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Endocrine (regulatory) System

Endocrine (regulatory) System. Chapter 45. Introductory Questions #3. Name the nine major endocrine glands found in the body. Which one ins called the “master gland”? Name three major local regulators that act on nearby target cells. (pgs. 947-948)

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Endocrine (regulatory) System

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  1. Endocrine (regulatory) System Chapter 45

  2. Introductory Questions #3 • Name the nine major endocrine glands found in the body. Which one ins called the “master gland”? • Name three major local regulators that act on nearby target cells. (pgs. 947-948) • Name three key molecules that play a role in the signal transduction pathway (typical reactions in the endocrine system). • How is the anterior part of the pituitary gland different from the posterior part? Name the hormones secreted from each area. Which region secretes fewer types of hormones? • Using the table on pg. 949, name the hormone(s) that: -Raises blood-calcium levels -maintains metabolic processes

  3. Vertebrate Endocrine System • Tropic hormones ~ a hormone that has another endocrine gland as a target • Hypothalamus~pituitary • Pituitary gland • Pineal gland • Thyroid gland • Parathyroid glands • Thymus • Adrenal glands • Pancreas • Gonads (ovary, testis)

  4. Regulatory Systems • Hormone~ chemical signal secreted into body fluids (blood) communicating regulatory messages • Target cells~ body cells that respond to hormones • Endocrine system/glands~ hormone secreting system/glands (ductless); exocrine glands secrete chemicals (sweat, mucus, enzymes) through ducts • Neurosecretory cells~ actual cells that secrete hormones • Feedback mechanisms ~ negative and positive

  5. Local Regulators: cells adjacent to or near point of secretion • Growth factors ~ proteins for cell proliferation • Nitric oxide (NO) ~ neurotransmitter; cell destruction; vessel dilation • Prostaglandins ~ modified fatty acids secreted by placenta and immune system; also found in semen

  6. Mode of Action: Chemical Signaling • 1- Plasma membrane reception • signal-transduction pathways (neurotransmitters, growth factors, most hormones) • 2- Cell nucleus reception • steroid hormones, thyroid hormones, some local regulators

  7. Hypothalamus & Pituitary Gland • Releasing and inhibiting hormones • Anterior pituitary: • Growth (GH)~bones √gigantism/dwarfism √acromegaly • Prolactin (PRL)~mammary glands; milk production • Follicle-stimulating (FSH) & • Luteinizing (LH)~ovaries/testes • Thyroid-stimulating (TSH)~ thyroid • Adrenocorticotropic (ACTH)~ adrenal cortex • Melanocyte-stimulating (MSH) • Endorphins~natural ‘opiates’; brain pain receptors

  8. Hypothalamus & Pituitary Gland

  9. Posterior Region of the Pituitary Gland • The posterior pituitary: • Oxytocin~ uterine and mammary gland cell contraction • Antidiuretic (ADH)~ retention of water by kidneys

  10. The Pineal, Thyroid, & Parathyroid • Melatonin~ pineal gland; biological rhythms • Thyroid hormones: Calcitonin~ lowers blood calcium Thyroxine~ metabolic processes • Parathyroid (PTH)~raises blood calcium

  11. The Pancreas • Islets of Langerhans • Alpha cells: •glucagon~ raises blood glucose levels • Beta cells: •insulin~ lowers blood glucose levels • Type I diabetes mellitus (insulin-dependent; autoimmune disorder) • Type II diabetes mellitus (non-insulin-dependent; reduced responsiveness in insulin targets)

  12. The Adrenal Glands • Adrenal medulla (catecholamines): •epinephrine & norepinephrine~increase basal metabolic rate (blood glucose and pressure) • Adrenal cortex (corticosteroids): •glucocorticoids(cortisol)~raise blood glucose•mineralocorticoids (aldosterone)~reabsorption of Na+ and K+

  13. The Gonads • Steroid hormones: precursor is cholesterol • Androgens (testosterone) • sperm formation • male secondary sex characteristics; gonadotropin • Estrogens (estradiol) • uterine lining growth • female secondary sex characteristics • gonadotropin • Progestins (progesterone) • uterine lining growth

  14. Ch. 45 Endocrine System: Systems in Balance • What organism does Dr. Hunt & Dr. Fry use to discuss and show how a toxic chemical affects hormone balance? • How is a hormone defined in the video and how do these chemicals control metabolic activities in animals? • What two structures in the brain does Dr. Catherine Rivier explore that relates to stress? • How is the endocrine system similar to the nervous system? How do they interact? • In the final segment name two methods scientists use to study the endocrine system and the effects of hormones? Important Text Pages: Pg. **Write the title for each segment and FIVE statements for each segment.

  15. The Gonads • Steroid hormones: precursor is cholesterol • androgens (testosterone)~ sperm formation; male secondary sex characteristics; gonadotropin • estrogens (estradiol)~uterine lining growth; female secondary sex characteristics; gonadotropin • progestins (progesterone)~uterine lining growth

  16. Homeostasis & Osmoregulation Chapter

  17. Let Sleeping Bears Lie • Bears don’t technically hibernate • They do enter a dormant state, when their body temperature drops by several degrees • Bears are endotherms • Endothermic animals derive most of their body heat from metabolism • Ectothermic animals warm themselves mainly by absorbing heat from their surroundings

  18. Thermoregulation maintains the body temperature within a tolerable range • Osmoregulation controls the gain and loss of water and dissolved solutes • Excretion is the disposal of metabolic wastes • Dormant bears have internal homeostatic mechanisms that compensate for fluctuations in the external environment

  19. Heat is gained or lost in four ways • Body temperature regulation requires adjustment to heat gained from or lost to an animal’s environment Convection Radiation Evaporation Conduction Figure 25.1

  20. Fur and feathers help the body retain heat • Shivering, as these honeybees are doing, also increases metabolic heat production • Hormonal changes may increase heat production by raising the metabolic rate Figure 25.2A

  21. The liver is vital in homeostasis • It assists the kidneys by • making urea from ammonia • breaking down toxic chemicals

  22. Homeostasis: regulation of internal environment • Thermoregulation internal temperature • Osmoregulation solute and water balance • Excretion nitrogen containing waste

  23. Regulation of body temperature • Thermoregulation • 4 physical processes: • Conduction~transfer of heat between molecules of body and environment • Convection~transfer of heat as water/air move across body surface • Radiation~transfer of heat produced by organisms • Evaporation~loss of heat from liquid to gas • Sources of body heat: • Ectothermic: determined by environment • Endothermic: high metabolic rate generates high body heat

  24. Regulation during environmental extremes • Torpor~ low activity; decrease in metabolic rate • 1- Hibernation long term or winter torpor (winter cold and food scarcity); bears, squirrels • 2- Estivation short term or summer torpor (high temperatures and water scarcity); fish, amphibians, reptiles • Both often triggered by length of daylight

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