Chapter 45,46,48

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

D) 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

B) 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

A) 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

D) 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

B) 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

A) 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

C) 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

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

Question 9

Which of the following processes results in the offspring of sexual reproduction being genetically different from their parents?
A) fertilization
B) protein synthesis
C) cytokinesis
D) mitosis

Answer 9

D) mitosis

Question 10

Animals that use external fertilization are most likely to reproduce in which of the following areas?
A) sand dune
B) polar ice sheet
C) shallow lake
D) tallgrass prairie

Answer 10

C) shallow lake

Question 11

Which of the following describes an advantage of internal fertilization over external fertilization?
A) parents invest less time and energy in reproduction
B) the offspring are more likely to survive
C) populations increase faster
D) offspring are more genetically diverse

Answer 11

B) the offspring are more likely to survive

Question 12

Which of the following structures in females is analogous in function to the vas deferens in males?
A) urethra
B) oviduct
C) uterus
D) vagina

Answer 12

B) oviduct

Question 13

An inactivating mutation in the progesterone receptor gene would likely result in ________.
A) the absence of secondary sex characteristics
B) the inability of the uterus to support pregnancy
C) enlarged and hyperactive uterine endometrium
D) the absence of mammary gland development

Answer 13

B) the inability of the uterus to support pregnancy

Question 14

Which would most likely happen if the temperature of the human scrotum was increased by 2°C for several weeks? The male would experience ________.
A) reduced fertility due to impaired production of gonadal steroid hormones
B) reduced fertility due to impaired spermatogenesis
C) an increase in the rate of spermatogenesis due to faster chemical reactions
D) an increase in semen volume due to faster chemical reactions

Answer 14

B) reduced fertility due to impaired spermatogenesis

Question 15

Which of the following changes is most likely to occur as an immediate result of an injection of LH into a male mammal?
A) a decrease in production of inhibin
B) an increase in production of GnRH
C) a decrease in production of testosterone
D) an increase in production of testosterone

Answer 15

D) an increase in production of testosterone

Question 16

Which statement correctly describes the primary function of the corpus luteum?
A) to nourish and protect the egg cell
B) to maintain progesterone and estradiol synthesis after ovulation has occurred
C) to stimulate the development of the mammary glands
D) to support pregnancy in the second and third trimesters

Answer 16

B) to maintain progesterone and estradiol synthesis after ovulation has occurred

Question 17

For which of the following is the number the same in human males and females?
A) interruptions in meiotic divisions
B) functional gametes produced by meiosis
C) meiotic divisions required to produce each gamete
D) different cell types produced by meiosis

Answer 17

C) meiotic divisions required to produce each gamete

Question 18

What type of neurons is responsible for the interpretation of sensory input?
A) sensory neurons
B) motor neurons
C) interneurons
D) peripheral neurons

Answer 18

C) interneurons

Question 19

A nerve is a collection of ________.
A) dendrites
B) nerve cell bodies
C) synapses
D) axons

Answer 19

D) axons

Question 20

Which of these ions is more abundant in the interior of a resting neuron than in the fluid surrounding the neuron?
A) Cl-
B) Ca++
C) Na+
D) K+

Answer 20

D) K+

Question 21

If you experimentally increase the concentration of Na+ outside a cell while maintaining other ion concentrations as they were, what would happen to the cell’s membrane potential?
A) The membrane potential would become more negative.
B) The membrane potential would become less negative.
C) The membrane potential would be unaffected.
D) The membrane potential would become positive.

Answer 21

B) The membrane potential would become less negative.

Question 22

The concentrations of sodium and potassium ions are very different inside and outside a neuron. What contributes to these differences?
A) osmosis
B) diffusion of chloride ions
C) sodium-potassium pumps
D) exocytosis and endocytosis

Answer 22

C) sodium-potassium pumps

Question 23

Action potentials move along axons ________.
A) more slowly in axons of large diameter than in axons of small diameter
B) by activating the sodium-potassium “pump” at each point along the axonal membrane
C) more rapidly in myelinated than in unmyelinated axons
D) by reversing the concentration gradients for sodium and potassium ions

Answer 23

C) more rapidly in myelinated than in unmyelinated axons

Question 24

The following are events in the transmission of a signal at a chemical synapse.
1. Neurotransmitter binds with receptors associated with the postsynaptic membrane.
2. Calcium ions rush into neuron’s cytoplasm.
3. An action potential depolarizes the membrane of the presynaptic axon terminal.
4. The ligand-gated ion channels open.
5. The synaptic vesicles release neurotransmitter into the synaptic cleft.
Which sequence of events is correct?
A) 1 → 2 → 3 → 4 → 5
B) 2 → 3 → 5 → 4 → 1
C) 3 → 2 → 5 → 1 → 4
D) 4 → 3 → 1 → 2 → 5

Answer 24

C) 3 → 2 → 5 → 1 → 4

Question 25

Where are neurotransmitters released in a synapse?
A) the presynaptic membrane
B) axon hillocks
C) cell bodies
D) the smooth endoplasmic reticulum

Answer 25

A) the presynaptic membrane