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Questions and Answers
What is the principal action of the hormone prolactin?
Which hormone produced by the anterior pituitary is most abundant and directly stimulates growth of all body tissues?
Which condition is characterized by an overproduction of adrenocorticotrophic hormone (ACTH)?
What effect does excess secretion of growth hormone have after the epiphyseal growth plates have closed?
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What does arginine vasopressin primarily regulate?
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What is the precursor of endorphins found in the posterior pituitary?
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Which factor primarily inhibits the release of growth hormone?
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Destruction of neurons in or near the hypothalamus can lead to which condition related to vasopressin?
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What is the primary function of luteinizing hormone in males?
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Which of the following hormones promotes uterine contractions during childbirth?
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Study Notes
Pituitary Gland - The Master Gland
- Pea-sized, bilobed structure located beneath the hypothalamus
- Divided into anterior (adenohypophysis) and posterior (neurohypophysis) segments
- Anterior is derived from upper GI cells during development
- Posterior is derived from neural tissue
- Releases hormones that regulate various bodily processes, including homeostasis, growth, reproduction, lactation, and thyroid hormone release
Anterior Pituitary Hormones
-
Human Growth Hormone (GH)
- Secreted by somatotropes
- Accelerates body growth and opposes insulin action
- Excess GH secretion leads to giantism (before epiphyseal plate closure) or acromegaly (after plate closure)
- Release stimulated by GH-releasing hormone, stress, sleep, hypoglycemia, fasting, estrogens, dopamine, and α-adrenergic agonists
- Release inhibited by GH-inhibiting hormone, pregnancy, hyperglycemia, cortisol, and obesity
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Prolactin
- Secreted by lactotropes
- Stimulates milk secretion and maternal behavior
- Inhibits ovulation
- Release stimulated by stress, pregnancy, and certain medications (metoclopramide, cimetidine, opioids, methyldopa)
-
Luteinizing Hormone (LH)
- Secreted by gonadotropes
- Stimulates ovulation in females
- Stimulates testosterone secretion in males
-
Follicle-Stimulating Hormone (FSH)
- Secreted by gonadotropes
- Stimulates ovarian follicle growth in females
- Supports spermatogenesis in males
-
Adrenocorticotrophic Hormone (ACTH)
- Secreted by corticotropes
- Stimulates adrenal cortex growth and steroid production
- Release stimulated by stress, hypoglycemia, trauma, low cortisol, α-agonists, and β-antagonists
- Excess ACTH production leads to Cushing Syndrome
-
Thyroid-Stimulating Hormone (TSH)
- Secreted by thyrotropes
- Stimulates thyroid growth and hormone secretion
Posterior Pituitary Hormones
-
Antidiuretic Hormone (AVP) / Vasopressin
- Stored in the posterior pituitary
- Synthesized in the supraoptic nuclei of the hypothalamus
- Promotes water retention and regulates plasma osmolarity
-
Oxytocin
- Stored in the posterior pituitary
- Synthesized in the paraventricular nuclei of the hypothalamus
- Causes milk ejection and uterine contraction
Posterior Pituitary Disorders
-
Diabetes Insipidus
- Occurs due to decreased AVP production/release
- Can be caused by damage to the supraoptic and paraventricular nuclei from surgery, trauma, cerebral ischemia, or malignancy
-
Syndrome of Inappropriate Antidiuretic Hormone (SIADH)
- Occurs due to excess AVP production/release
- Can be caused by head injury, tumors, meningitis, and certain infections
- Commonly associated with small cell lung cancer
- Characterized by dilutional hyponatremia
- Assessed by urine specific gravity
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Description
Test your knowledge about the pituitary gland, its structure, and the hormones it produces. This quiz covers both the anterior and posterior segments, emphasizing their roles in growth, reproduction, and metabolic regulation. Understand the significance of hormones like Human Growth Hormone and Prolactin.
