Endocrine System:

1. Endocrine System: Holden Laurance Elgin Dailey Block 1

2. What is the endocrine system? • It, much like the nervous system, coordinates and directs the activities of the body’s cells. The endocrine system slowly affects the body by use of chemical messengers called hormones. The processes these hormones control are reproduction, growth and development, mobilizing body defenses against stressors, maintaining electrolyte, water and nutrient balance, and regulating cellular metabolism and energy balance.

3. Organs of the endocrine: • The organs of the endocrine include the pancreas, testis, ovaries, thymus, hypothalamus, and the adrenal, thyroid, parathyroid, pituitary, and pineal glands.

4. Function of organs- • Thyroid gland- Hormone producing gland located at the base of the throat under the Adam’s apple. Makes two hormones called thyroid hormone (thyroxine and triidothyronine) and calcitonin. • Hypothalamus- The center for many drives and emotions, regulates the pituitary gland, and produces oxytocin and antidiuretic hormone. • Pituitary gland- Controls the activities of many of the other endocrine glands. Releases a variety of hormones including thyrotropic hormone, adrenocorticotropic hormone, prolactin, HGH, luteinizing hormone, and follicle-stimulating hormone. There are two divisions of the pituitary, the anterior and posterior, the posterior is more of a storage space than anything as it does not produce any hormones of its own. • Pancreas- The pancreatic islets are small groupings of cells that produce hormones. The most important hormones produced by these islets are insulin and glucagon. • Thymus- Produces a hormone known as thymosin, which is necessary for normal development of the immune system. • Gonads- The testis and ovaries are reproductive organs that produce sex cells and sex hormones. In females estrogen and progesterone are produced in large quantities, whereas in males androgens and testosterone are produced.

5. Function of Organs Cont. • Pineal Gland- Produces melatonin and affects sleeping patterns. • Adrenal Gland- Releases hormones in response to stress and produces the hormones epinephrine (adrenaline), and cortisol. • Parathyroid Gland- Produce parathyroid hormone. Regulate the amount of calcium within the blood and bones.

6. Endocrine system stimulus: • The endocrine can be stimulated either hormonally, humorally, or neurally. • Hormonal- Is the most common. Is triggered by hormones. Ex. Hypothalamic hormones tell pituitary gland to secrete hormones. • Humoral- Changing blood levels of certain ions and nutrients can trigger a release of humoral stimuli, blood-borne chemicals. • Neural- Nerve fibers stimulate hormone release, and target cells that are said to respond to neural stimuli.

7. Endocrine related diseases • Cretinism- An underproduction of thyroxine can result in cretinism, a form of dwarfism that causes adult body proportions to remain childlike. • Underproduction of HGH (Human growth hormone) can result in pituitary dwarfism where body proportions are normal, but the person is a living miniature. Overproduction can lead to gigantism, where a person becomes extremely tall, 8-9 feet is common. • Sterility- An inability to reproduce that is caused by a deficiency of follicle-stimulating hormone or luteinizing hormone. • Diabetes insipidus- A condition of excessive urine output causing continual thirst and consumption of vast quantities of water. • Goiter- An enlargement of the thyroid gland due to a lack of iodine in the body.

8. Developmental aspects: • As we age our bodies grow and change and some aspects become less necessary than they used to be, such as in the thymus which becomes unused during adult life. Other instances such as menopause in women and andropause in men are encountered during aging, usually around the age of retirement.