Flashcards in Ch. 10: Endocrine Function Deck (102):
how do hormones influence processes?
by binding to receptors on the surface or within their target cells. only small amounts of these potent substances are required to make a significant impact at the cellular and organism levels
what are hormones classified or described based on?
their action, source, or chemical structure
when the end product of a biochemical process inhibits it's own production - the hormone is released only when its levels decline, and production stops when its levels rise
negative feedback loop
rare and occurs when one hormone product stimulates the production of more
positive feedback loop
what is the difference between tropic and nontropic hormones?
tropic hormones- regulate endocrine glands to produce other hormones
nontropic hormones - directly stimulate cellular metabolism and other activities
what happens once the hormone has acted upon the target cell?
the liver metabolizes and the kidneys excrete it to prevent an accumulative effect
"master gland", located at the base of the brain, regulated by the hypothalamus
basal portion of the diencephalon which regulates the pituitary gland. connects the nervous and endocrine systems. contains receptors that monitor hormone, nutrient, and ion levels
what is the difference between the anterior and posterior pituitary with how they are regulated?
the anterior pituitary is regulated by hormones released by the hypothalamus. the brain controls the posterior pituitary gland by neurohormones in this region
what are the endocrine functions of the pancreas carried out by?
the islest of langerhan
which cells secrete glucagon and which secrete insulin?
alpha cells secrete glucagon and beta cells secrete insulin. these are in the islets of langerhan
what hormones are secreted by the anterior pituitary gland?
thyroid-stimulating hormone, adrenocorticotropin, prolactin, growth hormone, gonadotropins
what hormones are secreted by the posterior pituitary gland?
antidiuretic hormone and oxytocin
released when serum glucose levels fall and stimulates the breakdown of glycogen to glucose which raises serum glucose levels
released when serum glucose levels increase. stimulates cellular uptake of glucose, which in turn decreases serum glucose levels
hormones are produced within the follicles of the thyroid. what are these hormones?
thyroxin or T4, triiodothyronine or T3, and thyrocalcitonin or calcitonin.
two hormones together that regulate cellular metabolism as well as growth and development
T3 and T4 together
how does the hypothalamus influence the thyroid gland?
it stimulates the pituitary gland to release thyroid-stimulating hormone, using a negative feedback loop. TSH drives the thyroid to produce T3 and T4
what does the thyroid require in order to synthesize T3 and T4
this, along with parathyroid hormone, regulates serum calcium levels
how does calcitonin regulate serum calcium levels?
inhibits osteoclast activity and stimulates osteoblast activity.
when is calcitonin secreted?
when serum calcium levels are high
usually four of theses, on the posterior surface of the thyroid gland
works in the opposite way of calcitonin to regulate serum calcium levels. secreted when calcium levels drop
parathyroid hormones (PTH)
how does PTH regulate serum calcium levels?
by increasing osteoclast activity (which increases calcium release from the bone) as well as increasing the absorption of calcium in the GI tract and kidneys
what is the difference between the ways that the hypothalamus stimulates the adrenal medulla and the cortex?
adrenal cortex is regulated by negative feedback involving the hypothalamus and adrenocorticotropic hormones. the medulla is regulated by nerve impuleses from the hypothalamus
part of the adrenal gland that produces epinephrine and norepinephrine in times of stress.
what are the three separate regions of the adrenal cortex? what hormones do they secrete?
outermost region of the adrenal cortex secretes mineralocorticoids (adlosterone acts to conserve sodium and water in the body)
middle region of the adrenal cortex secretes gluocorticoids (cortisol increases serum glucose levels)
inner region secretes gonadocorticoids (sex hormones)
rare, complex condition in which the pituitary gland does not produce sufficient amounts of some or all of its hormones
what are the causes of hypopituitarism?
congenital defects, cerebral or pituitary trauma, autoimmune conditions, infections of the brain and tissues that support the brain, TB, pituitary tumors, hemochromatosis, histiocytosis X, sarcoidosis, hypothalamic dysfunction (the only secondary cause)
what can hypopituitarism cause? what are they?
dwarfism - short stature caused by deficient levels of growth hormone, somatoropin, or somatotropin-releasing hormone
diabetes insipidus - excessive fluid excretion in the kidneys caused by deficient antidiuretic hormone levels
does hypopituitarism develop slowly or suddenly?
it can develop suddenly, but most often develops slowly
what are the clinical manifestations of hypopituitarism?
fatigue, headache, cessation of menstruation, infertility, decreased libido, low tolerance for stress, hypotension, muscle weakness, nausea, constipatoin, weight loss or gain, anorexia, abdominal discomfort, cold sensitivity, visual disturbances, loss of body or facial hair, joint stiffness, hoarseness, facial edema, thirst, excessive urination, short stature, delayed growth and development
condition in which the pituitary gland secretes excessive amounts of one or all of the pituitary hormones. most commonly caused by tumors that secrete hormones or hormone-like substances
what conditions can be caused by hyperpituitarism?
gigantism, acromegaly, syndrome of inappropriate antidiuretic hormone (SIADH), hyperprolactinemia, Cushing's syndrome, hyperthyroidism
tall stature caused by excessive grotwth hormone levels prior to puberty
increased bone size caused by excessive growth hormone levels in adulthood
increased renal water retention caused by excessive antidiuretic hormone levels
excessive prolactin levels that result in menstrual dysfunction and galactorrhea (inappropriate lactation)
excessive cortisol levels that result from the increased ACTH levels
hypermetabolic state caused by excessive thyroid hormones that result from increased TSH
does hyperpituitarism develop suddenly or slowly?
can occur suddenly but usually develops slowly
what are the manifestations of hyperpituitarism?
headache, visual field loss or double vision, excessive sweating, hoarseness, galactorrhea, sleep apnea, carpal tunnel syndrome, joint pain and stiffness, muscle weakness, paresthesia
group of conditions characterized by hyperglycemia resulting from defects in insulin production, insulin action, or both
diabetes mellitus (DM)
what can impiared insulin production or action result in?
abnormal carbohydrate, protein, and fat metabolism because of the glucose transportation issue
what are risk factors for the development of DM?
older than 65, Native Americans (have the highest rates), African Americans, and Hispanics
what are some acute complications of diabetes mellitus?
hyperglycemia, diabetic ketoacidosis, hypoglycemia
what may hyperglycemia be the result of?
excessive dietary carbohydrate intake as well as insufficient or inappropriate diabetic pharmacologic therapy
pH imbalance characterized by increased ketones in the urine caused by insufficient insulin; if cells are starved for energy, the body may begin to break down fat-producing toxic acids
what may hypoglycemia result from?
insufficient dietary intake, increased physical activity, and excessive diabetic pharmacologic therapy
what are the chronic complications of DM caused by?
long-term excessive glucose levels which contribute to the thickening and hardening of vessel walls, causing diffuse ischemia and necrosis
what are the chronic complications of DM?
heart disease, stroke, hypertension, diabetic retinopathy, blindness, kidney disease, diabetic neuropathy, amputations, periodontal disease, pregnancy complications, increased susceptibility to infections and delayed healing, erectile dysfunction, depression
what are the clinical manifestations of DM?
hyperglycemia, glucosuria, polyuria, polydipsia, polyphagia, weight loss, blurred vision, fatigue
develops when the body's immune system destroys pancreatic beta cells. these people must have insulin because they are not making their own
type 1 diabetes
when does type 1 diabetes usually begin?
usually strikes children and young adults, but it can start at any age
what is though to be the cause of type 1 diabetes?
most likely a viral or environmental trigger in genetically susceptible people causes an autoimmune reaction. cannot be prevented.
insulin resistance, a disorder in which the body's cells do not use insulin properly. as the need for insulin rises, the pancreas gradually loses its ability to produce insulin, so they may become insulin dependent
type 2 diabetes
what are the risk factors for the development of type 2 diabetes?
advancing age, obesity, family history, history of gestational DM, impaired glucose metabolism, and physical inactivity.
which races are at highest risk for type 2 diabetes?
african americans, hispanics, native americans, asians, native hawaiians, and other Pacific Islanders
form of glucose intolerance diagnosed during pregnancy
who is gestational DM most commonly occuring in?
african americans, hyispanics, and native americans. other risk factors include obesity and a family history of DM
are women more or less likely to develop DM after they have gestational DM?
they are 40-60% more likely to develop it within 5-10 years
cluster of risk factors for DM occurring together that include hyperglycemia, high BP, high cholesterol, and increased waist circumference
visible enlargement of the thyroid gland, usually painless but may affect the GI and respiratory tracts
which thyroid states do goiters occur with?
hypothyroidism, hyperthyroidsm, and normal thyroid states
what is the most common cause of goiters in the US?
how does iodine deficiency cause goiter?
decrease iodine leads to decreased T3 and T4 production, and TSH production increases in an attempt to compensate for low levels of thyroid hormones. increased levels of TSH produce thyroid hyperplasia and hypertrophy
condition in which the thyroid does not produce sufficient amounts of thyroid hormones
what may hypothyroidism be a cause of?
hypothalamus, pituitary, or thyroid dysfunction
true or false: the risk of hypothyroidism increases with age
what are the causes of hypothyroidism?
a previous or current inflammation of the thyroid gland can leave a large percentage of thyroid cells damaged and incapable of producing sufficient hormone amounts. autoimmune thyroiditis is the most common cause of thyroid gland failure. the second major cause is iatrogenic (resulting from medical treatments)
what is the most common cause of hypothyroidism?
what are the manifestations of hypothyroidism?
fatigue, sluggishness, increased sensitivity to cold, constipatoin, pale dry skin, edema in the face hands and feet, hoarseness, hypercholesterolemia, unexplained weight gain, myalgia, arthralgia, muscle weakness, heavier than normal menstrual periods, infertility, brittle fingernails, hair loss or thinning, bradycardia, hypotension, depression, goiter
rare, advanced hypothyroidism that can be life threatening
what are the manifestations of myxedema?
marked hypotension, respiratory depressoin, hypothermia, lethargy, and coma
what are the things that hormones regulate?
growth and development, metabolism, sexual function, reproduction, mood stability
condition of excessive levels of thyroid hormones that results in a hypermetabolic state
what are the conditions that can cause hyperthyroidism?
excessive iodine, Grave's disease, nonmalignant thyroid tumors that secrete thyroid or thyroidlike hormones, thyroid inflammation which increases capillary permeability resulting from the inflammatory process causes additional thyroid hormones to be released in the blood stream, taking large amounts of thyroid hormone replacement
what are the clinical manifestations of hyperthyroidism?
sudden weight loss, tachycardia, dysrhythmias, hypertension, increased appetite, nervousness, anxiety or anxiety attacks, irritability, difficulty concentrating, tremor (usually a fine trembling in the hands), diaphoresis, changes in menstrual patterns, increased sensitivity to heat, diarrhea, goiter, difficulty sleeping, exophthalmos
autoimmune condition that stimulates thyroid hormone productoin
protruding eyes with decreased blinking and movement
sudden worsening of hyperthyroidism symptoms that may occur with infection or stress
thyroid crisis (storm), or thyrotoxicosis
what are the manifestations of thyrotoxicosis? what complications can it cause?
fever, decreased mental alertness, and abdominal pain. can cause cardiomyopathy, heart failure, osteoporosis
condition in which the parathyroid gland does not produce sufficient amounts of PTH
what things can hypoparathyroidism?
can be caused by congenital defects (a lack of one or more of the four parathyroid glands), damage following surgery, radiation, autoimmune conditions, hypomagnesemia, or metabolic alkalosis
what does hypoparathyroidism result in?
hypocalcemia and a subsequent increase in phosphorus levels
what are the clinical manifestations of hypoparathyroidism?
paresthesias of the fingertips, toes, and lips; muscle twitching or spasms; seizures; fatigue or weakness; dysrhythmias; hypotension; abdominal cramping; diarrhea; painful menstruation; patchy hair loss; dry, coarse skin; brittle nails; anxiety or nervousness; headaches; depression or mood swings; memory loss
condition of excessive PTH production by the parathyroid gland. this imbalance is caused by tumors, hyperplasia, or chronic hypocalcemia
what will hyperparathyroidism result in?
hypercalcemia. the excessive calcium levels can lead to decreases in phosphorus levels, increases in magnesium levels, and metabolic acidosis
what are the manifestations of hyperparathyroidism?
osteoporosis, bone pain, pathological fractures, renal calculi, polyuria, abdominal pain, constipation, fatigue or weakness, flaccid muscles, dysrhythmias, hypertension, depression or forgetfulness, nausea and vomiting, anorexia
what are the complications of hyperparathyroidism?
hypocalcemia, hyperphosphatemia, hypomagnesemia, matabolic alkalosis
rare tumor of the adrenal medulla that excretes epinephrine or norepinephrine and can be life threatening because of the affects of these hormones. can occur as a single tumor or multiple tumors in one or both adrenal glands, rarely malignant.
when is pheochromocytoma more common?
in early to middle adulthood
how long do the manifestations of pheochromocytoma last?
in unpredictable attacks that usually last 15-20 minutes. reflect the fight-or-flight response
what are the clinical manifestations of pheochromocytoma?
hypertension, tachycardia, dysrhythmias, forceful heartbeat, chest pain, profound diaphoresis, hyperglycemia, abdominal pain, sudden onset of severe headaches, anxiety, feeling of extreme fright, pallor, weight loss, difficulty sleeping
condition of excessive amounts of glucocorticoids
what is the causes of the glucocorticoid excess with Cushing's syndrome? what is the most common cause?
iatrogenic, resulting from ingestion of glucocorticoid medications. thes medications mimic the body's own hormones. can also be caused by adrenal tumors that secrete glucocorticoids or by pituitary tumors that secrete ACTH and cortisol. paraneoplastic syndrome resulting from cancers outside the endocrine system can also cause it by increasing the production of ACTH and cortisol
what are the manifestations of Cushing's syndrome?
obesity (especially around the trunk); moon face (round, full, red face); fatty pad between the shoulders (buffalo hump); muscle weakness; delayed growth and development; acne; broad purple striae on the abdomen, thighs, and breast; thin skin that bruises easily; delayed wound healing; osteoporosis; hirsutism (abnormal hair growth); changes in menstruation; decreased libido; erectile dysfunction; insulin resistance; hypertension; edema; hypokalemia; mood changes and psychosis
deficiency of adrenal cortex hormones that can be caused by damage resulting from autoimmune conditoins (the most common cause), infections, hemorrhage, and tumors. may alos result from pituitary dysfunction that results in insufficient ACTH levels
what are the clinical manifestations of Addison's disease?
hypotension, changes in heart rate, hypoglycemia, chronic diarrhea, patchy hyperpigmentation, pallor, extreme weakness and fatigue, anorexia, mouth lesions on the insides of the cheeks, nausea and vomiting, salt craving, slow sluggish movement, unintentional weight loss, mood changes and depression, electrolyte disturbances
medical emergency. more severe version of Addison's disease