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47 Cards in this Set
- Front
- Back
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What are the 3 types of too little hormone?
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Primary- gland that makes the hormone is not working
Secondary- gland is not being told what to do Hormone resistance- receptor is resistant to the hormone |
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What are the 3 types of too much hormone?
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Primary- Gland keeps pumping out hormone
Secondary- Gland being over signalled to produce hormone Receptor activation mutation -> receptor is just activated without any hormone. |
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What are the 3 classes of hormones?
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Peptide Hormones, Steroid hormones, and tyrosine derivatives.
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What do the tyrosine hormones include?
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The catecholamines (norepinephrine, epinephrine, dopamine) and the thyroid hormones (triiodothryroxine and thyroxine)
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What do the steroid hormones include?
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PAVCET
Progesterone Aldosterone Vitamin D Cortisol Estradiol Testosterone |
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What are some peptide hormones?
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Important ones: insulin, glucagon, vasopressin, angiotensin, oxytocin, gastrin, GH, FSH, LH..basically anything that is not steroid or tyrosine derivative.
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What are some of the endocrine glands in the body?
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Hypothalamus, pituitary, thyroid gland, parathyroid, thymus (B cells make Ig), stomach, adrenal glands, pancreas, kidney (renin/Epo), adipose tissue (leptin,adipokine), SI, ovaries/testes
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What determines whether a hormone exerts an effect on a tissue?
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Hormones are released into the blood and must be metabolized. They must be carried to the site of action. What determines whether action occurs is whether or not theres a receptor present.
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Are steroid hormones bound? How will cortisol's metabolic clearance differ from aldosterone's
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Steroid hormones are bound SOMEWHAT (variation between cortisol and aldosterone). Cortisol has a lower metabolic clearance than aldosterone because it is more tightly bound to proteins (longer half life for cortisol).
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Are thyroid hormones bound? What does this say about their clearance rate?
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Thyroid hormones circulate bound to plasma protein. VERY LITTLE FREE. To exert action, these hormones must be released- they therefore have low clearance rates.
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Are protein hormones bound? What does this say bout their clearance rate?
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No, peptide hormones are not bound. The bigger the peptide, the slower the clearance.
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What are the 3 types of endocrine rhythms?
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1) Circadian- around a day (testosterone)
2) Ultradian- pulsatile (LH) 3) Stimulus induced - hormone is not released until a stimulus comes along (prolactin) |
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How does negative feedback of blood sugar work?
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alpha cells secrete glucagon to raise blood glucose levels. raised glucose levels then inhibit the release of glucagon. High glucose levels stimulate insulin from beta cells to be secreted to bring down glucose levels.
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Why does ACTH stimulate cortisol release not estrogen release or some other hormone?
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Hormones work through receptors that are unique to that hormone. Adrenal cells are the ones that have ACTH receptors.
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Describe how the g protein coupled receptor works?
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The receptor crosses the membrane 7 times and has an EC binding domain for the hormone. There is a tail in the cytoplasm that tells the cell a hormone is bound. The G protein complex is inactive usually- when a hormone binds, the tail changes conformation and the g protein complex binds the receptor. The gamma and beta subunits dissociate, and the alpha subunit and the GTP activate the target protein. This target protein then makes cAMP, etc.
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How does the enzyme linked receptor system work?
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This is a both fast and slow system. Leptin binds Leptin receptor and causes Jak phosphorylation. This activates enzymes and leads to immediate physiological effects (FAST).
This system also has transcription effects- leptin binds, stat3 transcription factor dissociates from the receptor and then goes into the nucleus to affect transcription (SLOW) |
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How does ACTH generate a cell response through the G protein system?
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ACTH binds the receptor- this activates alpha subunit of g protein that goes onto activate the adenylyl cyclase. This catalyzes ATP -> cAMP. cAMP then causes a cascade, leading to successive phosphorylation and an amplified response. This causes a final phosphorylation that leads to the cell's response.
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Explain how the G protein can be coupled to IP3 and DAG rather than cAMP.
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A hormone binds to the receptor that liberates the alpha subunit of the G protein. Instead of activating adenylyl cyclase, it activates phospholipase C. This cleaves PIP2 to IP3/DAG. dAG can act like cAMP and cause a cascade. IP3 has a response too.
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How do steroid hormones generate a response?
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Steroid hormones elicit slow responses. These lipophilic hormones diffuse into the cell right through the membrane binding a cytoplasmic receptor or nuclear receptor. This hormone/receptor complex acts as a transcription factor and increases transcription of genes through specific hormone response elements. This leads to new proteins.
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Which form of thyroid hormone is more active?
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T3 is 10 times more potent than T4.
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What is transphenoidal surgery?
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Transphenoidal surgery is how neurosurgeons get at the pituitary gland.
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How is the anterior pituitary supplied?
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From blood that supplies the brain.
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What arteries and sinus surround the pituitary?
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The pituitary sits in the sella turcica near the sphenoid sinus and carotid sinus. The pituitary stalk connects to the gland.
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What is homology?
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Peptides that look alike but are different (bind different receptors) are homologous
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What are the 3 families of hormones in the pituitary?
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Glycoprotein family,
Growth hormone/prolactin family Proopiomelanocortin family |
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What hormones belong to the glycoprotein family?
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TSH (thyrotropin), FSH, LH.
FSH and LH are called conadotropin. |
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What hormones belong to the growth hormone and prolactin family?
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Growth hormone (somatotropic hormone) and prolactin
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What are the members of the proopiomelanocortin family
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ACTH, endorphins
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What is the function of TSH/thyrotropin
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Stimulates the synthesis and secretion of thyroid hormones
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What is the function of FSH
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Stimulates growth of follicles and estrogen secretion
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What is the function of LH
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Stimulates ovulation and formation of corpus luteum. Corpus luteum stimulates estrogen and progesterone synthesis.
In males, it stimulates Leydig cells to synthesize and secrete testosterone. |
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What is the function of GH
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Promotes growth in stature and mass. Inhibits glucose utilization, promotes fat utilization, and stimulates protein synthesis.
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What is the function of prolactin?
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Prolactin promotes milk production
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What is the function of ACTH
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Promotes synthesis and secretion of adrenal cortical hormones
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Are cells that secrete GH localized to one specific area or are they all over the pituitary?
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There are nests of particular cell types that make the hormones. (GH secreting cells are lateral etc)
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How is anterior pituitary hormone release controlled?
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Hypothalamic nuclei have cell bodies that synthesize neurohormones that control Anterior pituitary.
1) Nuclei make neural hormones that are transported down the axon that terminates on the median eminance on blood vessels. 2) This arterial supply breaks up into capillaries that pick up these neural hormones and transport them into the capillary plexus via blood. 3) This is the hypothalamic-hypophysial portal system. The hormones then reach the anterior pituitary, where they exert their action. |
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What are the hormones made in the hypothalamus that affect the pituitary?
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CRH- corticotropin releasing hormone- stimulates secretion of ACTH, endorphin
GnRH- stimulates FSH and LH GH-RH - growth hormone releasing hormone SRIF- somatostatin- inhibits secretion of GH Dopamine - inhibits prolactin TRH- thyrotropin releasing hormone- stimulates secretion of TSH. |
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What is the general model for hypothalamic pituitary target gland control
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Neural and humoral inputs to hypothalamus prompt release. These hormones go down portal blood vessels to anterior pituitary, which releases tropic hormones that affects the target gland. In relatively rare cases, pituitary hormones can directly inhibit hypothalamus (SHORT loop) but usually the target gland releases the desired hormone to complete the biological action. This hormone then exhibits negative feedback (Iong loop on both pituitary and hypothalamus).
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If the target gland is removed, the concentration of the tropic hormones will be increased or decreased
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Increased
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If I am given too much of a drug that mimics a target gland, tropic hormone is increased or decreased?
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Decreased
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What is the hypothalamic pituitary adrenal axis? How does it work
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Controls cortisol. Paraventricular nuclei make CRH which stimulates ACTH from pituitary. ACTH stimulates adrenal gland acutely -tropic -cortisol
and chronically -trophic - growth. Cortisol has long loop negative feedback on both hypothalamus and pituitary. |
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What is the hypothalamic pituitary thyroid axis? How does it work?
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Controls thyroid hormone release.There is long loop feedback but only to the pituitary. Why do we need TRH then? It is a set point- just secrete less or more TRH depending on what we want.
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How is growth hormone controlled?
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There are 2 factors - GH-rf (growth hormone releasing factor - stimulatory) and somatostatin (inhibitory). GH goes to target cells and acts through IGF-1 (insulin like growth factor-homology to insulin but different fn)
GH has long and short loop feedback. The short loop is important for GH. IGF exerts long and short loop feedback. Because somatostatin is inhibitory and we want to turn off GH, we have to actually stimulate somatostatin. |
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Hypopituitarism refers to a lack of pituitary hormone in what compartment
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Anterior pituitary hormones.
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What does prolactin do? Oxytocin?
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Prolactin causes milk synthesis. Oxytocin controls ejection.
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Fill in blanks for prolactin release pathway: Hypothalamus releases dopamine, an inhibitory factor on _________. These cells normally produce produce prolactin unless being inhibited by dopamine.
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Lactotroph.
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If a patient has bilateral nipple discharge, irregular and then absent menses, and occipitofrontal headaches what could be diagnosis
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Prolactin excess. treat with dopamine agonist.
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