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82 Cards in this Set
- Front
- Back
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What are the three types of intracellular signaling?
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Paracrine, NT, and Hormones
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What is paracrine signaling? Do they get into the circ. system? How long do they last and how do they travel?
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Adjacent cell signaling. No. They are short-lived and travel by diffusion.
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NT's a special type of what? What makes them special?
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Paracrine cell signaling. Their presynaptic and postsynaptic structures make them different
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Why are hormones produced and by what? How are they transported? Is there specificity?
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They are produced in response to a stimulus by endocrine cells and are carried to the target by the circulatory system. The target has affinity and specificity for the hormone.
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What are the two types of feedback mechanisms? In which one does a hormone shut off a response?
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Simple and Complex/Multi-Level. Complex.
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What type of feedback is typically found in the Simple category? How does it all pan out?
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Negative. Endocrine cells release a hormone that CAUSES A BIO RESPONSE that turns off the hormone release.
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What is an example of Simple feedback? How does it work?
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Glucose/Insulin Regulation--Insulin is released in response to low glucose lvls, then glucose lvls in the plasma go up, which turns off insulin release
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Describe Complex Feedback. What is an example of this type?
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A hormone produced in at some point in the system shuts off the system itself. The Thyroid Releasing Hormone(TRH) system is an example of this type.
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Describe the TRH System. Where does the final hormone produced work?
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Hypo --(TRH)-->Ant. Pit. --(TSH)-->Thyroid---->Produces Thyroxin(T4, T3). T4 and T3 work on the Ant. Pit. AND hypothalamus to shut off the system.
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What are the three classes of hormones based on their chemical nature? Which is the largest class?
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A.a. derivatives, peptide and protein hormones, and steroid hormones. Protein hormones are the largest group.
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What is the structure of a.a. derivative hormones? What is an example of this type?
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Small and Hydrophilic; Thyroxine and Epinephrine
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What is the structure of peptide and protein hormones? What is an example of this type?
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Large sized and hydrophilic; MOST HORMONES including insulin
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What is the structure of steroid hormones? What difficulty does this present and how is it overcome?
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Synthesized from cholesterol and hydrophobic; since they are hydrophobic, they need to be attached to a plasma protein to be transported in the blood or they will be filtered out.
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Where are protein hormones synthesized? Briefly describe their production.
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Made in ribosomes as pro-hormones and transported to the Golgi complex
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What about steroid hormone synthesis results in their delayed action? Where do they typically work?
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They are NOT STORED so it takes longer to produce. They typically work on the nucleus.
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Do protein hormones work directly on the nucleus?
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No they operate by means of a secondary messenger; some actually change membrane permeability
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What is another name for the pituitary gland? Where is it located and what protects it?
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The hypophysis is located at the base of the brain and protected by the SPHENOID bone
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What is a depression in the sphenoid bone where the hypophysis sits?
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The Sella Turcica
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What did scientists used to think about the hypophysis that is known to be wrong now?
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That it is a VITAL ORGAN. The hypophysectomy was what was killing the test subjects--not the lack of the gland itself
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What are the two parts of the pituitary gland? From what do they develop?
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The adenohypophysis develops from Rathke's pouch and the neurohypophysis develops from the Infundibulum
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Name the three lobes of the anterior pituitary gland. Which one wraps around what?
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The Pars Tuberalis, Pars Distalis, and Pars Intermedia. The Pars Tuberalis wraps around the infundibular stalk
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What are the two structures that communicate directly with the Posterior Pituitary Gland? What does each secrete?
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The supraoptic nucleus synthesizes ADH and the paraventricular nucleus synthesizes oxytocin.
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Describe the HPS. What does it provide for?
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Superior hypophyseal artery to primary plexus to hypophyseal portal vein to secondary plexus to veinous drainage. It provides for easy pickupanddropoff of hormones
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Name the 5 types of anterior pituitary hormones. Which is the largest class? The smallest?
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Somatotrophs, Lactotrophs, Coricotrophs, Thyrotrophs, and Gonadotrophs. Somatotrophs are the largest and Thyrotrophs are the smallest.
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To what class of anterior pituitary gland hormones does hGH belong?
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Somatotrophs
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What class of pituitary hormones does Prolactin belong in?
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Lactotrophs
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What class of pituitary hormones do ACTH and MSH belong in? Which one isn't important in humans?
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Coricotrophs--MSH isn't important(these two hormones are analogs)
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What class of pituitary hormones does TSH belong in?
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Thyrotrophs
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What class of pituitary hormones do FSH and LH belong in?
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Gonadotrophs
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Name the Hypothalamic Releasing/Inhibiting Hormones. Where do all of them work?
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TRH, CRH, GnRH, GHRH, GHIH, and PIH. They all work on the anterior pituitary
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TRH levels go up. What happens as a result? What does TRH stand for?
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TSH and Prolactin are released. Thyrotrophin releasing hormone
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ACTH and MSH levels are increasing. What has happened?
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Coricotrophin releasing hormone(CRH) has been released
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FSH levels are increasing. So are LH levels. What is going on?
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Gonadotrophin releasing hormone(GnRH) from the hypothalamus is causing their release from the anterior pituitary gland
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What hormones from the hypothalamus adjust GH levels? One has two names what is the second one?
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GHRH and GHIH(also called Somatostatin)
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What does dopamine do as a hormone? What is it therefore called?
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Inhibits the release of prolactin--it is called PIH or prolactin inhibiting hormone
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Name a somatotroph. What is special about this hormone class. What releases this hormone?
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hGH. It is the largest at 40 to 50%. Ant. Pit. releases it.
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Name a lactotroph. What percent of Ant. Pit. hormones do lactotrophs compromise?
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Prolactin--10 to 15%
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ACTH and MSH are examples of what type of Ant. Pit. hormone?
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Coricotrophs
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Name one thyrotroph. What is important about the thyrotroph class?
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TSH--it is the smallest at 3 to 5%
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Name two gonadotrophs. What releases these hormones?
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FSH and LH--the anterior pituitary gland
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What hormone causes growth and maturation of the follicle in females? What are some additional functions?
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FSH--influences estrogen secretion and is NECESSARY FOR SPERM DEV. in MALES
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What hormone causes ovulation? What hormone causes corpus luteum formation? What is one other function?
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LH--LH--testosterone secretion by the cell of Leydig
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What does the hormone ACTH do?
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Stimulates GLUCOCORTICOID production by the adrenal cortex
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Name the two glucocorticoids.
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Cortisol and aldosterone
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What causes growth and maintenance of thyroid tissue as well as hormone production?
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TSH
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What does prolactin do? What is a strange fact about it?
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Milk production but NOT LETDOWN--males have it but there is no known function
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Does MSH have a role in humans? What does it do? What is one uncommonly thought of organ system that is influenced by this hormone? What is an analog of MSH?
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No--camouflage in some animals--fat--ACTH
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Name the hormones produced by the posterior pituitary gland.
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ADH(Vasopressin) and oxytocin
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What body produces ADH? What is another name for this hormone? What does it regulate? Where does it act?
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The supraoptic nucleus--vasopressin--urine production and blood pressure--the collecting duct?
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What body produces oxytocin? What does this hormone do? What is a stimulus that can begin this reflex? What is one other function of oxytocin and what is the name for the analog used in its place?
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The paraventricular nucleus--causes milk letdown--baby's cry--parturition--Pitocin
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What does oxytocin do in males?
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Assists with sperm transport
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What does the pineal gland produce? What is a secondary function of this hormone? So what happens as a result?
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Melatonin--inhibits production of FSH and LH--less ovulation and less growth and maturation of follicle in females; less sperm maturation and less secretion of testosterone in males
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What is the most abundant anterior pituitary gland hormone produced? What cell type produces it?
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Human growth hormone--somatotrophs
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What are some other random things affected by melatonin?
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PMS, puberty onset, and Seasonal Affective Disorder
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What used to be the only source of hGH before artificial sources existed?
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Cadavers
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Name four effects of hGH. Describe its structure.
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Decreases fatty tissue, increases lean muscle mass, increases linear cartilage growth of chondrocytes, and increase tissue size
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There are three categories of metabolism affected by hGH. Name them.
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Protein metabolism, lipid metabolism, and carbohydrate metabolism
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Describe protein metabolism affected by hGH. It causes an increase in what? It causes a decrease in what?
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Increased a.a. uptake into cells and increased ribosomal translation of those amino acids--decreased breakdown
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Describe lipid metabolism affected by hGH. It causes an increase in what? It causes a decrease in what?
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Increased lipolysis and beta oxidation and lean body mass--no decreases(except for straight up fat)
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Describe carbohydrate metabolism affected by hGH. It causes an increase in what? Describe some negatives.
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Increased cellular uptake of glucose. This can cause diabetes and it makes fat and muscle cells more resistant to insulin
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What are some factors that hGH does not affect? What are some additional factors that affect growth besides hGH?
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Fetal growth and neonatal growth until several months after birth--Diet, stress, race
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What are two types of growth? Name two categories in both
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Soft tissue and bone growth--Hypertrophy and Hyperplasia; Intramembraneous ossification and endochondral ossification
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Describe intramembraneous ossification. What bones employ this type of growth? What grows? What stimulates this growth?
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Small flat bones grow in DIAMETER--the periosteum grows as a result of OSTEOBLAST stimulation by hGH
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What is hypertrophy a growth in?
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Increase in cell size
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What is hyperplasia a growth in?
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Increase in cell number
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Endochoncdral ossification is a growth in what regions? What bones grow this way?
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Growth occurs in the epiphyseal plates of the primary and secondary ossification centers.
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How does hGH play a role in endochondral ossification?
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It stimulates prochondrocytes to lay down cartilage until adolescence--it also stimulates osteoblasts
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What can hGH have no effect on?
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Fused epiphyseal plates
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hGH doesn't act directly on its targets..what does?
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Somatomedins, also called IGF's
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Where are IGF's manufactured? Which one mirror hGH levels?
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In the liver--IGF 1
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What are IGF levels like during childhood? Adulthood?
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They are low during early childhood and normal during adulthood even when GH levels drop(they eventually drop as well)
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What two hormones control the release of hGH? Where are they released?
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GHRH and GHIH(Somatostatin)--released by the hypothalamus into the hypophyseal portal system
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When is hGH secreted?
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In children it is secreted in bursts--in adults it is secreted at night
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What are some additional factors besides hormonal control of hGH that influence its secretion?
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Low plasma glucose, low plasma fatty acid levels, high plasma amino acid levels, sleep, stress, exercise, starvation, somatomedins, and GHELIN(secretion by the stomach that causes hunger and inhibits GH)
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What organ produces somatomedins? What feedback activity do these chemicals take part in?
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The liver--feedback to the hypothalamus and the production of GHIH and GHRH to decrease hGH secretion.
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What is panhypopituitarianism(that was fucking hard to spell)?
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decrease in all Ant. Pit. hormones due to a tumor or cutoff in circulation
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What are the three types of dwarfism?
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Pituitary dwarfism, Laron dwarfs, and Pygmies
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What is the cause of Laron dwarfism?
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Normal GH levels but an ability to make IGF-1. GH receptors on the liver are mutated
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What dwarfism is caused by low IGF-1 levels and normal but insufficient GH receptors? What is normal in this condition?
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Pygmies--normal IGF-2
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What is the cause of the spectrum of poodle sizes?
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IGF-1 Spectrum--GH levels are normal
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There are two types of giantism. What causes the first and what is a risk associated with it? What causes the second and what is a risk associated with it?
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Pituitary giantism caused by excessive GH has problems with diabetes--Acromegaly is caused by hGH levels that are too high after the fusion of the epiphyseal plates and there is a significant growth in soft tissue; this can cause problems with heart enlargement
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What are 4 additional uses of GH besides in treating growth deficiencies?
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Burn victims, obesity treatment, a cure for aging, and athletics
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