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- 1. © 2012 Pearson Education, Inc. Lecture by Edward J. Zalisko PowerPoint Lectures for Campbell Biology: Concepts & Connections, Seventh Edition Reece, Taylor, Simon, and Dickey Chapter 26Chapter 26 Hormones and the Endocrine System
- 2. Introduction In lions, the hormone testosterone promotes the development and maintenance of male traits including – growth and maintenance of the mane and – increased height and weight. © 2012 Pearson Education, Inc.
- 3. Figure 26.0_1 Chapter 26: Big Ideas The Vertebrate Endocrine System Hormones and Homeostasis Hypothalamus The Nature of Chemical Regulation
- 5. Copyright © 2009 Pearson Education, Inc. THE NATURE OF CHEMICAL REGULATION
- 6. 26.1 Chemical signals coordinate body functions The endocrine system – consists of all hormone-secreting cells and – works with the nervous system in regulating body activities. © 2012 Pearson Education, Inc.
- 7. 26.1 Chemical signals coordinate body functions The nervous system also – communicates, – regulates, and – uses electrical signals via nerve cells. © 2012 Pearson Education, Inc.
- 8. 26.1 Chemical signals coordinate body functions Comparing the endocrine and nervous systems – The nervous system reacts faster. – The responses of the endocrine system last longer. © 2012 Pearson Education, Inc.
- 9. 26.1 Chemical signals coordinate body functions Hormones are – chemical signals, – produced by endocrine glands, – usually carried in the blood, and – responsible for specific changes in target cells. Hormones may also be released from specialized nerve cells called neurosecretory cells. © 2012 Pearson Education, Inc.
- 10. Figure 26.1A Secretory vesicles Endocrine cell Hormone molecules Blood vessel Target cell
- 12. 26.2 Hormones affect target cells using two main signaling mechanisms Two major classes of molecules function as hormones in vertebrates. – The first class includes hydrophilic (water-soluble), amino-acid-derived hormones. Among these are – proteins, – peptides, and – amines. – The second class of hormones are steroid hormones, which include small, hydrophobic molecules made from cholesterol. © 2012 Pearson Education, Inc.
- 13. 26.2 Hormones affect target cells using two main signaling mechanisms Hormone signaling involves three key events: – reception, – signal transduction, and – response. © 2012 Pearson Education, Inc.
- 14. 26.2 Hormones affect target cells using two main signaling mechanisms An amino-acid-derived hormone – binds to plasma-membrane receptors on target cells and – initiates a signal transduction pathway. © 2012 Pearson Education, Inc. Animation: Water-Soluble Hormone
- 16. Figure 26.2A_s2 Target cell Receptor protein Plasma membrane Nucleus 1 Interstitial fluid 2 Signal transduction pathway Relay molecules Water-soluble hormone
- 17. Figure 26.2A_s3 Target cell Receptor protein Plasma membrane Nucleus 1 Interstitial fluid 2 Signal transduction pathway Relay molecules Cellular responses or Gene regulation Cytoplasmic response 3 Water-soluble hormone
- 18. 26.2 Hormones affect target cells using two main signaling mechanisms A steroid hormone can – diffuse through plasma membranes, – bind to a receptor protein in the cytoplasm or nucleus, and – form a hormone-receptor complex that carries out the transduction of the hormonal signal. © 2012 Pearson Education, Inc. Animation: Lipid-Soluble Hormone
- 20. Figure 26.2B_s2 Steroid hormone Target cell Nucleus 1 Interstitial fluid 2 Receptor protein
- 21. Figure 26.2B_s3 Steroid hormone Target cell Nucleus 1 Interstitial fluid 2 Receptor protein 3 Hormone- receptor complex DNA
- 22. Figure 26.2B_s4 Steroid hormone Target cell Nucleus 1 Interstitial fluid 2 Receptor protein 3 Hormone- receptor complex DNA 4 Transcription mRNA New protein Cellular response: activation of a gene and synthesis of new protein
- 23. THE VERTEBRATE ENDOCRINE SYSTEM © 2012 Pearson Education, Inc.
- 24. 26.3 Overview: The vertebrate endocrine system consists of more than a dozen major glands Some endocrine glands (such as the thyroid) primarily secrete hormones into the blood. Other glands (such as the pancreas) have – endocrine and – nonendocrine functions. Other organs (such as the stomach) are primarily nonendocrine but have some cells that secrete hormones. © 2012 Pearson Education, Inc.
- 25. The following figure shows the locations of the major endocrine glands. 26.3 Overview: The vertebrate endocrine system consists of more than a dozen major glands © 2012 Pearson Education, Inc.
- 26. Figure 26.3 Thyroid gland Parathyroid glands (embedded within thyroid) Thymus Adrenal glands (atop kidneys) Pancreas Testes (male) Ovaries (female) Hypothalamus Pituitary gland
- 27. The following table summarizes the main hormones produced by the major endocrine glands and indicates how they – function and – are controlled. 26.3 Overview: The vertebrate endocrine system consists of more than a dozen major glands © 2012 Pearson Education, Inc.
- 28. Table 26.3
- 29. Table 26.3_1
- 30. Table 26.3_2
- 31. Two endocrine glands are not discussed further. – The pineal gland – is pea-sized, located near the center of the brain, and – secretes melatonin, a hormone that links environmental light conditions with biological rhythms. – The thymus gland – lies above the heart, under the breastbone, and – secretes a peptide that stimulates the development of T-cells. 26.3 Overview: The vertebrate endocrine system consists of more than a dozen major glands © 2012 Pearson Education, Inc.
- 32. 26.4 The hypothalamus, which is closely tied to the pituitary, connects the nervous and endocrine systems The hypothalamus – blurs the distinction between endocrine and nervous systems, – receives input from nerves about the internal conditions of the body and the external environment, – responds by sending out appropriate nervous or endocrine signals, and – uses the pituitary gland to exert master control over the endocrine system. © 2012 Pearson Education, Inc.
- 33. Figure 26.4A Brain Hypothalamus Posterior pituitary Anterior pituitary Bone
- 34. 26.4 The hypothalamus, which is closely tied to the pituitary, connects the nervous and endocrine systems The pituitary gland consists of two parts. The posterior pituitary – is composed of nervous tissue, – is an extension of the hypothalamus, and – stores and secretes oxytocin and ADH, which are made in the hypothalamus. © 2012 Pearson Education, Inc.
- 35. Figure 26.4B Hypothalamus Neurosecretory cell Anterior pituitary Hormone Posterior pituitary Blood vessel Uterine muscles Mammary glands Kidney tubules ADHOxytocin
- 36. Figure 26.4C Neurosecretory cell of hypothalamus Endocrine cells of the anterior pituitary Pituitary hormones Blood vessel Releasing hormones from hypothalamus Thyroid TSH Prolactin (PRL) Adrenal cortex Testes or ovaries FSH and LH Mammary glands (in mammals) Growth hormone (GH) ACTH Entire body Endorphins Pain receptors in the brain
- 37. Figure 26.4D
- 39. 26.4 The hypothalamus, which is closely tied to the pituitary, connects the nervous and endocrine systems The anterior pituitary – synthesizes and secretes hormones that control the activity of other glands and – is controlled by two types of hormones released from the hypothalamus: – releasing hormones stimulate the anterior pituitary, and – inhibiting hormones inhibit the anterior pituitary. © 2012 Pearson Education, Inc.
- 40. 26.4 The hypothalamus, which is closely tied to the pituitary, connects the nervous and endocrine systems Pituitary secretions include – growth hormone (GH) that promotes protein synthesis and the use of body fat for energy metabolism, – endorphins that function as natural painkillers, and – TRH (TSH-releasing hormone) that stimulates the thyroid (another endocrine gland) to release thyroxine. © 2012 Pearson Education, Inc.
- 41. HORMONES AND HOMEOSTASIS © 2012 Pearson Education, Inc.
- 42. 26.5 The thyroid regulates development and metabolism The thyroid gland is located in the neck, just under the larynx (voice box). The thyroid gland produces two similar hormones, – thyroxine (T4) and – triiodothyronine (T3). These hormones regulate many aspects of – metabolism, – reproduction, and – development. © 2012 Pearson Education, Inc.
- 43. Figure 26.5A
- 44. Figure 26.5A_1
- 45. Figure 26.5A_2
- 46. 26.5 The thyroid regulates development and metabolism Thyroid imbalance can cause disease. – Hyperthyroidism – results from too much T4 and T3 in the blood, – leads to high blood pressure, loss of weight, overheating, and irritability, and – produces Graves’ disease. – Hypothyroidism – results from too little T4 and T3 in the blood and – leads to low blood pressure, being overweight, and often feeling cold and lethargic. © 2012 Pearson Education, Inc.
- 47. 26.5 The thyroid regulates development and metabolism Iodine deficiency can produce a goiter, an enlargement of the thyroid. In this condition, – the thyroid gland cannot synthesize adequate amounts of T4 and T3, and – the thyroid gland enlarges. © 2012 Pearson Education, Inc.
- 48. Figure 2.2A
- 49. Figure 26.5B Hypothalamus No inhibition No inhibition No iodine Insufficient T4 and T3 produced Thyroid grows to form goiter TSH Anterior pituitary TRH Thyroid
- 50. 26.6 Hormones from the thyroid and parathyroid glands maintain calcium homeostasis Blood calcium level is regulated by antagonistic hormones each working to oppose the actions of the other hormone: – calcitonin, from the thyroid, lowers the calcium level in the blood, and – parathyroid hormone (PTH), from the parathyroid glands, raises the calcium level in the blood. © 2012 Pearson Education, Inc.
- 51. Figure 26.6 Thyroid gland releases calcitonin Stimulus: Rising blood Ca2+ level (imbalance) Ca2+ level Calcitonin Homeostasis: Normal blood calcium level (about 10 mg/100 mL) Ca2+ level Stimulates Ca2+ deposition in bones Reduces Ca2+ reabsorption in kidneys Blood Ca2+ falls Stimulus: Falling blood Ca2+ level (imbalance) Parathyroid glands release parathyroid hormone (PTH) PTH Parathyroid gland Stimulates Ca2+ release from bones Increases Ca2+ reabsorption in kidneys Blood Ca2+ rises Increases Ca2+ uptake in intestines 5 Active vitamin D 4 3 2 1 9 8 7 6
- 52. Figure 26.6_1 Ca2+ level Homeostasis Ca2+ level Ca2+ release Ca2+ reabsorp- tion Ca2+ uptake Blood Ca2+ rises Stimulus: Falling blood Ca2+ level Release of parathyroid hormone PTHActive vita- min D 5 4 3 1 2
- 53. Figure 26.6_2 Thyroid gland releases calcitonin Stimulus: Rising blood Ca2+ level Calcitonin Stimulates Ca2+ deposition Reduces Ca2+ reabsorption Blood Ca2+ fallsCa2+ level Ca2+ level Homeostasis 6 7 8 9
- 54. 26.7 Pancreatic hormones regulate blood glucose levels The pancreas secretes two hormones that control blood glucose: – insulin signals cells to use and store glucose, and – glucagon causes cells to release stored glucose into the blood. © 2012 Pearson Education, Inc.
- 55. Figure 26.7 Beta cells of pancreas stimulated to release insulin into the blood 5 6 5 7 8 1 2 3 4 High blood glucose level Glucose level Insulin Body cells take up more glucose Liver takes up glucose and stores it as glycogen Stimulus: Rising blood glucose level (e.g., after eating a carbohydrate-rich meal) Blood glucose level rises to set point; stimulus for glucagon release diminishes Glucagon Liver breaks down glycogen and releases glucose to the blood Alpha cells of pancreas stimulated to release glucagon into the blood Glucose level Homeostasis: Normal blood glucose level (about 90 mg/100 mL) Low blood glucose level Stimulus: Declining blood glucose level (e.g., after skipping a meal) Blood glucose level declines to a set point; stimulus for insulin release diminishes
- 56. Figure 26.7_1 Beta cells of pancreas stimulated 2 Glucose level Insulin Body cells take up glucose Liver takes up glucose; stores as glycogen Stimulus: Rising blood glucose level Glucose level Homeostasis Blood glucose declines; insulin release stimulus diminishes 3 1 4
- 57. Figure 26.7_2 Glucose level Glucose level Homeostasis Blood glucose rises; glucagon release stimulus decreases Glucagon Liver breaks down glycogen; glucose is released Alpha cells of pancreas stimulated Stimulus: Declining blood glucose level 5 6 7 8
- 58. 26.8 CONNECTION: Diabetes is a common endocrine disorder Diabetes mellitus – affects about 8% of the U.S. population and – results from a – lack of insulin or – failure of cells to respond to insulin. © 2012 Pearson Education, Inc.
- 59. 26.8 CONNECTION: Diabetes is a common endocrine disorder There are three types of diabetes mellitus. 1. Type 1 (insulin-dependent) is – an autoimmune disease – caused by the destruction of insulin-producing cells. © 2012 Pearson Education, Inc.
- 60. 26.8 CONNECTION: Diabetes is a common endocrine disorder 2. Type 2 (non-insulin-dependent) is – caused by a reduced response to insulin, – associated with being overweight and underactive, and – the cause of more than 90% of diabetes. © 2012 Pearson Education, Inc.
- 61. 26.8 CONNECTION: Diabetes is a common endocrine disorder 3. Gestational diabetes – can affect any pregnant woman and – lead to dangerously large babies, which can complicate delivery. © 2012 Pearson Education, Inc.
- 62. Figure 26.8A
- 63. Figure 26.8A_1
- 64. Figure 26.8A_2
- 65. Figure 26.8B Diabetic Healthy Hours after glucose ingestion Bloodglucose(mg/100mL) 400 350 300 250 200 150 100 50 0 0 1 2 3 4 5 1 2
- 66. 26.9 The adrenal glands mobilize responses to stress The endocrine system includes two adrenal glands, sitting on top of each kidney. Each adrenal gland is made of two glands fused together, the – adrenal medulla and – adrenal cortex. Both glands secrete hormones that enable the body to respond to stress. © 2012 Pearson Education, Inc.
- 68. 26.9 The adrenal glands mobilize responses to stress Nerve signals from the hypothalamus stimulate the adrenal medulla to secrete – epinephrine (adrenaline) and – norepinephrine (noradrenaline). These hormones quickly trigger the “fight-or-flight” responses, which are short-term responses to stress. © 2012 Pearson Education, Inc.
- 69. Figure 26.9 Adrenal gland Adrenal medulla Adrenal cortex Nerve signals Kidney Cross section of spinal cord Nerve cell Nerve cell Adrenal medulla ACTH ACTH Adrenal cortex Stress Hypothalamus Releasing hormone Anterior pituitary Blood vessel 5 4 3 1 2 GlucocorticoidsMineralocorticoids Long-term stress responseShort-term stress response Epinephrine and norepinephrine Mineralocorticoids Glucocorticoids Retention of sodium ions and water by kidneys 1. 2. 1. 2. Increased blood volume and blood pressure Proteins and fats broken down and converted to glucose, leading to increased blood glucose Immune system may be suppressed Glycogen broken down to glucose; increased blood glucose 1. 2. 3. 4. 5. Increased blood pressure Increased breathing rate Increased metabolic rate Change in blood flow patterns, leading to increased alertness and decreased digestive and kidney activity
- 70. Figure 26.9_2 Nerve signals Cross section of spinal cord Nerve cell Nerve cell Adrenal medulla ACTH Adrenal cortex Stress Hypothalamus Releasing hormone Anterior pituitary Blood vessel GlucocorticoidsMineralocorticoids Epinephrine and norepinephrine Long-term stress responseShort-term stress response 1 3 5 4 2 ACTH
- 71. Figure 26.9_3 Glycogen broken down to glucose; increased blood glucose 1. 2. 4. 5. Increased blood pressure Increased breathing rate Increased metabolic rate Change in blood flow patterns, leading to increased alertness and decreased digestive and kidney activity 3. Short-term stress response
- 72. 26.9 The adrenal glands mobilize responses to stress Adrenocorticotropic hormone (ACTH) from the pituitary causes the adrenal cortex to secrete – glucocorticoids and – mineralocorticoids. The effects of these hormones cause long-term responses to stress. © 2012 Pearson Education, Inc.
- 73. Figure 26.9_4 Long-term stress response Glucocorticoids Retention of sodium ions and water by kidneys 1. 2. 1. 2. Increased blood volume and blood pressure Proteins and fats broken down and converted to glucose, leading to increased blood glucose Immune system may be suppressed Mineralocorticoids
- 74. 26.10 The gonads secrete sex hormones Steroid sex hormones – affect growth, – affect development, and – regulate reproductive cycles and sexual behavior. © 2012 Pearson Education, Inc.
- 75. 26.10 The gonads secrete sex hormones Sex hormones include – estrogens, which maintain the female reproductive system and promote the development of female characteristics, – progestins, such as progesterone, which prepare and maintain the uterus to support a developing embryo, and – androgens, such as testosterone, which stimulate the development and maintenance of the male reproductive system. © 2012 Pearson Education, Inc.
- 76. Figure 26.10
- 77. 26.10 The gonads secrete sex hormones The synthesis of sex hormones by the gonads is regulated by the – hypothalamus and – pituitary. © 2012 Pearson Education, Inc.
- 78. 26.11 EVOLUTION CONNECTION: A single hormone can perform a variety of functions in different animals The peptide hormone prolactin (PRL) in humans stimulates mammary glands to grow and produce milk during late pregnancy. Suckling by a newborn stimulates further release of PRL. High PRL during nursing inhibits ovulation. © 2012 Pearson Education, Inc.
- 79. Figure 26.11
- 80. PRL has many roles unrelated to childbirth, suggesting that PRL is an ancient hormone diversified through evolution. – In some nonhuman mammals, PRL stimulates nest building. – In birds, PRL regulates fat metabolism and reproduction. – In amphibians, PRL stimulates movement to water. – In fish that migrate between salt and fresh water, PRL helps regulate salt and water balance. 26.11 EVOLUTION CONNECTION: A single hormone can perform a variety of functions in different animals © 2012 Pearson Education, Inc.
- 81. You should now be able to 1. Explain how testosterone affects lions. 2. Compare the mechanisms and functions of the endocrine and nervous systems. 3. Distinguish between the two major classes of vertebrate hormones. 4. Describe the different types and functions of vertebrate endocrine organs. © 2012 Pearson Education, Inc.
- 82. You should now be able to 5. Describe the interrelationships between the hypothalamus and pituitary glands. 6. Describe the functions of the thyroid and parathyroid glands. 7. Explain how insulin and glucagon manage blood glucose levels. 8. Describe the causes and symptoms of type 1 and type 2 diabetes and gestational diabetes. © 2012 Pearson Education, Inc.
- 83. You should now be able to 9. Compare the functions of the adrenal gland hormones. 10. Describe the three major types of sex hormones and their functions. 11. Describe the diverse functions of prolactin in vertebrate groups and its evolutionary significance. © 2012 Pearson Education, Inc.
- 84. Figure 26.UN01 Water- soluble hormone Lipid- soluble hormone Receptor protein in cytoplasm Receptor protein in plasma membrane Hormone receptor protein Gene regulationGene regulation Cytoplasmic response or Signal transduction pathway
- 85. Figure 26.UN02 Brain Hypothalamus: • Master control center of the endocrine system Anterior pituitary: • Composed of endocrine tissue • Controlled by hypothalamus • Produces and secretes its own hormones Posterior pituitary: • Composed of nervous tissue • Stores and secretes hormones made by hypothalamus
- 86. Figure 26.UN03 Pancreas Glucagon Insulin Causes Causes Glucose in blood Glucose in blood Releases Releases
- 87. Figure 26.UN04 Testes Adrenal medulla Pancreas Thyroid gland Pineal gland Parathyroid gland Hypothalamus Anterior pituitary 1. thyroxine 2. epinephrine 3. androgens 4. insulin 5. melatonin 6. FSH 7. PTH 8. ADH a. lowers blood glucose b. stimulates ovaries f. influences sleep/wake rhythms d. promotes male characteristics e. regulates metabolism g. raises blood calcium level h. boosts water retention c. triggers fight-or-flight
Editor's Notes
- Figure 26.0_1 Chapter 26: Big Ideas
- Figure 26.0_2 Phenotypic difference between the sexes (Panthera leo)
- Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies upon a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been taught recently in your course, consider giving students a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways in which coordination and communication are achieved between the body’s cells. Endocrine signals generally work like a radio transmitter, sending signals outward. Only target cells, like people with radios tuned to a particular frequency, will receive the signal. In contrast, the nervous system provides a direct, two-way connection between the sender and receiver, much more like a land-based telephone call. Teaching Tips The nervous and endocrine systems coordinate and regulate most other systems of the body. You might consider comparing the speed and duration of each system’s response. The nervous system generally responds faster but for a shorter duration than the endocrine system. This helps to explain why it takes many minutes for a person to calm down after a very upsetting event. The hormones do not clear quickly from the systems.
- Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies upon a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been taught recently in your course, consider giving students a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways in which coordination and communication are achieved between the body’s cells. Endocrine signals generally work like a radio transmitter, sending signals outward. Only target cells, like people with radios tuned to a particular frequency, will receive the signal. In contrast, the nervous system provides a direct, two-way connection between the sender and receiver, much more like a land-based telephone call. Teaching Tips The nervous and endocrine systems coordinate and regulate most other systems of the body. You might consider comparing the speed and duration of each system’s response. The nervous system generally responds faster but for a shorter duration than the endocrine system. This helps to explain why it takes many minutes for a person to calm down after a very upsetting event. The hormones do not clear quickly from the systems.
- Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies upon a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been taught recently in your course, consider giving students a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways in which coordination and communication are achieved between the body’s cells. Endocrine signals generally work like a radio transmitter, sending signals outward. Only target cells, like people with radios tuned to a particular frequency, will receive the signal. In contrast, the nervous system provides a direct, two-way connection between the sender and receiver, much more like a land-based telephone call. Teaching Tips The nervous and endocrine systems coordinate and regulate most other systems of the body. You might consider comparing the speed and duration of each system’s response. The nervous system generally responds faster but for a shorter duration than the endocrine system. This helps to explain why it takes many minutes for a person to calm down after a very upsetting event. The hormones do not clear quickly from the systems.
- Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies upon a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been taught recently in your course, consider giving students a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways in which coordination and communication are achieved between the body’s cells. Endocrine signals generally work like a radio transmitter, sending signals outward. Only target cells, like people with radios tuned to a particular frequency, will receive the signal. In contrast, the nervous system provides a direct, two-way connection between the sender and receiver, much more like a land-based telephone call. Teaching Tips The nervous and endocrine systems coordinate and regulate most other systems of the body. You might consider comparing the speed and duration of each system’s response. The nervous system generally responds faster but for a shorter duration than the endocrine system. This helps to explain why it takes many minutes for a person to calm down after a very upsetting event. The hormones do not clear quickly from the systems.
- Figure 26.1A Hormone from an endocrine cell
- Figure 26.1B Neurotransmitter from a nerve cell
- Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies upon a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been taught recently in your course, consider giving students a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways in which coordination and communication are achieved between the body’s cells. Endocrine signals generally work like a radio transmitter, sending signals outward. Only target cells, like people with radios tuned to a particular frequency, will receive the signal. In contrast, the nervous system provides a direct, two-way connection between the sender and receiver, much more like a land-based telephone call. Teaching Tips The two mechanisms by which hormones trigger changes in target cells can be compared using this analogy. If a house is like a cell, ringing the doorbell and having someone answer it is like using a signal-transduction pathway. Pushing the doorbell, like a hormone binding to plasma-membrane receptors, causes an internal change. Using steroid hormones, on the other hand, is like walking up to the house, opening the door, and walking inside to deliver a message. Here the signal passes through the surface and into the interior of the home/cell to directly communicate the message.
- Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies upon a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been taught recently in your course, consider giving students a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways in which coordination and communication are achieved between the body’s cells. Endocrine signals generally work like a radio transmitter, sending signals outward. Only target cells, like people with radios tuned to a particular frequency, will receive the signal. In contrast, the nervous system provides a direct, two-way connection between the sender and receiver, much more like a land-based telephone call. Teaching Tips The two mechanisms by which hormones trigger changes in target cells can be compared using this analogy. If a house is like a cell, ringing the doorbell and having someone answer it is like using a signal-transduction pathway. Pushing the doorbell, like a hormone binding to plasma-membrane receptors, causes an internal change. Using steroid hormones, on the other hand, is like walking up to the house, opening the door, and walking inside to deliver a message. Here the signal passes through the surface and into the interior of the home/cell to directly communicate the message.
- Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies upon a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been taught recently in your course, consider giving students a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways in which coordination and communication are achieved between the body’s cells. Endocrine signals generally work like a radio transmitter, sending signals outward. Only target cells, like people with radios tuned to a particular frequency, will receive the signal. In contrast, the nervous system provides a direct, two-way connection between the sender and receiver, much more like a land-based telephone call. Teaching Tips The two mechanisms by which hormones trigger changes in target cells can be compared using this analogy. If a house is like a cell, ringing the doorbell and having someone answer it is like using a signal-transduction pathway. Pushing the doorbell, like a hormone binding to plasma-membrane receptors, causes an internal change. Using steroid hormones, on the other hand, is like walking up to the house, opening the door, and walking inside to deliver a message. Here the signal passes through the surface and into the interior of the home/cell to directly communicate the message.
- Figure 26.2A_s1 A hormone that binds a plasma membrane receptor (step 1)
- Figure 26.2A_s2 A hormone that binds a plasma membrane receptor (step 2)
- Figure 26.2A_s3 A hormone that binds a plasma membrane receptor (step 3)
- Student Misconceptions and Concerns 1. Student comprehension of the two mechanisms by which hormones trigger changes in target cells relies upon a good understanding of cell membranes and basic cellular chemistry. If these subjects have not been taught recently in your course, consider giving students a brief refresher before distinguishing between these mechanisms. 2. Students might not appreciate the diverse ways in which coordination and communication are achieved between the body’s cells. Endocrine signals generally work like a radio transmitter, sending signals outward. Only target cells, like people with radios tuned to a particular frequency, will receive the signal. In contrast, the nervous system provides a direct, two-way connection between the sender and receiver, much more like a land-based telephone call. Teaching Tips The two mechanisms by which hormones trigger changes in target cells can be compared using this analogy. If a house is like a cell, ringing the doorbell and having someone answer it is like using a signal-transduction pathway. Pushing the doorbell, like a hormone binding to plasma-membrane receptors, causes an internal change. Using steroid hormones, on the other hand, is like walking up to the house, opening the door, and walking inside to deliver a message. Here the signal passes through the surface and into the interior of the home/cell to directly communicate the message.
- Figure 26.2B_s1 A hormone that binds an intracellular receptor (step 1)
- Figure 26.2B_s2 A hormone that binds an intracellular receptor (step 2)
- Figure 26.2B_s3 A hormone that binds an intracellular receptor (step 3)
- Figure 26.2B_s4 A hormone that binds an intracellular receptor (step 4)
- Student Misconceptions and Concerns Appreciating the precise actions of hormones requires a thorough understanding of the specificity of target cells. The fact that only certain target cells will respond to a given hormone signal allows hormones to be “broadcast” generally throughout the circulatory system without affecting every single cell. Teaching Tips Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the potential benefits and risks of human growth hormone injections in the elderly.
- Student Misconceptions and Concerns Appreciating the precise actions of hormones requires a thorough understanding of the specificity of target cells. The fact that only certain target cells will respond to a given hormone signal allows hormones to be “broadcast” generally throughout the circulatory system without affecting every single cell. Teaching Tips Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the potential benefits and risks of human growth hormone injections in the elderly.
- Figure 26.3 The major endocrine glands in humans
- Student Misconceptions and Concerns Appreciating the precise actions of hormones requires a thorough understanding of the specificity of target cells. The fact that only certain target cells will respond to a given hormone signal allows hormones to be “broadcast” generally throughout the circulatory system without affecting every single cell. Teaching Tips Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the potential benefits and risks of human growth hormone injections in the elderly.
- Table 26.3 Major Human Endocrine Glands and Some of Their Hormones
- Table 26.3_1 Major Human Endocrine Glands and Some of their Hormones (Part 1)
- Table 26.3_2 Major Human Endocrine Glands and Some of their Hormones (Part 2)
- Student Misconceptions and Concerns Appreciating the precise actions of hormones requires a thorough understanding of the specificity of target cells. The fact that only certain target cells will respond to a given hormone signal allows hormones to be “broadcast” generally throughout the circulatory system without affecting every single cell. Teaching Tips Growth hormone levels typically decline as we age. Recent studies suggest that injections of engineered human growth hormone may promote muscle growth and decrease body fat. However, additional research is necessary to fully appreciate the potential benefits and risks of human growth hormone injections in the elderly.
- Student Misconceptions and Concerns The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. Although this is mentioned briefly in the text, consider emphasizing further the potential negative consequences of the abuse of these powerful hormones. The National Institute of Health provides additional details on its website at www.drugabuse.gov/ResearchReports/Steroids/AnabolicSteroids.html. Teaching Tips 1. Morphine and other opiates bind to the same cell receptors that naturally bind endorphins, producing powerful pain-killing effects. 2. Students may not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. The authors note the risks of stopping pain in an injured part of the body. Based on this, challenge students to propose explanations as to why endorphins nonetheless evolved.
- Figure 26.4A Location of the hypothalamus and pituitary
- Student Misconceptions and Concerns The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. Although this is mentioned briefly in the text, consider emphasizing further the potential negative consequences of the abuse of these powerful hormones. The National Institute of Health provides additional details on its website at www.drugabuse.gov/ResearchReports/Steroids/AnabolicSteroids.html. Teaching Tips 1. Morphine and other opiates bind to the same cell receptors that naturally bind endorphins, producing powerful pain-killing effects. 2. Students may not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. The authors note the risks of stopping pain in an injured part of the body. Based on this, challenge students to propose explanations as to why endorphins nonetheless evolved.
- Figure 26.4B Hormones of the posterior pituitary
- Figure 26.4C Hormones of the anterior pituitary
- Figure 26.4D Gigantism, caused by an excess of growth hormone during childhood
- Figure 26.4E Control of thyroxine secretion
- Student Misconceptions and Concerns The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. Although this is mentioned briefly in the text, consider emphasizing further the potential negative consequences of the abuse of these powerful hormones. The National Institute of Health provides additional details on its website at www.drugabuse.gov/ResearchReports/Steroids/AnabolicSteroids.html. Teaching Tips 1. Morphine and other opiates bind to the same cell receptors that naturally bind endorphins, producing powerful pain-killing effects. 2. Students may not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. The authors note the risks of stopping pain in an injured part of the body. Based on this, challenge students to propose explanations as to why endorphins nonetheless evolved.
- Student Misconceptions and Concerns The abuse of growth hormones and steroids is of great concern in the world of professional and amateur sports. Although this is mentioned briefly in the text, consider emphasizing further the potential negative consequences of the abuse of these powerful hormones. The National Institute of Health provides additional details on its website at www.drugabuse.gov/ResearchReports/Steroids/AnabolicSteroids.html. Teaching Tips 1. Morphine and other opiates bind to the same cell receptors that naturally bind endorphins, producing powerful pain-killing effects. 2. Students may not have carefully considered the benefits of pain. Consider emphasizing the adaptive nature of pain to your class. The authors note the risks of stopping pain in an injured part of the body. Based on this, challenge students to propose explanations as to why endorphins nonetheless evolved.
- Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. 2. As the section title indicates, a central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. Teaching Tips Hypothyroidism produces symptoms that are like turning down a furnace during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence.
- Figure 26.5A The maturation of a tadpole (below) into an adult frog (above), as regulated by thyroid hormones
- Figure 26.5A_1 The maturation of a tadpole into an adult frog, as regulated by thyroid hormones (part 1)
- Figure 26.5A_2 The maturation of a tadpole into an adult frog, as regulated by thyroid hormones (part 2)
- Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. 2. As the section title indicates, a central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. Teaching Tips Hypothyroidism produces symptoms that are like turning down a furnace during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence.
- Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. 2. As the section title indicates, a central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. Teaching Tips Hypothyroidism produces symptoms that are like turning down a furnace during a cold winter. When thyroid levels are low, cells produce ATP and heat at a slower rate, and the person feels colder and is more lethargic than others in the same room. This reminds students that aerobic respiration produces heat and ATP. Hyperthyroidism is just the opposite, with an overproduction of heat as the consequence.
- Figure 2.2A Goiter, a symptom of iodine deficiency, in a Burmese woman
- Figure 26.5B How iodine deficiency causes goiter
- Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. 2. As the section title indicates, a central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. Teaching Tips The use of calcitonin and parathyroid hormone to hold blood calcium levels steady is similar to the use of a heater and chiller on a fish tank or a furnace and air conditioner in a home to keep temperatures steady. The same analogy can be applied to the contrasting functions of insulin and glucagon.
- Figure 26.6 Calcium homeostasis
- Figure 26.6_1 Calcium homeostasis (part 1)
- Figure 26.6_2 Calcium homeostasis (part 2)
- Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. 2. As the section title indicates, a central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. Teaching Tips 1. The use of calcitonin and parathyroid hormone to hold blood calcium levels steady is similar to the use of a heater and chiller on a fish tank or a furnace and air conditioner in a home to keep temperatures steady. The same analogy can be applied to the contrasting functions of insulin and glucagon. 2. Scientists are exploring the use of pancreatic cell transplants as a new source of insulin for patients with type 1 diabetes. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is http://diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/.
- Figure 26.7 Glucose homeostasis
- Figure 26.7_1 Glucose homeostasis (part 1)
- Figure 26.7_2 Glucose homeostasis (part 2)
- Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. 2. As the section title indicates, a central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. Teaching Tips Scientists are exploring the use of pancreatic cell transplants as a new source of insulin for patients with type 1 diabetes. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is http://diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/.
- Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. 2. As the section title indicates, a central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. Teaching Tips Scientists are exploring the use of pancreatic cell transplants as a new source of insulin for patients with type 1 diabetes. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is http://diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/.
- Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. 2. As the section title indicates, a central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. Teaching Tips Scientists are exploring the use of pancreatic cell transplants as a new source of insulin for patients with type 1 diabetes. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is http://diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/.
- Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. 2. As the section title indicates, a central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. Teaching Tips Scientists are exploring the use of pancreatic cell transplants as a new source of insulin for patients with type 1 diabetes. Pancreatic cells may be derived from donors and/or modified from other cells using stem cell technology. One website devoted to this subject is http://diabetes.niddk.nih.gov/dm/pubs/pancreaticislet/.
- Figure 26.8A Testing glucose levels (above) and injecting human insulin (left)
- Figure 26.8A_1 Testing glucose levels and injecting human insulin (part 1)
- Figure 26.8A_2 Testing glucose levels and injecting human insulin (part 2)
- Figure 26.8B Results of glucose tolerance tests
- Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. 2. As the section title indicates, a central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. Teaching Tips The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling such a person to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will most likely reverse the condition.
- Figure 26.9_1 How the adrenal glands control our responses to stress (part 1)
- Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. 2. As the section title indicates, a central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. Teaching Tips The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling such a person to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will most likely reverse the condition.
- Figure 26.9 How the adrenal glands control our responses to stress
- Figure 26.9_2 How the adrenal glands control our responses to stress (part 2)
- Figure 26.9_3 How the adrenal glands control our responses to stress (part 3)
- Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. 2. As the section title indicates, a central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. Teaching Tips The effects of the “fight-or-flight” response will likely last many minutes after the initial events that triggered the response. Telling such a person to calm down is unlikely to help. Instead, removing the person from the stimulus (if possible), engaging in mild exercise such as walking, and allowing many minutes of time will most likely reverse the condition.
- Figure 26.9_4 How the adrenal glands control our responses to stress (part 4)
- Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. 2. As the section title indicates, a central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. Teaching Tips In humans, differences in the concentrations of sex hormones decrease between the sexes throughout adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic.
- Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. 2. As the section title indicates, a central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. Teaching Tips In humans, differences in the concentrations of sex hormones decrease between the sexes throughout adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic.
- Figure 26.10 Male elephant seals in combat
- Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. 2. As the section title indicates, a central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. Teaching Tips In humans, differences in the concentrations of sex hormones decrease between the sexes throughout adulthood. Differences in secondary sexual characteristics such as muscle tone and hair growth may diminish as a natural part of aging. Students with interests in geriatrics may enjoy assignments or extra credit to investigate this topic.
- Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. 2. As the section title indicates, a central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. Teaching Tips The shifting functions of prolactin reflect the kind of “remodeling” frequently found in evolution. Typically, new structures and functions result from modifications of ancestral structures and functions. In this case, as reproductive strategies evolved, the functional significance of prolactin was remodeled.
- Figure 26.11 Suckling promotes prolactin production
- Student Misconceptions and Concerns 1. Many students struggle to remember the basic structures, functions, and locations of the major vertebrate organs. Understanding and remembering the specific control mechanisms are typically beyond their background knowledge entering a general biology college course. Students will appreciate any reminders or reference materials that help them to organize this information. 2. As the section title indicates, a central theme of endocrine function is the maintenance of homeostasis. Repeatedly framing the details of hormonal and glandular function in the context of homeostasis can increase levels of student comprehension. Teaching Tips The shifting functions of prolactin reflect the kind of “remodeling” frequently found in evolution. Typically, new structures and functions result from modifications of ancestral structures and functions. In this case, as reproductive strategies evolved, the functional significance of prolactin was remodeled.
- Figure 26.UN01 Reviewing the Concepts, 26.2
- Figure 26.UN02 Reviewing the Concepts, 26.4
- Figure 26.UN03 Reviewing the Concepts, 26.7
- Figure 26.UN04 Connecting the Concepts, questions 1–8