endocrine patho Flashcards
anterior pituitary aka
adenohypophysis
posterior pituitary aka
neurohypophysis
anterior and posterior pituitaries connected to hypothalamus how? x2
anterior: portal vesselsposterior: nerve tract (supraopticohypophysial)
adenohypophysis secretes…
GHACTHLH, FSHMSHPRL
neurohypophysis secretes…
HP & POA!hormones, posterior pituitary: oxytocin & ADH
anterior pituitary anatomy
pars distalispars tuberalispars intermedia
growth hormone functions
- direct effects d/t GH binding on target cell- indirect: mediated mostly by insulin-like growth factor (IGF-I) to promote bone growth- etc1. fat utilization (energy)2. ↑ carb use (↓ gluc uptake of tissues, ↑ glu production in liver, ↑ insulin secretion)3. stim cartilage & bone growth (stim liver to create somatomedins)- somatomedin C most important
growth hormone stimulated & inhibited by x2
stimulated by GHRH (from hypothalamus)inhibited by somatostatin
how growth ↑ carb use
↓ gluc uptake of tissues↑ glu production in liver↑ insulin secretion
adrenocorticotropic hormone: function
stimulates adrenal cortext- glucocorticoids secreted- some control over aldosterone (CRH released in resp to stress events; inhibited by glucocorticoids)
thyroid stimulating hormone: function
circulates, binds w receptor sites in thyroid follicular cells
TRH to T4 pathway
in response to concentration free T4 → hypothalamus releases TRH → anterior pituitary → thyroid gland → TSH → T4free T4 can also inhibit hypothalamus & pituitary
prolactin fxn
lactation, target mammary glandsstimulated by estrogen
follicle-stimulating hormone fxn (females & males)
females: stim ovaries to produce hormones - follicular phase: estradiol- progesterone: lutealmales: stim spermatogenesis (Sertoli cells)- produces inhibin = neg feedback to reduce FSH
luteinizing hormone (females & males)
females: stim corpus luteum to secrete progesterone, surge triggers ovluation- promotes luteinzation of granulosa in dominant folliclemales: stim leydig cells → testosterone
melanocyte stimulating hormone fxn
causes darkening of skin (melanin pigments) - stimulated by exposure to light
antidiuretic hormone: fxns & target
aka vasopressin- normal osmolality of body fluids- blood volumetargets distal renal tubule & principal cells of collecting ducts (virutually impermeable to H2O otherwise)
antidiuretic hormone released in response to
↑ ECF osmolality↓ blood vol / pressureif vasodilatory shock, ADH levels can ↑ 100x
oxytocin function: females & males
female: uterine motility (enhanced contraction, prevents excessive bleeding, promotes placental delivery, prevents), milk letdownmale: role in sperm motility (?)
thyroid gland secerts
T4, T3 (depend on TSH)calcitonin
90% of metabolically active hormone secreted by thyroid gland
T4
T4 vs T3 potency
T3 4x potent but exists for a shorter period in circulation
substrate that binds to iodine to form thyroid hormone
tyrosine amino acids, which are in thyroglobulin moleculesresultant thyroid hormones then hang out in the follicular colloid until needed - cleaved into active forms of T4 & T3
thyroid hormone fxns: cellular↑↓
↑ gene transcription ↑ fxnal activity throughout body↑ metabolic activity (carb, fat, basal metabolism)↑ #/activity mitochondria (more ATP)↑ active ion transport (through cell membranes)
thyroid hormone fxns: body
↓ body weight↑ blood flow, CO, HR, contractilitynormal atrial pressure↑ respiration, GI motility↑ rate of secretion of other endocrine glands
TSH fxn
increases…- proteolysis of thyroglobulin (releases T4 to blood)- iodide pump activity (iodide trapping)- tyrosine iodination - #, size, secretory activity of thyroid cells
parathyroid gland anatomy & fxn
- regulates serum Ca- works in conjunction w Vit D- affects bone, renal Ca deposition/reabs- produces PTH (↑ Ca, ↓ phos)
primary glucose transporter in body
Glut 4
insulin: fxn re: protein metabolism & growth
promotes protein synthesis & storage1. stimulates aa transport into cells2. increases mRNA translation3. increases rate of transcription of certain DNA sequences4. inhibits catabolism of proteins5. liver: ↓ rate of glyconeogenesis
glucagon secreted by
alpha cells of pancreas in response to low levels of blood glucose
glucagon fxns
↑ gluconeogenesisactivates adipose cell lipase: more fatty acids for energy↑ glucagon can cause1. ↑ strength of the heart2. ↑ blood flow to certain tissues (esp kidneys)3. enhances bile secretion4. ⊣ gastric acid secretion
somatostatin fxns
⊣ glucagon, insulin secretion↓ motility in stomach, duodenum, gallbladder↓ secretion, abs in GI tract
somatostatin released by
delta cells of pancreas
cortisol: metabolic effects
- Stimulates gluconeogenesis- ↑ enzymes req to convert aa to glucose (liver cells)- mobilization of aa from muscle tissues2. ↓ protein synthesis and cellular protein
cortisol: glucose effects
- ↓ glucose utilization by cells (mechanism poorly understood)2. ↑ blood glucose - ↑ glucose production- ↑ utilization by cells
cortisol regulated by
ACTH (anterior pituitary)
cortisol & inflammation
- stabilizes lysosomal membranes (prev contents from expulsion)2. ↓ capillary permeability (worsens inflammation a bit)3. ↓ WBC migration, phagocytosis of damaged cells4. suppresses immune system (↓ lymphocyte reproduction)5. attenuates fever (↓ temp = ↓ vasodilation)
aldosterone fxns
Na retention by ↑ tubular reabsUrine excretion K (∴ ↓ ECF K)helps kidneys excrete excess K, ↑ blood vol + atrial pressure
most potent of all naturally occuring mineralocorticoids
aldosterone
aldosterone secretion regulation x4
- ↑ extracellular K+ 2. ↑ extracellular angiotensin II 3. ↑ extracellular Na, slightly ↓ aldosterone secretion4. ACTH req for secretion but has little effect on controlling rate
where are catecholamines stored?
chromaffin cells of adrenal medula
