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39 Cards in this Set
- Front
- Back
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The hypothalamus primarily consists of clusters of neuron cell bodies called ____________ ____________ that each have a distinct name.
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hypothalmic nuclei
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The ________ pituitary also contains a class of neuroglial cells called _______ that support the functioning of the neurosecretory cells.
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posterior, pituicytes
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What are the two cell bodies that originate in the hypothalamus and makes up the posterior pituitary?
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supraoptic and paraventricular nuclei
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The hypothalamus is located in the __________ of the brain inferior to the thalamus.
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diencephalon
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The neurons in the ________ associated with the endocrine system are somewhat different than your "classical" neurons. Structurally, they tend to be ______; functionally, they produce __________ instead of neurotransmitters. As a result, these neurons have come to be known as magnocellular neurons, neuroendocrine cells or neurosecretory cells (depending upon which textbook you read).
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hypothalamus, larger, hormones
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The pituitary gland (1-1.5 cm in diameter) is located in the ______ ______ of the sphenoid bone and is connected to the hypothalamus by a thin stalk called the _____________. It consists of two anatomically and functionally distinct lobes:
•posterior pituitary or __________ •anterior pituitary or ________ |
sella turcia, infundibulum, neurohypophysis, adenohypophysis
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Supraoptic and paraventricular nuclei of the hypothalamus; The hormones _______ and __________ synthesized by the cell bodies are transported down the axons and stored in axon terminals within the ___________________. A rich capillary network surrounds the axon terminals which allows the hormones to enter the circulation.
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ADH, oxytocin, posterior pituitary
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These hormones are synthesized by the neuron cell bodies in the hypothalamic nuclei. However, unlike ADH and oxytocin, these 6 hormones are released into the hypophyseal portal system of the anterior pituitary. They are secreted episodically and not continuously.
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•GHRH growth hormone releasing hormone
•GHIH (somatostatin)growth hormone inhibiting hormone •PIH (dopamine) prolactin inhibiting hormone •TRH thyroid releasing hormone •CRH corticotropin releasing hormone •GnRH gonadotropin releasing hormone |
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Histologically, the anterior pituitary consists of a variety of hormone-producing cells (i.e. -- the _____ cells -- corticotropes, gonadotropes, lactotropes, somatotropes & thyrotropes) that are surrounded by a sinusoidal capillary system known as the ___________ ____________ __________.
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trophic, hypophyseal portal system
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The _______ pituitary gland secretes two hormones -- ___________ or ________ (sometimes called arginine vasopressin) and _______ ("rapid birth").
Both are nonapeptides (i.e. - 9 amino acids) whose structures are closely related and differ by only 2 amino acids. ADH and oxytocin are synthesized in separate magnocellular neurons whose cell bodies are located in the SON and PVN. (supraoptic nuclei and paraventricular nuclei) |
posterior, anti-diuretic hormone or vasopressin, oxytocin
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The most potent stimulus for ADH secretion is water _________, which results in increased plasma osmolality. The __________ are exquisitely sensitive and elicit increased secretion of ADH when the plasma osmolality increases by as little as ______%.
This rise in plasma osmolality is sensed by specialized neurons in the brain called ___________. |
deprivation, osmoreceptors, osmoreceptors, 1 to 2%
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The primary action of ADH is water __________ by the kidneys. This results in an _________ in urine osmolality and a ___________ in urine flow.
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reabsorption, increase, decrease
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Other potent stimuli for ADH include a fall in blood volume of greater than ~8% (hemorrhage; isotonic dehydration) and quiet standing (orthostatic hypotension), both of which reduce cardiac output and central blood volume. Baroreceptors in the __________ (3 areas) sense small alterations in blood volume & pressure and communicate with the _________ via cranial nerves ___________ (2 of them)
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carotids, left atrium, aortic arch, hypothalamus, IX, X
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In addition to its effects on the kidneys, ADH exerts potent vascular actions as well by causing arteriolar __________ & _____________ total peripheral resistance (TPR).
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vasoconstriction, increase
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Diabetes insipidus (syndrome where ____ is not effective) is characterized by the inability to produce a concentrated urine, frequent urination (with low specific gravity & osmolality) and often excessive thirst. There are two types:
1)_________ (central) diabetes insipidus 2)__________ diabetes insipidus |
ADH, neurogenic (pituitary), nephrogenic
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SIADH (________________) is a disorder that leads to excessively high levels of plasma ADH which, in turn, leads to plasma hypo-osmolality, hyponatremia, and urine hyper-osmolality.
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syndrome of inappropriate ADH secretion
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Stimulation of the nipple through suckling produces a neurohumoral reflex that causes secretion of ________. In turn, ________ causes contraction of the __________ cells of the mammary alveoli & ducts and the ejection of milk.
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oxytocin, oxytocin, myoepithelial
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__________ primarily affects uterine smooth muscle (i.e. - the myometrium). It increases both the _________ and the _________ of action potentials during uterine contractions. Thus, administration of oxytocin initiates contractions in a quiescent uterus and increases the strength and frequency of muscle contractions in an active uterus.
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oxytocin, frequency, duration
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Synthetic oxytocin called _______ is sometimes given to reduce postpartum bleeding that can occur when the placenta fails to be expulsed. _______ can also be used to induce labor at term.
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pitocin, pitocin
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Hypothalamic Hormones Associated with the Anterior Pituitary Gland
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GnRH (gonadotropin releasing h.)
TRH (thyrotropin releasing h.) CRH (corticotropin releasing h.) PIH (dopamine) (prolactin inhibing) GHRH (growth hormone releasing h,) GHIH (somatostatin) (growth hormone inhibiting h.) PRF ?? |
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Overview of Anterior Pituitary Hormones
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GH (growth hormone)
PRL (prolactin) TSH (thyroid stimulating hormone) ACTH (adrenocorticotropin hormone) LH (luteinizing hormone) FSH (follicle stimulating hormone) |
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__________ decreases glucose uptake in tissues such as skeletal muscle and fat & increases glucose production by the liver. These two events, in turn, stimulate insulin secretion.
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growth hormone
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___________ stimulates the release of fatty acids from adipose tissue and increases their concentration in the circulation. These fatty acids are then used by cells for energy preferentially over carbohydrates and proteins. __________ influence in promoting fat utilization, together with its effect on stimulating protein deposition, causes an increase in lead body mass.
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growth hormone, growth hormones
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The effects of GH on soft tissue growth, bone lengthening and protein metabolism depend on an interaction between GH and _______________, which are group of growth factors secreted mainly by the ____ and a few other tissues. The principal circulating somatomedins in humans are _____________ I (IGF-1 or somatomedin C) and ____________ II (IGF-II).
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somatomedins, insulin growth like factor, insulin growth like factor
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What results from decreased GH secretion before or at puberty?
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pituitary dwarfism
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What results from hypersecretion of GH at/or during puberty?
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Gigantism
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Hypersecretion of GH after puberty results in?
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acromegaly,
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Growth hormone promotes protein _________ in tissues by enhancing amino acid transport through cell membranes, stimulating mRNA translation and ________ protein catabolism. This usually leads to a __________ nitrogen balance. It is believed that GH stimulates soft tissue growth (e.g. - heart, skin, liver, etc.) via this "protein-sparing" mechanism.
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deposition, inhibits, positive
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Even synthetic GH, if taken in excessive doses, can lead to several side effects, including _____________ (3 things).
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acromegaly, diabetes, ketosis
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Some athletes are using illicit ___ (derived from human pituitary tissue) which can lead to the infection of Creutzfeldt-Jacob disease, a fatal condition affecting the _____________ system.
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growth hormone, central nervous
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_____ is a 198-amino acid protein hormone synthesized and secreted by the _________. Both the number and size of the _________ are increased by _________, and this becomes particularly noticeable during pregnancy, at which the lactotropes increase from comprising 15% of the weight of the anterior pituitary to about 70% in anticipation of the need for _________ to support postpartum milk synthesis.
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prolactin releasing hormone, lactotropes, lactotropes, estrogen, prolactin
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Although PRL does not appear to play a physiological role in the regulation of gonadal function, hyperprolactinemia in humans leads to ___________. In women, initially there is a shortening of the luteal phase; subsequently, anovulation, oligomenorrhea or amenorrhea, and infertility occur.
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hypogonadism
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In men, _____ excess leads to decreased testosterone synthesis and decreased spermatogenesis, which clinically present as decreased libido, impotence, and infertility.
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PRL
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Although the thyroid gland can carry out all the steps of thyroid hormone synthesis & secretion, autonomous function is too sluggish to meet bodily needs for thyroid hormone. The principal regulator of thyroid function is _____, a _______hormone produced by the __________.
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TSH, glycoprotein, thyrotropes
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_____ causes an increase in thyroid gland size and vascularity by promoting mRNA and protein synthesis.
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TSH
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Functions of TSH:
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-stimulates iodide uptake by thyroid follicular cells
-activates thyroid peroxidase -secretion of thyroid hormones |
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The primary action of ACTH is to stimulate the synthesis & secretion of _____________ or ____________ (e.g. - cortisol) from the _______ gland. ACTH is necessary for the "rate-limiting" step or corticosteroid synthesis (i.e. -- the conversion of cholesterol into pregnenolone).
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glucocorticoids, corticosteroids, adrenal
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FSH stimulates _____________ growth in females and __________ in males.
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ovarian follicle, spermatogenesis
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LH stimulates _______ and ________ of ovarian follicles in females and ____________ secretion in males (by acting on interstitial cells or _____ cells).
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ovulation, luteinization, testosterone, Leydig
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