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Chapter 9

Chapter 9. Endocrine System. Intro video. http://www.youtube.com/watch?v=- S_vQZDH9hY&feature=BFa&list=UUEik-U3T6u6JA0XiHLbNbOw&lf=plcp Skip lipid/water section. Endocrine function. MAINTAINS HOMEOSTASIS BY RELEASING CHEMICALS CALLED HORMONES INTO THE BLOOD CONTROLS GROWTH & DEVELOPMENT

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Chapter 9

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  1. Chapter 9 Endocrine System

  2. Intro video • http://www.youtube.com/watch?v=-S_vQZDH9hY&feature=BFa&list=UUEik-U3T6u6JA0XiHLbNbOw&lf=plcp • Skip lipid/water section

  3. Endocrine function • MAINTAINS HOMEOSTASIS BY • RELEASING CHEMICALS CALLED HORMONES INTO THE BLOOD • CONTROLS GROWTH & DEVELOPMENT • CONTROLS REPRODUCTION • CONTROLS METABOLISM • MOBILIZATION OF BODY’S DEFENSES • MAINTAIN WATER/NUTRIENT BALANCE

  4. Hormone Overview • Hormones are produced by specialized cells • Cells secrete hormones into extracellular fluids • Blood transfers hormones to target sites • These hormones regulate the activity of other cells

  5. Mechanisms of Hormone Action • Hormones affect only certain tissues or organs (target cells or organs) • Target cells must have specific protein receptors • Hormone binding influences the working of the cells

  6. Effects Caused by Hormones • Changes in plasma membrane permeability or electrical state • Synthesis of proteins, such as enzymes • Activation or inactivation of enzymes • Stimulation of mitosis

  7. Control of Hormone Release • Hormone levels in the blood are maintained by negative feedback • A stimulus or low hormone levels in the blood triggers the release of more hormone • Hormone release stops once an appropriate level in the blood is reached

  8. STIMULI THAT ACTIVIATE ENDOCRINE ORGANS • HORMONAL • MOST COMMON • ENDOCRINE GLANDS ACT DUE TO OTHER HORMONES • EX: HYPOTHALAMIC --->ANT. PITUITARY --->OTHER ENDOCRINE ORGANS • HUMORAL • CHANGING BLOOD LEVELS OF CERTAIN IONS/NUTRIENTS STIMULATE HORMONE RELEASE • NEURAL • NERVE FIBERS STIMULATE HORMONE RELEASE

  9. STIMULI THAT ACTIVIATE ENDOCRINE ORGANS NEURAL HORMONAL HUMORAL

  10. MAJOR ENDOCRINE ORGANS • PITUITARY • HYPOTHALAMUS • THYROID • PARATHYROID • ADRENAL • PANCREAS • PINEAL • THYMUS • OVARIES/TESTES

  11. video • http://www.youtube.com/watch?v=Ry5fTZfZHIs&feature=related

  12. Pituitary Gland • Size of a grape • Hangs by a stalk from the hypothalamus • Protected by the sphenoid bone • Has two functional lobes: • Anterior pituitary – glandular tissue • Posterior pituitary – nervous tissue

  13. Pituitary Gland

  14. Anterior Pituitary Gland • Six anterior pituitary hormones • Two affect non-endocrine targets • Four stimulate other endocrine glands (tropic hormones) • Characteristics of all anterior pituitary hormones • Regulated by hormonal stimuli, mostly negative feedback

  15. Anterior Pituitary Gland

  16. HORMONES OF Anterior Pituitary Gland • Growth Hormone (GH) • General metabolic hormone • Major effects are directed to growth of skeletal muscles and long bones • Causes amino acids to be built into proteins • Causes fats to be broken down for a source of energy

  17. HORMONES OF Anterior Pituitary Gland • Prolactin (PRL) • Stimulates and maintains milk production following childbirth • Function in males is unknown • Adrenocorticotropic hormone (ACTH) • Regulates endocrine activity of the adrenal cortex • Thyroid-stimulating hormone (TSH) • Influences growth and activity of the thyroid

  18. HORMONES OF Anterior Pituitary Gland • Follicle-stimulating hormone (FSH) • Stimulates follicle development in ovaries • Stimulates sperm development in testes • Luteinizing hormone (LH) • Triggers ovulation • Causes ruptured follicle to become the corpus luteum • Stimulates testosterone production in males (ICSH)

  19. Pituitary - Hypothalamus Relationship • Release of anterior pituitary hormones is controlled by releasing and inhibiting hormones produced by the hypothalamus • Hypothalamus produces two hormones that are transported to neurosecretory cells of the posterior pituitary for storage • The posterior pituitary is not strictly an endocrine gland, but does release hormones

  20. HORMONES OF POSTERIOR PITUITARY • Oxytocin • Stimulates contractions of the uterus during labor • Causes milk ejection • Antidiuretic hormone (ADH) • Can inhibit urine production • In large amounts, causes vasoconstriction leading to increased blood pressure (vasopressin) • Hyposecretion can lead to diabetes insipidus

  21. HORMONES OF POSTERIOR PITUITARY

  22. Thyroid gland • Found at the base of the throat • Consists of two lobes and a connecting isthmus • Produces two hormones • Thyroid hormone • Calcitonin

  23. Thyroid hormone • Major metabolic hormone • Composed of two active iodine-containing hormones • Thyroxine • Triiodothyronine

  24. Calcitonin hormone • Decreases blood calcium levels by causing calcium to be deposited into the bones • Antagonistic to parathyroid hormone • Few effects of hypo- or hyper- are known • Meager production in adults --->decalcification w/ aging

  25. Parathyroid Glands • Tiny masses on the posterior of the thyroid • Secrete parathyroid hormone (PTH) • Stimulate osteoclasts to remove calcium from bone • Stimulate the kidneys and intestine to absorb more calcium • Raise calcium levels in the blood

  26. Adrenal Glands • Two glands • Cortex – outer glandular region • Medulla – inner neural tissue region • Sits on top of the kidneys

  27. Adrenal cortex hormones • Collectively called: • Corticosteroids • Mineralocorticoids • Glucocorticoids • Sex hormones

  28. Adrenal cortex hormones • Aldosterone (mineralocorticoid) • Regulate mineral content in blood, water, and electrolyte balance • Target organ is the kidney • Cortisone and Cortisol (Glucocorticoids) • Promote normal cell metabolism • Help resist long-term stressors • Released in response to increased blood levels of ACTH

  29. Adrenal cortex hormones • Sex hormones • Produced throughout life in small amounts. • Mostly Androgens (male) and some estrogen (female), regardless of gender

  30. Adrenal MEDULLA hormones • Produces two similar hormones (catecholamines) • Epinephrine (also called adrenaline) • Norepinephrine (similar to epinephrine) • These hormones prepare the body to deal with short-term stress • Stimulated by the sympathetic nervous system

  31. PANCREAS • The pancreas produces hormones: • Insulin – allows glucose to cross plasma membranes into body cells • Glucagon – allows glucose to enter the blood; stimulates liver to release glucose into the blood • These hormones are antagonists that maintain blood sugar homeostasis

  32. PANCREAtic islets • Aka – Islets of Langerhans • Scattered in pancreatic tissue • Where insulin & glucagon are produced • High levels of glucose in blood stimulate release of insulin from BETA cells • INSULIN sweeps glucose OUT of the blood • GLUCAGON acts as an antagonist of insulin ---> regulates blood glucose levels opposite of insulin • Released by ALPHA cells when blood sugar level is LOW

  33. Video • http://www.youtube.com/watch?v=qzjjW--I-2Q

  34. PANCREAtic islets

  35. Pineal gland • Found on the third ventricle of the brain • Secretes melatonin • Helps establish the body’s wake and sleep cycles • May have other as-yet-unsubstantiated functions

  36. thymus • Located posterior to the sternum • Largest in infants and children • Produces thymosin • Matures some types of white blood cells • Important in developing the immune system

  37. ovaries • HORMONE ESTROGEN: • Produced by Graafian follicles or the placenta • Stimulates the development of secondary female characteristics • Matures female reproductive organs • Helps prepare the uterus to receive a fertilized egg • Helps maintain pregnancy • Prepares the breasts to produce milk

  38. ovaries • HORMONE PROGESTERONE • Produced by the corpus luteum • Acts with estrogen to bring about the menstrual cycle • Helps in the implantation of an embryo in the uterus

  39. TESTES • Interstitial cells of testes are hormone-producing • Produce several androgens • Testosterone is the most important androgen • Responsible for adult male secondary sex characteristics • Promotes growth and maturation of male reproductive system • Required for sperm cell production

  40. Other Hormone-Producing Tissues and Organs • Parts of the small intestine • Parts of the stomach • Kidneys • Heart • Many other areas have scattered endocrine cells

  41. Endocrine Function of the Placenta • Produces hormones that maintain the pregnancy • Some hormones play a part in the delivery of the baby • Produces HCG in addition to estrogen, progesterone, and other hormones

  42. diseases

  43. Developmental Aspects of the Endocrine System • Most endocrine organs operate smoothly until old age • Menopause is brought about by lack of efficiency of the ovaries • Problems associated with reduced estrogen are common • Growth hormone production declines with age • Many endocrine glands decrease output with age

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