What is the primary function of the Endocrine System?
Control & coordination of body systems via hormones.
hormone:
A chemical messenger, usually secreted by endocrine glands, that alters the physiological activity of other cell.
What is the difference between endocrine and exocrine glands?
1. Exocrine glands release their secretions into ducts and where they act locally.
2. Endocrine glands release their secretions interstitially and they may either act locally or make their way to other parts of the body via the bloodstream.
What are the endocrine glands of the body?
1. Pituitary gland
2. Thyroid gland
3. Parathyroid gland
4. Adrenal gland
5. Pineal gland
Name several organs and tissues of the body that secrete hormones but are not defined as glands.
1. Hypothalamus
2. Thymus
3. Pancreas
4. Gonads (ovaries & testes)
5. Kidneys
6. Stomach
7. Liver
8. Small Intestine
9. Skin
10. Heart
11. Adipose tissue
12. Placenta
Why are some organs and tissues that secrete hormones not considered glands?
They perform numerous other functions not limited to just secreting hormones.
T/F: Norepinephrine can function as both a hormone and a neurotransmitter.
True
What is the difference between a positive feedback system and an negative feedback system?
Positive = Reinforces reported condition
Negative = Reverses reported condition
Name the parts of the pituitary gland and describe them.
2. Posterior pituitary = Non-glandular portion that stores/release Oxytocin & ADH produced by hypothalamus
neurosecretory cells:
Hypothalamic neurons that transport transport hormones to the anterior and posterior lobes of the pituitary gland.
1. Hormones destined for the anterior pituitary are released at the hypophyseal portal veins.
2. Hormones destined for the posterior pituitary travel through axons via the infundibulum.
tropic hormone:
1. A hormone whose target is another endocrine gland.
2. These hormones affect the growth, function, or nutrition of other endocrine cells.
What are the 7 anterior pituitary hormones?
1. Growth Hormone (GH, HGH)
2. Thyroid-stimulating Hormone (TSH)
3. Follicle-stimulating Hormone (FSH)
4. Luteinizing Hormone (LH)
5. Prolactin
6. Adrenocorticotropic Hormone (ACTH)
7. Melanocyte-stimulating Hormone (MSH)
What is growth hormone (GH)?
1. Hormone that promotes tissue growth, maintenance and healing by stimulating the synthesis of IGFs by various tissues of the body.
2. Most abundant hormone of the anterior pituitary.
3. The release of GH is regulated by the hypothalamus via its release of GHRH and GHIH.
What is insulinlike growth factors (IGFs)?
1. Small protein hormones that have actions similar to insulin.
2. IGFs stimulate protein synthesis, maintain bone/muscle mass, promote healing/tissue repair, enhance breakdown of triglycerides and liver glycogen for ATP production
What are GHRH and GHIH?
GHRH = growth hormone-releasing hormone-Hypothalamic hormone that promotes the release of GH.
GHIH = growth hormone-inhibiting hormone-Hypothalamic hormone that inhibits the release of GH.
What is Follicle-stimulating Hormone (FSH)?
1. Anterior pituitary hormone that each month stimulates the development of several ovarian follicles in females and sperm production in males.
2. Gonadotropin-releasing hormone (GnRH) from the hypothalamus stimulates the release of FSH.
3. Estrogen in females and testosterone in males suppresses the release of both FSH, LH, and GnRH.
What is Luteinizing Hormone (LH)?
1. An anterior pituitary hormone that each month triggers ovulation in females and the secretion of testosterone in males.
2. Gonadotropin-releasing hormone (GnRH) from the hypothalamus also stimulates the release of LH.
3. Estrogen in females and testosterone in males suppresses the release of both FSH, LH, and GnRH.
What is Prolactin (PRL)?
1. This anterior pituitary hormone acts with other hormones to initiate and maintain milk production by the mammary glands in females.
2. Prolactin hyper secretion in males causes erectile dysfunction.
3. The secretion of PRL is regulated via the release of Prolactin-inhibiting Hormone (PIH) and Prolactin-releasing Hormone (PRH).
