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88 Cards in this Set
- Front
- Back
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What dictates how much or a hormone can interact with the target cell?
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The Concentration of the hormone in plasma
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What are the functions of hormones?
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Act as primary and secondary messangers.
-They turn on or turn off body functions -Take part in feedback regulation |
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List the problems that can occur with hormones. (Where do things go wrong?)
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1. Rate of secretion
2 Activation or Inactivation of the hormone 3. Receptors problems 4. Signaling problems |
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What is the general treatment if there is a problem with the rate of secretion of the hormone?
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You either give more hormone or give something to shut it off.
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What section of the pituitary gland is considered an extension of the hypothalamus?
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The posterior
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What hormones are produced in the posterior pituitary gland?
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ADH and oxytocin
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What type of reaction occurs between the connection of the hypothalamus and the anterior pituitary?
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A true endocrine reaction
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List the cell types in the anterior pituitary gland.
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1. Corticotrophs
2. Lactotrophs 3. Somatotrophs 4. Thryrotrophs 5. Gonadotrophs |
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What hormone(s) are released from the corticotrophs?
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ACTH
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What is the function of ACTH?
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Goes off and bind to the adrenal cortex and stimulates the release of cortisol
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What cells produce prolactiin? WHere?
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Lactotrophs in the anterior pituitary
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Somatotrophs are responsible for what hormone?
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GH: has direct actions as well as activating the liver to produce IGF 1 and 2
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What cells produce FSH and LH?
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Gonadotrophs
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What is the most common cause of disorders of the anterior pituitary gland?
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Disorders caused by something that interrupts the connection of the 2 structures (hypoth and AP), ie an injury to the stalk
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What are the causes of SIADH?
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1. Increased hypothalamic production
2. Pulmonary Diseases 3. Severe Nausea and/or pain 4. Ectopic production of ADH 5. Drug induced potentiation of ADH 6. Idiopathic |
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Describe what is meant by ectopic causes of SIADH.
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There is a source of secretion in the body that is not normally there and not under feedback regulation.
-Oat cell carcinoma -bronchogenic carcinoma -carcinoma of duodenum |
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How does severe nausea or pain cause SIADH?
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Things that trigger stress responses tend to stimulate the release of ADH and it is not appropriate compared to plasma osmolarity.
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List the pulmonary disease that can cause SIADH? How do they do it?
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Pneumonia, TB, ARF, Asthma
-Mechanism is unclear, but the thought is that theses conditions can cause hypoxemia and the response is to stimulate RBC production and plasma volume thus an excessive release of ADH. |
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What are the 5 clinical manifestations of SIADH?
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1. Blood Serum hypoosmolarity and hyponatremia
2. Urine hyperosmolarity 3. Urine sodium excretion that matches sodium intake 4. Normal adrenal and thyroid function 5. Absence of conditions that can alter volume status |
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What do the different types (ABC) of osmoregulatory defects tell about SIADH?
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Can look at the relationship of plasma osmolarity and ADH and guess what the cause is.
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Describe Type A SIADH.
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Random.
-Observed in 20%, large and unrelated fluctuations in AVP arginine vasopressin occur. -unrelated to the rise in plasma osmolality (usually occurs in association with tumors). -usually do to ectopic production |
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What is Type B Osmoregulatory Defects?
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Reset osmostat.
-Analogous to a thermostat. Observed 35% of the time and typical of pulmonary disorders. -You have a lowering of the threshold for the release of ADH. |
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What is the Leak type of osmoregulatory defects? Describe it.
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Type C:
-Observed in 35%. AVP is persistently elevated at low and normal plasma osmolality; however, above the threhold for AVP release, plasma AVP increases normally. This pattern is observed with meningitis or head injuries. -Never have full suppression of ADH. Slow constant leak. |
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What is Diabetes Insipidus?
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A failure to secrete (central DI) ADH or a failure to respond (nephrogenic DI) to ADH
-Characterized by the excretion of large volumes of dilute urine |
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How much urine output is possible in one day with DI?
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4-12L
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What are the causes of DI?
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1. Nongenetic causes: head trauma, tumor, destructive lesions of the pituitary and or hypothalamus
2. Genetic: know the causes |
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What are the genetic causes of DI?
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-CDI with an autosomal dominant pattern
-CDI with DM etc may be recessive -X-linked -NDI with an autosomal dominant or recessive pattern in the AQP2 gene |
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Which is more common, central DI or nephrogenic DI?
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Central
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In central DI, what will the serum levels of ADH be?
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Low
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How are the serum levels of ADH in nephrogenic DI described?
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Normal or even high
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WHat is psychogenic Di or psychogenic polydypsia?
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psychiatric disorder that the person has manic thirst. They do not have DI, but feel thirsty.
-Their plasma concentration is a proper response to their intake of H2O |
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How do you treat DI?
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Central: Give ADH
Nephrogenic: paradoxical treatement of THZ diuretics. Given for the side effect. long term use increase the rate water reabsorption at other parts of the nephron |
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What are the major causes of hypopituitarism?
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1. Pituitary tumors (adenomas)
2. Sheehan Syndrome 3. Iatrogentic 4. Trauma 5. Infiltrative disease 6. Genetic abnormalities of pit development 7. growth hormone insensitivity (laron syndrome) |
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What is Sheehan Syndrome and what does it lead to?
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Complication of postpartum hemorrhage. The pituitary gland in pregnancy slightly enlarges and when you have hemorrhage it is vulnerable to ischemic damage. The damage leads to long term HYPOPITUITARISM.
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The adenomas of the pituitary gland that can lead to underproduction originate in which cells? What do these USUALLY cause?
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The 5 cells of the anterior pituitary.
Are the number one cause of hyperpituitarism |
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Describe growth hormone insensitivity in relation to hypopituitarism.
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Manifests as a hypo problem, but the actual amount of the hormone is normal! Dwarfism.
Levels are normal but the sensitivity to the target cell are not functioning. |
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How are pituitary adenomas classified?
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Histologically according to their staining properties
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What are the Acidophil adenomas?
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Associated with oversecretion of GH
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The adenomas associated with the oversecretion of ACTH are classified as?
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Basophil
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What is the classification Chromophobe represent?
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Adenoma leading to No endocrine hyperfunction
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Other than staining, how else are pituitary adenomas classified?
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By size (less than 10mm = microadenoma)
(greater than 10mm (macroadenoma) |
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What are the consequences of marco pituitary adenomas?
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1. Can cause over secretion of the hormone.
2. Can grow so large that it impinges on other functions such as sight and headaches |
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WHat is the most common pituitary adenoma?
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Lactotrope adenomas: prolactinomas
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Describe the characteristics and manifestations of lactotope adenomas.
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Are microadenomas
Females: amenorrhea, galactorhea, and infertitility Males: decreased libido and erectile dysfunction. |
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What are the adenomas associated with over secretion of GH? Describe the other characteristics.
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Somatotrope adenomas.
75% of the time they are macro |
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If somatotropes manifest before puberty what is the result?
after puberty? |
Before: Gigantinism
After: Acromegaly |
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Which adenomas are connected to Cushing syndrome? What hormone is it associated with?
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Corticotrope adenomas. ACTH and is a microadenomas.
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What is the name given to the rare overproduction of cells leading to hyperthyroidism?
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Thyrotrope Adenomas
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Which type of pituitary adenomas are only a concern if they become too large?
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The Nonfuncitonal pituitary adenomas:
Null cell adenomas Oncocytoma Silent adenomas |
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Describe gigantism. What is the cause of this?
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Vey tall stature, enlarged hands and feet, thickening of the facial structure
Caused by somatotrope adenomas prior to puberty. |
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What result does an increase in GH and IGFs have on children?
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An increase in growth of their long bones.
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What occurs in long bones after puberty?
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The epiphyseal growth plates calcify and can no longer grow.
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What does hypersecretion of GH cause in adults?
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increase proliferation in connective tissue, cytoplasmic matrix, and increased bony growth
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What are the metabolic effects of somatotrope adenomas?
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Increase metabolic rate, GH inhibition of glucose uptake and increased hepatic production of glucose (hyperglycemia)
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WHat condition are people with somatotrope adenomas at most risk for?
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Diabetes mellitus type II, HTN and heart failure
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What are the clinical manifestations of an overgrowth of GH?
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-Oversized tongue
-edema in peripheral tissue -increase size and activity of sebaceous glands and sweat glands: vulnerable to offensive odor -coarsness of skin and hair -enlargement and thickening of facial bones: prominent brow -barrel chest, large hands and feet |
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What are the Tx options for excess growth hormone?
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Sometimes surgery.
Administration of somatostatin: inhibits GH from the AP |
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What is a goiter?
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Enlargement of the thyroid gland
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Describe how one can have a goiter with normal thyroid levels.
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When a problem occurs with the thyroid gland and a transient drop in T3 and T4 occur, the feedback sys will tell the Hypo and AP to produce more TRH and TSH.
TSH also stimulates the growth of the gland. SO elevated baseline TSH will cause the goiter |
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What would lab values show for a person with a non-toxic goiter?
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Normal T3 and T4 levels but elevated TSH and TRH levels.
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Who is most at risk for non-toxic goiter and what can cause it?
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More common in women.
May be hereditary or from certain medication: lithium Or from exposure to large amounts of substances that inhibit thyroid production: cabage, turnips, brussels sprouts, seaweed and millet |
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List the primary causes of hypothyroidism.
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1. autoimmune: hasmimoto
2. Postradioactive iodine therapy for hyperthyroidism 3. Total or subtotal thyroidectomy 4. radiation therapy of head and neck 5. iodine deficiency 6. congenital disorder of thyroid hormone synthesis. |
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What are the secondary causes of hypothyroidism?
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1. iodine excess: can cause the cells to be toxic and die
2. Drugs: lithium, interferon alpha, antiepileptics |
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Describe the mechanism behind Hashimoto's.
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: starts of with CD4 T cells that are reactive to thyroid cell antigens. One group of the cells produces CD8 T cells and B cells that are reactive to the thyroid cells and when they produce antibodies that correspond to the thyroid cells, they kill the thyroid cells. So T cell mediated and B cell attack against thyroid cells
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What is the manifestation of hashimotos?
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A goiter
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What disease is associated with the production of antibodies that act as TSH agonists when they attach the receptor?
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Graves disease: hyperthyroidism
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Why can a goiter occur in graves disease?
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Because the antibody acts as a TSH agonist and is not under any regulation. Thus it can increase T3 and T4 levels as well as the size of the thyroid.
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what are the clinical manifestations of hypothyroidism?
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1. Goiter
2. Low metabolic rate 3. muscle weakness 4. always cold and tired 5. coarse, brittle hair and thins skin with pallor 6. Myxedema 7. CNS manifestations |
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Describe myxedema? Which disorder is this associated with?
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Hypothyroidism
water attaches to the extracellular matrix of cells. -puffiness of the face -thick tongue -enlarged heart (brady) -CNS depression (LOC or coma) |
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What is the most common cause of hyperthyroidism?
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Graves
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What are the general causes of hyperthyroidism?
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1. Presence of abnormal thyroid stimulator: graves
2. Intrinsic disease of the thyroid: toxic multinodular goiter or functional adenoma 3. Excess production of TSH by AP (rare) |
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what is the hallmark sign of graves disease?
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Bulging eyes: exophthalmos
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List the clinical manifestation of graves disease.
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1. bulging eyes
2. goiter 3. profusely sweat 4. weight loss 5. amenorrhea 6. tachycardia 7. fine tremors 8. hard time sitting still |
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A deficiency is the enzyme 21-hydroxylase is associated with 90% of the cases of which disorder?
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Congenital adrenal hyperplasia
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What is congenital adrenal hyperplasia CAH?
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A result of a number of autosomal recessive enzymatic defects in the biosynthesis of cortisol from cholesterol.
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What is the most common manifestation of CAH?
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ambiguous genitalia in newborn girls
-infant boys experience sexual precocity and stunted growth |
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What is the direct consequence of too little cortisol production in CAH?
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CRH and ACTH will elevate and will get hyperplasia of the adrenal gland
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Why does CAH cause ambiguous genitalia in newborns?
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WHen the end product of cortisol is not completed, the buildup of intermediates occurs. These intermediates include androgens: male sex hormones causing masculination of the female genitalia.
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WHat is the primary cause of addisons disease?
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Autoimmune: usually b/c of Tcell and antibody mediated destruction of the adrenal tissue.
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WHat 2 classes of hormones are effected with Addison's disease?
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Glucocorticoids and mineralcorticoids
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List the effects of Addison's Disease.
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1. hyperpigmentation
2. progressive weakness, fatigue, poor appetite, and weight loss 3. Dizziness with orthostasis due to hypotension occasionally may lead to syncope (volume depletion) 4. hyponatremia and hyperkalemia 5. salt craving |
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What is an adrenal crisis? What disorder does it occur in?
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Brought about by acute stress (sepsis, surgical) in absence of adrenal cortex hormones stress results in hypotension, shock, and risk of death.
Addison's Disease |
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What hormones result in the greatest consequence when lost because of Addison's Disease? Why?
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Mineralcorticoids because the person will have a difficult time maintaining plasma volume and BP.
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What is Cushing Syndrome?
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Disorder caused by prolonged exposure to elevated levels of either endogenous glucocorticoids or exogenous glucocorticoids.
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What are the causes of Cushing Syndrome?
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1. Exogenous steroid administration
-PT with diseases that respond to steroid therapy or who have undergone organ transplants 2. Endogenous glucocorticoid overproduction -ACTH-producing pituitary adenoma 3. Primary adrenal lesions -adrenal adenomas, carcinomas 4. Ectopic ACTH production: can be tumors of the lungs |
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What are the clinical manifestations of Cushings?
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Pt will have excess anti-inflammation and will be immunosuppressed.
-bone demineralization -moon face, obese stomach, buffalo hump, redness of the face. -thin arms and legs. -adrenal tumor or hyperplasia -thin, wrinkled skin -amenorrhea, muscle weakness -purpura and skin ulcers. -cardiac hypertophy |
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Which disorder is associated with the "moon face" and "buffalo hump"?
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Cushings
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What neurological manifestations are seen in cushings?
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Emotional disturbances and enlarged sella turcica
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