All flashcards
Flashcard 1: Which adrenal cortex layer secretes cortisol?
Answer: Zona fasciculata. This middle layer synthesizes glucocorticoids like cortisol in response to ACTH for stress adaptation and immune modulation.
Flashcard 2: Which adrenal cortex layer secretes androgens such as DHEA?
Answer: Zona reticularis. This innermost layer generates weak androgens that serve as precursors for sex hormone synthesis in peripheral tissues.
Flashcard 3: Which thyroid gland cell type secretes calcitonin?
Answer: Parafollicular (C) cells. These cells lower serum calcium by inhibiting osteoclast activity and promoting renal calcium excretion.
Flashcard 4: What is the defining property of peptide hormones regarding membrane permeability and receptor location?
Answer: Water-soluble; bind cell-surface receptors. Their hydrophilic nature prevents membrane crossing, so they activate G-protein-coupled receptors to initiate intracellular signaling.
Flashcard 5: Which hormone increases serum calcium by increasing bone resorption and renal calcium reabsorption?
Answer: Parathyroid hormone (PTH). It elevates blood calcium levels by stimulating osteoclasts and enhancing renal and intestinal calcium absorption.
Flashcard 6: Which endocrine gland is the master regulator that secretes tropic hormones to control other glands?
Answer: Anterior pituitary. It acts as the central controller by releasing tropic hormones that stimulate and regulate hormone production in target endocrine glands.
Flashcard 7: What is the key anatomical link that connects the hypothalamus to the posterior pituitary?
Answer: Infundibulum (pituitary stalk). This structure facilitates the transport of hormones from hypothalamic neurons to the posterior pituitary for storage and release.
Flashcard 8: Which two hormones are synthesized in the hypothalamus and released from the posterior pituitary?
Answer: ADH (vasopressin) and oxytocin. These hormones are produced in hypothalamic nuclei and transported via axons to the posterior pituitary for secretion into the bloodstream.
Flashcard 9: What is the primary physiologic effect of ADH on the kidney?
Answer: Increases water reabsorption in collecting ducts. It promotes aquaporin insertion in renal collecting ducts, enhancing water permeability and reducing urine volume to maintain blood osmolarity.
Flashcard 10: What is the primary reproductive physiologic effect of oxytocin?
Answer: Stimulates uterine contractions and milk ejection. It binds to receptors in uterine smooth muscle and mammary myoepithelial cells, facilitating labor and milk letdown during breastfeeding.
Flashcard 11: Which anterior pituitary hormone directly stimulates the thyroid gland to secrete T3 and T4?
Answer: TSH (thyroid-stimulating hormone). It binds to thyroid receptors, promoting the synthesis and release of thyroid hormones that regulate metabolism and development.
Flashcard 12: Which anterior pituitary hormone stimulates the adrenal cortex to secrete cortisol?
Answer: ACTH (adrenocorticotropic hormone). It targets the adrenal cortex to induce glucocorticoid production, which modulates stress responses and metabolism.
Flashcard 13: Which anterior pituitary hormone stimulates ovarian follicle development and Sertoli cell function?
Answer: FSH (follicle-stimulating hormone). It promotes gametogenesis by stimulating follicle maturation in ovaries and spermatogenesis support in testicular Sertoli cells.
Flashcard 14: Which anterior pituitary hormone triggers ovulation and stimulates Leydig cells to produce testosterone?
Answer: LH (luteinizing hormone). It surges to induce egg release in females and stimulates androgen production in male Leydig cells for reproductive function.
Flashcard 15: Which anterior pituitary hormone stimulates milk production in the mammary glands?
Answer: Prolactin. It acts on mammary alveolar cells to promote lactogenesis, essential for postpartum milk synthesis and secretion.
Flashcard 16: Which hypothalamic hormone inhibits prolactin release from the anterior pituitary?
Answer: Dopamine (prolactin-inhibiting factor). It tonically suppresses prolactin secretion via the hypothalamic-pituitary portal system, preventing inappropriate lactation.
Flashcard 17: Which anterior pituitary hormone stimulates linear bone growth and increases IGF-1 production?
Answer: Growth hormone (GH). It promotes tissue growth by direct anabolic effects and indirectly via liver-derived IGF-1, crucial for development and metabolism.
Flashcard 18: Which endocrine gland secretes melatonin to regulate circadian rhythms?
Answer: Pineal gland. It produces melatonin in response to darkness, influencing sleep-wake cycles and seasonal biological rhythms.
Flashcard 19: Which hormone increases blood glucose primarily by stimulating glycogenolysis and gluconeogenesis?
Answer: Glucagon. It acts on liver enzymes to break down glycogen and synthesize glucose, maintaining blood sugar levels during fasting.
Flashcard 20: Which adrenal region secretes epinephrine and norepinephrine?
Answer: Adrenal medulla. This chromaffin cell-rich region responds to sympathetic stimulation by releasing catecholamines for fight-or-flight responses.
Flashcard 21: Which adrenal cortex layer secretes aldosterone?
Answer: Zona glomerulosa. This outermost layer produces mineralocorticoids under renin-angiotensin system control to regulate electrolyte balance.
Flashcard 22: What is the defining property of steroid hormones regarding transport and receptor location?
Answer: Lipid-soluble; intracellular receptors; carrier-bound. Derived from cholesterol, they diffuse through membranes to bind nuclear receptors, altering gene expression, and require plasma carriers for transport.
Flashcard 23: Which hormone class typically uses second messengers such as cAMP to amplify the signal?
Answer: Peptide (and catecholamine) hormones. They activate membrane receptors linked to signaling cascades that amplify responses via molecules like cAMP for rapid cellular effects.