Quiz 3 Flashcards
Why are infants of diabetic mothers with high levels of BG often larger than average and at risk for neonatal hypoglycemia?
Elevated maternal glucose stimulates fetal beta cell hypertrophy and hyperplasia (insulin is potent anabolic growth hormone)
What are the major susceptibility genes for T1DM?
HLA DR4 and DR3
What type of receptor does ADH target at low concentrations? Where are these receptors found?
What type of receptor does ADH target at high concentrations? Where are these receptors found?
In Sheehan syndrome, why is the anterior pituitary subject to ischemic damage (due to hypovolemic shock), but the posterior pituitary is rarely affected?
The anterior pituitary receives blood supply from the low-pressure hypophyseal portal system, making it more vulnerable to hypervolemic episodes
Define an endocrine gland:
A gland that secretes products directly into the blood
Define an exocrine gland:
A gland that secretes products into a duct to be distributed onto an epithelial surface (i.e. sebaceous & sweat glands, pancreatic islet cells, goblet cells, and liver secretion of bile)
What other fluid can hormones travel in besides blood?
Lymph
What are peptide hormones synthesized from? Where in the target cell are their receptors found?
Amino-acids (amines, peptides, and proteins)
Receptors on the cell membrane
What are the two classes of Tyrosine derived amine hormones?
Catecholamines- NE, EPI, and DA
Thyroid hormones- T3 and T4
What makes thyroid hormones unique to other peptide hormones?
They behave like steroids (i.e. binding a nuclear hormone receptor and traveling in the blood bound to TBG)
How do peptide hormones exert an effect on target tissues?
How do steroid hormones exert an effect on target tissues?
In what cranieal stricture does the pituitary gland sit?
The sella turcica
What embryological structure does the anterior pituitary gland develop out of? What structure does the posterior pituitary gland, infundibulum and hypothalamus develop out of?
Which arteriole feeds into the hypophyseal portal system? Which sinus does the hypophyseal portal system drain into?
What are three common names for the anterior pituitary gland?
Pars distalis
Pars anterior
Adenohypophysis
What are the 6 hormones released by the anterior pituitary gland?
FSH
LH
ACTH
TSH
Prolactin
GH
ACTH has the largest effect on which of the adrenal hormones?
Cortisol
In a pathology involving high secretion of ACTH (i.e. Addison’s disease), what hormone is responsible for the often-seen hyperpimentation of the skin?
The prohormone to ACTH, POMC, is also a precursor to several other hormones, such as MSH (melanocyte stimulating hormone), which is responsible for increased melanin production by epithelial basal cells
Prolactin is tonically inhibited by DA (Prolactin inhibiting hormone/PIH), but existence of prolactin releasing hormone (PRH) is only hypothetical at this point. What factors exist that can stimulate prolactin release?
TRH
Oxytocin
Vasoactive intestinal peptide
Estrogen
Oxytocin release during childbirth is involved in what type of feedback loop?
What types of cells surround colloid in the thyroid? What structure do these two cell types form?
What other major cell type forms aggregates in between thyroid follicles?
What are the 8 steps of thyroid hormone synthesis? Where do steps 1-3 occur? Steps 4-6? Step 7 and 8?
What are the two major functions of calcitonin?
What are the two main cell types that compose the parathyroid gland? Which cell is responsible for making parathyroid hormone?
Parathyroid hormone directly and indirectly has an effect on calcium through what three mechanisms?
What is the main mechanism through which parathyroid hormone exerts an effect on bone?
What are the three main effects that parathyroid hormone has on renal tubular cells?
What is the main effect that vitamin D has on the intestines?
Parathyroid hormone has what overall effect on serum calcium and phosphate levels?
The adrenal gland receives blood from which three arteries?
What are the three parts of the adrenal cortex?
Zona glomerulosa
Zona fasciculata
Zona reticularis
What organ is responsible for creation of angiotensinogen?
What catalyzes the conversion of angiotensinogen to angiotensin I?
What catalyzes the conversion of angiotensin I to angiotensin II? Where is it found?
Angiotensin converting enzyme (ACE)
It is found mainly in pulmonary capillaries, but also in the kidneys as well to a smaller degree
What is the most important function of angiotensin II? What are two other functions?
Stimulating aldosterone secretion from the adrenal cortex
-Vasoconstriction
-Na+ reabsorption from Na/H antiporter in PCT
What are the 7 main effects of cortisol on the body?
What type of receptor does glucagon bind to? What second messenger cascade is used?
Recurrent episodes of hyperglycemia can lead to what pathology involving the autonomic nervous system?
Hypoglycemia Associated Autonomic Failure (HAAF)
*It is also known to contribute to dementia later in life
What are the 2 most common forms of ketones found in the human body?
B-hydroxybutyrate Acetoacetate
What acronym is used to help describe common causes of anion gap acidosis?
Methanol
Uremia
DKA
Propylene glycol
Isoniazid, Iron
Lactic acid
Ethylene glycol
Salicylates
What acronym is used to help describe common causes of normal gap acidsosis?
Hyperalimentation
Addison’s disease
Renal tubular acidosis
Diarrhea
Acetazolamide
Spironolactone
Saline infusion
What is a common presentation of DKA?
What are the two main aspects of the pathophysiology of DKA?
Acidosis
Osmotic diuresis
What are three major causes of DKA? Which is most common?
What lab results are used to define DKA?
Also a lack of insulin and elevation of counter regulatory hormones
What are the two normal ranges for anion gap?
How is DKA treated?
Note it is important to give potassium if levels are low/normal before adminstering insulin
*IV bicarbonate is indicated in pH <7.0
T/F: DKA patients may present with hyperkalemia upon arrival to clinic
True
Acidic environment/lack of insulin is thought to affect H/K ATPase and Na/K ATPase respectively
In what type of diabetes does a hyperosmolar hyperglycemic state occur? Why?
Does DKA or HHS present with higher average plasma glucose? Which presents with higher pH (less acidic)?
What does the ADA recommend for screening for diabetes?
What should be included in routine care for diabetic patients?
What are the three main microvascular complications for diabetes?
Nephropathy
Neuropathy
Retinopathy
What role is sorbitol thought to play in microvascular complications of diabetes?
What is the significant of advanced glycosylation end products (AGE) in microvascular complications of diabetes?
How does protein kinase C activation in microvascular complications of diabetes lead to neuropathy symptoms?
What two characteristics of diabetic neuropathy are most common?
It is most likely to be distal and symmetrical
What is the lifetime risk of a foot ulcer for all patienst with diabetes?
25%
What are the most common treatments for diabetic foot ulcers?
Debridement
Antibiotics if infected
Revascularization
Mechnical offloading (shoes, casts, knee walker, etc.)
What are common GI complications for diabetics?
What kind of fungal infections are diabetics especially at risk for?
What is the number one killer of diabetics?
Heart attack, stroke, PVD
What is the pathogenesis of diabetic nephropathy?
Will a glucagon response be activated in diabetics if there is no decrease in insulin (T1DM or advanced T2DM)
No, glucagon response is dependent on a decrease in insulin release
What two other notable hormones besides aldosterone can bind the mineralocorticoid receptor?
Cortisol
Deoxycorticosterone
What types of steroid-like hormones utilize a type I nuclear hormone receptor? What are the 3 steps in gene activation involving a T1 NHR?
What types of steroid-like hormones utilize a type II nuclear hormone receptor? What are the 2 steps in gene activation involving a T2 NHR?
What type of receptor is used for nearly all peptide/protein hormones, as well as some small molecule hormones?
A GPCR is in its active state when it is bound to what molecule?
GTP
Increased GTPase activity of a GPCR would lead to it spending more time in the active or inactive state?
Inactive state
What are four pathologies of hormone excess found in patients?
What are four pathologies of hormone deficiency found in patients?
What are iodothyronine transporters? Is there tissue specific expression (i.e. brain, muscles)?
T4 activity and feedback to the hypothalamus and pituitary glands is determined by what type of T4?
Free T4 (unbound by TBG)
In a patient with clinically low T4 but no symptoms of hypothyroidism, what is the most likely adaptation the body has induced?
Reduced levels of thyroxine-binding globulin (TBG)
What significant enzyme is inhibited by glycyrrhetinic acid? How can this lead to metabolic derangements? What food is known to be high in glycyrrhetinic acid?
11B-hydroxysteroid dehydrogenase 2
Cortisol cannot be converted to cortisone (metabolically inactive), so excess cortisol is formed, which can bind the MRC receptor
Licorice
What kind of testing should be done if hormone excess is suspected? If hormone deficiency is suspected?
What abnormality is visible on the CT image indicated by the arrow?
An adrenal tumor
Note the right adrenal gland has an upside “Y” shape
What lab testing could be done to confirm a suspected pheochromocytoma or paraganglioma?
What lab testing could be done to confirm a suspected case of Cushing’s syndrome?
What lab testing could be done to confirm primary aldonsteronism?
What lab testing could be done to confirm primary adrenal insufficiency?
ACTH, cortisol
How should a hormone-producing adrenal nodule be treated? What if it is not producing excess hormones?
What treatments are available for primary aldosteronsim?
Why could a midnight salivary cortisol be used as an additional screening test for Cushing’s disease?
Cortisol should normally be minimal at midnight, so abnormally high levels may indicate CS
Why would a patient presenting with dark gums be an indication for elevated ACTH in primary adrenal insufficiency?
Elevated ACTH would indicate probable increase in POMC, which can also be used to make MSH, which can cause hyperpigmentation (resulting in darkened gums)
Though muscle weakness, unintentional weight loss and loss of appetite can be seen in severeal pathologies, what additional 3 symptoms would make adrenal insufficiency more likely?
Hypotension
Salt cravings
Darkened gums
What are 3 common gluccocorticoids used to treat adrenal insufficiency or CAH?
What is the most common mineralocorticoid used to treat adrenal insufficiency?
What are three important points of patient education to be given to patients diagnosed with adrenal insufficiency?
Which organ is reponsible for producing DHEA-S? Will exogenous testosterone use cause in increase in DHEA-S?
The adrenal gland
No
What further diagnostic evaluation should be done in a case of suspected pheochromocytoma-paraganglioma with elevated metanephrines?
CT scan or MRI
What further diagnostic tests should be done in a case of suspected primary aldonsteronism with elevated aldosterone and low renin?
24 hour urine aldosterone and a saline suppression test
What further diagnostic tests should be done in a case of suspected Cushing’s syndrome with elevated 24 hour uriine cortisol and elevated MN salivary cortisol?
High dose dexamethasone suppression test
What further diagnostic tests should be done in a case of suspected primary adrenal insufficiency with elevated ACTH and low cortisol?
ACTH stimulation test
What criteria are necessary for a diagnosis of diabetes?
Screening for T2DM is indicated in children/adolescents who meet what criteria?
What screening should be done for T2DM in adults? What populations should be screened? How often?
Approximately what percentage of US children and adolescents are clinically overweight or obese?
40%
If IGF-1 screening is done and is found to be high, what will be the next step in testing? Why?
OGTT with GH levels afterwords; in normal physiology glucose would suppress GH levels
What imaging should be done if an OGTT with GH levels shows inadequate suppression?
What is the Jod Basedow effect?
Exposure to iodine results in hyperthyroidism
-usually in iodine deficient areas
-usually someone with pre-disposition for thyroid hormone overproduction
Is T4 or T3 more strongly bound to TBG?
T4 (its in the name; thyroxine binding globulin)
What would be the expected TSH and T4 for subclinical hypothyroidism?
Why do pregnant women or patients using OCP need more T4 replacement than an average patient with hypothyroidism?
Estrogen raises TBG levels
What is the most likely cause of Low TSH, high T4 with undetectable levels of thyroglobulin?
Exogenous thyroid hormone use (thyroglobulin is T4 precursor)
If microcalcifications are noted in a thyroid nodule ulstrasound, what next step is indicated?
Fine needle aspiration (FNA)
What effect does PTH have on kidney resorption of phosphate?
Decreased tubular resorption of phosphate
Vitamin D increases absorption of both calcium and what other mineral?
Phosphorous
