Hormones Flashcards
exocrine
non-hormonal secretions transported through ducts to membrane surface of cells
endocrine
duct-less secrete specific chem (hormones) released into surrounding tissue fluid (intersistial) rich vascular lymphatic drainage specific target organs
Strictly endocrine glands
pituitary thyroid parathyroid adrenal pineal
humoral stimuli
has a direct response to what it finds in the blood stream
hormonal stimuli
indirect - release of factors has to be stimulated by other hormones - chain of actions
hormonal activation on a target cell depends on what 3 things?
blood level of hormone
number of receptors on cell
affinity between hormone and receptor
types of hormones
amino acid hormones
steroid hormones
hypothalamus
inferior to the thalamus and is the major integrating link between the nervous and endocrine system
where does hypothalamus get input from
limbic system, cerebral cortex, thalamus and RAS
hypothalamus outputs info to
pit gland
where does the pit gland sit and where and how does it connect to the hypothalamus
it sits in hypophyseal fossa of the sphenoid bone and is connected inferiorly to the hypothalamus by the infundibulum
posterior lobe of pit
neural tissue
connected to infundibulum
derives from neural tube
anterior lobe
glandular - 75% of total weight
derives from rathickes pouch (roof of mouth)
pituitcytes
main part responsible for storage and release of hormones of posterior pituitary (dont produce hormones)
what tracts provide to posterior pit
hypothalamic-hypophyseal
supraoptic cells secrete
oxytocin
paraventricular cells secretes
ADH
What is ACTH stimulated by
CRH (corticotrophin releasing hormone)
what does acth stimulate
adrenal cortex - help body fight stressors, release glucocorticoids (cortisol)
cushings disease is from what
excess glucocorticoids - from ACTH
MSH is stimulated by what
corticotrope cells
MSH then stimulates
melanin production (pigmentation)
MSH acts as a CNS neurtransmitter for what
appetite control
HGH is regulated by what 2 hypothalamic factors
GHRH - stimulates release
somatostatin - hinhibits release
What produces HGH
somatotopes - specialized cells in pit
TSH is stimulated by
TRH (produced by thyrotropes)
TSH stimulates
T3 and T4 secretion
Thyroid hormones is what kind of system
negative feedback
Gonadotropins are stimulated by
GnRH (gonadotropin releasing hormone) - secreted by gonadotropes
activated at puberty
what are the 2 types of gonadotropin hormones
LH (lutenizing hormone)
FSH (follicle stimulating hormone)
LH
in females - stimulates secretion of estrogens and progesterone, ovulation and formation of corpus luteum
males - stimulates testes to produce testosterone
FSH
stimulates gamete prod (sperm/egg)
regulates development of follicle
stim estrogen prod
prolactin is produced by
lactotropes
what does prolactin do
stim milk prod in mammary glands
high levels of prolactin in males can =
hypogonadism - underdevelopment of gonads, gynecomastia - development of breast tissue
what is gigantism and what hormone does it result from
childhood disease - excessive linear growth before closure of epiphyseal plates
- excessive hGH
what is acromegly and what hormone is it from
adult disease - big hands, feet, internal organs, jaw
- excessive hGH normally from a tumour
cushings disease is from excess
acth
hyperpolactinemia `
- over prod of milk from excess prolactin
- diff in male v. female
posterior lobe hormones
ADH and oxytocin
anterior lobe
GH FSH LH TSH MSH PROLACTIN
what is the largest pure endocrine gland
thyroid
how are the 2 lobes of the thyroid connected
isthmus
the thyroid spans from
C5-T1
nervous supply to the thyroid
postganglionic fibers - superior and middle cervical sympathetic ganglia
main BS to thyroid
superior thyroid artery (from external carotid) and inferior thyroid artery (from subclavian) draining into superior, middle and inferior (drain into branchiocephalic viens or internal jug)
function of T3 and T4
increase metabolic rate
increase body heat prod
involved in growth and development
what are parafollicular cells
cells embedded within a follicle and creates calicitonin
calcitonin function
regulates Ca+ homestasis by:
lowering blood caclium
inhibiting bone reabsorption via inhibiting osteoclasts and by accelleratig uptake of calcium and phosophates into bone extracelluar matrix
what is graves disease
an autoimmune disease from HYPERthyroidism
