T1 L3 histology Flashcards
endocrine glands and hormones
ductless
Hormones: organic chems released at specific times in small amounts into tissue fluids/ BVs
Pancreas: has exocrine and endocrine function
endocrine definition
action of hormone on target organ away from secreting cell
autocrine definition
action on self cell
paracrine definition
adjacent cell
neuroendocrine
neural stimulation of endocrine cells to secrete hormones (medulla of adrenal)
structure of endocrine glands
- cuboidal secretory cells w/ lumen at centre, supported by myoepithelial cells
- all have lumen except pituitary and parathyroid
clinical manifestations of endocrine diseases
- hormone overproduction
- hormone underproduction
- tumor/ mass lesion (ass. w/ overproduction of hormones, if non-functional there is a pressure effect)
pituitary gland divisions
- adenohypophysis: anterior lobe
2. neurohypophysis: posterior lobe
anterior pituitary gland (adenohypophysis) cells present in relation to staining patterns
- acidophils: take up acid dyes
- basophils: take up basic dyes
- chromophobe: no staining features
staining method to identify specific hormone secreting cells
Antibody staining against specific hormone (antibodies to GH identify cells secreting GH)
hormones from ant. pituitary, cells responsible and target organ
- GH secreted by somatotroph, targets bones
- prolactin secreted by lactotroph targets breasts
- ACTH secreted by corticotroph targets adrenal gland
- FHS secreted by gonadotroph targets ovaries and testes
- TSH secreted by thydotroph targets thyroid gland
hormones of posterior pituitary (neurohypophysis)
- ADH: facilitates H2O absorption in kidneys, makes more concentrated (lack in diabetes insipidus = increase in vol, decrease in conc)
- oxytocin: contraction of smooth muscle in uterus during birth and myoepithelial cells in breast (feeding)
pituitary adenomas (benign tumors)
arise from anterior lobe
can be functional/ non-functional
-Functional: productive, cause hyperpituitarism
-non-fucntional: pressure effects and hypopituitarism bc space occupying lesion. Space occupying effects of functional/ non-functional adenomas (headache, nausea, vomiting, diplopia, vision impairment)
compression of optic chiasm due to pituitary adenoma
bitemporal hemianopsia
Thyroid gland synthesises:
- T4 (thyroxine)
- T3 (triiodothyroxine)
which stimulate metabolic rate, synthesis of these require iodine
goitre
thyroid enlargement due to lack of iodine, thyroid enlarges to absorb max conc of iodine