Chapter 38, Problem 1TY

Summary Introduction

Introduction: Hormones can be defined as chemical substances that are produced in the body which regulates the action of some cells or organs. Many hormones are released by special glands such as the thyroid hormone that is formed by the thyroid gland.

Answer to Problem 1TY

The correct answer is the option (b) They are secreted into the blood, where they might arrive at one or more isolated target cells, thus changing the function of the cell throughout the body.

Explanation of Solution

Explanation/justification for the correct answer:

Option (b) They are secreted into the blood, where they might arrive at one or more isolated target cells, thus changing the function of the cell throughout the body.

Hormones are the chemical messengers that are secreted and released into the blood or the extracellular fluid by one cell that affects the performance of other cells. Most of the hormones circulate in the blood and comes in contact with basically all the cells. Hence, option (b) is correct.

Explanation for the incorrect answer:

Option (a) They are only produced in endocrine glands. They are not only produced in endocrine glands but also in exocrine glands. Hence, the option (a) is incorrect.

Option (c) They are only released by neurons. They are released by particular glands and not by neurons. Hence, the option (c) is incorrect.

Option (d) They are never released by neurons. They are released by specific glands. Hence, option (d) is incorrect.

Option (e) They are secreted into the ducts, where they diffuse to another, nearby gland or other structure. They can directly be released into the blood or with the help of the duct. Hence, the option (e) is incorrect.

Conclusion

Hormones are the chemical messengers that are secreted and released into the blood or the extracellular fluid by one cell that affects the performance of other cells. Hence, option (b) is correct.