System Structure: Endocrine - Massage and Bodywork Licensing Examination Mblex

1. Which gland secretes melatonin and helps regulate circadian rhythms?

   Pineal gland. Melatonin production varies with light exposure, modulating sleep-wake cycles and seasonal biological rhythms.

2. Which adrenal cortex hormone increases sodium retention and water retention?

   Aldosterone. This mineralocorticoid promotes renal sodium reabsorption, leading to osmotic water retention and blood pressure regulation.

3. Which thyroid hormone lowers blood calcium levels by inhibiting osteoclast activity?

   Calcitonin. Calcitonin promotes calcium deposition in bones by reducing osteoclast-mediated bone resorption.

4. Which ovarian hormone is most associated with maintaining the uterine lining for pregnancy?

   Progesterone. From the corpus luteum, it thickens the endometrium and inhibits uterine contractions to support implantation.

5. Which pancreatic hormone lowers blood glucose by promoting cellular uptake and storage?

   Insulin. From pancreatic beta cells, it facilitates glucose transporter activation for uptake and storage as glycogen.

6. What is the primary function of the endocrine system in the human body?

   Regulates body processes via hormones released into the bloodstream. This system maintains homeostasis by influencing metabolism, growth, reproduction, and other functions through hormonal signaling across distant tissues.

7. Which thyroid hormones primarily increase basal metabolic rate?

   Thyroxine (T4) and triiodothyronine (T3). These iodinated hormones enhance cellular oxygen consumption and heat production, elevating overall energy expenditure.

8. Which gland is considered the "master gland" because it regulates other endocrine glands?

   Pituitary gland. It produces tropic hormones that control the activity of other endocrine glands like the thyroid, adrenals, and gonads.

9. Which ovarian hormone is most associated with development of female secondary sex characteristics?

   Estrogen. Secreted by ovaries, it promotes breast development, fat distribution, and regulation of the menstrual cycle.

10. What does the anterior pituitary secrete to stimulate the adrenal cortex?

    Adrenocorticotropic hormone (ACTH). ACTH stimulates the adrenal cortex to produce glucocorticoids essential for stress response and metabolism.

11. Which gonadal hormone is primarily responsible for development of male secondary sex characteristics?

    Testosterone. Produced in testes, it drives development of muscle mass, deepening voice, and body hair patterns in males.

12. What does the anterior pituitary secrete to stimulate thyroid hormone production?

    Thyroid-stimulating hormone (TSH). TSH binds to thyroid receptors, prompting synthesis and release of thyroid hormones that regulate metabolism.

13. What is negative feedback in endocrine regulation?

    A rise in output inhibits further hormone release to maintain homeostasis. This regulatory loop senses elevated hormone levels and suppresses further secretion to stabilize physiological conditions.

14. Which hormone from the posterior pituitary increases water reabsorption by the kidneys?

    Antidiuretic hormone (ADH, vasopressin). ADH enhances aquaporin channels in renal collecting ducts, increasing water permeability to conserve body fluids.

15. What is the primary endocrine function of the thymus gland?

    Secretes thymosins that support T-lymphocyte maturation. Thymosins promote differentiation and maturation of T-cells crucial for adaptive immune responses.

16. Which part of the adrenal gland secretes epinephrine and norepinephrine?

    Adrenal medulla. The inner layer responds to sympathetic stimulation by releasing catecholamines for acute stress responses.

17. Which brain structure controls the pituitary gland and links nervous and endocrine systems?

    Hypothalamus. It releases releasing and inhibiting hormones that regulate pituitary secretions, integrating neural signals with endocrine responses.

18. Which pancreatic hormone raises blood glucose by stimulating glycogen breakdown?

    Glucagon. From alpha cells, it activates liver enzymes for glycogenolysis and gluconeogenesis to increase blood sugar.

19. Which adrenal cortex hormone is the primary glucocorticoid involved in stress response?

    Cortisol. As a glucocorticoid, it mobilizes energy reserves, suppresses immune function, and aids long-term stress adaptation.

20. What is a hormone, in endocrine system terminology?

    A chemical messenger secreted into blood to act on target cells. Hormones are signaling molecules that travel through the bloodstream to elicit specific physiological responses in distant target cells with appropriate receptors.

21. What is the term for a gland that releases its secretions directly into the bloodstream?

    Endocrine gland (ductless gland). These ductless glands release hormones directly into circulation for systemic effects on distant target organs.

22. Which posterior pituitary hormone stimulates uterine contractions and milk ejection?

    Oxytocin. Oxytocin binds to receptors in uterine and mammary smooth muscle, inducing contractions for labor and lactation.

23. What is the primary effect of parathyroid hormone (PTH) on blood calcium?

    Raises blood calcium levels. PTH stimulates bone resorption, renal calcium reabsorption, and vitamin D activation to elevate serum calcium.

24. Which glands secrete parathyroid hormone (PTH)?

    Parathyroid glands. Four small glands embedded in the thyroid produce PTH to regulate calcium and phosphate balance.

25. What is the primary action of growth hormone (GH) from the anterior pituitary?

    Stimulates body growth and protein synthesis. GH promotes cell division, amino acid uptake, and protein synthesis in bones and muscles to facilitate overall growth.

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