Physiology 2 Flashcards
What is the effect of prolonged insulin on insulin receptors?
Downregulates
What are the two clinical pictures of an insulinoma?
Hypoglycemia initially, then hyperglycemia later on d/t downregulation of the receptors
What is the serum protein that binds to cortisol?
Transcortin
What is the effect of estrogen on cortisol binding globulin?
Decreases
What is the most important amino acid in producing a glucogenic response?
Alanine***
What is the effect of cortisol in the liver? Muscle? Adipose tissue?
Liver = glycogen synthesis
Other - glycogenolysis
How does cortisol decrease the inflammatory response?
Inhibits phospholipase A2
What are the three products of COX enzymes?
- Prostacyclins
- Prostaglandins
- Thromboxanes
What is the enzyme that produce leukotrienes? What is the substrate for this?
Lipoxygenase
Arachidonic acid
Why may NSAIDs exacerbate asthma attacks?
Block COX will shunt to lipoxygenase pathway
What nonsteroid hormone has intranuclear transduction?
Thyroxine
What is the major hormone that is needed for neurological development in the newborn?
Thyroxine
What is the most potent glucocorticoid?
Dexamethasone
What is the most selective mineralocorticoid?
Fludrocortisone
Why is it that low leads to lower insulin levels?
Lack of depolarization in the beta cells of the pancreas
Why is it that cushing’s causes peptic ulcers?
Lower amounts of COX-1
Why does Cushing’s cause myopathy?
Loss of muscle glycogen and protein d/t gluconeogenesis
What are the three major drugs that inhibit the adrenal cortex?
- Ketoconazole
- Aminoglutethimide (aromatase inhibitor)
- Spironolactone
What is the MOA of ketoconazole in terms of adrenal function?
Inhibits desmolase
What are the three major steroids that have mineralocorticoid effects?
- Aldosterone
- Fludrocortisone
- Deoxycorticosterone
What are the two major lethal side effects of corticosteroids?
CHF
Hypokalemia
What is the major breakdown product of testosterone / estrogen, androsterone etc? When are these elevated?
Ketosteroids–Cushing’s, testicular CA, PCOS
What is Cushing’s disease vs syndrome?
Disease is primary pituitary adenoma
Syndrome = 2/2 to some other cause
Which is active: cortisol or cortisone?
Cortisol is active
What is the function of HSD-1? HSD2?
HSD-2 is only in the nephrons, and inactivates cortisol, to prevent action on the mineralocorticoid receptors
What is the issue with licorice?
Inhibits 11-HSB 2
What happens to WBCs with cushing’s and addison’s?
Eosinophilia in addison’s
Eosinopenia in cushing’s
What is the classic metabolic disturbance with Cushing’s?
Hypokalemic alkalosis
What are the classic cancers that cause Cushing’s?
Thymomas Oat cell CA Pheo Islet cell tumors Carcinoid tumors
(TOPIC)
What is Conn’s syndrome?
Adenoma or hyperplasia of the zona glomerulosa
What are the cells that produce renin?
JG cells
What does the macula densa sense, and do?
Senses renal flow, and will decrease JG cells from releasing Renin
What are the two main immediate stimulants of aldosterone secretion?
Hyperkalemia and ANG II
What happens to renin with CHF?
Increases
What are the receptors on JG cells?
Beta 1 receptors
How does hyperthyroidism cause HTN?
Y is a part of thyroid hormone, and will increase epi/NE synthesis. This activates Beta-1 Receptors on JG cells, and activates the RAAS
What is Bartter’s syndrome?
Renal defect of Na reabsorption and aldosterone failure to reabsorb Na and renal resistance to ANG II
(acts just like spironolactone? diuretics)
Causes JG cell hyperplasia, but still no Na reabsorption
Is there HTN or peripheral edema with Bartter’s syndrome?
Nah dawg
What is Liddle syndrome?
AD defect of Na channels in the kidney, that usually presents with high ECF, low renin
