Anatomy and Physiology Answer Key

2 the pituitary produces gh and tsh tsh controls the

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Unformatted text preview: TSH is controlled by a regulating factor, thyrotropin releasing factor (hormone) or TRF(TRH) from the hypothalamus. Low levels of thyroid hormones or low metabolic rate stimulate release of TRF from the hypothalamus. TRF stimulates release of TSH (and increase secretion of thyroid hormones). When normal thyroid hormone levels are restored, TRF release stops. 4. Iodine deficiency results in the thyroid swelling because TSH is stimulating the gland to make thyroxin and T3. This condition is called goiter. Note: Iodine deficiency is also responsible for some cases of thyroid underactivity (hypothyroidism). The Hypothalamus and Pituitary (page 97) Anatomy and Physiology 1. (a) The anterior pituitary is glandular and secretes hormones in response to releasing hormones from the hypothalamus. The posterior pituitary is neural in origin and simply stores and releases neurohormones that originate in the hypothalamic neurosecretory cells. (b) The posterior pituitary secretes neurohormones from modified secretory neurons, whereas the anterior pituitary secretes peptide hormones when influenced by other hormonal signals. 2. Neurosecretory cells in the hypothalamus produce oxytocin and ADH which are stored in, and released from, the posterior pituitary. Other neurohormones secreted by the hypothalamus control the release of hormones from the anterior pituitary. 3. The functioning of the adrenal and thyroid glands relies on the influence of regulatory hormones from the anterior pituitary. Without the input of these hormones, there is no stimulation of the glands and they become underactive and atrophy. Note: ACTH deficiency as a result of pituitary malfunction is one of the most serious. Disorders of thyroid function most commonly result from thyroid disorders directly rather than pituitary insufficiency. 4. The hypothalamus controls the activity of the hormonal secretion from the pituitary. Without its regulatory input, the pituitary would cease to function. The Stress Response (page 98) 1. The body's short term response to stress is adaptiv...
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