Problem 4 - Campbell Biology

Question

\(\begin{equation} \begin{array}{l}{\text { Which hormone is incorrectly paired with its action? }} \\ {\text { (A) oxytocin-stimulates uterine contractions during }} \\\ {\text { childbirth }} \\ {\text { (B) thyroxine-inhibits metabolic processes }} \\ {\text { (C) ACTH-stimulates the release of glucocorticoids by the }} \\\ {\text { adrenal cortex }} \\ {\text { (D) melatonin- affects biological rhythms and seasonal }} \\ {\text { reproduction }}\end{array} \end{equation}\)

Step-by-Step Solution

Answer

(B) thyroxine-inhibits metabolic processes

Step 1: Understand the Question

The question asks to identify which hormone is incorrectly paired with its action among the given choices.

Step 2: Review Each Hormone and Its Action

Evaluate each hormone and its described action: (A) Oxytocin is known to stimulate uterine contractions during childbirth. (B) Thyroxine is known to stimulate, not inhibit, metabolic processes. (C) ACTH (Adrenocorticotropic hormone) stimulates the release of glucocorticoids by the adrenal cortex. (D) Melatonin affects biological rhythms and seasonal reproduction.

Step 3: Determine the Incorrect Pair

Among the options, choice (B) is incorrect. Thyroxine in reality stimulates metabolic processes, contrary to the statement that it inhibits them.

Step 4: Conclusion

Conclude that option (B) is the incorrect pairing of hormone and action.

Key Concepts

Oxytocin

Oxytocin is a hormone produced in the hypothalamus and released by the pituitary gland, principally known for its role during childbirth and breastfeeding. Oxytocin stimulates uterine contractions, which helps a woman deliver her baby.
It also plays a significant role in helping the uterus shrink post-delivery. Another important function of oxytocin is to facilitate milk ejection during breastfeeding.
This hormone is often referred to as the 'love hormone' or 'bonding hormone,' as it influences social behaviors and emotional bonding between individuals.

Thyroxine

Thyroxine, also known as T4, is a hormone produced by the thyroid gland. It is critical for regulating metabolism in the body.
Thyroxine increases the rate at which cells consume oxygen and convert nutrients into energy, which is essential for normal growth and development.
An important point to note is that thyroxine stimulates, rather than inhibits, metabolic processes. When levels of thyroxine are too low, it can lead to conditions such as hypothyroidism, characterized by fatigue and weight gain. Conversely, high levels can lead to hyperthyroidism, which may cause weight loss and increased heart rate.

ACTH

Adrenocorticotropic hormone (ACTH) is produced in the pituitary gland. It stimulates the adrenal cortex to release glucocorticoids, primarily cortisol.
Cortisol has significant impacts on various bodily functions, including the body's response to stress, immune response, and regulation of metabolism.
By stimulating the release of glucocorticoids, ACTH plays a vital role in how the body manages stress and maintains homeostasis. Elevated levels of ACTH can be indicative of stress, while low levels could suggest issues with adrenal gland function.

Melatonin

Melatonin is a hormone primarily released by the pineal gland in the brain. It is fundamentally involved in regulating sleep-wake cycles, also known as circadian rhythms.
The production and release of melatonin are influenced by the time of day, increasing in response to darkness and decreasing with light exposure.
This hormone helps signal to the body that it is time to prepare for sleep, thus promoting restful sleep patterns. In addition to affecting sleep, melatonin also plays a role in seasonal reproduction in certain animals, making it a crucial hormone for survival and adaptation.