endocrine and exocrine glands Flashcards
what are glands?
epithelial cells which produce secretion
what is the origin of glands?
ectodermal
name the two types of glands
endocrine and exocrine
which glands produce hormones?
endocrine
which glands have ducts?
exocrine
where do endocrine glands secrete their hormones?
out of the cell, into the interstitial tissue then into the capillaries scattered within the endocrine gland tissues- the horomones enter the bloodstream
where do exocrine glands secrete their many different substances?
into the lumen or organ surface through ducts
where can endocrine glands be found?
- as part of the epithelial surface (eg lining of GIT)
- or as separate organs (eg thyroid gland)
what is the function of the secretions produced by the endocrine gland?
(hormones) function to regulate bodily functions and maintain homeostasis
what is homeostasis?
the body’s steady state of equilibrium
what are the possible patterns of hormone secretion?
- chronic
- acute
- episodic
describe chronic pattern of hormone secretion
hormones secreted at regular intervals
what is an example of a hormone with a chronic pattern of secretion?
thyroxine
describe acute pattern of hormone secretion
the amount of hormone secreted depends on the stimulus (some stimuli cause large secretions some cause smaller secretions)
what are examples of hormones which have an acute secretion pattern?
adrenaline and cortisol
describe an episodic pattern of hormone secretion?
increased secretion following eating
what is an example of a hormone which has an episodic pattern of secretion?
insulin
what are the three mechanisms that can regulate hormone secretion?
- humoral
- neural
- hormonal
how does humoral hormone secretion regulation occur?
by the presence of certain blood borne molecules
what is an example of humoral hormone secretion regulation?
high glucose levels stimulates insulin secretion
how does neural hormone secretion regulation occur?
neurons stimulate hormone production
what is an example of neural hormone regulation?
sympathetic nervous system (fight or flight) stimulates epinephrine release
how does hormonal hormone regulation occur?
hormone secretion stimulates another hormone to be secreted
what is an example of hormonal hormone regulation?
hormones from pituitary glands stimulate testes to make testosterone
what are the three classes of hormones?
- proteins and polypeptides secreted by the pancreas and parathyroid gland (stored in the cell and released when needed)
- steroids are synthesised in the adrenal cortex, ovaries and placenta (synthesised from cholesterol and released directly into the circulation and cannot be stored
- derivates of amino acid tyrosine (adrenal medulla and thyroid)
what is the function of the hypothalamus?
it makes hormones that control the pituitary gland and makes hormones that are stored in the pituitary gland
what is the function of the pituitary gland?
produces hormones that regulate many of the other endocrine glands
what is the function of the parathyroid glands (there’s four)?
release parathyroid hormone which regulates the level of calcium in the blood
what is the function of the thymus?
during childhood, it releases thymosin which stimulates Tcell development
what is the function of the adrenal glands?
release epinephrine and nonepinephrine which help the body deal with stress