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Section 10.2: The Endocrine Glands
Section 10.2 Questions, page 482
1. The hormones primarily responsible for regulating the metabolism of the body are thyroid
hormones.
2. The hormones that help the body respond to stress are the adrenal hormones.
3. The function of the posterior pituitary gland differs from the function of the anterior pituitary
gland in that the posterior lobe of the pituitary does not produce hormones like the anterior, but
stores two hormones produced by the hypothalamus, which are then released into the
bloodstream after signals from the hypothalamus. Unlike the anterior pituitary’s hormones, these
two hormones, antidiuretic hormone and oxytocin, do not control other hormones, but affect their
target tissues directly.
4. Presentations may vary, but should include: The hypothalamus is the link between the
endocrine and nervous systems. In response to messages from the brain and nerve receptors, the
hypothalamus releases hormones that control the pituitary gland’s release of hormones, which in
turn control the rest of the endocrine glands.
5. Answers may vary. Sample answer: If the thyroid gland had to be removed due to cancer, the
main effect would be slowing of the body’s metabolism, since the thyroid regulates metabolism.
Supplemental hormones or stimulants may need to be administered to control metabolism and
prevent metabolic slow down, leading to excessive weight gain. Calcium levels in the blood
would also have to be monitored and bones watched for signs of weakening, since calcitonin
levels would be lower. Calcitonin prevents the dissolution of calcium from the bones. The patient
may need to increase his or her intake of calcium.
6. The hormones from the anterior pituitary gland that are important for reproduction are follicle
stimulating hormone (FSH), which stimulates egg growth and development as well as secretion
of sex hormones in females and stimulates sperm production in males; luteinizing hormone (LH),
which regulates ovulation in females and secretion of sex hormones in males; and prolactin
(PRL), which stimulates breast development and milk secretion.
7. Alcohol (ethanol) and caffeine increase urination because they inhibit the secretion of
antidiuretic hormone (ADH), which, when present, stimulates the kidneys to take up more water
from the blood. When kidneys take up more water, more is present in the urine and urination
increases.
8. Epinephrine is therapeutic for anaphalaxis because it opens airways and raises blood pressure,
reversing two deadly symptoms of anaphylaxis. If a person was not suffering from anaphylaxis
but had very high blood pressure, taking epinephrine could make his or her blood pressure
dangerously high.
9. The forerunner of the modern pineal gland may have been a light-sensitive “third eye” early in
evolutionary history. The modern pineal gland responds to light by suppressing its secretion of
melatonin, a hormone that plays a role in establishing diurnal rhythms.
10. A complete lack of ecdysone in a growing invertebrate would prevent moulting
(i.e., shedding its exoskeleton and making room for a new exoskeleton). Without moulting, a
growing invertebrate has no room to grow, and may even die by crushing itself inside its rigid
exoskeleton.
11. The hypothalamus is part of the nervous system. The releasing hormones released by the
hypothalamus travel along nerve cells into the bloodstream, and then to the pituitary gland,
which is part of the endocrine system. Once in the pituitary gland, they cause the release of other
hormones that work to regulate various body processes.
Copyright © 2012 Nelson Education Ltd.
Chapter 10: The Endocrine System
10.2-1
12. (a) If the pituitary produced too much TSH, the thyroid would respond by increasing its
production of thyroid hormones. Since these hormones regulate your metabolism, you could
develop increased rates of metabolism leading to increased heart rate, abnormal heart rhythm,
increased body heat, moist skin due to increased perspiration, increased nerve activity
(nervousness or slight trembling of hands), increased activity level (despite feeling tired and
week), increased appetite (usually accompanied by weight loss), and goiter.
(b) If the pituitary gland produced too little TSH (hypothyroidism), metabolic rate would
decrease and the opposite effects as those outlined in part (a) would be seen.
13. The pineal gland is light-sensitive because specialized photoreceptors in the eyes make
connections to the pineal gland.
Copyright © 2012 Nelson Education Ltd.
Chapter 10: The Endocrine System
10.2-2