1. Human Anatomy, 3rd edition
Endocrine System
Chapter 11
Human Anatomy, 3rd edition
Prentice Hall, © 2001

2. Introduction
The endocrine system consists of cells, tissues, & organs that secrete hormones into the blood
Hormone – an organic substance secreted by a cell that has an effect on the metabolic activity of another cell or tissue
Target cells – cells that are affected by the hormone
Have specific receptors for the hormones

3. How Hormones Work Basic action The hormone combines with a receptor
The new molecular structure causes cellular changes

4. Human Anatomy, 3rd edition
How Hormones Work
Activation of 2nd messengers
Involves a cell membrane receptor
Activation of genes
Involves intracellular receptors
Human Anatomy, 3rd edition
Prentice Hall, © 2001

5. The Hypothalamus & Endocrine Regulation
Controls the adrenal medulla
Adrenalin
Releases hormones
Antidiuretic hormone (ADH)
Oxytocin
Secretes substances that control the anterior pituitary gland
Releasing factors
Inhibiting factors
Human Anatomy, 3rd edition
Prentice Hall, © 2001

6. Overview of the Endocrine System
Human Anatomy, 3rd edition
Prentice Hall, © 2001

7. Human Anatomy, 3rd edition
The Pituitary Gland
Connected to the hypothalamus
Infundibulum
Master gland of the endocrine system
2 parts
Posterior pituitary
Nervous tissue
Anterior pituitary
Glandular tissue
Human Anatomy, 3rd edition
Prentice Hall, © 2001

8. Human Anatomy, 3rd edition
The Pituitary Gland
Posterior pituitary
Receives hormones from the hypothalamus via axons
Anterior pituitary
Receives hormones from the hypothalamus via capillaries
Human Anatomy, 3rd edition
Prentice Hall, © 2001

9. Posterior Pituitary Produces 2 Hormones
Antidiuretic hormone (ADH)
Target – kidneys
Effect – reabsorption of water
Oxytocin
Targets – reproductive organs
Effects – contractions of smooth muscles (labor contractions, milk ejection; ductus deferens, prostate gland – ejaculations)

10. Anterior Pituitary Hormones
Follicle stimulating hormone (FSH) stimulates gametes
Targets – follicle cells (females), testes (males)
Effects – follicle development & estrogen secretion (females), sperm maturation (males)
Luteinizing hormone (LH)
Targets – follicle cells (females), interstitial cells of testes (males)
Effects – ovulation, formation of corpus luteum, secretion of progesterone (females), secretion of testosterone (males)

11. Anterior Pituitary Hormones
Thyroid stimulating hormone (TSH)
Target – thyroid gland
Effect – triggers the release of thyroid hormones
Adrenocorticotropic hormone (ACTH)
Target – adrenal cortex
Effect – cells that produce steroid hormones

12. Anterior Pituitary Hormones
Prolactin
Target - breast
Effect - stimulates milk production
Growth hormone
Target – all cells
Effect - stimulates growth in general and the skeletal system in particular
Melanocyte stimulating hormone (MSH)
Target - melanocytes
Effect – increases melanin production and distribution
Human Anatomy, 3rd edition
Prentice Hall, © 2001

13. Human Anatomy, 3rd edition
Pituitary Hormones
FG19_05.JPG
Title: Pituitary Hormones and Their Targets
Notes: This schematic diagram shows the hypothalamic control of the pituitary gland, the pituitary hormones produced, and the responses of representative target tissues.
Keywords: pituitary hormones, targets, adrenal medulla, adrenal cortex, thyroid, peripheral tissues, mammary glands, testes, ovaries, melanocytes, kidneys, anterior pituitary, posterior pituitary, ACTH, TSH, GH, PRL, FSH, LH, MSH, ADH, hypothalamus, oxytocin
Human Anatomy, 3rd edition
Prentice Hall, © 2001

14. The Thyroid Gland Location – anterior to larynx
Thyroid hormones include iodine in their structure
Target cells – most cells
Effect of thyroid hormones
increase energy utilization, oxygen consumption, growth, development

15. Human Anatomy, 3rd edition
The Thyroid Gland
Other cells
Produce calcitonin (CT)
Targets – bone, kidneys
Effect – lowers blood calcium levels
Human Anatomy, 3rd edition
Prentice Hall, © 2001

16. Control of Thyroid Hormones
FG19_08.JPG
Title: The Regulation of Thyroid Secretion
Notes: This negative feedback loop is responsible for the homeostatic control of thyroid hormone release.
Keywords: thyroid activity, regulation, homeostasis, anterior pituitary, TSH, thyroid gland, T3, T4, body temperature
Human Anatomy, 3rd edition
Prentice Hall, © 2001

17. The Parathyroid Glands
Location – posterior surfaces of thyroid gland
Produce parathyroid hormone (PTH)
Target cells – bone, kidneys, intestines
Effect
Increases blood calcium levels
Human Anatomy, 3rd edition
Prentice Hall, © 2001

18. Human Anatomy, 3rd edition
The Thymus Gland
Location – posterior to the sternum
Hormones enhance lymphycyte production
Development
Childhood – large
Puberty – largest
Adulthood – decreases in size
Human Anatomy, 3rd edition
Prentice Hall, © 2001

19. Human Anatomy, 3rd edition
The Adrenal Glands
Location – on top of the kidney
Structure
Capsule
Cortex
Medulla
Human Anatomy, 3rd edition
Prentice Hall, © 2001

20. Human Anatomy, 3rd edition
The Adrenal Medulla
Secretes epinephrine & norepinephrine
Target – most cells
Effect - stimulates heart beat & tissue metabolism, increases alertness, prepares body to deal with emergencies
Human Anatomy, 3rd edition
Prentice Hall, © 2001

21. Human Anatomy, 3rd edition
The Adrenal Cortex
Secretes aldosterone
Target – kidneys
Effect – increases blood sodium, decreases blood potassium
Secretes steroid hormones (cortisol, corticosterone)
Target – most cells
Effect – conserve blood glucose, anti-inflammatory effects
Human Anatomy, 3rd edition
Prentice Hall, © 2001

22. Human Anatomy, 3rd edition
The Pancreas
Location – between the spleen and the duodenum
Functions – both exocrine and endocrine
Endocrine cells are in the Islets of Langerhans
Human Anatomy, 3rd edition
Prentice Hall, © 2001

23. Human Anatomy, 3rd edition
Islets of Langerhans
Glucagon
Targets – liver, adipose tissues
Effect - increase blood sugar levels
Insulin
Targets - most cells
Effect - decrease blood sugar levels
Diabetes mellitis
Human Anatomy, 3rd edition
Prentice Hall, © 2001

24. Human Anatomy, 3rd edition
The Pineal Gland
Location = epithalamus
Secretes melatonin
Light inhibits production
Regulates circadian rythms
Target – hypothalamus
Effects – Inhibits FSH & LH secretion
Human Anatomy, 3rd edition
Prentice Hall, © 2001

25. Human Anatomy, 3rd edition
The Testes
Divided into internal compartments containing seminiferous tubules
Spermatogenesis
Human Anatomy, 3rd edition
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26. Human Anatomy, 3rd edition
Seminiferous Tubules
Androgens (male sex hormones)
Testosterone is the most important
Target – most cells
Effects – maturation of sperm; protein synthesis in skeletal muscle; male secondary sex characteristics & behaviors
Human Anatomy, 3rd edition
Prentice Hall, © 2001

27. The Ovaries – Follicle Cells
Estrogen
Targets – most cells
Effects – follicle maturation; female secondary sex characteristics and behaviors
Human Anatomy, 3rd edition
Prentice Hall, © 2001

28. The Ovaries – Corpus Luteum
Progesterone
Targets – uterus, mammary glands
Effects – prepare uterus for implantation, mammary glands for secretion
Relaxin
Targets – pubic symphysis, uterus, mammary glands
Effects – loosens pubic symphysis, relaxes cervical muscles, stimulates mammary gland development
Human Anatomy, 3rd edition
Prentice Hall, © 2001

29. Hormonal Regulation of the Female Reproductive System
FG27_18.JPG
Title: The Hormonal Regulation of Female Reproductive Function
Notes: A diagrammatic view of the hormonal regulation of female reproductive function.
Keywords: hormones, female reproductive functions, hypothalamus, pituitary, estrogens, progestins, GnRH, LH, FSH
Human Anatomy, 3rd edition
Prentice Hall, © 2001