Question 1

Seasonal changes in snake activity are due to the fact that snakes are

Accepted Answer

The answer of Seasonal changes in snake activity are due...

Question 2

Different cells in the body are able to uniquely respond to the same hormones because

Accepted Answer

Different target cells may use different signal transduction pathways. This means that even though the same hormone may bind to different cells, each cell may activate a different set of downstream signals and produce a different response. For example, epinephrine can stimulate both heart rate and glycogen breakdown in liver cells, but these responses are mediated by different signal transduction pathways in the two cell types.

Question 3

Prolactin stimulates mammary gland growth and development in mammals,and it also 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 multiple functions in different species suggests that it is evolutionarily conserved, meaning that it has been maintained throughout the course of evolution because of its importance in different organisms.

Question 4

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

Accepted Answer

Oxytocin is a hormone that is involved in a positive feedback loop during labor and delivery. As the baby's head pushes against the cervix, it signals the release of more oxytocin, which further stimulates contractions. This positive feedback loop helps to increase the intensity and frequency of contractions, ultimately leading to the delivery of the baby.

Question 5

Most types of communication between cells utilize

Accepted Answer

Most communication between cells happens through the release or reception of chemical signaling molecules. This includes neurotransmitters between nerve cells, hormones between endocrine cells, and cytokines between immune cells. Options A, B, and D are not commonly used for cell communication.

Question 6

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

Accepted Answer

Neurosecretory cells in the hypothalamus secrete hormones that regulate the pituitary gland, which in turn releases hormones that regulate other endocrine glands. This interplay between the nervous and endocrine systems is known as the hypothalamic-pituitary axis.

Question 7

Fight-or-flight reactions include activation of

Accepted Answer

The adrenal medulla is responsible for producing and secreting epinephrine (adrenaline) and norepinephrine, which are involved in the fight-or-flight response.

Question 8

An example of an ectothermic organism that would have difficulty adjusting its body temperature due to its typical physical environment is a

Accepted Answer

Sea stars are ectothermic organisms that rely on the temperature of their surrounding water to regulate their body temperature. They would have difficulty adjusting their body temperature if the temperature of the water changes rapidly or drastically, such as during a sudden change in ocean currents or a marine heatwave. Unlike sea stars, terrestrial lizards can adjust their body temperature by moving to different locations, such as basking in the sun or seeking Shade. Sharks are also ectothermic but are able to regulate their body temperature to some extent by moving to different depths of water. Hummingbirds are endothermic, meaning they can regulate their own body temperature internally. House flies are also ectothermic but are able to adjust their body temperature by moving to different locations and by using evaporative cooling.

Question 9

The temperature-regulating center of vertebrate animals is located in the

Accepted Answer

The temperature-regulating center of vertebrate animals is located in the hypothalamus. The hypothalamus acts as a thermometer and controls body temperature by initiating responses such as sweating, shivering, or changes in blood flow to the skin.

Question 10

Coordinating body functions via release of chemical signals into the vascular system is accomplished by

Accepted Answer

The endocrine system releases hormones into the bloodstream to coordinate body functions. The respiratory system is responsible for gas exchange, the integumentary system protects the body and helps regulate body temperature, and the nervous system transmits signals between neurons and other cells.

Question 11

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

Accepted Answer

Prolactin promotes milk synthesis, while oxytocin promotes milk release (also known as letdown). Both hormones are released in response to suckling or stimulation of the nipples.

Question 12

Oxytocin and antidiuretic hormone are synthesized in the

Accepted Answer

Oxytocin and antidiuretic hormone (ADH) are synthesized in the hypothalamus and then transported to and released from the posterior pituitary gland.

Question 13

The panting responses that are observed in overheated birds and mammals dissipate excess heat by

Accepted Answer

Panting responses in overheated animals promote evaporation of water from the respiratory surfaces, which helps in dissipating excess heat.

Question 14

The steroid hormone aldosterone affects only a small number of cells in the body because

Accepted Answer

Aldosterone affects only its target cells because only these cells possess aldosterone receptors. In the absence of these receptors, the hormone cannot enter the cell or elicit a response.

Question 15

All hormones

Accepted Answer

Hormones are carried to target cells in the blood.

Question 16

An example of an organism that has only behavioral controls over its body temperature is the

Accepted Answer

The rosy boa, like other snakes, is ectothermic, meaning it cannot internally regulate its body temperature through physiological means. Instead, it relies on behavioral adaptations, such as basking in the sun or seeking shade, to control its body temperature.

Question 17

Positive feedback differs from negative feedback in that

Accepted Answer

Positive feedback systems amplify the response in the same direction as the original stimulus, while negative feedback systems work to counteract the stimulus and bring the system back to homeostasis. Neither type of feedback is inherently beneficial or detrimental; the effects depend on the specific context and outcome. The other answer choices are incorrect; for example, negative feedback can result in increases or decreases to a parameter depending on the situation, and both types of feedback can have control centers.

Question 18

Animals can lose heat,but cannot gain heat,through the process of

Accepted Answer

Animals can lose heat through the process of evaporation, such as when they sweat or pant. However, they cannot actively gain heat through any of the other options listed (conduction, convection, or radiation). Heat must come from an external source, such as the sun or from contact with a warmer surface.

Question 19

A cell with membrane-bound proteins that selectively binds to a specific hormone is called that hormone's

Accepted Answer

A target cell has membrane-bound proteins that selectively bind to a specific hormone, allowing for the hormone to exert its effects on the cell. Neurosecretory cells secrete hormones, but they do not necessarily have membrane-bound proteins that selectively bind to those hormones. Endocrine cells secrete hormones into the bloodstream, but they may not necessarily have membrane-bound proteins that selectively bind to those hormones. Daughter cells are cells that result from cell division and are not relevant to hormone binding.

Question 20

Most land-dwelling invertebrates and all of the amphibians

Accepted Answer

Most land-dwelling invertebrates and all amphibians are ectothermic organisms, meaning they rely on external sources of heat to regulate their body temperature instead of producing heat internally. They have variable body temperatures that fluctuate with changes in the environment.

Quiz 32: Homeostasis and Endocrine Signaling