Endocrine System & Hormone Balance Flashcards

Cortisol, the primary stress hormone, is produced by which gland?

Answer: Adrenal cortex

Cortisol is a glucocorticoid made in the adrenal cortex. The adrenal medulla produces epinephrine and norepinephrine.

What does the 'HPA axis' refer to?

Answer: Hypothalamus–Pituitary–Adrenal

The HPA axis is the feedback loop through which the hypothalamus (CRH) signals the pituitary (ACTH), which then signals the adrenals to release cortisol during stress.

Which mineral is required by the enzymes that convert inactive T4 to active T3?

Answer: Selenium

The deiodinase enzymes that convert T4 to T3 are selenium-dependent. Selenium deficiency can impair thyroid hormone activation even when iodine intake is adequate.

Which molecule is the precursor for all steroid hormones, including cortisol, estrogen, and testosterone?

Answer: Cholesterol

Cholesterol is converted to pregnenolone, which is the starting point for every steroid hormone. This is why very low-fat or low-cholesterol diets can affect hormone production.

Insulin is secreted by which cells?

Answer: Beta cells of the pancreas

Beta cells in the pancreatic islets release insulin in response to rising blood glucose. Alpha cells release glucagon.

Which organ plays a primary role in conjugating (deactivating) estrogen so it can be eliminated?

Answer: Liver

The liver conjugates estrogens through phase II detoxification pathways (glucuronidation, sulfation, methylation) so they can be excreted via bile and stool. Poor liver function or constipation can lead to estrogen recirculation.