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What is a mediator molecule that is released in one part of the body but regulates the activity of cells in other parts of the body?
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Secrete their products into ducts that carry the secretions into body cavities, into the lumen of an organ, or to the outer surface of the body?
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A&P II Test 1
| Question | Answer |
|---|---|
| What is a mediator molecule that is released in one part of the body but regulates the activity of cells in other parts of the body? | hormone. |
| Secrete their products into ducts that carry the secretions into body cavities, into the lumen of an organ, or to the outer surface of the body? | exocrine glands. |
| Secrete their products (hormones) into the interstitial fluid surrounding the secretory cells rather into ducts? | endocrine glands. |
| Nervous system: mediator molecules? | neurotransmitters released locally in response to nerve impulses. |
| Endocrine system: mediator molecules? | hormones delivered to tissues throughout body by the blood. |
| Nervous system: site of mediator action? | close to site of release, at synapse; binds to receptors in postsynaptic membrane. |
| Endocrine system: site of mediator action? | far from site of release (usually); binds to receptors on or in target cells. |
| Nervous system: types of target cells? | muscle (smooth, cardiac, and skeletal) cells, gland cells, other neurons. |
| Endocrine system: types of target cells? | cells throughout body. |
| Nervous system: time to onset of action? | typically within milliseconds (thousandths of a second). |
| Endocrine system: time to onset of action? | seconds to hours or days. |
| Nervous system: duration of action? | generally briefer (milliseconds). |
| Endocrine system: duration of action? | generally longer (seconds to days). |
| What are the chemical classes of hormones? | lipid soluble and water soluble. |
| Lipid soluble hormones include | steroid hormones, thyroid hormones, and nitric oxide. |
| Water soluble hormones include | amine hormones, peptide and protein hormones, and eicosanoid hormones. |
| Hormones influence their target cells by what? | chemically binding to specific protein receptors. |
| If a hormone is present in excess, the number of target-cell receptors may decrease an effect called what? | down-regulation. |
| Down-regulation makes a target cell _________ to a hormone. | less sensitive. |
| When a hormone is deficient, the number of receptors may increase this is known as what? | up-regulation. |
| Up-regulation makes a target cell ______ to a hormone. | more sensitive. |
| Hormone secretion is regulated by | signals from the nervous system, chemical changes in the blood, and other hormones. |
| What gland was called the master gland and why? | pituitary gland; it secretes several hormones that control other endocrine glands. |
| We now know that the pituitary gland itself has a master- | hypothalamus. |
| The pituitary and hypothalamus play important roles in the | regulation of virtually all aspects of growth, development, metabolism, and homeostasis. |
| What gland has a pea shaped structure that measures 1-1.5cm in diameter and lies in the hypophyseal fossa of the sella turcica of the sphenoid bone? | pituitary gland. |
| The pituitary gland attaches to the hypophyseal by a stalk, which is called what? | infundibulum. |
| What is another name for the anterior pituitary gland? | adenohypophysis. |
| What are the two parts of the anterior pituitary gland? | pars distaslis and pars tuberalis. |
| What is another name for the posterior pituitary gland? | neurohyophysis. |
| What are the two parts of the posterior pituitary gland? | pars nervosa and pars intermedia. |
| Mechanism of action of the lipid soluble steroid hormones and thyroid hormones (1) | a free lipid soluble hormone molecule diffuses form the blood, through interstitial fluid, and through the lipid bilayer of the plasma membrane into a cell. |
| Mechanism of action of the lipid soluble steroid hormones and thyroid hormones (2) | if the cell is a target cell, the hormone binds to and activates receptors located within the cytosol or nucleus. The activated receptor-hormone complex then alters gene expression: it turns specific genes of the nuclearDNA on or off. |
| Mechanism of action of the lipid soluble steroid hormones and thyroid hormones (3) | as the DNA is transcribed, new messenger RNA (mRNA) forms, leaves the nucleus, and enters the cytosol. There, it directs synthesis of a new protein, often an enzyme on the ribosomes. |
| Mechanism of action of the lipid soluble steroid hormones and thyroid hormones (4) | the new proteins alter the cell's activity and cause the responses typical of that hormone. |
| Mechanism of action of the water soluble hormones (amines, peptides, proteins, eicosanoids) (1) | binding of hormone (first messenger) to its receptor activates G protein, which activates adenylate cyclase. |
| Mechanism of action of the water soluble hormones (amines, peptides, proteins, eicosanoids) (2) | adenylate cyclase converts ATP into cyclic AMP (cAMP). Because the enzyme's activate site is on the inner surface of the plasma membrane, this reaction occurs in the cytosol of the cell. |
| Mechanism of action of the water soluble hormones (amines, peptides, proteins, eicosanoids) (3) | cyclic AMP (the second messenger) activates one or more protein kinases, which may be free in the cytosol or bound to the plasma membrane. A protein kinase is an enzyme that phosphorylates (adds a phosphate group to) other cellular proteins. |
| Mechanism of action of the water soluble hormones (amines, peptides, proteins, eicosanoids) (4) | activated protein kinases phosphorylate one or more cellular proteins. Phosphorylation activates some of these proteins and inactivates others, rather like turning a switch on or off. |
| Mechanism of action of the water soluble hormones (amines, peptides, proteins, eicosanoids) (5) | phosphorylated proteins in turn cause reactions that produce physiological responses. |
| Mechanism of action of the water soluble hormones (amines, peptides, proteins, eicosanoids) (6) | after a brief period, an enzyme called phosphodiesterase inactivates cAMP. Thus, the cell's response is turned off unless new hormone molecules continue to bind to their receptors in the plasma membrane. |
| The responsiveness of a target cell to a hormone depends on | (1) the hormone's concentration in the blood, (2) the abundance of the target's cell's hormone receptors, and (3) influences exerted by other hormones. |
| Hormone secretion is regulated by | (1) signals from the nervous system, (2) chemical changes in the blood, and (3) other hormones. |
| Human growth hormone (hGH) is secreted by | somatotrophs. |
| Thyroid-stimulating hormone (TSH) is secreted by | thyrotrophs. |
| Follicle-stimulating hormone (FSH) is secreted by | gonadotrophs. |
| Lutenizing hormone (LH) is secreted by | gonadotrophs. |
| Prolactin (PRL) is secreted by | lactotrophs. |
| Adrenocorticotropic hormone (ACTH) is secreted by | cortcotrophs. |
| Melanocyte-stimulating hormone (MSH) is secreted by | corticotrophs. |
| Human growth hormone stimulates several tissues to secrete | insulinlike growth factors, hormones that stimulate general body growth and regulate aspects of metabolism. |
| FSH and LH stimulate secretion of | estrogens and progesterone and the maturation of oocytes in the ovaries, and they stimulate sperm production and secretion of testosterone in the testes. |
| Prolactin initiates what | milk production in the mammary glands. |
| ACTH stimulates the | adrenal cortex to secrete glucocorticoids such as cortisol. |
| Target tissue for hGH? | liver. |
| Target tissue for TSH? | thyroid gland. |
| Target tissue for FSH? | ovaries and testes. |
| Target tissue for LH? | ovaries and testes. |
| Target tissue for PRL? | mammary glands. |
| Target tissue for ACTH? | adrenal cortex. |
| Target tissue for MSH? | brain. |
| Where is the thyroid located? | just inferior to the larynx (voice box). |
| Parathyroid hormone is the major regulator of the | levels of calcium, magnesium, and phosphate. |
| The specific action of PTH is to increase the | number and activity of osteoclasts. |
| The adrenal cortex is subdivided into three zones, which are | zona gomerulosa, zona fasciculata, and zona reticularis. |
| What is the outer layer of the adrenal cortex? | zona glomerulosa. |
| In the zona glomerulosa; the cells are closely packed and arranged in spherical clusters and arched columns, secrete hormones called | mineralocorticoids. |
| What is the middle zone of the adrenal cortex? | zona fasciculata. |
| The cells of zona fasciculata secrete mainly what? | glucocortcoids. |
| What is the inner zone of the adrenal cortex? | zona reticularis. |
| The zona reticularis synthesizes small amounts of what? | weak androgens, steroid hormones that have masculinizing effects. |
| Glucocorticoids have what effects? | protein breakdown, glucose formation, lipolysis, resistance to stress, anti-inflammatory effects, depression of immune responses. |
| What are the two major hormones synthesized by the adrenal medulla are what? | epinephrine and norepinephrine. |
| Alpha cells of the pancreatic islets secrete what? | glucagon. |
| Beta cells of the pancreatic islets secrete what? | insulin. |
| Delta cells of the pancreatic islets secrete what? | somatostatin. |
| F cells of the pancreatic islets secrete what? | pancreatic polypeptide. |
| Where is the pineal gland located? | it is attached to the roof of the third ventricle of the brain at the midline. |
| What does the pineal gland secrete? | melatonin. |
| Melatonin appears to contribute to the what? | setting of the body's biological clock. |
| Where is the thymus located? | behind the sternum between the lungs. |
| A liquid connective tissue that consists of cells surrounded by a liquid extracellular matrix? | blood. |
| Is the fluid that bathes body cells and is constantly renewed by the blood? | interstitial fluid. |
| What are the functions of the blood? | transportation, regulation, protection. |
| Whole blood has two components what are they? | blood plasma and formed elements. |
| A watery liquid extracellular matrix that contains dissolved substances is what? | blood plasma. |
| What are the proteins in blood? | albumins, globulins, and fibrinogen. |
| Formed elements consist of what in blood? | platelets, white blood cells, and red blood cells. |
| What are the different types of white blood cells? | neutrophils, leukocytes, monocytes, eosinophils, basophils. |
| The percentage of total blood volume occupied by RBC's is called what | hematocrit. |
| Polycythemia? | the percentage of RBCs is abnormally high. |
| What are some causes of polycythemia? | abnormal increases in RBC production, tissue hypoxia, dehydration, and blood doping or the use of EPO by athletes. |
| The process by which the formed elements of blood develop is called | hemopoiesis. |
| EPO (erythropoietin) does what? | increases the number of red blood cell precursors. |
| Where is EPO produced? | by cells in the kidneys that lie between the kidney tubules. |
| Thrombopoietin (TPO) is what? | a hormone produced by the liver that stimulates the formation the formation of platelets from megakarocytes. |
| What is oxygen carrying protein? | hemoglobin. |
| Red blood cells live only about | 120 days because of the wear and tear their plasma membranes undergo as they squeeze through blood capillaries. |
| What is the name for the production of RBCs? | erythropoiesis. |
Created by:
danreid