Module 9 - Alterations of Hormonal Regulation

Regulation of the release of T3 and T4 from the thyroid gland is controlled by: A) neural feedback. B) negative feedback. C) positive feedback. D) all of the above. B) negative feedback. Thyroid hormone, like most other hormones, is regulated through negative feedback. An example of neural regulation is the release of epinephrine from the adrenal medulla. An example of positive feedback or feed-forward control is the release of oxytocin to stimulate labor during pregnancy. Thyroid hormone levels are regulated through negative feedback only. Which of the following is a steroid hormone? A) Insulin B) Thyroxine (T4) C) Cortisol D) Growth hormone C) Cortisol Cortisol is one example of a steroid hormone. Insulin and growth hormone are protein hormones. Although T4 is lipid soluble like steroid hormones, it is an amine hormone. 01:22 01:35 To adapt to high hormone concentrations, many target cells have the capacity for: A) negative feedback. B) positive feedback. C) up-regulation. D) down-regulation. D) down-regulation. To adapt to high levels of hormones, some cells have the capacity to decrease the number of receptors for that hormone through the process of down-regulation. Growth hormone is secreted into the bloodstream by the: A) anterior pituitary. B) posterior pituitary. C) hypothalamus. D) thymus. A) anterior pituitary. Growth hormone from the anterior pituitary regulates metabolic processes related to cellular growth. The posterior pituitary releases antidiuretic hormone and oxytocin. The hypothalamus releases hormones that control the release of anterior pituitary hormones, including growth hormone. The thymus is not an endocrine gland. Target cells for aldosterone are located in the: A) adrenal cortex. B) adrenal medulla. C) liver. D) kidneys. D) kidneys. Aldosterone stimulates sodium reabsorption by the kidneys. The primary effect of antidiuretic hormone (ADH) in the kidneys is to stimulate: A) water reabsorption. B) sodium reabsorption. C) sodium and water excretion. D) acid secretion. A) water reabsorption. The presence of ADH makes the renal tubules more permeable to water, which enhances water reabsorption. ADH does not affect sodium reabsorption in the kidneys. The presence of ADH makes the renal tubules more permeable to water, which enhances water reabsorption and decreases water excretion. The presence of ADH makes the renal tubules more permeable to water, which enhances water reabsorption. The presence of aldosterone will stimulate hydrogen ion (acid) secretion. Calcitonin and parathyroid hormone strictly regulate serum levels of: A) potassium. B) calcium. C) iron. D) magnesium. B) calcium. Together, calcitonin and parathyroid hormone regulate calcium levels in the blood. Which of the following nutrients is essential for thyroid hormone synthesis? A) Iron B) Iodine C) Phosphate D) Calcium B) Iodine An essential ingredient for thyroid hormone synthesis is iodine. The main function of thyroid hormone (T3 and T4) is control of: A) gastric secretions. B) synaptic activity. C) insulin secretion. D) metabolic rate. D) metabolic rate. Increased secretion of thyroid hormone results in increased metabolic rate of all cells. Synaptic activity is not under the direct control of the endocrine system. Increased secretion of thyroid hormone results in increased metabolic rate of all cells. Increased thyroid hormone levels in the blood result in: A) further stimulus to produce thyroid hormone. B) decreased release of thyroid-stimulating hormone from the anterior pituitary. C) increased secretion of thyrotropin-releasing hormone from the hypothalamus. D) inhibition of parathyroid hormone release from the parathyroid glands. B) decreased release of thyroid-stimulating hormone from the anterior pituitary. Increased thyroid hormone levels provide negative feedback to the hypothalamus and anterior pituitary to shut off production of thyrotropin-releasing hormone and thyroid-stimulating hormone, respectively. Which cells in the pancreas secrete insulin? A) Alpha B) Beta C) Delta D) Acinar B) Beta Alpha cells secrete glucagon. Beta cells secrete insulin. Delta cells secrete somatostatin. Acinar cells secrete pancreatic digestive enzymes. The primary physiologic effect of insulin is to: A) stimulate nutrient absorption from the digestive tract. B) raise blood glucose levels. C) decrease basal metabolic rate. D) promote glucose uptake into cells. D) promote glucose uptake into cells. Insulin does not affect nutrient absorption from the digestive tract; rather, it stimulates glucose uptake into cells. Insulin lowers blood sugar levels by stimulating glucose uptake into cells. In addition to stimulating glucose uptake into cells, insulin also increases the metabolic rate of cells. promote glucose uptake into cells. The presence of insulin stimulates the transport of glucose into cells to be stored or used as a substrate for metabolism.