34.1 The Endocrine System

Understand Key Concepts

1. Which choice is a chemical messenger that can directly influence gene expression?

   1. nonsteroid hormone

   2. steroid hormone

   3. ATP

   4. cAMP

2. A modified fatty acid that is released by a cell and affects local cells and tissues is likely a(n)

   1. nonsteroid hormone.

   2. steroid hormone.

   3. prostaglandin.

   4. exocrine secretion.

3. What is the relationship between a hormone and a target cell? Use a specific example to explain your answer.

4. Many body functions are influenced by the action of two hormones with opposing effects. Why are such pairs of hormones useful?

Think Critically

5. Use Analogies In many areas during rush hour, radio stations broadcast traffic reports. How are traffic reports similar to hormones? How do the reports act as a feedback control mechanism to control the flow of traffic?

6. Infer After a hormone is secreted by a gland, the circulatory system transports it all through the body. Why doesn't every cell respond to the hormone?

34.2 Glands of the Endocrine System

Understand Key Concepts

7. Hormones that help regulate blood calcium levels are produced by the

   1. posterior pituitary.

   2. thymus.

   3. pancreas.

   4. parathyroid gland.

8. Which hormone influences a person's rate of metabolism?

   1. PTH

   2. aldosterone

   3. thyroxine

   4. calcitonin

9. How does a feedback mechanism regulate the activity of the endocrine system?

10. How does the secretion of epinephrine prepare the body to handle emergencies?

11. What happens if blood glucose levels are not properly regulated?

Think Critically

12. Apply Concepts The heartbeat of a swimmer was found to increase significantly both before and during a swim meet. Explain why this could happen.

13. Form a Hypothesis Iodine is required to complete the production of thyroxine. Why do you think the thyroid gland enlarges in response to iodine deficiency?

34.3 The Reproductive System

Understand Key Concepts

14. The diagram shows the female reproductive system. Which structure is indicated by the X?

    

    1. uterus

    2. Fallopian tube

    3. ovary

    4. cervix

15. Which male reproductive structure releases sperm into the urethra?

    1. epididymis

    2. vas deferens

    3. prostate gland

    4. testis

16. Which two hormones stimulate the gonads to produce their hormones?

17. List the secondary sex characteristics that appear in males and females at puberty.

18. Trace the path of a sperm from a testis until it leaves the body.

19. Trace the path of an unfertilized egg from a follicle until it leaves the body.

20. Provide one example of how the menstrual cycle works by negative feedback.