16. Endocrine System

Hypothalamus and the pituitary gland

Endocrine Organs

Hypothalamus and Pituitary Gland Functions

 The parathyroid’s glandular cells are arranged in thick, branching cords containing scattered oxyphil cells and large numbers of smaller parathyroid cells. The parathyroid cells secrete parathyroid hormone. The function of the oxyphil cells is unclear. 

 The cells found within the parathyroid glands that secrete parathyroid hormone are called __________. 

The Endocrine System

Hypothalamic Pituitary Axis

 an increase of growth hormone in an adult 

 An increase of growth hormone in an adult would lead to acromegaly, not osteitis fibrosa cystica. 

 An increase in ADH would not cause osteitis fibrosa cystica. 

 An increase in calcitonin would not cause osteitis fibrosa cystica. 

 Osteitis fibrosa cystica is caused by __________. 

 It is through the hypophyseal portal system that releasing and inhibiting hormones secreted by neurons in the ventral hypothalamus circulate to the adenohypophysis, where they regulate secretion of its hormones. 

 anterior pituitary gland (adenohypophysis) 

 The hypophyseal portal system transports releasing and inhibiting hormones from the hypothalamus to the __________. 

Follicular Cells & the Synthesis of Thyroid Hormones

Endocrine

 The production of functional thyroid hormone requires iodine. 

 Which of the following elements is required for the synthesis of thyroid hormone? 

 Excess growth hormone would cause acromegaly in adults. 

 Excess growth hormone would cause gigantism in children. 

 Excess growth hormone can lead to diabetes. 

 Excess growth hormone would cause all the following EXCEPT __________. 

Thyroid Hormone Synthesis

 Hyposecretion of growth hormone (GH) in adults usually causes no problems. GH deficiency in children results in slowed long-bone growth, a condition called pituitary dwarfism. 

 Which of the following homeostatic imbalances results from hyposecretion of growth hormone? 

 The anterior pituitary has traditionally been called the “master endocrine gland” because many of the numerous hormones it produces regulate the activity of other endocrine glands. In recent years, however, it has been dethroned by the hypothalamus, which is now known to control the activity of the anterior pituitary. 

 The anterior pituitary is known as the “master endocrine gland” because it controls the hypothalamus. 

Neuroscience: Melatonin

 Pro-opiomelanocortin (POMC) is a prohormone for __________. 

 Insulin enhances the membrane transport of glucose in all of these tissues except the brain. 

 Insulin enhances the membrane transport of glucose in all of the following tissues EXCEPT __________. 

 A deficiency of thymosin during fetal development would cause failure of the T lymphocytes to become immunocompetent. 

 Insulin deficiency leads to hypoglycemia and diabetes mellitus, but it does not present with these clinical features. 

 An excess of synthetic growth hormone might cause skeletal abnormalities, but it has not been associated with mental retardation. 

 A congenital condition that includes mental retardation; short, disproportional body size; and a thick tongue and neck is caused by __________. 

 Hypoparathyroidism, or PTH deficiency, most often follows parathyroid gland trauma or removal during thyroid surgery. However, an extended deficiency of dietary magnesium (required for PTH secretion) can cause functional hypoparathyroidism. The resulting hypocalcemia increases the excitability of neurons and accounts for the classical symptoms of tetany, such as loss of sensation, muscle twitches, and convulsions. Untreated, the symptoms progress to respiratory paralysis and death. 

 Which of the following conditions, if left untreated, progresses to respiratory paralysis and death? 

 The Golgi apparatus is involved in the production of the colloid part of thyroid hormones but not in their iodination. 

 Cell lysosomes are involved in the formation of thyroid hormone but not in the iodination process. 

 Colloid endocytosis is involved in the formation of thyroid hormones but not at the iodination stage. 

 Iodination of thyroid hormones is mediated by __________. 

 Polydipsia is one of the three cardinal signs of diabetes mellitus, in which dehydration stimulates the thirst centers of the hypothalamus, triggering excessive thirst. 

 Polydipsia is excessive __________ associated with diabetes mellitus. 

 Thyroid hormones control the consumption of oxygen by all body tissues by way of an increase in glucose metabolism. 

 The metabolic rate of most body tissues is controlled directly by __________. 

 Excess glucose levels in the blood stimulate beta cells in the pancreas to secrete insulin. 

 The stimulus for producing insulin is __________. 

 Growth hormone (GH; somatotropin) is produced by cells called somatotropic cells of the anterior lobe and has both growth-promoting and metabolic actions. Although GH stimulates most body cells to increase in size and divide, its major targets are the bones and skeletal muscles. 

 Which of the following stimulate(s) most body cells to increase in size and divide?  

 Resistin is a hormone produced by the adipose tissue. 

 Resistin, an insulin antagonist, is a hormone produced by the __________. 

 A goiter may form in the absence of iodine as colloid continues to be produced but cannot be iodinated to synthesize thyroid hormone. 

 Which hormone is NOT being synthesized if a goiter forms? 

Adrenal Gland Function

 As blood levels of oxytocin rise, the expulsive contractions of labor gain momentum and finally end in birth. 

 As blood levels of __________ rise, the expulsive contractions of labor gain momentum and finally end in birth. 

 Oxytocin and ADH are synthesized in the hypothalamus. 

 Which of the following is NOT synthesized in the pituitary gland? 

Neuroscience: Hypothalamus & Pituitary Gland

Calcium Homeostasis | Parathyroid Hormone and Vitamin D

THYROID HORMONES

 normal skeletal and nervous system development and maturation 

 Because TH provokes an increase in the number of adrenergic receptors in blood vessels, it plays an important role in maintaining blood pressure. Additionally, it is important in regulating tissue growth and development. It is critical for normal skeletal and nervous system development and maturation and for reproductive capabilities. 

 helping the body avoid dehydration and water overload 

 regulating tissue growth and development 

 Which of the following is NOT one of the areas in which thyroid hormone (TH) plays an important role? 

 ectopic ADH secretion by pulmonary cancer 

 Hypersecretion of ADH can occur from ectopic ADH secretion by pulmonary cancer. 

 Hypersecretion of ADH can occur after general anesthesia. 

 Hypersecretion of ADH can occur following neurosurgery. 

 Hypersecretion of antidiuretic hormone (ADH) can occur in all of the following situations EXCEPT __________. 

Homeostasis: Regulating Blood Sugar

Endocrine System: Response to Stress

Hypothalamic-Pituitary Axis

 In both sexes, follicle-stimulating hormone (FSH) stimulates gamete (sperm or egg) production and luteinizing hormone (LH) promotes production of gonadal hormones. 

 Which of the following hormones stimulates gamete (sperm or egg) production? 

Insulin and Glucagon

Regulation of Blood Calcium via PTH and Calcitonin

Thyroid Gland, Hormones and Thyroid Problems

 Addison’s disease, the major hyposecretory disorder of the adrenal cortex, usually involves deficits in both glucocorticoids and mineralocorticoids. Its victims tend to lose weight; their plasma glucose and sodium levels drop, and potassium levels rise. Severe dehydration and hypotension are common.  

 Which of the following homeostatic imbalances usually results from deficits in both glucocorticoids and mineralocorticoids?  

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