Human Endocrine System Anatomy and Physiology Lab II Fall 2017 Dr. Santos

General terms Endocrine organ (gland)- Any of several diverse ductless glands that play a major role in maintaining the body’s homeostasis through the secretion of hormones into the bloodstream Hormone- Chemical messengers secreted into the bloodstream by endocrine glands that initiate a change in a target cell Target tissue- Tissue that contains the cells with receptors for a particular hormone Negative feedback- A mechanism in which a deviation in a physiological variable triggers a response that restores the variable to its set point; when the set point is restored, the response decreases

Endocrine glands Hypothalamus -The inferior portion of the diencephalon; releases hormones that stimulate or inhibit the anterior pituitary and two hormones (ADH and oxytocin) stored in the posterior pituitary Anterior pituitary- Anterior portion of the pituitary gland; secretes hormones that largely affect other glands Posterior pituitary- Posterior portion of the pituitary gland; stores ADH and oxytocin produced by the hypothalamus Thyroid gland- Gland located in the anteroinferior neck; composed of thyroid follicles that produce thyroid hormone and calcitonin.

Endocrine glands Parathyroid glands- Three to five small glands located on the posterior thyroid gland; secrete parathyroid hormones that maintain calcium ion homeostasis Pineal gland -Small gland located in the posterior/superior diencephalon; secretes melatonin in response to decreased light levels Thymus gland- Gland located in the superior mediastinum; largest and most active during infancy and childhood when it is actively secreting thymosin and thypopoietin

Pancreas- Endocrine and exocrine gland that secretes insulin and glucagon from pancreatic islets Adrenal cortex- Superficial region of the adrenal gland; consists of glandular tissue that secretes steroid hormones Adrenal medulla -The deep region of the adrenal gland that consists of modified sympathetic neurons that secrete epinephrine and norepinephrine in response to sympathetic stimulation Ovaries- Female reproductive organs that produce estrogens and progesterone Testes -Male reproductive organs that produce testosterone

Hormones

Hormones

Hormones

Endocrine mystery case Case 1: The Cold Colonel You are called upon to visit the ailing Col. Lemon. Before you see him, you speak with three witnesses who were with him when he fell ill. Witness statements: ■ Ms. Magenta: “Col. Lemon has been hot-blooded for as long as I’ve known him. But I noticed that he couldn’t seem to keep warm. He kept complaining about being cold . . .” ■ Mr. Olive: “Just between you and me, I’ve noticed that the old chap has put on quite a bit of weight lately.” ■ Professor Purple: “The colonel and I used to go on major expeditions together. Now he just doesn’t seem to have the energy to do much of anything.” What are your initial thoughts about the witnesses’ statements? Does one hormone come to mind that may be the cause? Explain.