Endnotes

1. Testosterone is not exclusive to males; women’s ovaries make small amounts of it. Similarly, estrogen is not the exclusively “female” hormone; the testes also produce it. It is the relative amounts of these hormones that are sex-specific; females produce more estrogen and males more testosterone. Both sexes have both hormones throughout life. ♠

2. An enzyme is a chemical that changes the speed of a chemical reaction without itself being changed in the process. ♠

3. No one knows for sure why depression in India isn’t more frequent in women. Indian women themselves think that it is because of the structure of domestic life there, in which several generations of women live together, share domestic responsibilities, and support one another in a tightly knit social fabric. In fact, the incidence of depression in men who are confined to the home and are responsible for child care and domestic chores approaches that of women. The predominance of this illness in women may be more situational than biological! ♠

4. In this test, the cardiologist threads a catheter into the heart through an artery in the leg, pushing it past the valve that separates the left ventricle from the great artery that carries fresh, oxygenated blood to the body, the aorta. She then injects dye through the catheter into the right and left coronary arteries, the first branches of the aorta that carry blood to the heart muscle itself. The resulting picture of the coronary arteries tells doctors whether there is obstruction, and where it is located in the heart. ♠

5. Angioplasty is a procedure in which a catheter threaded into a blocked artery carries an expandable balloon or other device for destroying plaque in the artery. (Plaque is made of cholesterol, calcium, clot, and other elements.) Coronary artery bypass surgery (CABG) is a procedure in which part of a blood vessel is harvested from the body (a leg vein or an artery in the chest or wrist) and is grafted onto the diseased coronary artery above the point of obstruction. The other end is grafted below the obstructed area, so that blood is routed around the obstruction and bypasses it completely. ♠

6. Coronary artery disease is the illness in which a combination of cholesterol, calcium, clot, and other elements called plaque builds up inside the coronary arteries, narrowing the passageway for blood to reach and nourish the heart muscle. If the obstruction is too great, part of the heart muscle dies. This is called a heart attack (or myocardial infarction). ♠

7. Among these chemicals are chemokines, which cause defending white cells, or leukocytes, to migrate to the toxic agent or substance, and cytokines, which prime to leukocytes for attack. ♠

8. The thymus is a gland that forms in the chest during development. It partially disappears at puberty, but rudiments of it remain throughout our life. The minimizing of the thymus gland appears to be regulated by testosterone. ♠

9. There are two major classes of genes that make these HLA molecules, and within each class further variations are possible (six genes in class I and ten in class II). ♠

10. The TCR is so cunningly fashioned that it will not recognize any of our own proteins as enemy; the gene that governs its production is fixed and cannot change. ♠

11. Multiple sclerosis is a chronic inflammatory disease of the central nervous system. ♠

12. This is the reason pregnancy dampens the activity of rheumatoid arthritis and multiple sclerosis: A T_H2 environment prevails, and the activity of T_H1 cells is diminished. ♠

13. In Greek mythology a chimera was a being composed of body parts of several different animals: the most familiar is the sphinx, with the hindquarters of a lion and the chest and head of a woman. The combination of cells of two different origins (fetal and maternal) is called a microchimerism for this reason. ♠

14. An allele is the corresponding gene on the matching chromosome of a pair. ♠

15. There are several kinds of bones, and each is individually regulated and shaped as the skeleton matures. The back bones, called vertebrae, are made up of trabecular, or spongy bone. The bone of the arms and legs is much denser and is called cortical bone. Hip bones are intermediate in composition. ♠

16. An enzyme is a chemical that changes the speed of a chemical reaction without itself being changed in the process. ♠

17. Unfortunately for these individuals, there are two types of 5-alpha reductase: type 1 stimulates oil production by the sebaceous glands in the skin, while type 2 is the form found only in the hair follicles. These males lack only type 2, so they can—and often still do—develop acne. ♠

18. Both kinds of ultraviolet radiation, A and B, are harmful to the skin. Sunblock protects only against A. ♠

19. ”Wastebasket illness” is a commonly used phrase for diseases doctors don’t understand and many believe are not genuine illnesses. ♠

20. Pain associated with sex is not limited to pain on actual intercourse. Noncoital sexual pain occurs simply on being sexually stimulated. ♠

21. Day 26 of the month preceding menses and the first 4 days of the next month. ♠