1. The Endocrine System

2. Chemical messages (hormones) are released into the bloodstream Some of the major processes controlled by hormones include… –Reproduction –Growth and Development –Body Defense –Maintaining Homeostasis –Regulating Metabolism

3. What are Hormones? Hormones are produced by specialized cells Cells secrete hormones into extracellular fluids (blood, lymph) Blood transfers hormones to target sites These hormones regulate the activity of other cells!

4. What are Hormones? Two major chemical classifications of hormones –Amino acid-based hormones Examples: proteins, peptides, amines –Steroids: made from cholesterol

5. What do Hormones cause? Synthesis of proteins, such as enzymes Activation or inactivation of enzymes Stimulation of mitosis Changes in the plasma membrane These changes all have one common goal – to cause some larger, long-lasting change in the body!

6. What causes Hormones to be Released? Some sort of stimulus will trigger hormones to be released! –Hormonal Stimulus Some hormones released will stimulate other hormones to be released

7. What causes Hormones to be Released? –Humoral Stimulus Changing blood levels of ions & nutrients will stimulate hormones to be released Examples: Parathyroid hormone (PTH) will cause calcium to be released from bone into blood, ADH will cause water to be reabsorbed into blood

8. What causes Hormones to be Released? –Neural Stimulus Nerve fibers stimulate hormones to be released Examples: norepinephrine and epinephrine released during stress

9. What are some of the major endocrine organs?

10. Endocrine Organs Hypothalamus –Found in brain –Releases hormones that regulate the pituitary gland

11. Endocrine Organs Pituitary Gland –Hangs from hypothalamus, broken into two lobes –Releases hormones to control other glands –Hormones released by the two lobes include…

13. Pituitary Gland –Posterior Lobe Oxytocin: contraction of uterus, release of milk Antidiuretic hormone (ADH): reabsorption of water by kidneys –Anterior Lobe Prolactin: milk production (pro= for; lact = milk) Follicle-Stimulating Hormone (FSH): –In females, stimulates development of follicles in the ovaries. »You will soon learn that a follicle consists of follicle cells and the developing egg –In males, FSH stimulates sperm development within the testes Lutenizing Hormone (LH): –In females, triggers ovulation and the production of progesterone and some estrogen –In males, stimulates testosterone production and release of sperm

14. Pituitary Gland cont Thyroid Stimulating Hormone (TSH): stimulates thyroid gland Growth Hormone (GH): stimulates growth, especially of bones and muscles

15. Endocrine Organs Gigantism –Most of the tallest people in the world are so because they have a tumor on their pituitary gland –This causes an overproduction of GH

16. Leonid Stadnyk – 8 ft 5 in

17. Robert Wadlow – 8 ft 11 in Tallest man ever on record Lived to be only 22

18. Endocrine Organs Pineal Gland –Found in brain –Produces Melatonin, which helps establish day/night cycle

19. Endocrine Organs Thyroid Gland –Found at base of throat –Produces Thyroid Hormone, which controls the rate at which glucose is used & converted to body heat and energy

20. Endocrine Organs Hyperthyroidism: overactive thyroid –Produce too much thyroid hormone –Symptoms include increased heart beat, tremors, weight loss, and diarrhea Hypothyroidism: underactive thyroid –Produce too little thyroid hormone –Can be brought on by iodine deficiency or genetics –Symptoms include poor muscle tone, fatigue, decreased heart beat, weight gain, and constipation

21. Thyroid Gland Continued* A second important hormone produced by the thyroid is called calcitonin –Causes calcium to be deposited into the bones *please add these notes to your packet o notes

22. Endocrine Organs Parathyroid –Tiny gland masses on the back of the thyroid gland –Produces Parathyroid Hormone (PTH), which controls calcium release from the bones into the blood –*PTH is a hypercalcemic hormone (increases blood levels of calcium) whereas calcitonin is a hypocalcemic hormone.

23. Endocrine Organs Thymus –Sits right above heart in the upper chest –Produces Thymosin, which helps mature T cells (immunity)

24. Endocrine Organs Adrenal Glands –Sits on top of the kidneys –Produce Aldosterone, which helps with water balance of urine/blood –Produce Glucocorticoids, which increase blood glucose levels –Produce Epinephrine/Norepinephrine, which helps with short-term stresses –Some sex hormones also made here

25. Endocrine Organs Pancreas –Located at curvature of duodenum just underneath the stomach –While produces enzymes that help with digestion, it also produces hormones such as… –Insulin, which increases ability of cells to transport glucose across their plasma membranes, thereby reducing glucose levels of blood

26. Diabetes There are generally two types of diabetes Type 1/ Juvenile –Pancreas self-destructs, causing lack of production of insulin. Without insulin, sugar can not be absorbed by the body –Symptoms of Type 1 diabetes (when not treated!) are Very high blood sugar Weight loss 3 ‘Ps’ –Polydipsia - Excessive thirst –Polyphagia - Excessive hunger –Polyuria - Excessive urination

27. Type 1 –Treatment of Type 1 diabetes Diet Daily Insulin Injections –Or -- Insulin pump that continuously releases insulin into body.

28. Diabetes Type 2 / Adult Onset –Body cells become resistant to insulin Or –Pancreas is not producing enough insulin –Symptoms of Type 2 diabetes (when not treated) are Moderately high blood glucose levels Polydipsia, Polyphagia & polyuria (3Ps) –When glucose flushes out of body along with water, resulting dehydration. Because glucose is unavailable, the body will use fats and proteins for energy instead which can cause weight loss.

29. Diabetes –Treatment of type 2 diabetes Diet –Reduce the amount of sugar in diet and encourage weight loss Oral medications that help –increase absorption of sugar –increase production of insulin –decrease release of internal glucose stores Lastly, insulin injection if all above fail.

33. Endocrine Organs Gonads –Male: Testes Produces Androgen hormones (especially Testosterone), which promotes male sex characteristics and helps sperm production Stimulated to be released b/c of LH –Female: Ovaries Produces Estrogen, which promotes female sex characteristics, stimulates growth of uterine lining Stimulated to be released b/c of FSH Produces Progesterone, which stimulates growth of uterine lining