Lewis/Life - Teaching Techniques

Chapter 33 - Teaching Techniques

A. General Tips
** See the General Tips notes in Chapter 30 of this Instructor's Manual.
A chapter on endocrinology is often called "alphabet soup." Lewis does a good job of NOT overwhelming the reader with acronyms. Nevertheless, some students will be overwhelmed anyway. Be careful with your own use of terminology so as not to confuse those who have trouble keeping acronyms straight; something which only comes with practice. And some people are better at it than others.
If you have students who are really interested in hormones, you might suggest that they make a "Hormone Booklet." Such a booklet should include at least 35 hormones. For each hormone, the students should include the chemical nature of the hormone, where it is produced, what triggers its production, what its function is, what its target is, how it performs its function, how it interacts with other structures or substances, what happens when there is an excess or deficit of the hormone, etc.
You might wish to copy and distribute to your students the Overview of Chapter Objectives flowchart found at the beginning of this Instructor's Manual Chapter.
B. Possible Approaches to the Chapter
This chapter affords numerous opportunities for outside assignments. Be careful with these, however, because student misinformation about hormones is rampant.
If you are interested in giving your class a non-quiz, here are some possible true or false questions. 1) All hormones are steroids. 2) If it is a hormone, it has something to do with reproductive functions. 3) Pheromones are only found in insects. Of course, these three statements are all false.
C. Hints Related to Specific Chapter Topics
- III. Homeostasis was first defined on page 9 of the text. It would be a good idea to refer back to that simple definition. Some students think of homeostasis as a static thing rather than as a dynamic tendency toward balance. Levels of all substances are continuously shifting and interacting in order to maintain constancy.
  The term "homeostasis" can also be applied to items and events outside the animal body. For instance, what happens in nature to maintain an ecological homeostasis?
- IV. The subject of possible human pheromones is an interesting one. Part of it points directly to a definition of pheromone. Although no human pheromones have specifically been identified, it is well known that when two or more women begin sharing a home or apartment or dorm room, their menstrual cycles soon synchronize. This is well documented for women's sports teams and households with four or five daughters. The female menstrual cycle is hormonally induced. Why does one woman's hormones cause what seems to be a pheromonal reaction in another woman?
- V.C. Lewis uses oxytocin as the example of the positive feedback loop. Ask the students to think of a few others. For instance, blood clotting is a positive feedback mechanism.
  If you have students who need some help in remembering which feedback is positive and which is negative, try this. The baby is crying. That is a stimulus for you, so you get up and get the baby's bottle. But the baby wasn't crying from hunger, so the response (the bottle) only increases the stimulus. That is positive feedback. The baby really wanted its diaper changed. You change the diaper and the baby stops crying. That is negative feedback, the response decreased the stimulus.
- VI.A.1. Students usually find this section taking an insect from larva to adult to be very interesting. Show some pictures if possible.
- VI.B.1. The section on induced ovulation is usually quite interesting. Ask the students why being an induced ovulator can be an evolutionary advantage. Animals that are loners tend to be induced ovulators. Think of the cat. The female may go for days without seeing a male. If she ovulates during that time, her eggs are lost because they cannot survive for very long after being released from the ovary. She can be ready for ovulation (in heat) for days but not actually ovulate until copulation. The ova are fertilized and the species continues.
- VII.C. Embryologically the intermediate region of the pituitary has its origins as part of the anterior pituitary.
- VIII.B. The statement that the parathyroid glands are four small groups of cells embedded in the posterior thyroid gland is true for humans and most other animals. The cat poses an interesting exception. In cats these glands are called the internal and external parathyroid glands and sometimes a pair is found on the anterior thyroid. Pigs have only one pair of parathyroid glands and these are embedded in the thymus in fetal animals and in adipose tissue in older animals.
- VIII.C. In some animals, including the cat, the adrenal glands do not sit on top of the kidney but rather are located some distance above the kidney.
  A person (or animal) can survive without the adrenal medulla but not without the adrenal cortex. Ask the students why. Also ask how that could be scientifically demonstrated.
  Another interesting question is why in post-menopausal women the problems associated with the adrenal sex hormones usually result from an excess rather than from a deficiency.
- VIII.D. The pancreas is both an endocrine (ductless) and an exocrine (ducted) gland. You can relate that to Banting and Best's experiment.
- VIII.D.1. Diabetes mellitus is a fascinating disease. You might challenge the class to explain how our thinking about diabetes has changed over the years and how scientific methodology has aided in this change.
  Lewis very wisely uses the term usually when stating that type I diabetes usually begins in childhood. This used to be called juvenile onset diabetes. But, age is not a requisite so it is more correct to call it type I diabetes. People of any age can get it. Type II diabetes was formerly called adult onset diabetes. Again, age is not a requisite, even though this condition is far more common in adults.
  A few points of interest: Yes, there are subtypes of diabetes mellitus. Causes can also include accidents (or injuries to the pancreas), pathogenic diseases, or medications for other conditions, to name a few. Sometimes the disease is progressive, sometimes it is not. This certainly adds to the statement Lewis makes that diabetes symptoms may develop in several ways.
- VIII.D.2. Alcoholics often have severe cravings for alcohol while in the middle of a hypoglycemic attack. Challenge the students to find out why.
- IX.B. Interstitial-cell-stimulating hormone (ICSH) is biochemically identical to luteinizing hormone. Some books do not use the ICSH term any longer.