1. Endocrine System
Chapter 9

2. Overview of Hormones
The endocrine and nervous systems often work together to bring about homeostasis.
The blood stream transports hormones throughout the body.

3. Overview of Hormones
Each hormone acts on a certain type of tissue called its target tissue.
Organs, tissues, or cells lacking the specific receptor do not respond to its stimulating effects.

4. Negative Feedback Loop
A decrease in function in response to a stimulus
The system controls how much product it makes by shutting down manufacturing when levels of output or the amount of accumulated product gets too high
Example # 1: the regulation of the blood glucose level in the body
Example # 2: regulation of body temperature

5. Negative Feedback Loop

6. Positive Feedback Loop
An increase in function in response to a stimulus
“A” produces more of “B” which in turn produces more of “A”
Only a few positive feedback loops occur in the human endocrine system.
Example: the process of birthing a child

7. Positive Feedback Loop

8. Glands

9. Glands
Exocrine glands – secretions released into ducts opening onto an epithelial surface
Endocrine glands – ductless organs that secrete their molecules directly into the bloodstream

10. Glands
Endocrine glands are activated by other hormones

11. Hypothalamus Controls the pituitary gland
Receives information from the nervous system

12. Pituitary Location: Inferior to the hypothalamus
Known as the master gland

13. I. Anterior Pituitary 1. Growth hormone (GH) General metabolic hormone
Major effects are directed to growth of skeletal muscles and long bones

14. I. Anterior Pituitary 2. Prolactin (PRL)
Stimulates and maintains milk production following childbirth
Function in males is unknown

15. I. Anterior Pituitary 3. Adrenocorticotropic hormone (ACTH)
Regulates endocrine activity of the adrenal cortex which makes a hormone called cortisol (helps the body manage stress)

16. I. Anterior Pituitary 4. Thyroid-stimulating hormone (TSH)
Produces the hormone thyroxine
Regulates the rate of metabolism

17. I. Anterior Pituitary
Gonadotropic hormones – Regulate hormonal activity of the gonads
5. Follicle-stimulating hormone (FSH)
Stimulates follicle development in ovaries
Stimulates sperm development in testes

18. I. Anterior Pituitary
Gonadotropic hormones – Regulate hormonal activity of the gonads
6. Luteinizing hormone (LH)
Triggers ovulation
Prepares uterus for fertilized egg
Stimulates testosterone production in males

19. II. Posterior Pituitary
1. Oxytocin
Stimulates contractions of the uterus during labor
Causes milk ejection

20. II. Posterior Pituitary
2. Antidiuretic hormone (ADH)
Can inhibit urine production
In large amounts, causes vasoconstriction leading to increased blood pressure

22. Posterior Pituitary
Anterior Pituitary

24. Mnemonic Device for anterior and posterior pituitary gland
Anterior pituitary
FLAT PIG
1. FSH
2. LH
3. ACTH
4. TSH
5. Prolactin
(Ignore)
6. Growth Hormone
Posterior pituitary
Audio Osmosis = AO
1. ADH
2. Oxytocin

25. Anterior Pituitary Gland Chart
Mnemonic Device
(Letter)
Hormone
Targeted Area
Produces F
FSH
Ovaries and Testes
Sperm and egg L LH
Ovulation and testosterone A
ACTH
Adrenal Gland
Cortisol T
TSH
Thyroid
Thryoxine P
Prolactin
Breast
Milk I
Ignore - G GH
Muscles and bones
Growth of muscles and bones

26. Posterior Pituitary Gland Chart
Mnemonic Device (Letter)
Hormone
Targeted Area
Produces A
ADH
Kidneys
Inhibit urine production O
Oxytocin
Uterus and breast
Uterine contraction and milk letdown

27. Pineal
Location: Between the left and right hemispheres (thalamus region)
Hormone: Melatonin
Function: maintains the body’s circadian cycle (a daily cycle of activity observed in many living organisms)

28. Thyroid Located in the neck in front of the trachea
Thyroid gland releases the hormone thyroxine.
Function: regulates the rate of metabolism

29. Parathyroid Location: embedded in back of thyroid gland
Hormone: Parathormone
Function: Controls the metabolism of calcium

30. Thymus Located posterior to the sternum
Helps develop the immune system in infants
Helps lymphocytes to mature

31. Adrenal Gland Location: on top of kidney Hormone: Adrenaline
Function: Raises blood sugar level and increases heart beat and breathing rates

32. Islets of Langerhans Location: Pancreas Hormones: Insulin
Produced by beta cells
Function: Stimulates glucose uptake by cells

33. Islets of Langerhans Location: Pancreas Hormone: Glucagon
Produced by alpha cells
Function: Promote conversion (change of glycogen to glucose)

34. body cells take up sugar from blood
Endocrine System Control
Feedback
Regulation of Blood Sugar
insulin
body cells take up sugar from blood
liver stores sugar
reduces appetite
pancreas
liver
high
blood sugar level
(90mg/100ml)
low
liver releases sugar
triggers hunger
pancreas
liver
glucagon

35. Ovary Hormones: estrogen and progesterone Functions:
Estrogen helps develop secondary characteristics in females
Progesterone prepares the uterus for the fertilized ovum and maintains pregnancy

36. Testes The testes secrete “male sex hormones” called androgens.
Testosterone is an androgen that develops the secondary characteristics in men.