1. https://www.youtube.com/watch?v=GmcsG6kL HKo

2. Major Endocrine Organs Part 2
Objectives:
I will be able to:
Identify the major endocrine glands and tissues.
List hormones produced by endocrine glands and discuss their general functions.

4. Pineal Gland
The pineal gland is a small, cone-shaped gland that hangs from the roof of the 3rd ventricle of the brain.
Many chemical substances are found in the pineal gland but only the hormone melatonin is secreted in substantial amounts.
Melatonin levels rise at night and fall during the day and regulate our sleep-wake cycle.
In addition, melatonin inhibits the reproductive system until the body matures.

6. Thyroid Gland The thyroid gland is located at the base of the throat.
It is a large gland consisting of two lobes joined by a central mass called the isthmus.
Thyroid hormones and their targets:
thyroid hormone  controls rate of glucose oxidation
calcitonin  decreases blood calcium ion levels

7. Thyroid Gland
Internally, the thyroid is made up of hollow structures called follicles.
Follicles store a sticky colloidal substance from which thyroid hormone is synthesized.
Thyroid hormone is considered the “major metabolic hormone” because it controls metabolism in all cells by stimulating the start of the process for making ATP.

8. Thyroid Gland
Thyroid hormone actually consists of two active iodine-containing hormones:
Thyroxine
Triiodothyronine
These hormones require iodine to function properly. Without iodine, they don’t work.
A condition called goiter can develop where the thyroid enlarges without iodine.

9.  What is the “sleep” hormone? Which gland produces it?
Why is thyroid hormone considered “the“ major metabolic hormone?
Why is iodine important for proper thyroid gland function?
Melatonin
Pineal gland
It controls the start of ATP synthesis
Without iodine, PTH is not functional and ATP cannot be made

10. Parathyroid Glands
Parathyroid glands are tiny masses of glandular tissue located on the posterior surface of the thyroid gland.
It consists of 4 small lobes, 2 on each thyroid lobe
Hormone and Target:
parathyroid hormone (PTH)
 increases blood calcium ion levels

11. Parathyroid Glands
When blood calcium ion levels decrease, PTH stimulates release of calcium from bones (making them weaker) to bring Ca+ levels back to normal.
Calcitonin and PTH work together in negative feedback to maintain homeostasis.
Ca+ is used:
by every cell for neural communication
to activate platelets for blood coagulation
building bone tissue.

12.  How do the thyroid and parathyroid glands work together?
Which hormone increase blood Ca+?
Which hormone decreases blood Ca+?
Why is it important to maintain Ca+ levels?

13. Thymus
The thymus is located in the upper thorax, posterior to the sternum (breastbone). It is below the thyroid.
Hormone and its target:
thymosin  development of white blood cells (T lymphocytes) and the immune response

14. Adrenal Glands

15. Adrenal Glands
The adrenal glands curve over the top of the kidneys like triangular hats.
The two adrenal glands function together as one organ.
The adrenal glands are composed of both glandular tissue (cortex) and neural tissue (medulla).
The adrenal cortex forms the outer portion of the adrenal gland and contains three layers.

16. Hormones of the Adrenal Cortex
The adrenal cortex produces three major groups of hormones, collectively called corticosteroids.
Corticosteroids include:
mineralocorticoids
glucocorticoids
sex hormones

17. Hormones of the Adrenal Cortex
Mineralocorticoids, mainly aldosterone, are produced in the outer cortex layer and regulate sodium and potassium ion levels in the blood.
Glucocorticoids are produced in the middle layer of the cortex.
The glucocorticoid hormones cortisone and cortisol promote normal cell metabolism and help the body resist long-term stressors by increasing blood glucose level.

18. Hormones of the Adrenal Cortex
Glucocorticoid hormones are often prescribed as drugs to suppress inflammation from rheumatoid arthritis.
Small levels of sex hormones are produced in the inner layer of the cortex. Most of these are androgens (male sex hormones) while some estrogens (female sex hormones) are also produced.

19.  How does thymosin and other hormones help protect the body?
Which hormone stimulates the kidneys to reabsorb Na+?
Which group of hormones produced by the adrenal cortex have anti-inflammatory effects?

20. Hormones of the Adrenal Medulla
The adrenal medulla is located in the interior of the adrenal glands and is composed of mostly nervous tissue.
When stimulated by the sympathetic nervous system, the medulla releases epinephrine and norepinephrine.
Together, these two hormones are called catecholamines.

21. Hormones of the Adrenal Medulla
Catecholamines increase heart rate, blood pressure, blood glucose level, and circulation of the blood.
Catecholamines affect short-term or alarm- stage responses to stimuli.
Glucocorticoids affect long-term or resistance- stage responses to stimuli.

22. Pancreatic Islets

23. Pancreatic Islets
The pancreas is located near the stomach in the abdominal cavity.
Pancreatic islets (also called islets of Langerhans) are little masses of endocrine tissue scattered throughout the exocrine tissue of the pancreas.
The acinar (exocrine) portion of the pancreas works with the digestive system and the pancreatic islets with the endocrine system.

24. Pancreatic Islets
The one million islets work together as one organ to synthesize hormones.
Pancreatic islet hormones and their targets:
insulin  reduces blood glucose levels
glucagon  increases blood glucose levels
Insulin and glucagon work together to regulate blood glucose levels.

25.  Which pancreatic hormone stimulates uptake of glucose?
Is the pancreatic islet endocrine or exocrine?
What types of hormones are produced in the pancreatic islets?
Insulin
Endocrine
Insulin and glucagon

26. Gonads

27. Gonads Gonads are located in the pelvic cavity.
The two types of gonads are testes (male) and ovaries (female).
The gonads produce sex cells (sperm and eggs) and sex hormones (testosterone (male), estrogen and progesterone (female)).
The sex hormones are steroid hormones.

28. Hormones of the ovaries
The ovaries are paired organs slightly larger than almonds.
Ovaries produce:
female sex cells (ova or eggs)
estrogens
progesterone

29. Hormones of the ovaries
Hormone function:
Estrogen (by itself) targets
1) development of sex characteristics in women (growth and maturation of reproductive organs) and
2) the appearance of secondary sex characteristics at puberty.

30. Hormones of the ovaries
Estrogen and progesterone (together) stimulate breast development and cyclic changes in the uterine lining (menstruation).
Progesterone (by itself)
1) quiets the muscles of the uterus during pregnancy to prevent abortion/miscarriage of the implanted embryo and
2) prepares breast tissue for lactation.

31. Hormones of the Testes
Testes are oval-shaped, paired organs suspended in the scrotum outside the pelvic cavity.
Testes produce:
male sex cells (sperm)
male sex hormones (androgens)
Testosterone is the primary androgen.

32. Hormones of the Testes
Luteinizing hormone (LH) stimulates the testes to produce testosterone through out life.
Testosterone promotes growth and maturation of the reproductive organs.
Additionally, it causes the secondary sex characteristics to develop (facial hair, heavy bones and muscles, lower voice) and stimulates the male sex drive.

33. 
Which gonadal hormone causes a young girl’s reproductive organs to mature at puberty?
What might be the result of a male suffering from hyposecretion of testosterone?
Which gonadal hormone prevents miscarriage of an embryo?
estrogen
sterility
progesterone

34. Other Hormone-Producing Tissues and Organs
Objectives:
I will be able to:
discuss ways in which hormones promote body homeostasis.
describe major pathological consequences of hypersecretion and hyposecretion of hormones.
describe the endocrine role of the kidneys, stomach, intestines, heart, and placenta.

35. Other Hormone-Producing Tissues and Organs
Pockets of hormone producing cells are found in fatty tissue and in the walls of:
small intestine
stomach
kidneys
heart
placenta

36. Other Hormone-Producing Tissues and Organs
The stomach produces gastrin which targets stomach glands to release hydrochloric acid (HCl).
The heart produces atrial natriuretic peptide (ANP).
ANP targets:
kidney where it inhibits reabsorption of Na+ and renin release.
adrenal cortex where it inhibits secretion of aldosterone, decreasing blood volume and pressure.

37. Other Hormone-Producing Tissues and Organs
The kidneys produce:
Erythropoitin which targets bone marrow and stimulates red blood cell production.
Active vitamin D3 which targets the small intestine and stimulates active transport of dietary Ca+ across intestinal cell membranes.

38. Other Hormone-Producing Tissues and Organs
The placenta is a remarkable, temporary organ that forms in the female uterus during pregnancy.
The placenta functions as the respiratory, excretory, and nutrition delivery systems for the fetus.
It also produces several protein and steroid hormones that maintain pregnancy and prepare for delivery.

39. Other Hormone-Producing Tissues and Organs
Human chorionic gonadotropin (hCG) is first produced by the developing embryo and later by the fetal portion of the placenta.
hCG stimulates the ovaries to continue producing estrogen and progesterone to stop menstruation.
Human placental lactogen (hPL) helps prepare the breasts for lactation.
Relaxin causes pelvic ligaments and the pubic symphysis to relax and become more flexible for birth.

40.  Review

41. Web Links
Great Glands - Your Endocrine System: CrashCourse Biology #33
Endocrine System, part 1 - Glands & Hormones: Crash Course A&P #23