Question 1

The endocrine glands include the

Accepted Answer

The parathyroid glands are endocrine glands, but the salivary and sweat glands are not. The gallbladder is not a gland at all, but rather an organ of the digestive system.

Question 2

The endocrine gland that produces epinephrine is the

Accepted Answer

The adrenal medulla is the endocrine gland that produces epinephrine, also known as adrenaline.

Question 3

Iodine is added to table salt to help prevent deficiencies of an essential mineral needed for the proper function of the

Accepted Answer

Iodine is an important mineral required for the production of thyroid hormones by the thyroid gland. Deficiency of iodine can lead to thyroid disorders such as goiter, hypothyroidism, and cretinism. Therefore, the addition of iodine to table salt helps prevent iodine deficiency and ensures proper thyroid function.

Question 4

The increased contraction of the human uterus during labor and delivery is at least partially due to the actions of

Accepted Answer

Oxytocin is a hormone released by the posterior pituitary gland during labor and delivery that causes increased contraction of the uterus.

Question 5

Prolactin stimulates mammary gland growth and development in mammals, and it regulates salt and water balance in freshwater fish. Many scientists think that this wide range of functions indicates that prolactin

Accepted Answer

The fact that prolactin has functions in both mammals and fish suggests that it has been conserved throughout evolution.

Answer: B
 The diverse functions of prolactin may suggest that it has a unique mechanism for controlling its effects, rather than acting through a more general signal transduction pathway.

Overall, both C and B could be valid choices as the question asks for the "best" choice without specifying a single correct answer.

Question 6

In a positive-feedback system where hormone A alters the amount of protein X,

Accepted Answer

In a positive-feedback system, an initial increase in A will lead to an increase in X, which will, in turn, lead to an increase in A. This will continue in a loop until an external factor limits the feedback loop. Therefore, an increase in A always produces an increase in X, which results in an increase in A.

Question 7

Abnormally reduced somatic growth (dwarfism) can be a consequence of decreased hormone secretion from the

Accepted Answer

Abnormally reduced somatic growth (dwarfism) is often caused by decreased secretion of growth hormone from the anterior pituitary gland.

Question 8

In a lactating mammal, the two hormones that promote milk synthesis and milk release, respectively, are

Accepted Answer

Prolactin is responsible for milk synthesis, while oxytocin triggers milk release (also known as the let-down reflex).

Question 9

Fight-or-flight reactions include activation of

Accepted Answer

Fight-or-flight reactions involve activation of the adrenal medulla, leading to increased secretion of epinephrine (also known as adrenaline). This hormone helps prepare the body for physical activity and is a key component of the body's response to stress.

Question 10

Melatonin is secreted by

Accepted Answer

Melatonin is primarily secreted by the pineal gland, a small endocrine gland located deep in the brain.

Question 11

The interrelationships between the endocrine and the nervous systems are especially apparent in

Accepted Answer

Neurosecretory cells in the hypothalamus release hormones that regulate the release of hormones from the pituitary gland, which in turn regulate the endocrine system. This demonstrates the interrelationship between the nervous and endocrine systems.

Question 12

Compared to the seawater around them, most marine invertebrates are

Accepted Answer

Marine invertebrates have evolved to be isoosmotic with the seawater around them, meaning they maintain an internal osmotic concentration similar to that of their environment. This allows them to osmoregulate without expending excess energy, as water and ions pass freely through their cell membranes in both directions. Hyperosmotic or hypoosmotic animals would have to expend energy to regulate their internal osmolarity, which would be disadvantageous in an environment where the osmolarity can vary greatly.

Question 13

A necropsy (post-mortem analysis) of a marine sea star that died after it was mistakenly placed in fresh water would likely show that it died because

Accepted Answer

Sea stars are osmoconformers, meaning they allow the concentration of their body fluids to be the same as their environment. When placed in a freshwater environment, the sea star would become hyperosmotic, causing water to move out of its body, leading to dehydration and death. The necropsy would likely show signs of dehydration and an inability to osmoregulate.

Question 14

Most of the exchange surfaces of multicellular animals are lined with

Accepted Answer

Epithelial tissue is specialized for exchange functions, such as absorption and secretion, and lines the surfaces of organs and tissues that interact with the environment, such as the lungs and intestines.

Question 15

The body's reaction to PTH (parathyroid hormone), a reduction in plasma levels of calcium, can be opposed by

Accepted Answer

Calcitonin opposes the actions of PTH by decreasing plasma levels of calcium. T3 and T4, epinephrine, growth hormone, and glucagon are not involved in the regulation of calcium levels in this manner.

Question 16

Organisms categorized as osmoconformers are most likely

Accepted Answer

Osmoconformers are organisms that can maintain an internal osmotic concentration that is equal to the external environment. This is often seen in marine organisms, as the ocean has a relatively stable salinity. Other environments, such as freshwater or terrestrial, may have more variable osmotic conditions, making it more challenging for organisms to conform to the external environment.

Question 17

Oxytocin and antidiuretic hormone are synthesized in the

Accepted Answer

Oxytocin and antidiuretic hormone (ADH) are synthesized in the hypothalamus and then transported to the posterior pituitary gland for storage and release.

Question 18

The body fluids of an osmoconformer would be ________ with its ________ environment.

Accepted Answer

Osmoconformers are organisms that maintain their body fluids isotonic or isoosmotic with their surrounding environment. In the case of a saltwater environment, an osmoconformer's body fluids would be isoosmotic with the saltwater, meaning the osmotic pressure inside the organism is the same as the osmotic pressure of the surrounding saltwater.

Question 19

During mammalian labor and delivery, the contraction of uterine muscles is enhanced by oxytocin. This is an example of

Accepted Answer

Oxytocin is involved in a positive feedback loop during labor and delivery. As contractions of the uterine muscles increase, more oxytocin is released, which further enhances contractions. This positive feedback continues until the baby is born.

Question 20

The hypothalamus

Accepted Answer

The hypothalamus is a key player in neuroendocrine signaling, controlling the release of hormones from the pituitary gland and regulating various bodily functions such as hunger, thirst, and sleep. While it does have some neural functions, its primary role is in endocrine signaling. It also produces and secretes hormones such as oxytocin and vasopressin, which have various effects on the body.

Quiz 32: Homeostasis and Endocrine Signaling