Which of the following sets of hormones are antagonists? a. Insulin and glucagon bCalcitonin and cortisol. CEpinephrine and norepinephrine d. Growth hormone and thyroxine 8 Matching: Match the following endocrine organs with the hormone(s) each secretes. Pineal gland A Antidiuretic hormone and oxytocin В. Insulin and glucagon Thyroid gland C. Aldosterone and cortisol Pancreas D. Epinephrine and norepinephrine Thymus E. Thyroxine, triiodothyronine, and calcitonin F. Thyroid-stimulating hormone, growth hormone Hypothalamus G Melatonin Adrenal cortex H. Thymosin and thymopoietin Anterior pituitary Adrenal medulla 9 Which of the following is true regarding endocrine organ histology? a. The thyroid gland consists of rings of stratified cuboidal follicle cells surrounding colloid. b. The pancreas has an exocrine portion 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. 16 after 10 In a negative feedback loop, you would expect secretion from an endocrine gland to homeostasis has been restored. a. decrease b. increase cremain the same
The correct answer and explanation is:
Question 7: Identifying Antagonistic Hormone Pairs
Antagonistic hormones are pairs of hormones that have opposite effects on physiological processes, working together to maintain the body’s internal balance, or homeostasis. Among the provided options, the correct pair of antagonistic hormones is:
a. Insulin and glucagon
Explanation:
- Insulin and Glucagon: Both hormones are produced by the pancreas and play crucial roles in regulating blood glucose levels. Insulin, secreted by beta cells, lowers blood glucose by facilitating its uptake into cells and promoting its storage as glycogen in the liver. Conversely, glucagon, secreted by alpha cells, raises blood glucose levels by stimulating the conversion of glycogen back into glucose in the liver. This opposing action helps maintain glucose homeostasis. citeturn0search4
- Calcitonin and Cortisol: Calcitonin, produced by the thyroid gland, helps lower blood calcium levels by inhibiting bone resorption. Cortisol, produced by the adrenal cortex, is a glucocorticoid involved in stress responses, metabolism, and immune regulation. These hormones do not have directly opposing functions.
- Epinephrine and Norepinephrine: Both are produced by the adrenal medulla and work together to prepare the body for ‘fight or flight’ responses, increasing heart rate, blood pressure, and energy availability. They are synergistic, not antagonistic.
- Growth Hormone and Thyroxine: Growth hormone (GH), from the pituitary gland, stimulates growth and cell reproduction. Thyroxine (T4), from the thyroid gland, regulates metabolism. While both influence growth and development, they do not function as direct antagonists.
Question 8: Matching Endocrine Organs with Their Hormones
Matching the endocrine organs to the hormones they secrete:
- Pineal gland: G. Melatonin
- Thyroid gland: E. Thyroxine, triiodothyronine, and calcitonin
- 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, growth hormone
- Adrenal medulla: D. Epinephrine and norepinephrine
Explanation:
- Pineal gland: Produces melatonin, regulating sleep-wake cycles. citeturn0search1
- Thyroid gland: Secretes thyroxine (T4) and triiodothyronine (T3), which regulate metabolism, and calcitonin, which helps lower blood calcium levels. citeturn0search1
- Pancreas: Releases insulin and glucagon to regulate blood glucose levels. citeturn0search1
- Thymus: Produces thymosin and thymopoietin, which are involved in T-cell development and immune function. citeturn0search1
- Hypothalamus: Synthesizes antidiuretic hormone (ADH) and oxytocin, which are stored and released by the posterior pituitary. citeturn0search1
- Adrenal cortex: Produces aldosterone, which regulates salt and water balance, and cortisol, which is involved in stress responses and metabolism. citeturn0search1
- Anterior pituitary: Secretes hormones like thyroid-stimulating hormone (TSH) and growth hormone (GH), which regulate various physiological processes. citeturn0search1
- Adrenal medulla: Produces epinephrine and norepinephrine, which prepare the body for ‘fight or flight’ responses. citeturn0search1
Question 9: Endocrine Organ Histology
The correct statement regarding endocrine organ histology is:
c. The adrenal cortex has three zones of cells that secrete steroid hormones.
Explanation:
- Adrenal Cortex: It consists of three distinct zones:
- Zona glomerulosa: Secretes mineralocorticoids like aldosterone.
- Zona fasciculata: Secretes glucocorticoids like cortisol.
- Zona reticularis: Secretes androgens.
- Thyroid Gland: It consists of follicles lined by a single layer of cuboidal epithelial cells, not stratified cuboidal cells. These follicles surround a colloid that stores thyroid hormones.
- Pancreas: The endocrine portion consists of pancreatic islets (islets of Langerhans) that secrete hormones like insulin and glucagon. The exocrine portion consists of acinar cells that produce digestive enzymes.
- Adrenal Medulla: It is composed of chromaffin cells derived from neural crest cells and functions as part of the sympathetic nervous system, not the parasympathetic nervous system.
Question 10: Negative Feedback in Endocrine Regulation
In a negative feedback loop, you would expect secretion from an endocrine gland to decrease after homeostasis has been restored.
Explanation:
Negative feedback mechanisms are fundamental to maintaining homeostasis. When a deviation from a set point occurs, an endocrine gland secretes hormones to counteract this change