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207 Cards in this Set
- Front
- Back
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what pituitary hormones are produced by basophils?
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FSH
LH ACTH TSH |
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what pituitary hormones are released by acidophils?
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Prolactin
GH |
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what are the 4 types of cells in the pancreatic islet of langerhans and what do they produce?
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A cells: glucagon
B cells: insulin D cells: somatostatin F cells: pancreatic polypeptide (inhibits cholecystokinin) |
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what are the three layers of the adrenal cortex and what do they produce?
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glomerulosa: mineralcorticoids
fasciculata: glucocorticoids reticulata: some androgens |
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what are the functional cells of the adrenal medulla and what do they produce?
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chromaffin cells produce Epi and NE
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what is a pheochromocytoma?
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a tumor of the adrenal medulla secreting catecholamines
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what type of hormone is never stored?
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steroid hormones
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what is the concept of "spare receptors" and which hormone typedoes not have spare receptors?
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response saturation at sub-receptor saturation
steroid hormoens have no spare receptors |
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what is the connection between GPCRs and increased mRNA transcription?
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GPCR
cAMP PKA cAMP-Response-Element-Binding-protein (CREB) CREB can bind DNA |
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what is the intracellular fx of IP3
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it binds receptors on ER to release Ca
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what type of receptor in the Insulin Receptor?
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an autotyrosine kinase
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how do steroid hormones regulate gene transcription?
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their cytoplasmic receptors are bound to hsp90
steroid binding to the C-TERMINUS of the receptor releases it from hsp90 the receptor's DNA binding domain is now exposed |
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steroid hormones bind what end of their cytoplasmic receptors?
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the C terminus
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what is the difference between decreased sensitivity and decreased responsiveness to a hormone?
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decreased sensitivity: takes more hormone to get the same response
decreases responsiveness: max response decreased |
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what is the basis for radioimmunoassay
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in a mix have known amount of radioactive hormone, known amount of Ab.
at low concentrations of measured hormone, almost all radioactive hormone will be bound to Ab |
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what is hormone clearance?
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rate of disappearance of hormone/
plasma concentration of hormone final units ml/min |
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which arteries serve the adenohypophysis and neurohypophysis?
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adeno: S. Hypophyseal artery
neuro: I. Hypophyseal artery |
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what is the only hormone tonically inhibited? (and only secreted by release of inhibition)
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prolactin
tonically inhibited by "prolactin inhibitory factor-(PIF)" = dopamine |
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what is the mechanism of the GH receptor?
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1 GH binds 2 GH-receptors (dimmerization essential) =>
cytoplasmic Janus-kinase activated which P-late => Tyrosines on STATs => transcriptional regulation |
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how can you block GH signalling?
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synthetic GH that can only bind 1 GH-receptor, prevents dimerization
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what are the effects of GH?
|
INCREASE: protein synthesis and stability
INCREASE: fat utilization INCREASE gluconeogenesis by liver DECREASE Insulin sensitivity of muscle INCREASE: bone growth |
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how does GH effect bone growth differently in kids vs. adults?
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in kids: stimulates bones to grow longer
adults: stimulates bones to grow thicker |
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what are the effects of congenital loss of GH secretion?
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dwarfism
vulnerable to hypoglycemia (diminished insulin antangonist activity) |
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what are the effects of prepuberty hypersecretion of GH and post-puberty hypersecretion of GH?
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pre-puberty: gigantism
post-puberty: acromegaly (big hands and feet), enlarged membranous structures (tongue, nose, and HEART) |
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what organ produces IGFs (somatomedins)
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liver
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how do the theca and granulosa of the secondary follicle interact to release hormones?
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theca: makes andrestenedione
granulosa: converts andrestenedione to estradiol |
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what is the signal for the post ovulatory follicle to go to corpus luteum, and what is the signal for corp luteum to persist in pregnancy?
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LH signals for post-ovulatory follicle to go to corp. luteum
HCG signals for corp luteum to persist |
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how does the composition of hte cervix change around parturition?
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collagen is broken down to soften the cervix
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during pregnancy, the endometrium becomes _____ which serves what fx?
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the decidium
hormone release: protein hormones (don't know which) and prolactin |
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which part of the fetal placenta is in direct contact with materanl RBCs?
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the syncytiotrophoblast
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the cytotrophoblast disappears at _____ gestational month
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6th
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what causes growth of breasts during puberty?
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estrogen
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what hormone is crucial for normal brain development during fetal life?
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thyroid hormone
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parafollicular C cells of the thyroid secrete ______
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calcitonin
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what is teh source of tyrosines for Thyroid hormone?
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thyroglobulin
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when is bound T3 and T4 produced and when is FREE T3 and T4 produced?
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bound produced by TPO and Iodinase on thyroglobulin in the follicle lumen
free produced in follicular cell by proteases after thryoglobulin has been pinocytosed by follicular cell |
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what is responsible for the Iodine trapping/concentrating fx of thyroid follicular cells?
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Na/I symport protein (NIS) on basal surface of follicular cell
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in follicular cells, what happens to MIT and DIT that did not get coupled?
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it is deiodinated by "deiodinase" to recycle the iodide
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what binds almost all T3 and T4 in plasma?
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Thyroxine binding globulin
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what binds T3 and T4 for deliver to the CNS?
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transthyretin (TTR)
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where/what are the receptors and mechanism for T3 and T4?
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nuclear retinoid X receptor
as a heterodimer, it binds DNA to affect transcription (T4 is deiodinated before binding RXR) |
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which has a longer half life T4 or T3, and what is the utility of that?
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T4 has a longer half life, it can be deiodinated to T3 at target tissue
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what kind of feedback control regulates thyroid hormone secretion?
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ONLY long loop (both types of long loop)
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what are the effects of TSH on the thyroid and what is the mechanisms of signalling?
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increased...
proteolysis of thyroglobulin NIS pump Iodinase TPO size, number, and secretory activity of thyroid cells binds TSH receptors on basal membrane, elevates cAMP |
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thyroid hormone increases metabolic activity of most tissues except ____ and _____
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neurons
testis |
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what effect does thyroid hormone have on protein anabolism/catabolism?
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increases protein catabolism
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thyroid hormone promotes growth in which specific tissues?
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fetal CNS
tooth epidermis hair follicles |
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what is the effect of Thyroid hormone on cholesterol and what is the mechanism of action?
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decreases plasma cholesterol by increases secretion in feces
NO EFFECT on liver synthesis |
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what are the effects of thyroid hormone on the CV system?
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tachycardia
inotropic vasodilation |
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what is the effect of excess/deficiency of thyroid hormone on male reproductive system?
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excess: impotence
deficiency: decreased libido |
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what is the effect of excess/deficiency of thyroid hormone on female reproductive system?
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excess: infrequent menstruation
deficiency: menorrhagia (excessive and frequent menstruation) and decreased libido |
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what is the cause of Grave's disease?
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thyroid stimulating antibodies that mimic TSH
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what are the symptoms of hyperthyroidism
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heat intolerance
sweating weight loss diarrhea muscle weakness nervousness, inability to sleep exophthalmos (in grave's) |
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what are the 2 treatment strategies for hyperthyroidism
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radioactive iodine to kill some thyroid cells
thiouracil: decreases TPO activity |
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what are the symptoms of hypothyroidism (myxedema)?
|
edema (esp. in face)
dry brittle hair feel cold lethargic, depression elevated blood cholesterol |
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what is the cause and symptoms of a child with cretinism?
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lack of thyroid hormone in infancy
appearance of obesity stunted growth mental retardation |
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the adrenal medulla is homologous to...
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a sympathetic ganglion (secrets Epi and NEpi as hormones)
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the zona glomerulosa secretes
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mineralcorticoids (aldosteron)
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the zona fasciculata secretes
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glucocorticoids (cortisol)
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the zona reticularis secretes
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androgens (DHEA and Androstenedione)
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what is the effect of catecholamines on glucose balance?
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increases Liver gluconeogenesis
decreases muscle glucose utilization (to send glu to brain) increased muscle glycogenolysis |
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what is the effect of catecholamines on the cardiopulmonary system?
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increased Q
bronchial dilation |
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what is the one catecholamine receptor that only binds one of the two catecholamines?
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Beta-2 only binds Epi
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Beta adrenergic receptors are...
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GPCRs
increased cAMP |
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alpha-1 adrenergic receptors are...
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IP3 receptors
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alpha-2 adrenergic receptors are...
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inhibitory GPCRs (decreases cAMP!)
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how does cortisol affect catecholamine production by adrenal medulla?
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cortisol activates the last enzyme in chromaffin cells that makes Epi from NEpi
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how does sympathetic stimulation activate catecholamine production?
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activates tyrosine hydroxylase and dopamine hydroxylase
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what are the symptoms of pheochromocytoma?
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HTN
headache palpitations sweating anxiety |
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how does ACTH affect steroid hormone synthesis?
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it increases StAR transporter (which transports Cholesterol into mitochondria)
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how does aldosterone circulate in plasma
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mostly in free form...has a very high metabolic clearance
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what is the consequence of insufficient aldosterone?
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hyperkalemia (arrythmia, weak heart contractions)
hyponatremia (dehydration, reduced blood volume) |
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what is the consequence of excess aldosterone secretion?
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hypokalemia (muscle weakness)
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what is "aldosterone escape"?
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excess aldosterone can only increase BP so much because as volume goes up, GFR goes up, more Na excreted despite high aldosterone
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how does aldosterone affect renal tubule cells?
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it binds mineralcorticoid receptor (displaces hsp90)
increases luminal Na channels increases basolateral Na/K ATPase |
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what enzyme is responsible for inactivating cortisol in renal tubules?
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11-Beta HSD
degrades cortisol because otherwise it would bind Mineralcorticoid receptor and mimic aldosterone |
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what is the danger of eating way too much licorice?
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it inhibits 11-Beta HSD so cortisol can now act like aldosterone
severe HTN |
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what are the 4 main signals to get aldosterone secretion?
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elevated plasma K
Angiontensin II decreased plasma Na ACTH you can get aldosterone without ACTH, but you can only get max secretion with both |
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by what mechanism does ANP affect aldosterone secretion?
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it binds zona glomerulosa, increases cGMP
decreased aldosterone secretion |
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what is the effect of cortisol on glucose balance?
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increased gluconeogenesis
mobilize AA from muscle to liver glycogenesis in liver decreased cellular glucose utilization elevation of blood glucose |
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hypercortisol secretion leads to what pattern of fat deposition?
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mobilized from limbs, deposited in face (moon face)
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what are the effects of cortisol on the immune system?
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growth inhibits and lyse kills immature T cells
blocks inflammatory processes |
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how does cortisol interact with Epinephrine peripherally?
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it potentiates Epi as a vasopressor
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what effect does cortisol have on the renal system?
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increases GFR and suppresses ADH secretion
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which hormone activates surfactant production in fetal lungs?
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cortisol
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what hormones are encoded in the POMC gene?
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Melanocyte Stimulating Hormone
it is still active as part of ACTH, so you can get hyperpigmentation if you hypersecrete ACTH |
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how does ACTH act to increase cortisol production?
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it activates desmolase (mitochondria) the rate limiting enzyme for steroid biosynth
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how does cortisol mediate its effects at target tissues?
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it binds Glucocorticoid receptors (displacing hsp90)
cortisol-GR complex binds glucocorticoid response elements |
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what is the cause and symptoms of Addison's disease?
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autoimmune destruction of cortex
deficiency of mineralocorticoid and glucocorticoids hyponatremia (decreased BP) glucocorticoid deficiency - weight loss, muscle weakness, hypoglycemia hyperpigementation (ACTH hypersecretion to try to stim) |
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what is the difference between Cushing's Disease and Cushing's Syndrome?
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Disease: ant. pit. hypersecretes ACTH
Syndrome: ectopic hypersecretion of ACTH or cortisol, or iatrogenic glucocorticoid tx |
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what is the cause of congenital adrenal hyperplasia?
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defect in an enzyme producing cortisol, stimulates pit. to release LOTS of ACTH, the adrenal gets but it can't make cortisol, you get more androgens from adrenal (usually a negligible amount)
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what organ is subjected to highest levels of pancreatic hormones?
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Liver because of the portal system
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the insulin receptor is...
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an autotyrosine kinase
alpha chain- insulin binding beta chain- autotyrosine kinase also...there are spare receptors! 5% binding is response saturation! |
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what are the effects of insulin on glucose balance?
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decreases glycogenolysis (more glycogen)
increased glucose uptake |
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what are the effects of insulin on amino acid and TG balance?
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net protein synthesis, net TG synthesis
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what else can stimulate insulin secretion besides glucose?
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AAs potentiate insulin response to glucose
GH and cortisol also increase insulin secretion |
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what is the pancreatic result of glucokinase deficiency?
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diabetes! can't trap glucose to get insulin secretion
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what effect does glucagon have on glucose balance?
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increased gluconeogenesis and glycogenolysis
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high AAs increases secretion of what two enzymes?
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glucagon AND insulin
stiulates use of AA as energy |
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what effect does somatostatin have on pancreatic hormones?
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decreases secretion of both glucagon and insulin
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what is the insulin:glucagon ratio at...
basal postprandial fasting/exercise |
basal: 2
postprandial: 10 fasting/exercise: .5 |
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which diabetic type develops ketosis
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type I
the small response to insulin in type II is enough to prevent ketoacidosis |
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what hormones stimulate feeding/hunger
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cortisol, thyroid hormone, ghrelin
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what hormones inhibit hunger?
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leptin (from adipose)
CRH (from hypothalamus to pituitary) calcitonin Glucagon like peptide-1: GLP-1 (from gut, alt proteolyzed proglucagon) |
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overexpression of what mitochondrial protein could lead to diabetes?
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uncoupling protein
decreases H concentration in cytoplasm which helps to open Ca channel to release insulin |
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how do sulfonyureas help treat Type II diabetes?
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they close K channels in pancreatic Beta cells, allow Ca in
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how does metformin help treat type II diabetes?
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decreases liver gluconeogenesis
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which diabetic type develops ketosis
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type I
the small response to insulin in type II is enough to prevent ketoacidosis |
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what hormones stimulate feeding/hunger
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cortisol, thyroid hormone, ghrelin
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what hormones inhibit hunger?
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leptin (from adipose)
CRH (from hypothalamus to pituitary) calcitonin Glucagon like peptide-1: GLP-1 (from gut, alt proteolyzed proglucagon) |
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overexpression of what mitochondrial protein could lead to diabetes?
|
uncoupling protein
decreases H concentration in cytoplasm which helps to open Ca channel to release insulin |
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how do sulfonyureas help treat Type II diabetes?
|
they close K channels in pancreatic Beta cells, allow Ca in
|
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how does metformin help treat type II diabetes?
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decreases liver gluconeogenesis
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what are glands of littre?
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secrete mucous throughout penile urethra
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what male cells produce testosterone?
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interstitial cells of leydig
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what is the effect of FSH on male reproductive system?
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stimulates Sertoli cells to increase spermatogenesis
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what is the effect of LH on male reproductive system?
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stimulates Leydig cells to secrete testosterone
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what hormone decreases spermatogenesis?
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Inhibin decreases FSH secretion
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in males, what hormone decreases LH secretion?
|
testosterone (negative feedback)
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what are the sperm's enzymes to get through the corona radiata and zona pellucida of egg?
|
release of acrosomal enzymes (hyaluronidase)
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when does the second meiotic division of the sperm/ovum occur?
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2ndary spermatocyte to spermatid
ovum undergoes second meiotic division when sperm enters ovum |
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when does the lining of the sperm tubules change from sertoli to cuboidal?
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seminiferous tubules: sertoli
tubuli recti: sertoli retes testis: cuboidal |
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benign prostatic hypertrophy occurs in what zone of the prostate?
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transitional zone
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malignant adenocarcinoma of prostate usually arises in what zone?
|
the peripheral zone
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where does the lining epithelium of the testicular tubules change from cuboidal to columnar?
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head of the epididymis
|
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what is the effect of parathyroid hormone at the kidney?
|
increase phosphate excretion
increase Ca reabsorption |
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normally, plasma Ca is kept at what level?
|
9-10 mg/dL
|
|
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normally, plasma PO4 is around ____ and why is this different than Ca?
|
2.4-4.5 mg/dL
all plasma phosphate is free, so it is lower than Ca (about half of which is bound |
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what are the fast and slow effects of PTH on bone?
|
fast: osteoblasts and osteocytes (bone depositors) release Ca
slow: increased number and activity of osteoclasts |
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how does PTH increase osteoclast activity?
|
indirectly
activates osteoblasts which secrete paracrine factors (IL-6) to activate osteoclasts |
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what effect does PTH have on intestine?
|
it increases Ca and PO4 absorption by increasing Vit D formation by kidney
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what are the symptoms of hypoparathyroidism?
|
main: increased neuromuscular excitability
tingling fingers/toes impaired Ca absorption (no Vit D made by kidney) decreased myocardial contractility |
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how do you treat hypoparathyroidism?
|
Vitamin D and exogenous calcium
|
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what are the symptoms of hyperparathyroidism?
|
severe hypercalcemia: nervous system depression, muscular weakness, constipation, nausea, vomiting
shortened QT interval cystic bone disease |
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what is the diagnostic indicator of hyperparathyroidism?
|
increased serum alkaline phosphatase (secreted by overactive osteoclasts)
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what is the physiologic PTH antagonist?
|
calcitonin: weak
|
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plasma phosphate can be lowered by what two hormones?
|
PTH: increased urinary excretion
Calcitonin: increased bone deposition |
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alternate processing of the calcitonin gene yields _____
|
Calcitonin Gene Related peptide: a potent vasodilator
|
|
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PTH stimulates what step in active Vit D synthesis?
|
hydroxylation at the 1 position to get
1,25 OH D3 |
|
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what is the inactive form of Vit D?
|
24,25 OH D3
|
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how does 1,25 OH Vit D increase intestinal absorption of Ca?
|
binds RXR, increases synthesis of calbindin (stabilizes Ca) and of apical channel and basolateral Na-Ca exchanger
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what is the primary mode of transport for Ca and PO4?
|
Ca paracellular (transcellular stim by Vit D)
PO4 ONLY transcellular with Na Symport on apical |
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what do low-normal vs. very high levels of Vit D do to bone balance?
|
low-normal: promote bone calcification
very high: promote formation of osteoclasts (resorption) |
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how are osteoporosis and osteomalacia different?
|
ostoeporosis: loss of collagen (organic component)
osteomalacia: demineralization of bone (due to Vit D difficiency) |
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what is the cause of congenital hypophosphatemia?
|
kidneys can't reabsorb PO4.
resistant to tx with Vit D must give exogenous PO4 |
|
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FSH stimulates the granulosa to...
|
make estradiol from androgens (theca)
increase FSH receptor increase E receptor increase LH receptor |
|
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the LH surge is caused by...
|
positive feedback of estrogen potentiated by Progesterone
LH surge happens JUST after Estradiol levels start to drop |
|
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when is the significance of the progesterone blip?
|
occurs as Estradiol levels begin to fall, potentiates positive feedback for LH surge
|
|
|
what is the cause of congenital hypophosphatemia?
|
kidneys can't reabsorb PO4.
resistant to tx with Vit D must give exogenous PO4 |
|
|
what 3 things cause the drop in LH secretion at the end of the luteal phase?
|
estrogen inhibits LH
progesterone inhibits GnRH Inhibin A (also inhibits FSH secretion) |
|
|
FSH stimulates the granulosa to...
|
make estradiol from androgens (theca)
increase FSH receptor increase E receptor increase LH receptor |
|
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what causes the drop in FSH secretion in the luteal phase?
|
Inhibin B
Inhibin A (also inhibits LH) |
|
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the LH surge is caused by...
|
positive feedback of estrogen potentiated by Progesterone
LH surge happens JUST after Estradiol levels start to drop |
|
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hCG has similar hormonal properties to...
|
LH (prolongs life of CL)
|
|
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when is the significance of the progesterone blip?
|
occurs as Estradiol levels begin to fall, potentiates positive feedback for LH surge
|
|
|
estrogens stimulate what change in vagina epithelium?
|
change from cuboidal to stratified squamous
|
|
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what causes the drop in LH secretion at the end of the luteal phase?
|
estrogen inhibits LH
progesterone inhibits GnRH Inhibin A (also inhibits FSH secretion) |
|
|
what is the effect of estrogens on bones?
|
more osteoblast
they are anti-apoptotic on osteoblasts earlier fusion of epiphyses (shorter) |
|
|
what causes the drop in FSH secretion in the luteal phase?
|
Inhibin B
Inhibin A (also inhibits LH) |
|
|
what is the importance of estrogen and progesterone receptors in breast cancer tumors?
|
normal: estrogen binds E-receptor, increases synthesis of Progresterone-receptor
tumor: if progesterone receptor is not present, then the E-Receptor is not functioning and the tumor will NOT respond to anti-estrogen therapy |
|
|
hCG has similar hormonal properties to...
|
LH (prolongs life of CL)
|
|
|
estrogens stimulate what change in vagina epithelium?
|
change from cuboidal to stratified squamous
|
|
|
what is the effect of estrogens on bones?
|
more osteoblast
they are anti-apoptotic on osteoblasts earlier fusion of epiphyses (shorter) |
|
|
what is the importance of estrogen and progesterone receptors in breast cancer tumors?
|
normal: estrogen binds E-receptor, increases synthesis of Progresterone-receptor
tumor: if progesterone receptor is not present, then the E-Receptor is not functioning and the tumor will NOT respond to anti-estrogen therapy |
|
|
what are the functions of progesterone?
|
promotes secretory changes to favor implantation (most important)
decreases uterine contractions stimulates lactation (in concert with prolactin and oxytocin) |
|
|
a woman's body temperature is highest during what part of the endometrial phase?
|
during the secretory/luteal phase
|
|
|
what hormones are responsible for the proliferative and secretory endometrial phases, respectively?
|
proliferative: estrogen
secretory: progesterone |
|
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what stimulates uterine contractions to expel menses?
|
prostaglandins
|
|
|
why is the uterus resistant to infection?
|
because there is a high number of leukocytes during menstruation
|
|
|
what are the levels of Estrogen, progesterone, LH, and FSH after menopause?
|
estrogen/progesterone both decreased
LH and FSH increased (because negative feedback is released) |
|
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what is the source of estrogen and progesterone during pregnancy?
|
hCG (LH like) stimulates CL to persist and produce E and P long enough until placenta develops
then placenta provides E and P |
|
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hCG stimulates fetus to produce what hormone?
|
stimulates male testis to produce testosterone
|
|
|
what are the hormones of pregnancy?
|
estrogen
progesterone hCG human chorionic somatomammotropin (fx unclear) relaxin |
|
|
does progesterone decrease during parturition?
|
no
even though it inhibits uterine contractions |
|
|
how does estrogen increase late in pregnancy prepare for parturition?
|
it increases oxytocin receptor (sensitivity increases x100)
|
|
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what are the stimulants for uterine contractions?
|
oxytocin
prostaglandins estrogen decreased progesterone |
|
|
prolactin stimulates...
oxytocin stimulates... (mammilary glands) |
milk SYNTHESIS
|
|
|
what is the initial mammilary gland secretion and what is its content?
|
colostum: lactose, proteins, but little fat
|
|
|
what hormones stimulate milk secretion at the time of birth
|
when estrogen and progesterone go down (after birth) it allows prolactin to stimulate milk synthesis
|
|
|
why might breast feeding be a method of birth control?
|
prolactin inhibits FSH and LH secretion, but incompletely
|
|
|
what is the cause of cryptorchidism?
|
failure of fetal testes to descend into scrotum
|
|
|
what forms the blood testis barrier?
|
tight junctions of sertoli cells
|
|
|
what is the endocrine function of sertoli cells?
|
in response to FSH, they convert testosterone (from Leydig cells) to estradiol (necessary for spermatogenesis)
they also secrete androgen binding protein so that estradiol and testosterone can be secreted into lumen for access of sperm |
|
|
what stimulates sertoli cells to make estradiol and androgen-binding protein?
|
FSH
|
|
|
how do sertoli cells cause immunosuppression in seminifeerous tubules?
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produce FAS ligand to trigger apoptosis of T lymphocytes
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how do male fetuses end up with Wolffian ducts and not Mullerian ducts?
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hCG stimulates fetal testosterone
fetal testosterone promotes wolffian ducts fetal testes produce Mullerian Inhibiting Substance (MIS) this inhibits mullerian ducts from developing |
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what are the contents of seminal fluid?
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fructose,
ascorbic acid, prostaglandins (make cervix receptive to sperm) |
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what are the contents of prostatic fluid?
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Ca
clotting enzymes (to form plug) |
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what inhibits GnRH secretion in males?
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testosterone
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in males, estradiol is required for ____
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spermiogenesis: the terminal stage in spermatogenesis
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in some tissues, testosterone is converted to the more active form...
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5 DHT
this is a reduction product of testosterone |
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in a male's lifetime, when does testosterone peak?
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mid-gestation (male structures)
neonatal (male behaviors?) puberty to andropause |
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does LH increase after andropause
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NO
no release of inhibition... |
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how can anabolic steroids lead to infertility?
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increase in androgens leads to huge feedback inhibition
a. pituitary gonadotrophs atrophy and die when you go off anabolic steroids you can produce LH and FSH |
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what is the cause of adiposogenital syndrome?
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hypothalamus fails to secrete GnRH => no LH/FSH =>no testosterone
hypothalamic feeding center also injured, orexia |
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what happens to fluid balance during pregnancy?
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total body fluid and blood volume increase
RBCs do not increase that much |
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how does the renin angiotensin aldosterone system change during pregnancy?
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they all increase
contributes to increase BV hemodilution increased Q |
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what happens to venous return in pregnancy?
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uterus pushes on IVC
venous stasis in 2nd and 3rd trimesters |
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why are pregnant women at high risk for deep vein thromboses?
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increased estrogen leads to hypercoaguable state
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what are the functions of hCG?
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stimulates fetal testis
rescues CL to continue to produce estrogen/progesterone stimulates maternal thyroid |
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how is fetal circulation different than adult circulation?
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ductus arteriosus: from pulmonary artery to aorta
foramen ovale: from R atrium to L atrium oxygenated blood in umbilical vein deoxygenated blood in umbilical artery |
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what is the effect of progesterone on the kidney?
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it increases K retention
even with high aldosterone levels, you keep plenty of K |
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what is the effect of progesterone on SMC?
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relaxation (decreased total peripheral resistance)
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what is the dexamethasone test?
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in a person with Cushing's disease: dexamethasone will suppress pit. secretion of ACTH, and thus cortisol
in a person with Cushing's syndrome, dexamethasone will not change cortisol secretion |
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how does cortisol interact with the sympathetic nervous system?
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it increases alpha1 receptors on arteries, potentiating vasoconstriction
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how does Thyroid hormone interact with the sympathetic nervous system?
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it increases B1 receptors in the heart, increases HR
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what is the difference between ACTH deficiency and Addison's?
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ACTH deficiency: no hyperpigmentation (because of the MSH in ACTH)
no Volume contraction or hyperkalemia because aldosterone is normal |
