Which of the following sets of hormones are antagonists? a Insulin and glucagon. b. Calotonin and cortisol. c. Epinephrine and norepinephrine The disei d. Growth hormone and thyraxine sensitivit 3 Matching: Match the following endocrine organs with the hormonels) each secretes. Pineal gland Thyroid gland Pancreas Thymus Hypothalamus Adrenal cortex Anterior pituitary Adrenal medulla A. Antidiuretic hormone and oxytocin B. Insulin and glucagon C. Aldosterone and cortisol D. Epinephrine and norepinephrine Atype How v that c F. Thyroid-stimulating hormone and growth hormone G. Melatonin H. Thymosin and thymopoietir ? 3 Which of the following is true regarding endocrine organ histology? a. The thyroid gland consists of rings of stratified cuboidal folicle cells surrounding colloid. b. The pancreas has an exocrine partion consisting of pancreatic islets and an endocrine portion consisting of acinar cells. c. The adrenal cortex has three zones of cells that secrete steroid hormones d. The adrenal medulla is modified nervous tissue of the parasympathetic nervous system Int imi fee LO in a negative feedback loop, you would expect secretion from an endocrine gland to after homeostasis has been restored. a. decrease b. increase c remain the same 142 Exploring Anatomy& Physiology in the Laboratory
The Correct Answer and Explanation is:
Let’s go through each part of your question carefully, providing correct answers with a detailed explanation.
Multiple-Choice Question 1:
Which of the following sets of hormones are antagonists?
Correct Answer: a. Insulin and glucagon
Explanation:
Insulin and glucagon are classic examples of antagonistic hormones. They play essential but opposite roles in the regulation of blood glucose levels.
- Insulin is secreted by the beta cells of the pancreas in response to high blood glucose levels. It facilitates the uptake of glucose into cells and promotes the storage of glucose as glycogen in the liver and muscles. As a result, it lowers blood glucose levels.
- Glucagon is secreted by the alpha cells of the pancreas when blood glucose levels are low. It stimulates the liver to break down glycogen into glucose and release it into the bloodstream, thereby raising blood glucose levels.
These two hormones work in a negative feedback loop to maintain blood glucose within a narrow range — a process called homeostasis.
Incorrect Choices:
- b. Calcitonin and cortisol: These hormones are not antagonists. Calcitonin helps reduce blood calcium levels, while cortisol is involved in stress responses and metabolism.
- c. Epinephrine and norepinephrine: These are synergistic hormones, not antagonistic. Both increase heart rate and blood pressure as part of the sympathetic “fight or flight” response.
- d. Growth hormone and thyroxine: These hormones both promote growth and metabolism but are not directly antagonistic to each other.
Matching Question:
Match each endocrine organ with the correct hormone(s):
| Endocrine Organ | Hormone(s) |
|---|---|
| Pineal gland | G. Melatonin |
| Thyroid gland | F. Thyroid-stimulating hormone and growth hormone ✘ (Incorrect: this is from anterior pituitary) ✔ **Produces T3 and T4, and secretes calcitonin (but not an option here, so no perfect match given) |
| Pancreas | B. Insulin and glucagon |
| Thymus | H. Thymosin and thymopoietin |
| Hypothalamus | A. Antidiuretic hormone and oxytocin |
| Adrenal cortex | C. Aldosterone and cortisol |
| Anterior pituitary | F. Thyroid-stimulating hormone and growth hormone |
| Adrenal medulla | D. Epinephrine and norepinephrine |
Multiple-Choice Question 2:
Which of the following is true regarding endocrine organ histology?
Correct Answer: c. The adrenal cortex has three zones of cells that secrete steroid hormones.
Explanation:
The adrenal cortex consists of three distinct zones, each responsible for producing specific types of steroid hormones:
- Zona glomerulosa – Secretes mineralocorticoids, primarily aldosterone.
- Zona fasciculata – Secretes glucocorticoids, mainly cortisol.
- Zona reticularis – Produces androgens (sex hormones).
These layers are arranged from the outermost to the innermost and surround the adrenal medulla.
Incorrect Options:
- a. The thyroid gland consists of simple cuboidal follicular cells, not stratified. They surround the colloid-filled follicles.
- b. The pancreas’s exocrine portion is made of acinar cells, which secrete digestive enzymes. The endocrine portion consists of pancreatic islets (islets of Langerhans), not the other way around.
- d. The adrenal medulla is part of the sympathetic nervous system, not the parasympathetic.
Multiple-Choice Question 3:
In a negative feedback loop, you would expect secretion from an endocrine gland to ___ after homeostasis has been restored.
Correct Answer: a. decrease
Explanation:
In a negative feedback loop, the body reduces or stops the secretion of a hormone once the desired physiological condition has been achieved (homeostasis). This prevents overcorrection and maintains balance.
Example:
- When blood glucose is high, insulin is secreted.
- After glucose is absorbed and levels normalize, insulin secretion decreases.
This is a self-regulating system that keeps internal conditions stable.
Summary of Correct Answers:
- a. Insulin and glucagon
- Matching:
- Pineal gland → G. Melatonin
- Thyroid gland → (No perfect match)
- Pancreas → B. Insulin and glucagon
- Thymus → H. Thymosin and thymopoietin
- Hypothalamus → A. Antidiuretic hormone and oxytocin
- Adrenal cortex → C. Aldosterone and cortisol
- Anterior pituitary → F. Thyroid-stimulating hormone and growth hormone
- Adrenal medulla → D. Epinephrine and norepinephrine
- c. The adrenal cortex has three zones of cells that secrete steroid hormones
- a. decrease
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