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108 Cards in this Set
- Front
- Back
Name the functions of the endocrine system. |
1. metabolism and tissue maturation 2. ion regulation 3. water balance 4. immune system regulation 5. heart rate and blood pressure regulation 6. control of blood glucose and other nutrients 7.control of reproductive function 8. uterine contraction and milk release |
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What are the two main differences between the endocrine system and the nervous system? |
1. endocrine system is amplitude-modulated whereas nervous system is frequency-modulated 2. the response of target tissues to hormones is usually slower and of longer duration than that of neurons |
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Definition: chemical substances secreted by cells into the interstitial fluid and diffuse into the blood |
hormones |
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Hormones act on specific tissues called __________. They have lag times from a few _____ to _____. Hormones also tend to have prolonged effects. |
target tissues seconds hours |
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What are the four protein groups of hormones? |
proteins, glycoproteins, polypeptides, and amino acid derivatives |
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What are the two lipid groups of hormones? |
steroids and fatty acid derivatives |
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What controls the secretion of most hormones? |
negative feedback |
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What are the three mechanisms by which hormone secretion from endocrine tissue is regulated? |
1. changes in extracellular concentration of non-hormones substances 2. stimulation by the nervous systems 3. stimulation by a hormone from another endocrine tissue |
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TRH is released from the ______ and stimulates _____ release from the ______. Then ____ travels in the blood to stimulate the ______ gland to release ______ hormones. These hormones have a negative feedback effect on the _______ and the ______. |
hypothalamus TSH anterior pituitary gland TSH thyroid thyroid hypothalamus anterior pituitary gland |
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________ hormones do not bind the plasma proteins and/or readily diffuse out of the blood. They are quickly ____________ or taken up by tissues. They regulate activities that have a _____ and a ______. Examples include _____, _____, ______. |
water-soluble broken down by enzymes rapid onset short duration proteins epinephrine norepinephrine |
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______ and ______ hormones are not easily removed from the blood. They produce a _____ effect. |
lipid-soluble thyroid prolonged |
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Hormones either leave the blood to reach ______ or are excreted by the _____ or _____. |
target tissues kidneys liver |
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Definition: receptors that span the plasma membrane; bind to water-soluble or large-molecular-weight hormones |
membrane-bound receptors |
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Definition: receptors in the cell cytoplasm of nucleus; bind to lipid-soluble hormones |
intracellular receptors |
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What is the main function of intracellular receptors? |
To activate genes for protein or enzyme synthesis |
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What are the functions of the membrane-bound receptors? |
1. act on G proteins to open or close ion channels and activate existing enzymes 2. alter the activity of intracellular enzymes to activate existing enzymes |
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What are the three subunits of G proteins? |
alpha, beta, gamma |
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What are the active and inactive states of G proteins? |
GDP - inactive GTP - active |
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What is the function of G proteins? |
To produce responses when activated by membrane-bound receptors |
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Name three hormones that activate G proteins. |
LH, FSH, TSH, oxytocin, ADH, calcitonin, PTH, glucagon, epinephrine |
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What are the steps in the process of G protein activation? |
1. Hormone binds to a membrane-bound receptor 2. Receptor is altered and G protein binds to it. GTP replaces GDP alpha subunit 3. G protein separates from the receptor. GTP alpha subunit separates from G protein. 4. Hormone separates from its receptor. GTP's phosphate is cleaved and the remaining GDP binds to the G protein. |
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How does the GTP alpha subunit induce a cell response? |
It binds to a Ca+2 ion channel, causing it to open. Ca+2 flows in and binds to calmodulin which produces a cell response.
If its an enzyme, the GTP binds to the enzyme and activates it. The enzyme converts ATP to cAMP and 2PPi. cAMP is a intracellular modulator and activates protein kinases. |
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How do intracellular enzymes activated by a membrane-bound receptor initiate a cell response? |
1. they synthesize intracellular mediators 2. they add phosphate groups to intracellular enzymes, which alters their activity |
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Why do intracellular mediator mechanisms act so rapidly? |
They work on already existing enzymes to produce a cascade effect |
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How do intracellular receptors work? |
1. Hormone diffuses through the membrane and binds with a receptor. 2. Receptor-hormone complex diffuses into the nucleus where it activates genes. 3. mRNA is produced. 4. mRNA initiates the production of certain proteins that produce the response |
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Intracellular mechanisms are _____-acting because _________________. |
slow time is required to produce mRNA and protein |
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Steroid hormones are _______. They travel in the blood _______. |
water-soluble attached to protein carriers |
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The pituitary gland secretes at least __ hormones that regulate numerous body functions and other glands. The hypothalamus regulates ______ activity through _____ and ______. |
9 pituitary gland hormones action potentials |
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The posterior pituitary is called the _________. It develops from the ______ and connects to the hypothalamus by the ______. |
neurohypophysis floor of the brain infundibulum |
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The anterior pituitary is called the ______. It develops from the _______. |
adenohypophysis roof of the mouth |
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The _______________ connects the hypothalamus and the anterior pituitary. Hormones are produced in the ________. Through this, the hormones ____ or _____ hormone production in the anterior pituitary. |
hypothalamohypophyseal portal system hypothalamic neurons inhibit stimulate |
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The _______________ connects the hypothalamus and the posterior pituitary. Hormones are produced in the ________. The hormones move down the _______ and are secreted from the ______. |
hypothalamopophyseal tract hypothalamic neurons axons of the tract posterior pituitary |
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What two hormones does the neurohypophysis store/secrete and what do they do? |
Anti-diuretic hormone (ADH): promotes water retention by the kidneys Oxytocin: promotes uterine contractions during delivery and causes milk ejection in lactating women |
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Name 4 hormones that the anterior pituitary releases. |
growth hormone (GH) thyroid-stimulating hormone (TSH) adrenocorticotropic hormones (ACTH) melanocyte-stimulating hormone (MSH) luteinizing hormone (LH) follicle-stimulating hormone (FSH) prolactin |
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GH stimulates growth in ________ and is a regulator of _____. It stimulates the uptake of ____ and their ________, the breakdown of ____ and the synthesis of _____, and the production of _________ (which promote ____ and ____ growth). |
most tissues metabolism amino acids conversion into proteins fats glucose somatomedins bone catrilage |
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GH secretion increases in response to ______, ____, and an increase in certain ______. It is regulated by _____ and ______. |
low blood glucose stress amino acids growth hormone-releasing hormone (GHRH) growth hormone-inhibiting hormone (GHIH) |
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The pituitary gland is located in the _____ of the _____ bone. |
sella turcica sphenoid |
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The _____ is the largest gland in the body and is connected by a median tissue mass called the _____. It is composed of _____ that produce the glycoprotein ______. Other endocrine cells, called the __________, produce the hormone ______. |
thyroid isthmus follicles thyroglobulin parafollicular cells calcitonin |
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Thyroid hormones consist of two _____-containing compounds: __________ (90%) and __________ (10%). |
iodine triiodothyronine (T3) tetraiodothyronine (T4) |
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Name the release origin, function, and target tissue of ADH. |
Origin: posterior pituitary Target Tissue: kidney Function: increased water reabsorption |
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Name the release origin, function, and target tissue of oxytocin. |
Origin: posterior pituitary Target Tissue: uterus; mammary glands Function: increased uterine contractions; increased milk expulsion |
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Name the release origin, function, and target tissue of GH. |
Origin: anterior pituitary Target Tissue: most tissues Function: increased growth |
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Name the release origin, function, and target tissue of TSH. |
Origin: anterior pituitary Target Tissue: thyroid gland Function: increased thyroid hormone secretion |
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Name the release origin, function, and target tissue of ACTH. |
Origin: anterior pituitary Target Tissue: adrenal cortex Function: increased glucocorticoid hormone secretion |
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Name the release origin, function, and target tissue of MSH. |
Origin: anterior pituitary Target Tissue: melanocytes in skin Function: increased melanin production in melanocytes (makes skin darker) |
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Name the release origin, function, and target tissue of LH. |
Origin: anterior pituitary Target Tissue: ovaries/testes Function: ovulation and progesterone production; testosterone synthesis and sperm cell production |
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Name the release origin, function, and target tissue of FSH. |
Origin: anterior pituitary Target Tissue: follicles in ovaries; seminiferous tubes Function: follicle maturation and estrogen secretion; sperm cell production |
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Name the release origin, function, and target tissue of prolactin. |
Origin: anterior pituitary Target Tissue: ovaries and mammary glands Function: milk production; increased response of follicle to LH and FSH |
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Name the release origin, function, and target tissue of GHRH. |
Origin: hypothalamus Target Tissue: anterior pituitary Function: increased GH secretion |
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Name the release origin, function, and target tissue of GHIH. |
Origin: hypothalamus Target Tissue: anterior pituitary Function: decreased GH secretion |
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Name the release origin, function, and target tissue of TRH. |
Origin: hypothalamus Target Tissue: anterior pituitary Function: increased thyroid-stimulating hormone secretion |
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Name the release origin, function, and target tissue of CRH. |
Origin: hypothalamus Target Tissue: anterior pituitary Function: increased adrenocorticotropic hormone secretion |
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Name the release origin, function, and target tissue of GnRH. |
Origin: hypothalamus Target Tissue: anterior pituitary Function: increased secretion of LH and FSH |
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Name the release origin, function, and target tissue of PIH. |
Origin: hypothalamus Target Tissue: anterior pituitary Function: decrease prolactin secretion |
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Name the release origin, function, and target tissue of PRH. |
Origin: hypothalamus Target Tissue: anterior pituitary Function: increased prolactin secretion |
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How are thyroid hormones synthesized? |
1. iodides are taken up into the cell, oxidized to iodine, and released into the lumen. 2. thyrogobulin is synthesized and discharged into the lumen 3. iodine attaches to tyrosine via peroxidase enzymes (thyroglobulin) and forms T1 and T2 4. iodinated tyrosines link together to form T3 and T4. |
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How are T3/T4 stored? |
They are stored within the thyroid follicles as part of thyrogobulin (2-4 month supply). |
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How is thyroid hormone released into the bloodstream? |
Thyrogobulin is brought in by endocytosis and combined with a lysosome, which cleaves T3/T4 and they diffuse into the bloodstream. |
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What are the functions of T3/T4? |
-increase the rate of glucose, fat, and protein metabolism in many tissues -increase body temperature -help maintain BP -help regulate tissue growth -help in development of skeletal an nervous systems -help with maturation and reproductive capabilities |
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How is thyroid hormone regulated? |
-TRH from the hypothalamus increases TSH secretion -increased TSH from anterior pituitary increases thyroid hormone secretion -increased thyroid hormone have a negative feedback on TSH and TRH |
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Parafollicular cells secrete ______. This hormone is directly regulated by _________ levels. When levels drop, the hormone levels ______. When levels rise, the hormone levels ______. This hormone targets the ______ to inhibit ______ activity and the release of _____ from the _______. It also stimulates ______ uptake and incorporation into the ________. |
calcitonin blood calcium drop rise skeleton osteoclast calcium bone matrix calcium bone matrix |
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Definition: tiny glands embedded into the posterior aspect of the thyroid |
parathyroid glands |
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The parathyroid glands secrete a polypeptide hormone called _____. This hormone is essential in regulating _____________ (much more so than ______). This hormone ______ the release of ____ from bones into blood by increasing the number of _______. A decrease in ______ levels stimulates the release of this hormone. |
PTH calcium balance in the blood calcitonin increases calcium osteoclasts calcium |
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In addition to regulating blood calcium levels, PTH also promotes calcium reabsorption by the _____ and the formation of _______ by the _____. |
kidneys active vitamin D kidneys |
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Active vitamin D increases _______ absorption by the ______. |
calcium intestine |
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Definition: paired, pyramid-shaped organs that sit on top of the kidneys |
adrenal glands |
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The adrenal glands are divided into two parts: the _________ (inner area) and the ________(outer area). |
adrenal medulla adrenal cortex |
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The adrenal medulla arises from the same cells that give rise to __________ neurons. The adrenal cortex is _____ tissue derived from the embryonic ______. It is composed of 3 layers called ______, _____, ______. Structurally and functionally, they are three glands in one. |
postganglionic sympathetic glandular mesoderm zona glomerulosa zona fasciculata zona reticularis |
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Approximately 80% of the hormones released by the adrenal medulla is ______ and 20% is _____. Secretion of these hormones prepares the body for physical activity by increasing _____, increasing the use of ______ and _____ by skeletal muscle, increasing ___ and force of ________, causing _______ in the skin and viscera, and causing _______ in the skeletal and cardiac muscle. |
epinephrine norepinephrine blood glucose levels glycogen glucose HR contraction vasoconstriction vasodilation
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Epinephrine and NE are released from the adrenal medulla in response to what stimuli? |
emotions injury exercise stress low blood glucose levels |
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The adrenal cortex synthesizes and releases ____ hormones called ________. |
steroid corticosteroids |
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Name what hormones each of the layers of the adrenal cortex produce. |
zona glomerulosa: mineralocorticoids (aldosterone) zona fasciculata: glucocorticoids (cortisol) zona reticularis: gonadocorticoids (androgens) |
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What are the main functions of mineralocorticoids and which is the most important one? |
-regulate electrolytes in extracellular fluids -aldosterone |
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What is the function of aldosterone? |
-maintains sodium balance by reducing excretion of sodium from the body -stimulates reabsorption of sodium by the kidneys -decreases potassium and H+ levels in the blood |
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What is aldosterone secretion stimulated by? |
-rising blood levels of potassium -low blood sodium -decreasing blood volume or pressure |
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What are the main functions of glucocorticoids and which is the most important one? |
-help the body resist stress by keeping blood sugars constant -maintain blood volume and prevent water shift into tissue -cortisol |
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What are the functions of cortisol? |
-promotes gluconeogenesis -rise in blood glucose, fatty acids, and amino acids |
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Definition: formation of glucose from non-carbohydrates |
gluconeogenesis |
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What are the negative effects of excessive levels of glucocorticoids? |
-depress cartilage and bone formation -inhibit inflammation -depress the immune system -promote changes in cardiovascular, neural, and gastrointestinal function
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How is cortisol secretion regulated? |
-CRH is released from the hypothalamus in response to stimuli and travels to the anterior pituitary -anterior pituitary is stimulated to release ACTH -ACTH stimulates the release of cortisol from the adrenal cortex -cortisol has a negative feedback on CRH and ACTH |
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What are the main functions of gonadocorticoids and which is the most important one? |
-onset of puberty, appearance of secondary sex characteristics, sex drive in females -testosterone |
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Androgens can be converted to ______ after _____. |
estrogens menopause |
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Definition: a triangular gland which has both exocrine and endocrine cells; locate behind the stomach |
pancreas |
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In the pancreas, the ____ cells produce an enzyme-rich juice used for digestion (_____ product). The ______ (islets of ______) produces hormones (______ products). The islets contain two major cells types: alpha and beta. Alpha cells produce ____ and beta cells produce _____. |
acinar exocrine pancreatic islets Langerhans endocrine glucagon insulin |
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The target tissues of insulin are _____, _____, ______, and the _____ in the ______. The function of insulin is to maintain _______ by increasing the uptake of _____ and _______ by cells. |
liver adipose tissue muscle satiety center hypothalamus blood glucose levels glucose amino acids |
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Glucose is used for ______. It is stored as ______ and converted into _____. Amino acids are used to __________. |
energy glycogen fats synthesize proteins |
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Low levels of insulin promote the formation of ________ by the ______. |
ketone bodies liver |
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The target tissue of glucagon is mainly the ______. It causes the breakdown of ____ to _____ and stimulates the synthesis of ______ from ______. The ______ releases glucose into the blood. |
liver glycogen glucose glucose amino acids liver |
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What causes insulin levels to increase of decrease? |
Increase: elevated blood glucose levels, increase in some amino acids, parasympathetic stimulation, gastrointestinal hormones Decrease: sympathetic stimulation (somatostatin) |
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What causes glucagon levels to increase or decrease? |
Increase: low blood glucose levels, certain amino acids, sympathetic stimulation Decrease: somatostatin (inhibits both glucagon and insulin) |
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What happens are eating a meal? |
1. high glucose --> stimulates insulin, inhibits glucagon/cortisol/GH/Epi 2. insulin increases uptake of glucose, amino acids, and fats 3. after some time, glucose levels drop 4. insulin decreases, other hormones increase 5. glucose is released from tissues and liver 6. use of glucose by tissues decreases 7. adipose tissues release fatty acids and ketones, which most tissues use for energy |
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What happens after exercise? |
1. sympathetic activity increases Epi and glucagon --> release of glucose from liver into blood 2. uptake of glucose by muscle --> low blood sugar levels --> stimulates Epi, glucagon, GH, and cortisol secretion 3. increase in fatty acids and ketones in blood which are used for energy |
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The testes secrete ______. This hormone initiates the __________, causes appearance of _______ and _____, is necessary for _______, and maintains ____ in their functional state. |
testosterone maturation of male reproductive organs secondary sex characteristics sex drive sperm production sex organs |
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Ovaries secrete ______ and _______. This hormone is responsible for the __________, appearance of _______, _____ development, and cyclic changes in the _________. |
estrogens progesterone maturation of reproductive organs secondary sexual characteristics breast uterine mucosa |
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Definition: small, pinecone-shaped structure located superior and posterior to the thalamus |
pineal body |
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What is the secretary product of the pineal body? What is its function? |
melatonin - inhibits reproductive maturation, regulates sleep-wake cycles |
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How is melatonin secretion stimulated? |
1. light entering the eye stimulates neurons 2. signals are sent to hypothalamus 3. hypothalamus transmits signals through sympathetic system to pineal body 4. decrease in light increases pineal stimulation/melatonin levels; increase in light decreases pineal stimulation/melatonin levels |
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Definition: lobulated gland located deep in the sternum |
thymus |
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What are the major hormonal products of the thymus and what are their functions? |
thymopoietins and thymosins - essential for the development of T lymphocytes of the immune system |
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What are some of the hormones of the gastrointestinal tract and what are their functions? |
gastrin, secretin, and cholecystokinin - regulate digestive function |
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What hormone is secreted by the kidneys and what are it's functions? |
erythropoietin - stimulates red blood cell production |
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What hormone is secreted by the placenta and what are it's functions? |
human chronic gonadotropin - essential for the maintenance of pregnancy |
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Definition: chemical signals that locally affect cells of the same type as the cell producing the agent |
autocrine agents |
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What are some examples of autocrine agents? |
prostaglandins, thromboxanes, prostacyclins, and leukotrienes |
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Definition: chemical signals that locally affect cells of a different type than the cell producing the agent |
paracrine agent |
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What are some examples of paracrine agents? |
growth factors, clotting factors, and histamine |
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How do autocrine/paracrine chemical signals differ from hormones? |
-they are not secreted from discrete endocrine glands -they have local effects rather than systemic effects -they have functions that are not understood in all cases |
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As a person ages, there is a gradual ______ in the secretion ____ of most, but not all, hormones. Some decreases are secondary to gradual decreases in _________. |
decrease rate physical activity |