I had a Big Moment today in class in the first lecture of our block on the endocrine glands. The lecturer asked a question and I was the only person to stick up their hand. Sadly, the question was, "Does anyone not know what an endocrine gland is yet?"
To be fair, I have heard the term endocrine before and I could even name some endocrine glands - I was just a bit fuzzy as to the definition. To confuse the issue, there are also exocrine glands and paracrine glands. From the sound of them, endocrine glands secrete stuff into the body and exocrine glands secrete stuff outside the body and paracrine glands secrete stuff ... beside the body?
When I stuck up my hand and said, "Yo dawg!", the lecturer fixed me with a piercing glare. I'd like to think that it was because she was impressed with my intellectual honesty and wanted to make sure she remembered my face so that she could follow my future career and make a heartfelt speech in front of the King of Sweden when I am awarded the Nobel Prize for my discoveries in endocrinology, but to be honest she was probably sighing inwardly and pining for the olden days when idiots like me were sent over the trenches to charge the machine-guns rather than being admitted to medical school.
Anyway, it turns out that the definition is pretty prosaic. Endocrine glands secrete hormones into the blood, while exocrine glands secrete hormones into a duct that goes somewhere else, and paracrine glands just kind of ooze stuff over their neighbours. How dull.
It does, however, invite the obvious follow-up question, "What's a hormone?" - to which the equally obvious answer is, "Whatever you want her to, she's a professional." Boom boom! Thanks for reading, have a great night.