your kidneys when the acth binds to receptors on cells in an adrenal cortex, it triggers the release of a frenzy of different freakout compounds known as glucocorticoid and mineral accordicoid hormones, typically these hormones help us deal with day-to-day stress by keeping our blood sugar and blood pressure balanced but under major stress like waking up in a burning building stress these hormones like cortisol cause the classic fight-or-flight response ramping up your blood pressure dumping glucose into your bloodstream shutting down non-emergency services like your immune system and sperm and egg development and guess what now, that all these stress hormones are pulsing through your blood, the hypothalamus back in the brain senses them and because its job is to monitor and maintain balance whenever possible, it then stops secreting crh which eventually causes the other glands to stop secreting their panic hormones, now because this element of the stress response is hormonal rather than electrical, it comes on more slowly than the nervous system part and it takes longer to subside too as those stress hormones linger in the blood before being broken down by enzymes so we’re a long way from teenage crushes and zits and crying over commercials at this point aren’t we? as a lifelong owner of hormones, i hope you’ll join me in dispelling the stereotypes that surround these powerful and important chemicals and give them the respect they rightly deserve.
So we looked at the endocrine system and how it uses glands to produce hormones, these hormones are either amino acid based and water or steroidal and lipid-soluble and may target many types of cells or just turn on specific ones, we also touched on hormone cascades and how the hpa axis affects your stress response.

Leave a Reply