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The amplification of the signal from a water-soluble hormone is achieved through an increase in _______. water-soluble hormone in the blood |
cAMP in the cytoplasm Many cAMP can be generated as a second messenger to amplify the signal in response to hormone binding. |
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Water-soluble hormones affect target cells by binding to __________. cAMP |
plasma membrane receptors Water-soluble hormones bind to specific receptors in the plasma membrane, whereas steroid hormones bind to cytoplasmic receptors. |
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How do endocrine hormones reach their target cells? Hormones are transported through the blood stream to target cells. |
Hormones are transported through the blood stream to target cells. The blood stream allows hormones to be distributed throughout the body. |
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What is the role of activated protein kinases? Activate adenylate cyclase. |
Phosphorylate proteins. Phosphorylation can activate different proteins causing the response of the cell to water-soluble hormone. |
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Cyclic AMP is degraded by __________. protein kinase |
Phosphodiesterase degrades cyclic AMP into AMP. |
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Which of the following hormones has intracellular receptors? |
Yes, cortisol is one of the lipid-soluble steroid hormones. Thyroid hormones are also lipid soluble. |
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What is the mechanism of action of lipid-soluble hormones? phosphorylation of intracellular proteins |
activation of genes, which increases protein synthesis in the cell Yes, lipid-soluble hormones diffuse into the nucleus or they diffuse into the cytoplasm and then move into the nucleus, where they affect transcription and translation. |
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After a lipid-soluble hormone is bound to its intracellular receptor, what does the hormone complex do? phosphorylates a protein |
acts as a transcription factor and binds to DNA, activating a gene Yes, then mRNA is synthesized. |
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Which hormone’s receptor is always bound to DNA, even when the receptor is empty? thyroid hormone |
yes, thyroid hormones are lipid soluble and their receptors are bound to the response elements of the DNA. |
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What keeps intracellular receptors from binding to DNA before a hormone binds to the receptor? chaperone proteins (chaperonins) |
chaperone proteins (chaperonins). Yes, each receptor has two binding sites. The chaperone protein blocks the DNA binding site until a hormone binds at the hormone binding site. |
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Response to High Blood glucose |
1. Pancreas releases insulin 2. Body cells take up more glucose and liver takes up glucose and stores it as glycogen 3. Blood glucose decreases to normal |
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Response to low blood glucose |
1. Pancreas releases glucagon 2. Liver breaks down glycogen and releases glucose to the blood 3. Blood glucose increases to normal |
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Up-regulation involves the loss of receptors and prevents the target cells from overreacting to persistently high hormone levels. True or False? |
False. Down-regulation involves the loss of receptors and prevents the target cells from overreacting to persistently high hormone levels. |
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Which of the following occurs in situations where more than one hormone produces the same effects at the target cell and their combined effects are amplified? antagonism |
Synergism of hormones occurs in situations where one or more hormones produce the same effect at the target cell and their combined effects are amplified. |
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Hypocalcemia could be caused by the ______. apoptosis of parathyroid cells |
ALL. Parathyroid hormone (parathormone) is secreted in response to hypocalcemia. It functions to stimulate osteoclast activity, enhances the reabsorption of calcium by the kidneys, and increases absorption of calcium by the intestinal mucosal cells. |
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What hormone released into the blood (shown by letter D) by the posterior pituitary inhibits or prevents urine formation? thyroid-stimulating hormone (TSH) |
Antidiuretic hormone (ADH) targets the kidneys and modulates how much water is lost in the urine. |
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Where are the hormones oxytocin and antidiuretic hormone (ADH) stored? |
The axon terminals of neurons of the hypothalamic-hypophyseal tracts store and secrete ADH and oxytocin in the capillaries of the inferior hypophyseal artery. |
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What is the name for the type of hormone, secreted by the pituitary that regulates other endocrine organs? |
Tropins, or tropic hormones, are hormones that regulate the secretory action of other endocrine glands. |
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Which of the following hormones stimulates an increase in basal metabolic rate as a tropic hormone? adrenocorticotropic hormone |
Thyroid -stimulating hormone (TSH) stimulates the thyroid to release the hormone thyroxin, which increases metabolism in the body. |
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Which hormone aids in water resorption? parathyroid hormone |
Antidiuretic hormone (ADH) stimulates the kidney tubules to reabsorb water. |
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What tropic hormone stimulates cortisol from the adrenal gland? thyroid stimulating hormone (TSH) |
Yes, ACTH stimulates the adrenal cortex to produce cortisol. Stress and ACTH are the main stimuli for cortisol. |
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What is the function of the ventral hypothalamic neurons? control secretion of thyroid stimulating hormone (TSH) |
Yes, neurohormones from the ventral hypothalamic neurons, known as releasing (RH) and inhibiting (IH) hormones, control the release of anterior pituitary hormones such as adrenocorticotropic hormone (ACTH) and TSH. |
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Insulin-like growth factors (IGFs) are intermediary hormones stimulated by which of the following hormones? thyroid hormones |
Yes, GH stimulates IGFs from the liver. IGFs are required for the growth effect of GH on bone and skin. |
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Which of the following hormones is regulated by a neuroendocrine ("letdown") reflex? cortisol |
Yes, suckling of the infant (or stretching of the uterus) increases release of oxytocin, which causes the milk let-down effect (or increased uterine contractions). |
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Where is antidiuretic hormone (ADH), also known as vasopressin, synthesized? kidney |
Yes, ADH is synthesized mainly in the supraoptic nucleus of the hypothalamus. It is stored in the posterior pituitary in axon terminals. |
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What is the most important regulatory factor controlling the circulating levels of thyroid hormone? thyrotropin-releasing hormone (TRH) |
Yes, negative feedback controls the levels of circulating thyroid hormone. If levels are high, negative feedback will decrease thyroid-stimulating hormone (TSH) (and thyrotropin-releasing hormone (TRH) to some degree), thus decreasing the thyroid hormones. |
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Which of the following glands increases blood calcium levels? thyroid |
The parathyroid glands secrete PTH, which increases blood calcium levels. |
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What hormone, indicated by letter B, is released by the anterior pituitary to target the adrenal cortex when we are under stress? pg 618 textbook atrial natriuretic peptide (ANP) |
Adrenocorticotropic hormone (ACTH) from the pituitary modulates the release of aldosterone. The term tropic refers to a hormone that acts on another endocrine gland. |
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Which of these conditions would promote aldosterone release from the adrenal glands? pg 618 textbook A drop in blood pressure is sensed in the kidney. |
A drop in blood pressure would cause the kidney to release renin, a hormone that will eventually promote the release of aldosterone from the zona glomerulosa of the adrenal cortex. |
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Which letter represents the hormone that promotes a decrease in blood pressure and a loss of sodium and water in urine? |
The letter D indicates atrial natriuretic peptide, which is released from the heart when high blood pressure is sensed. It causes more sodium ("natrium") to be placed in the urine ("uretic"). Not Angiotensin II bc Angiotensin II is produced when blood pressure or blood volume is low. Angiotensin II stimulates the zona glomerulosa of the adrenal cortex to release aldosterone. Aldosterone regulates sodium and potassium in the blood and promotes an increase in blood volume and/or blood pressure. |
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Which of the following pairs correctly matches the adrenal gland zone, or area, with the class of hormones it produces? zona reticularis: aldosterone |
The zona glomerulosa produces mineralocorticoids. Zona fasciculata: glucocorticoids which are metabolic hormones. Zona Reticularis: gonadocorticoids. Medulla: catecholamins (Epinephrine and NE) |
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Which of the following best describes the hypoglycemic effect of insulin? [Histology of a pancreatic islet (islet of Langerhans).] pg 622-625 Insulin allows entry of glucose into most body cells. |
Insulin binds to receptor proteins in most body cells and allows membrane transport of glucose into these cells. |
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Which of the following brain structures would cause central diabetes insipidus if it were damaged? pons |
Hypothalmus |
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