1 - endocrine system Flashcards
(27 cards)
what are all the endocrine glands? (10)
- pineal gland
- hypothalamus
- pituitary gland
- thyroid gland
- parathyriod gland
- thymus
- adrenal gland
- pancreas
- ovary (female)
- testis (male)
what gland is considered the “master gland”?
pituitary gland
what do endocrine glands do?
- control growth & development
- processes of reproduction
- metabolism
- maintenance of fluid & electrolyte imbalance
- stress responce
what are the 3 different stimuli that hormones are released in response to?
- hormonal stimuli
- neural stimuli
- humoral stimuli
what is the production of hormones regulated by?
a negative feedback system
how does hormonal stimuli release their hormones?
hormones released in response to another hormone
- the stimulus is hormones from hypothalamus
- the response is AP gland secreting hormones that stimulate other endocrine glands to secrete hormones
how does neural stimuli release their hormones?
nerve fibres stimulate hormone release
- stimulus is action potentials in preganglionic sympathetic fibres
- the response is adrenal medulla cells secrete epinephrine and norepinephrine
how does humoral stimuli release their hormones?
changing blood levels of ions and nutrients directly simulate secretion of hormones
- the stimulus is low concentration of Ca2+ in capillary blood
- the response is parathyroid gland secreting PTH, increasing blood Ca2+
what are some examples of protein & peptide hormones?
insulin and growth hormone
what are some examples of amine & amino acids?
adrenaline and thyroxine
what are some examples of steroid hormones?
estrogen and testosterone
what is the process of negative feedback regulation?
- releasing hormones from hypothalamus
- tropic hormone from anterior pituitary
- target gland hormone from target gland
what is a primary disorder of the endocrine system?
originate in target organ releasing the hormone
what is a secondary/tertiary disorder of the endocrine system?
defects in hypothalamus-pituitary system
what causes hypofunction?
- congenital defects
- absence of enzymes
- destruction of gland
- atrophy of gland due to medication
- autoimmune disorder - Hashimoto’s
what causes hyperfunction?
- excessive hormone production
- hormone producing tumour
- autoimmune disorder - Grave’s Disease
what are tests used to examine endocrine function?
- blood: provides info about hormone levels
- stimulation: hypofunction
- supression: hyperfunction
- imaging: isotopic and non-isotopic
what is stimulation test?
- used for testing hypofunction
- a tropic or stimulating hormone is administered to test ability of endocrine organ to increase hormone production
- if there is an increase in hormone production then organ is working well
- if not then hypofunction of the endocrine organ
what is suppression test?
- used for testing hyperfunction
- normal negative feedback mechanism of an endocrine organ is not working
- excessive amount of hormone is being produced
- external stimulus given, if it doesn’t result in reduction of hormone then there is hyperfunction of the endocrine gland.
what is the purpose of the thyroid hormone (TH)?
- its the body’s major metabolic hormone, effects virtually every cell in the body
- found in 2 forms T4 and T3
- it enters target cells and binds to intracellular receptors
what is the difference between T4 and T3?
- T3 is the active form, has 2 tyrosine with 3 bound iodine atoms
- T4 has 2 tyrosine molecules with 4 bound iodine atoms
what is a thyroid function test?
- TSH - gives initial indication of thyroid function
what are symptoms of hyperthyriodism?
elevated metabolic rate, sweating, rapid and irregular heartbeats, nervousness and weight loss
treatment for hyperthyroidism?
Treatments include surgical removal of thyroid or radioactive iodine to destroy active thyroid cells
