Chapter 45 Study Guide

Question 1

Which of the following statements about endocrine glands is true?
A) They secrete a product onto a body surface or into a body cavity.
B) They secrete enzymes and bicarbonate.
C) The products are all enzymes.
D) They do not have ducts.

Answer 1

They do not have ducts.

Question 2

Which of the following best explains why the steroid hormone aldosterone affects only a small number of target cells in the body?
A) only target cells are exposed to aldosterone
B) only target cells contain aldosterone receptors
C) aldosterone is unable to diffuse through nontarget cell membranes
D) nontarget cells destroy aldosterone before it can bind

Answer 2

only target cells contain aldosterone receptors

Question 3

A certain hormone activates the cAMP second messenger system in its target cells. Which of the following would yield the greatest response by a target cell?
A) apply the hormone to the extracellular fluid surrounding the cell
B) inject the hormone into the cytoplasm of the cell
C) apply cAMP to the extracellular fluid surrounding the cell
D) inject activated, cAMP-dependent protein kinase into the cytoplasm of the cell

Answer 3

apply the hormone to the extracellular fluid surrounding the cell

Question 4

Which of the following are properties of steroid hormones?
A) Steroid hormones are water-soluble and travel freely in the bloodstream.
B) Steroid hormones usually exert their effects on target cells through membrane receptor proteins.
C) Steroid hormones only act locally, on cells close to where the steroid hormone was secreted.
D) Steroid hormones regulate gene transcription by binding to intracellular receptor proteins.

Answer 4

Steroid hormones regulate gene transcription by binding to intracellular receptor proteins.

Question 5

Tadpoles undergo metamorphosis in their development. The changes include reabsorption of the tail, growth of limbs, and the development of lungs. Amazingly, all of these changes are induced by thyroxine. Which of the following best explains the diverse effects of thyroxine?
A) Thyroxine binds to transport proteins that direct thyroxine to certain tissues.
B) Different tissues have thyroxine receptors that activate different signal transduction pathways.
C) Some tissues have membrane receptors for thyroxine, while other tissues have thyroxine receptors within the nucleus.
D) Thyroid hormone is divided into T3 and T4 as it travels through the bloodstream.

Answer 5

Different tissues have thyroxine receptors that activate different signal transduction pathways.

Question 6

Which of the following is a gas that functions as a local regulator and a neurotransmitter in humans?
A) nitric oxide
B) epinephrine
C) cortisol
D) carbon dioxide

Answer 6

nitric oxide

Question 7

Which of the following is the source of the hormones secreted by the posterior pituitary gland?
A) cerebellum
B) thalamus
C) hypothalamus
D) anterior pituitary gland

Answer 7

hypothalamus

Question 8

Growth factors are local regulators that ________.
A) are produced by the anterior pituitary
B) are modified fatty acids that stimulate bone and cartilage growth
C) are found on the surface of cancer cells and stimulate ­abnormal cell division
D) bind to cell-surface receptors and stimulate growth and ­development of target cells

Answer 8

bind to cell-surface receptors and stimulate growth and ­development of target cells