Ch 24: Endocrine System Flashcards
what are two main features of endocrine glands
ductless
secrete hormones directly into the bloodstream
what are the two main classes of hormones
amino-acid hormones
steroid hormones
what are amino-acid hormones
one or more amino acids ranging in size
generally are hydrophilic
hydrophilic and must bind to a receptor on the outisde of a cell
what are the three types of amino-acid hormones
amines
peptides
proteins
what is a type of amine
norepinephrine
what are the two types of negative acting hormones
prolactin inhibiting factor (PIF) - dopamine
somatostatin (SST)
their release prevents release of other things
what is a type of peptide
oxytocin
what is a type of protein
growth hormone
what is a hydrophilic hormone
a hormone that loves water and can travel throughout the blood
cannot get into a cell without binding to plasma membrane receptors
what are steroid hormones
hormones that are derived from cholesterol
generally hydrophobic and travel unbound
what are three types of steroid hormones
cortisol
testosterone
aldosterone
what is a hydrophobic steroid hormone
hormones that can cross cell membrane
travels bound to a protein
once inside cell, it binds to receptor in cytosol or on nucleus
what are the four main mechanisms of hormone regulation
they have specific rates and rhythms of secretion
they affect only cells with appropriate receptors
they operate within feedback systems
they’re excreted directly by kidneys or metabolized by the liver
how are hormones transported
via vessels, specifically the hypothalamic hypophyseal portal system
what is the struture of the hypothalamic hypophyseal portal system
vein
capillary
vein
capillary
what is a primary endocrine organ
one that has only endocrine functions
what are 5 examples of primary endocrine organs
anterior pituitary
thyroid
parathyroid
thymus
adrenal cortex
what is a secondary endocrine organ
belongs to another system but produces hormones
what are 7 examples of secondary endocrine organs
pancreas
ovaries
testes
hypothalamus
pineal gland
posterior pituitary gland
adrenal medulla
what is a neuroendocrine organ
organ made of nervous tissue but secretes chemicals that acts as neurohormones
stimulated by the nervous system
what are the four types of neuroendocrine organs
hypothalamus
pineal gland
posterior pituitary gland
adrenal medulla
what is the hypothalamic pituitary axis
complex neuroendocrine system that plays a central role in regulating a variety of physiological processes
what are four main functions of the hypothalamus
controls all hormones secreted by the pituitary gland
controls ANS
thermoregulation
regulation of feeding and thirst
how does the hypothalamus control hormones secreted by the pituitary gland
releases stimulating hormones which stimulate their release
releases inhibiting hormones like prolactin release inhibiting hormone (PRIH) and dopamine
which endocrine organ is the major regulatory of the body
hypothalamus
which endocrine gland is the master gland
pituitary gland
where is the pituitary gland found and what is it covered with
sella turcica of sphenoid bone
covered in diaphragma sella
what is the other name for the anterior pituitary
adenohypophysis
what is the other name for the posterior pituitary
neurohypophysis
which part of the pituitary gland, anterior or posterior, makes up 80% of the gland
anterior pituitary (adenohypophysis)
what are the 6 hormones released by the anterior (adenohypophysis) pituitary
growth hormone (GH)
adrenocorticotropic hormone (ACTH)
thyroid-sitmulating hormone (TSH)
gonadotropic hormones (LH and FSH)
melanocyte-stimulating hormone (MSH)
prolactin (PRL)
what are the two hormones released by the posterior (neurohypophysis) pituitary
oxytocin (OT)
antidiuretic hormone (ADH)
what is a somatotroph
cell of the pituitary stimulated by growth hormone releasing hormone (GHRH) to produce growth hormone (GH)
inhibited by somatostain (SST) to stop releasing growth hormone (GH)
what is a lactotroph
cell in pituitary
stimulated by prolactin-releasing hormone (PRH) to release prolactin (PRL)
inhibited by dopamine (PIF) to stop releasing prolactin (PRL)
what hormone inhibits the production of growth hormone by a somatotroph
somatostatin
what hormone inhibits the production of prolactin by a lactotroph
dopamine (prolactin inhibiting factor)
what is a corticotroph
cell in the pituitary
stimulated by corticotropin-releasing hormone (CRH) to produce adrenocorticotopic hormone (ACTH)
also makes pro-opiomelanocortin (POMC) which eventually leads to melanocyte-stimulating hormone (MSH)
what is a thyrotroph
cell of pituitary
stimulated by thyrotropin releasing hormone (TRH) to produce thyroid-stimulating hormone (TSH)
what is a gonadotroph
cell of pituitary
stimulated by gonadotropin-releasing hormone (GnRH) to produce follicle stimulating hormone (FSH) and leutinizing hormone (LH)
how is melanocyte-stimulating hormone (MSH) produced
corticotrophs produce pro-opiomelanocortin (POMC)
POMC is cleaved into adrenocorticotropic hormone (ACTH)
ACTH is the precursor to melanocyte-stimulating hormone (MSH)
where are antidiuretic hormone (ADH) and ocxytocin (OT) made and stored
made by the hypothalamus
stored in synaptic vesicles in axon terminals of hypothalamus
released into blood vessel from posterior pituitary
when is antidiuretic hormone (ADH) released and what does it do
released in response to high blood solute concentration or low blood volume
promotes reabsorption of salt and water in the kidney
what stimulates the release of oxytocin (OT) from the posterior pituitary
suckling of an infant
stretching of certix or uterus
both tell the hypothalamus to tell the posterior pituitary to release oxytocin
what are the two main posterior pituitary disorders
syndrome of inappropriate ADH secretion (SIADH)
diabetes insipidus (DI)
what is syndrome of inappropriate ADH secretion (SIADH) and what are some of its symptoms
hypersecretion of ADH from the posterior pituitary
symptoms: headache, seizures, confusion, fatigue, lethargy, and decreased urine output
what are the three main causes of syndrome of inappropriate ADH secretion (SIADH)
malignant neoplasms
drug-induced
CNS disorders (infections and trauma)
what type of malignant neoplasm can cause syndrome of inappropriate ADH secretion (SIADH)
small cell lung carcinoma
which two types of drugs can cause syndrome of inappropriate ADH secretion (SIADH)
carbamazepine
selective serotonin reuptake inhibitors (SSRI)
what is the mechanism of syndrome of inappropriate ADH secretion (SIADH)
too much ADH causes reabsorption of water which dilutes sodium levels in the blood (hyponatremia)
diluted blood leads to cerebral edema, neurological dysfunction, and coma
what is hyponatremia
low sodium levels in the blood
what are the two types of diabetes insipidus (DI)
neurogenic
nephrogenic
what is neurogenic diabetes insipidus
most common type of diabetes insipidus
hyposecretion of ADH from posterior pituitary
what are five causes of neurogenic diabetes insipidus (DI)
tumors
inflammatory disorders of hypothalamus and pituitary
head trauma
surgical complications of hypothalamus and pituitary
mutation of AVP gene
what is nephrogenic diabetes insipidus (DI)
least common type of diabetes insipidus
renal tubule unresponsive to circulating ADH
two types: acquired vs genetic
what are the four causes of aquired nephrogenic diabetes insipidus
chronic kidney disorders
lithium carbonate
colchicine
general anesthetics
what are the two causes of genetic nephrogenic diabetes insipidus
mutation of AVPR2 gene (V2 receptor protein)
mutation of aquaporin-2 (AQP2)
what is the most common genetic cause (90%) of nephrogenic diabetes insipidus
mutation of AVPR2 gene (V2 receptor protein)
what is the mechanism of diabetes insipidus (DI)
excretion of large volumes of water dilutes your blood and leads to hypernatremia and hyperosmolality
both cause dehydration
what is hypernatremia
excess sodium in the blood
what are the three main symptoms of diabetes insipidus (ID)
polyuria
thirst
polydipsia
what is polyuria
excess dilute urine output
what is polydipsia
excess thirst
what is hypopituitarism
deficiency of anterior pituitary hormones
what is hyperpituitarism
overproduction of anterior pituitary hormones
what is the most common cause of hypopituitarism
traumatic brain injury leading to a subarachnoid hemorrhage
what is Sheehan syndrome
cause of hypopituitarism
pituitary loses blood supply during a post-birth hemorrhage
leads to ischemic necrosis of gland
what is pituitary apoplexy
cause of hypopituitarism
acute hemorrhage due to rapidly growing pituitary adenoma
what is a rathke cleft cyst
cause of hypopituitarism
pituitary cyst that accumulates proteinaceous fluid and explands
what are hypothalamic lesions and what do they cause
benign or malignant tumors of the hypothalamus
affect the entire pituitary gland and lead to hypopituitarism
metastases to the hypothalamus of which two malignant tumors leads to hypopituitarism
metastases of breast and lung carcinomas
which type of infection can cause hypopituitarism
tuberculous meningitis
which rare genetic defect can cause hypopituitarism
mutation of PIT1 gene which leads to a decrease in GH, PRL, and TSH production
what is empty sella syndrome
iatrogenic cause (surgery or radiation) casues damage to the pituitary gland which leads to hypopituitarism
what is the mechanism of primary empty sella syndrome
cause of hypopituitarism
defected in diaphragma sella (dura covering) allows arachnoid mater and CSF to herniate
herniation leads to expansion of sella and compression of gland
who is most at risk for primary empty sella syndrome
obsese women with history of multiple pregnancies
what is the mechanism of secondary empty sella syndrome
cause of hypopituitarism
after a sella mass is removed, pituitary gland undergoes sponatenous necrosis
what is panhypopituitarism
absense of all pituitary hormone production
what percentage of lost pituitary parenchyma is considered hypofunction
75%
what does a deficiency in growth hormone lead to
dwarfism in children
a gonadotropin deficiency leads to which four things
amenorrhea (loss of period)
infertility
impotence (inability to get an erection)
loss of pubic and armpit hair in men
what does a thyroid stimulating hormone (TSH) deficiency lead to
hypothyroidism which leads to things like tiredness, coldness, weight gain, and depression
what does a deficiency in prolactin lead to
failure to lactate after birth
what does an adrenocorticotropin hormone deficiency lead to
hypoadrenalism which leads to weakness, fatigue, low blood pressure, and pallor
lack of cortisol and aldosterone production as well as deficient melanocyte function
what is cortisol important for
cellular metabolism
what 3 things happen when you have a cortisol deficiency due to an adrenocorticotropic hormone deficieny
hypoglycemia
depletion of glycogen stores
decreased gluconeogenesis
what is hyperpituitarism
over production of anterior pituitary hormone
what is the most common cause of hyperpituitarism and what does it cause
pituitary adenoma on the anterior lobe which causes excess hormone secretion
adenomatous tumors secrete how many hormones and which is the most common type of hormone
usually just two hormones
most commonly, prolactin
secrete hormones from cell type they arised from
what is acromegaly
a type of hyperpituitarism
large stature due to a somatotroph adenoma that releases excessive levels of growth hormone
elevation of insulin-like growth factor 1 (IGF-1)
exposure to these excessive levels comes after the epiphyseal plates close
what is giantism
somatotroph adenoma causes excessive production of growth hormone and elevated levels of IGF-1
exposure to these excessive levels comes before the epiphyseal plates close
who is more at risk, men or women, for acromegaly
females
tend to get diagnosed later in life
what are six clinical features of acromegaly
bony proliferation (hands, feet, and face)
hyperglycemia (insulin resistance)
arthritis
thick skin (skin tags)
congestive heart failure
increased risk of GI tumors
how is acromegaly treated
tumor in anterior pituitary is removed
what is a prolactinoma
benign, anterior pituitary lactotroph adenoma that secretes prolactin
what are the four signs of a prolactinoma in women
amenorrhea (lack of period)
infertility
galactorrhea
osteopenia (loss of bone mass)
what is galactorrhea
milky white discharge from breasts seen in those with prolactinomas
what are the two signs of a prolactinoma in men
hypogonadism
erectile dysfunction
what are the four roles of prolactin
mammary gland growth
initation of milk production
maintenance of milk production
shuts down gonadotropin-releasing hormone pathway
what are the 3-5 parathyroid glands derived from
pharyngeal pouches
what are the two types of cells of the parathyroid glands
chief cells
oxyphil (transitional) cells
what hormone is secreted from the chief cells of the parathyroid
parathyroid hormone (PTH)
how much do the parathyroid glands weigh in total
25-40 mg
what is the main function of parathyroid hormone (PTH) that is realased from the chief cells of the parathyroid glands
regulates calcium levels by raising them if they’re too low
what are the four effects of parathyroid hormone (PTH)
increases release of calcium ions from bone
causes kidneys to convert vitamin D into its active form
increases renal tubuluar reabsorption of calcium
increases urinary phosphate excretion
what is the active form of vitamin D
calcitriol (vitamin D3)
what does calcitriol do
increases absorption of dietary calcium from small intestine
what is primary hyperparathyroidism
overproduction of parathyroid hormone usually due to an adenoma
what are the three causes of primary hyperparathyroidism
adenoma that secretes parathyroid hormone (most common 85-85% of cases)
hyerplasia of parathyroid cells
parathyroid carcinoma (least common <1%)
who is most at risk for primary hyperparathyroidism
older women (4:1)
what is the most common clinical feature of primary hyperparathyroidism
hypercalcemia (too much calcium in blood)
body is responding to excessive PTH by releasing excessive amounts of calcium
what is secondary hyperparathyroidism
prolonged deficiency in calcium causes a hypersecretion of parathyroid hormone
seen mostly in cases of chronic renal failure
what is tertiary hyperparathyroidism
patient experiences prolonged calcium deficiency and are given a renal transplant
hypersecretion of parathyroid hormone (PTH) despite having the renal transplant
what is the saying for symptoms of primary hyperparathyroidism
painful bones, renal stones, abdominal groans, and psychic moans
what are six symptoms of primary hyperparathyroidism
bone disease, pain, and fractures due to demineralization
nephrolithiasis (kidney stones) which can cause obstruction
GI disturbances like constipation
CNS alterations like confusion and memory loss
neuromuscular issues like weakness and fatigue
aortic or mitral valve calcification
what is the mechanism of secondary hyperparathyroidism
chronic disease state like chronic renal failure leads to chronic hypocalcemia (decreased calcium levels)
hypocalcemia leads to hyperplasia of parathyroid
excess of parathyroid cells leads to increase in parathyroid hormone (PTH) secretion
what are the four causes of secondary hyperparathyroidism
chronic renal failure (most common)
intestinal malabsorption
vitamin D deficiency
paraneoplastic syndrome
what are paraneoplastic syndromes
tumors that ectopically produce parathyroid related protein (PTHrP)
cause of secondary hyperparathyroidism
what are the three ways to treat secondary hyperparathyroidism
treat underlying cause
increase calcium levels with calcium and vitamin D replacements
phosphate binders
what is the main cause of hypoparathyroidism
rare but usually caused by unintentional removal of parathyroid glands during thyroid or neck surgery
what are four lesser common causes of hypoparathyroidism
congenital absence of thyroid
familial isolated (inherited)
dominant mutation in CASR gene
autoimmune (body attacks endocrine organs)
in which syndrome is there a congenital absence of the thyroid leading to hypoparathyroidism
DiGeorge syndrome
what happens in a mutation of the CASR gene
calcium-sensing receptor is mutated and has a gain of function
your body thinks you have enough calcium so it supresses PTH, eventually leading to hypocalacemia
what are two conditions caused by hypoparathyroidism
hypocalacemia
hyperphosphatemia
what are four symptoms of hypoparathyroidism
cardiac issues (tetany)
dental abnormalities (enamel)
basal ganglia calcification
mental status change
what two hormones are secreted by the thyroid gland
thyroid hormone (T4 and T3)
calcitonin
what are the three main stimuli that trigger the release of thyrotropin releasing hormone (TRH) from the hypothalamus
decreased levels of thyroid hormone (T3 and T4) in blood
exposure to cold
rapid growth and development
what is the weight of a thyroid gland in an adult
10-30g
which cells of the thyroid gland secrete thyroid hormone (T4 and T3)
follicular cells
which cells of the thyroid gland secretes calcitonin
parafollicular cells
what is the thyroid hormone T4 (90%)
thyroxine
what is the thyroid hormone T3 (10%)
triiodothyronine (active derivative)
what two things does calcitonin do
lowers calcium levels if they’re too high
prevent bone breakdown
how do T4 and T3 work
T4 is converted to T3
T4 and T3 act on nulcear receptors to increase metabolism up to 100%
what are the three types of thyroid disorders
hyperthyroidism
hypothyroidism
lesions of thyroid
what is thyrotoxicosis
hypermetabolic state caused by excess thyroid hormones (T3 and T4)
associated with hyperthyroidism
can be primary or secondary
what is an example of secondary hyperthyroidism
pituitary tumor that secretes TSH
what are the three main causes of primary hyperthyroidism
diffuse hyperplasia
hyperfunctioning (toxic) multinodular goiter
hyperfunctioning (toxin) adenoma
what is an example of diffuse hyperplasia
graves disease
how does toxic multinodular goiter appear under a radioactive iodine uptake test
thyroid is enlarged with areas of darkly staining nodules
how does a thyroid with graves disease appear under a radioactive iodine uptake test
thyroid is homogenously darkened minus the periphery
how does a toxic adenoma appear under a radioactive iodine uptake test
thyroid has one singular darkly staining nodule
what do the dark areas in a radioactive iodine uptake test indicate
area of hormone hypersecretion
what are the four systemic clincial manifestations of someone with hyperthyroidism
warm skin
heat intolerance
sweating
weight loss
what is the GI clinical manifestation of hyperthyroidism
hypermobility which leads to malabsorption, steatorrhea (fat in stool), and hepatomegaly
what is a cardiac clincial manifestation of hyperthyroidism
tachycardia with palpatations
who with hyperthyroidism is most at risk for cardiac clinical manifestations
older individuals with A. fib and congestive heart failure
what are four neuromuscular clincial manifestations of hyperthyroidism
tremor
anxiety
proximal muscle weakness
loss of muscle mass
what are the two, ocular clinical manifestations of hyperthyroidism
wide staring gaze
lid lag (lids cannot close all the way)
what is the main skeletal clinical manifestation of hyperthyroidism
bone reabsorption which leads to osteoporosis (more fractures and muscle atrophy)
what are 6 general clincial manifestations of hyperthyroidism
pretibial myxedema
oligomenorrhea (irregular periods)
goiter
emotional issues
insomnia
fine hair
what is a thyrotoxic crisis (storm)
abrupt onset of severe hyperthyroidism due to some stressor that is most common in graves disease
can be fatal if not treated quickly
what are three stressors that can cause a thyrotoxic crisis (storm) and how does it happen
infection
surgery
cessation of antithyroid medication
all cause acute elevation of catecholamines and lead to the storm
what are the two main symptoms of a thyrotoxic crisis (storm)
tachycardia
fever out of proportion
what is graves disease
diffuse hyperplasia that causes primary hyperthyroidism
autoimmune disease that invovles over active thyroid (hyperthyroidism)
usually occurs in women and those 20-40 years old
what is the pathogenesis of graves disease
autoimmunity causes stimulation of thyroid stimulating immunoglobin autoantibodies
TSI autoantibodies bind to TSH receptor on thyroid follicular cells
binding causes uncontrolled production of T4 and T4
no negative feedback to pituitary
what are the lab findings in someone with graves disease
increased free T3 and T4 in serum
decreased TSH in serum
what are the three main clinical findings of graves disease
diffuse enlargement of thyroid gland
infiltrative ophthalmopathy
localized, infiltrative dermopathy (pretibial myxdema)
what are the 2 mechanisms of infiltrative ophthalmopathy of graves disease
T helper cells cause fibroblast proliferation and synthesis of ECM protein
leads to progressive infiltration of retroorbital space
accumulation of loose CT behind the eye causes protuberant appearence
what is localized, infiltrative dermopathy (pretibial myxedema)
symptom of graves disease
scaly thickening on shins
what are the three primary causes of hypothyroidism
autoimmune thyroid disease
congenital defects
iatrogenic (surgery, drugs, radiation)
what is the most common cause of primary hypothyroidism
hashimoto thyroiditis - an autoimmune thyroid
what does a primary thyroid malfunction lead to
low levels of thyroid hormone and high levels of thyroid stimulating hormone (TSH) and thyroid releasing hormone (TRH)
thyroid not making T3 and T4 so hypothalamus keeps trying to stimulate it
hypothyroidism
what does a pituitary malfunction lead to
low levels of thyroid stimulating hormone (TSH) and thyroid hormone (TH) and high levels of thyroid releasing hormone (TRH)
hypothalamus is trying to stimulate pituitary but it’s not working so thyroid isn’t getting stimulated
hypothyroidism
what does a hypothalamic malfunction lead to
low levels of thyroid releasing hormone (TRH), thyroid stimulating hormone (TSH), and thyroid hormone (TH)
if the main factor is low, everything down stream of it is low too
hypothyroidism
what are five clinical manifestations of hypothyroidism
weight gain
bradycardia
coarse hair
large tongue
menorrhagia (heavy bleeding)
what is cretinism
a symptom of hypothyroidism in developing children or infants
what are the two causes of cretinism
dietary iodine deficiency
genetic defects
what are some clinical features of cretinism
impaired development of skeletal system and CNS
intellectual disability
short
coarse facial features
protruding tongue
umbilical hernia
what is myxedema and what does it causes
a symptom of hypothyroidism in older children and adults
causes slowing of mental and physical activity
what causes the symptoms of myxedema
extracellular matrix protein accumulation in skin, subcutaenous tissue, and visceral sites
what are four symptoms of myxedema
non-pitting edema
deep voice
constipation
weight gain
what is hashimoto thyroiditis (chronic lymphocytic thyroiditis)
autoimmune disorder that causes decreased thyroid hormone secretion and fibrosis of thyroid gland (hypothyroidism)
what is the pathogenesis of hashimoto thyroiditis
helper T cells, cytotoxic T cells, and antibodies cause inflammatory disease and destruction of follicular cells of thyroid gland
causes decrease of thyroid hormone secretion
what are the two antigens involved in hashimoto thyroiditis
thyroglobulin (TGB)
thyroid peroxidase (TPO)
what is a goiter
enlargement of thyroid gland
two types: diffuse nontoxic (simple)(colloid goiter) and multinodular
what is the pathogenesis of a goiter
dietary iodine deficiency leads to production of impaired T3 and T4
leads to increase in thyroid stimulating hormone which causes hypertrophy and hyperplasic of thyroid follicular cells
what is a diffuse nontoxic (simple or colloid) goiter
enlargement of thyroid gland without nodules
two types: endemic and sporadic
what is an endemic diffuse nontoxic (simple or colloid) goiter
goiter caused by dietary iodine deficiency (10% of population)
most commonly seen in underdeveloped countries with low levels of salt (ex. south america)
what is a sporadic diffuse nontoxic (simple or colloid) goiter and who does it most commonly affect
goiter caused by ingestion of substances that interfere with thyroid hormone synthesis or enzymatic defect
most commonly affects women in puberty and young adulthood
what is a multinodular goiter
an advanced form of a simple goiter
irregular, nodulated enlargement of thyroid due to varied responses of thyroid follicular cells to external stimuli
what are the four main types of thyroid tumors
papillary (most common)
follicular
medullary
anaplastic
which type of thyroid carcinoma has the worst prognosis
anaplastic carcinoma
what does the zona glomerulosa of the adrenal cortex produce
mineralcorticoids
what is an example of a mineralcorticoid
aldosterone
what does the zona fasiculata of the adrenal cortex make
glucocorticoids
what is an example of a glucocorticoid
cortisol
what does the zona reticularis of the adrenal cortex make
androgens
what are two examples of androgens
testosterone
dehydroepiandrosterone (DHEA)
what are the three stimuli of adrenal glands
morning hours
stress
sympathetic nervous system
what are the three stimulatory effects of cortisol
gluconeogenesis in liver
release of amino acids from muscle tissue
release of fatty acids from adipose tissue
all provide more fuel sources for metabolism
what are the three types of adrenal cortical steroid hormones and what are they all derived from
mineralcorticoids
glucocorticoids
sex hormones
all derived from cholesterol
how does the endocrine system handle short-term stress
SNS stimulates adrenal gland to produce amino acid hormones like catecholamines (NE and EPI)
how does the endocrine system handle long-term stress
hypothalamus stimulates the pituitary to stimulate the adrenal glands to produce steroid hormones like mineralcorticoid and glucocorticoids
what are the three types of adrenocortical hyperfunction (hyperadrenalism)
cushing syndrome
hyperaldosteronism
androgenital or virilizing syndromes
what is cushing syndrome (hypercortisolism)
a type of hyperadrenalism
excess cortisol levels because of increased levels of glucocorticoids
what is the most common cause of cushing syndrome
administration of steroids to treat inflammatory diseases
cortisol is a steroid, so taking it causes too much in your system (hyperadrenalism)
what is a cause of cushing syndrome (not the most common)
adrenal tumor directly secretes cortisol
high cortisol despite low ACTH levels
what are two secondary causes of cushing syndrome
pituitary adenoma causes excessive ACTH secretion (causes Cushing disease)
ACTH-producing tumor elsewhere in the body
what are some clincal features of cushing syndrome
moon face
buffalo hump
glucose intolerance
thin skin
abdominal stretch marks
what is Conn syndrome
a type of hyperaldosteronism
solitary adenoma of adrenal gland causes secretion of aldosterone which leads to hypertension
what is the primary cause of adrenocortical insufficiency (hypoadrenalism)
adrenal disease
what is the secondary cause of adrenocortical insufficiency
deficiency of ACTH causes decreased adrenal stimulation
what are the three types of adrenocortical insufficiency
primary acute
primary chronic
secondary
what are the three caues of primary acute adrenocortical insufficiency (adrenal crisis)
stress requiring increase of steroid output from glands that can’t respond
rapid withdrawl of steroid in patient dependent on exogenous corticosteroids
massive adrenal hemorrhage
what is the most common cause of acute adrenocortical insufficiency (adrenal crisis)
massive adrenal hemorrhage
what is addison disease
aka chronic primary adrenosortical insufficiency
body destroys adrenal cortex which leads to deficiency in multiple hormones
90% of gland must be destroyed to show symptoms
what are some clincial manifestations of addison disease
hyperpigmentation (tanness) due to high ACTH
low blood volume
adrenal atrophy
weight loss
what is secondary adrenal cortical insufficiency (hypoadrenalism)
decreased pituitary secretion of ACTH or decreased hypothalamic secretion of CRH
what are the four causes of secondary adrenal cortical insufficiency
metastatic cancer
infection
infarction
irradiation
what are the two most common primary tumors that affect the adrenal medulla
pheochromocytoma
neuroblastoma
what is a pheochromocytoma
chromaffin cell tumor arising in the adrenal medulla
causes hypersecretion of catecholamines into blood
what three gene mutations cause pheochyromocytoma
mutations in RET, NF1, and VHL
what is the rule of 10 of adrenal medulla disorders
10% extra adrenal
10% bilateral
10% malignant
10% not HTN related
25% from oncogenic germline mutation
what are some clinical manifestations of adrenal medulla disorders
hypertension (90%)
headache
tachycardia
diaphoresis (excessive sweating)
tremors
catecholamine cardiomyopathy
what are the three types of hypertension
abrupt
precipitous (high all of the sudden)
episodic (comes and goes)
what are three things catecholamine cardiomyopathy can lead to
heart failure
myocardial infarction
ventricular fibrillation
what do the exocrine acinar cells of the pancreas do
secrete digestive enzymes
what do the endocrine pancreatic islets (islets of Langerhans) do
secrete hormones directly into blood stream
what are the three types of cells in a pancreatic islet (islet of langerhans)
alpha
beta
delta
what do alpha cells in the pancreas secrete
peptide hormone glucagon
what do the beta cells of the pancreas secrete
protein hormone insulin
what do the delta cells of the pancreas secrete
peptide hormone somatostatin
how does glucagon from the pancreas regulate glucose in the blood
releases it in response to low blood
stimulates breakdown of glycogen to glucose in the liver to raise blood glucose
how does insulin from the pancreas affect blood glucose levels
released in response to high blood sugar
stimulates glycogen formation in the liver
also stimualtes glucose uptake from blood so it can be stored in muscle, kidney, and fat tissue
both lower blood sugar
what happens when your blood glucose level decreases
alpha receptors in pancreas increase glucagon secretion
glucagon stimulates glycogen to be broken back down into glucose in the liver
what does insulin do
increases the rate of glucose transport mostly into muscle
reduces production of glucose from glycogen in the liver
what is the mechanism of insulin
insulin binds to receptor which activates it
AKT is produced which causes a GLUT-4 vesicle to be made
vesicle is released from cell which causes protein increase, decrease in glu synthesis, and increase glycogen synthesis
how does insulin affect adipose tissue
increases glucose uptake
increases lipogenesis
decreases lipolysis
how does insulin affect the striated muscle
increases glucose uptake, glycogen synthesis, and protein synthesis
how does insulin affect the liver
decreases gluconeogenesis
increases glycogen synthesis
increases lipogenesis
what happens when blood glucose levels increase
beta cells of the pancreas increase insulin secretion
this causes increased glucose uptake by cells as well as storage of glucose, amino acids, and fats
what is the mechanism of diabetes mellitus (DM)
defective insulin production or inadequate action of insulin leads to hyperglycemia
what are the two major forms of diabetes mellitus (DM)
type 1 diabetes (T1D) - insulin deficiency
type 2 diabetes (T2D) - insulin resistant
what is the most common type of diabetes mellitus (DM)
type 2 diabetes (T2D) - insulin resistant
in the US, what is the leading cause of ESRD, adult-onset blindness, and lower extremity amputation
diabetes mellitus (DM)
what is the mechanism of type 1 diabetes (T1D)
autoimmune
T helper cells release cytokines which causes inflamation
cytotoxic T cells destroy beta cells in pancreas
leads to a deficiency of insulin
when are those with type 1 diabetes (T1D) most commonly diagnosed
younger than 20 years old
what are the two abnormalities of type 2 diabetes (T2D)
insulin resistance in peripheral tissues (skeletal muscle, adipose tissue, and liver)
beta cell dysfunction due to insulin resistance and hyperglycemia
what is the major risk factor of type 2 diabetes
central or visceral obesity
when are those with type 2 diabetes (T2D) most commonly diagnosed
patients over 45 years of age
how does obesity cause type 2 diabetes (T2D)
increased adipokines, FFAs, and inflammation from fatty tissue leads to insulin resistance
this makes the beta cells compensate by making more insulin
eventually, beta cells fail and don’t secrete insulin, leading to type 2 diabetes
what are the clinical manifestations of type 1 diabetes (DI)
polyuria
polydipsia (excessive thirst)
polyphagia (extreme hunger)
ketoacidosis
(after 90% or more beta cells are destroyed)
what are the clincial manifestations of type 2 diabetes (T2D)
starts off asymptomatic but is found on blood testing
eventually:
polyuria
polydipsia (excessive thirst)
polyphagia (extreme hunger)
ketoacidosis
what are some complications of diabetes
damage to arteries
atherosclerosis - gangrene and necrosis of legs
diabetic neuropathy/nephropathy/retinopathy
coma
what are the three most common causes of mortality in diabetics
MI
renal vascular insufficiency
cerebrovascular accidents
