Chapter 34: The Endocrine System
LEARNING OUTCOMES
After completing Chapter 34, students should be able to:
34.1 Describe the general functions of hormones and the endocrine system.
34.2 Identify the hormones released by the pituitary gland, thyroid gland, parathyroid glands, adrenal glands, pancreas, and other hormone-producing organs, and give the functions of each.
34.3 Explain the effect of stressors on the body.
34.4 Describe the causes, signs and symptoms, and treatments of various endocrine disorders.
Lecture Outline
Learning Outcome 34.1: Describe the general functions of hormones and the endocrine system.
• Lecture Topics
• Teach your students that the endocrine system includes the organs of the body that secrete hormones directly into body fluids such as blood. Review the organs of the endocrine and their primary functions (Refer to Figure 34-1.)
• Introduce the function of the endocrine system by explaining that the purpose of hormones is to regulate cell and body functions. Point out that while the functions of the nervous system are quick or immediate, the functions of the endocrine system are slower and more long lasting. (Refer to PowerPoint Slides 4 – 5.)
• Compare and contrast steroidal and nonsteroidal hormones. (Refer to PowerPoint Slides 6 – 8.)
• Discussion Points
• Begin by telling the class that when they think of hormones, they are to think of the word endocrine. Ask the students the following question: What specialist treats hormone disorders? (Endocrinologist). Emphasize the word parts as a hint to the students (endo meaning within and crine meaning to secrete) that endocrine glands secrete their hormones directly to the tissues affected (prostaglandins) or directly into the bloodstream without the aid of ducts. (Refer to Table 34-1: Endocrine Glands: Their Hormones and Actions.)
• Explain to the class that hormones are chemicals that affect the functioning of other cells. Discuss the three types of hormones:
• Steroid hormones attach to the nucleus of a cell, turning a gene on or off (estrogen, progesterone, testosterone, cortisol.)
• Nonsteroidal hormones, which are made up of amino acids or proteins bind to the surface of a cell, activating a G-protein and causing an enzyme inside the cell to be turned on.
• Prostaglandins, which are local (tissue) hormones that do not travel to their targets, because their targets are close by. Ask students to name some organs that produce prostaglandins. (Kidneys, stomach, uterus, heart, brain.)
• Ask a volunteer to define the word feedback (a response). Explain that hormone levels are controlled by two bodily responses, negative and positive feedback. Using Figure 34-2, discuss the fact that a negative feedback loop occurs when the end product of a pathway turns off or slows down the pathway, whereas a positive feedback loop is involved when the end product of a pathway stimulates further pathway activity. (Refer to PowerPoint Slides 9 – 10.)
• Learning Activities
• Divide the class into two groups. Place the names of the endocrine glands on index cards (hypothalamus, anterior pituitary, posterior pituitary, pineal body, thyroid, parathyroid, thymus, adrenal cortex, adrenal medulla, pancreas, gonads). Give half the cards to one group and the other half to the second group. Ask one group to write the hormones produced by the glands on the back of the cards and the second group to write the functions of the hormones on the back of the cards. Collect the cards and redistribute them to both groups until all the cards have a hormone and function listed. Use the cards as flash cards to quiz the students during a class discussion. (Refer to Table 34-1: Endocrine Glands: Their Hormones and Actions.)
Learning Outcome 34.2: Identify the hormones released by the pituitary gland, thyroid gland,
parathyroid glands, adrenal glands, pancreas, and other hormone-producing organs, and give the
functions of each.
• Lecture Topics
• Teach your students that the hypothalamus is located in the diencephalon of the brain and produces the hormones oxytocin and antidiuretic hormone (ADH). (Refer to PowerPoint Slide 12.)
• Explain to the class that the clinical name for the pituitary gland is the hypophysis, and that it is often referred to as the master gland because it controls so many other glands. Point out that the pituitary gland consists of two lobes, anterior (adenohypophysis), and posterior (neurohypophysis). Beginning with the anterior lobe of the pituitary gland, ask students to name the hormones that it secretes and their functions. (Refer to Figures 34-1 and 34-3 and PowerPoint Slides 13 – 16.)
• Describe the location of the thyroid and parathyroid glands in the neck. Explain that the thyroid gland, like the pituitary gland, is divided into anterior and posterior lobes. The thyroid gland produces two types of hormones: thyroid hormones (triiodothyronine, or T3, and thyroxine, or T4) and calcitonin. Ask students the functions of these hormones. (T3 and T4 stimulate protein synthesis for the repair of damaged tissues; calcitonin increases bone calcium, decreasing the amount of calcium in the bloodstream. (Refer to PowerPoint Slides 17 – 18.)
• Review the location of the parathyroid glands, which are on the posterior surface of the thyroid gland. Explain that the parathyroid glands produce a hormone called parathyroid hormone, or PTH. Ask students to explain the actions of PTH (This hormone is the agonist [opposite] of calcitonin, so it decreases bone calcium and increases the amount of calcium in the blood.)
• Discussion Points
• Review the location of the adrenal glands, which are situated on top of each kidney. Explain that there are two layers of the adrenal glands, each with distinct functions. Ask students to name these two layers (adrenal medulla and adrenal cortex). Explain that the adrenal medulla is the inner layer, and that it secretes the hormones epinephrine and norepinephrine, which work with the sympathetic nervous system in the body's fight-or-flight response, increasing blood pressure, pulse rate, and respiratory rate in times of stress or danger. Note that the adrenal cortex is the outer layer. Ask students to name the two primary hormones produced by this layer and explain the actions of these hormones (aldosterone stimulates sodium, which retains water in the body in order to maintain blood pressure; cortisol helps to reduce inflammation). (Refer to PowerPoint Slides 19 – 20.)
• Review the location of the pancreas using Figure 34-1. Explain that the pancreas has both a digestive and an endocrine function. Ask students to name the digestive function (produces digestive enzymes). Explain that the islets of Langerhans, which are cells within the pancreas, facilitate its endocrine function through the production of two hormones. Ask your students: What are the names of these two hormones and what are their functions? (Glucagon, which is produced by the alpha cells of the islets, raises the body's blood sugar level by allowing slow protein synthesis, and insulin, which is produced by the beta cells, decreases this level by promoting glucose intake by cells.) Explain to students that these hormones work together to regulate the body's blood glucose level. See if they can tell you the type of feedback incorporated in this control (negative feedback loop). (Refer to PowerPoint Slides 21 – 22.)
• Pointing out the location of the pineal body (or gland) within the brain, explain that this gland secretes melatonin. Ask students to name the function of melatonin (the regulation of the body's biological clock; it is also thought to regulate puberty, including menarche for females). Next review the location of the thymus (in the mediastinum between the lungs). Remind students that the thymus gland produces the hormone thymosin, which assists in producing T lymphocytes. (Refer to PowerPoint Slide 23.)
• Finally, review the location of the gonads and ask students to name the organs that these sex glands are more commonly called (in males, the testes; in females, the ovaries). Ask students to name the primary hormones produced by these organs (the testes produce testosterone, and the ovaries produce estrogen and progesterone). (Refer to PowerPoint Slides 23 – 25.)
• Learning Activities
• To assist students in learning the organs of the endocrine system, have students make posters depicting each organ and the hormones it produces. The students should illustrate how the organ functions and what might occur if the organ was not functioning properly. (Refer to Table 34-1: Endocrine Glands: Their Hormones and Actions.)
Learning Outcome 34.3: Explain the effect of stressors on the body.
• Lecture Topics
• Teach your students that any stimulus that produces stress is termed a stressor. State that stressors include physical factors such as extreme heat or cold, infections, injuries, heavy exercise, and loud sounds, as well as psychological factors such as personal loss, grief, anxiety, depression, and guilt. Note that even positive stimuli such as sexual arousal, joy, and happiness can be stressors. (Refer to PowerPoint Slides 28 – 29.)
• Discussion Points
• Ask students to name some stresses in their lives, and list those stressors on the board. Note that no matter whether the stress is positive or negative, it has the same overall effect on the body.
• Explain that the physiological response to stress (general stress syndrome) includes an increased pulse rate, respiratory rate, and blood pressure rate, as well as, weight loss due to increased blood glucose levels and fatty acids in the blood. When the body is subjected to prolonged stress, cortisol from the adrenal cortex is also released, which decreases the functioning of the immune system. Emphasize the fact that this decreased immune system functioning often leads to illness.
• Learning Activities
• Ask your students to think back to a time when they were under stress (e.g., during an illness, during exam time, during an interview.) Then have them write down what they experienced both physically and mentally during this time and whether it was a good experience or not. Ask them to reflect on how they might handle the same type of experience after this analysis.
Learning Outcome 34.4: Describe the causes, signs and symptoms, and treatments of various endocrine disorders.
• Lecture Topics
• Review each of the conditions listed in the pathophysiology section and discuss their causes, signs and symptoms, and treatments. Point out that the major endocrine diseases relate to either a hypersecretion or hyposecretion of the endocrine gland involved. (Refer to PowerPoint Slides 31 – 37.)
• Discussion Points
• Answer students' questions and provide clarification for common endocrine disorders as necessary. (Refer to Table 34-2: Endocrine System Diseases/Conditions: Quick Reference Guide, which summarizes many of these diseases and relates them to the hyper-or hyposecretion of the applicable hormone.)
• Learning Activities
• Invite a medical assistant or nurse employed in an endocrinology office to speak to the class regarding diseases seen in patients in the office. Ask the speaker to include interesting symptoms or cases seen, some of the treatments the patients must undergo, and the outcomes to various diseases. Have students prepare questions for the speaker to answer at the conclusion of the presentation.
Case Studies
• The following case studies can be presented to students so that you can assess their responses to situations they may encounter in the workplace setting.
• Mrs. Porter is a 66-year-old woman who comes to your office for the first time. Her PCP has diagnosed her as having Cushing's disease and has requested a consultation with Dr. Greene.
• What physical symptoms might you expect Mrs. Porter to exhibit? (Full face, buffalo hump, thin arms and legs.) What clinical signs will likely be present? (Excessive urination, excessive thirst, high blood pressure, elevated blood sugar.) What is Dr. Greene's specialty? (Endocrinology.)
• Richard Santini is a 52-year-old gentleman who is somewhat overweight. He comes to the office complaining of increased thirst and urination accompanied by an increased appetite; however, he notes having lost 10 pounds in the last couple of weeks. He says he is "exhausted" and has also noted some blurring of his vision, which he attributes to being tired.
• What organ is probably malfunctioning? (Pancreas.) What do you suspect this patient's diagnosis to be? (Type 2 diabetes mellitus.) How could this diagnosis be confirmed? (Blood sugar testing and glucose tolerance testing.) What can Richard do to help himself? (Change his diet to lose weight, increase his physical activity.) If these measures don't help him, what are his medication options? (Antidiabetic medication or insulin.)
• Alice George has the following complaints: weight gain with inability to lose weight, even by decreasing calorie count; sluggishness and excessive tiredness; although she states that she is getting adequate sleep, she also says that sleeping is all she feels like doing most days. Upon exam, Dr. Gomez notes that her skin is very dry, her pulse seems slow, and, on CBC, she appears to be anemic.
• Alice is likely suffering from what condition? (Hypothyroidism, possibly myxedema.) What treatment options are available? (Hormone replacement therapy with thyroid hormone.)
Assessment
• Encourage students to use the various features in the Student Workbook for self-assessment. These features include vocabulary and content reviews, applications, case studies, and competency checklists (to assess mastery of procedures introduced in the chapter). You can assess students' grasp of the materials through a chapter test, using the vocabulary and content reviews. You can also refer to the activities and exercises on the Online Learning Center (OLC) and within the medical assisting student CD packaged with the student textbook.
Medical Assisting Media
Found on Connect Plus™
• Electronic Health Records (E.H.R.) SpringCharts® Exercises
• LearnSmart™
• BodyAnimat3dAdministration and Clinical Administration Videos
• eBook (if you’ve adopted ConnectPlus)
• Online Learning Center™: www.mhhe.com/BoothMA5e
Resources
In addition to the publications listed on the OLC, you may find the following materials useful.
Books
Goodman, H. Maurice. 2008. Basic Medical Endocrinology. St. Louis, MO. Elsevier Science.
Kress, Diane. 2009. The Metabolism Miracle: 3 Easy Steps to Regain Control of Your Weight . . . Permanently. New York, NY. Da Capo Press.
McDermott, M.T. 2009. Endocrine Secrets. St. Louis, MO. Elsevier Science.
Marieb, Elaine N, Hoehn, Katja. Anatomy & Physiology with IP 10 CD-ROM. Lebannon, IN. Benjamin Cummings.
Rodgers, Jill, Walker, Rosemary. 2009. Diabetes A Practical Guide to Managing your Health. New York, NY. DK Publishing.
Articles
McNearney, T.A, Shepherd, A.A., Chhabra, A., and Goel, N. 2006. Primary care house staff attitudes toward osteoporo- sis management. Southern Medical Journal 99(5):461-66.
Newell-Price, J., et al. 2006. Cushing's syndrome. Lancet 367(9522):1605-17.
Rakel, R.E. 2006. The role of the family physician in the diagnosis and treatment of type 2 diabetes mellitus. Journal of Family Practice 55:5-9.
Taylor, J. 2006. How to deal with the worried well. General Practitioner:50.
Audiovisuals
History on Video. Lifestyle #9: Diabetes. CSDC LLC. 2006. DVD.
History on Video. Diabetes and Your Heart. 2004. DVD.
Computer Software
A&P Revealed CD#4: Digestive, Urinary, Reproductive and Endocrine Systems. 2007. McGraw-Hill.
Water, J.R. Virtual Anatomy Dissection Review. CD Version 2. Penn State University. McGraw-Hill.
Chapter 34 Textbook Answers
Case Study Critical Thinking