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69 Cards in this Set
- Front
- Back
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hormone releasing tissues
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glands
(pituitary,thryroid,ovaries, testes,para thyroid, adrenal, pancrease) CNS (hypothalmus,GI,live,heart, kidneys,placenta) neoplasms like lung cancers that secrete hormones like PTH, ADH, and ACTH |
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Amine characteristics
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secreted from thyroid and adrenal gland
all are precursors from tyrosine |
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2 types of amine hormones
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1. Catecholamines-
dopamine,norepi,epi 2. Thyroid hormone all made from tyrosine and released from adrenal medula and thyroid gland |
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What classification are the majority of hormones?
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peptides
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how are peptides synthesized?
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from preprohormone with signal peptide, signal peptide is removed in golgi and forms prohormone which contains many hormones. Processing occurs to make hormones. All this occurs in golgi
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3 chem classifications of hormones
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1.amines
2.peptides 3.steroids |
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precursor of all steroid hormones
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cholesterol
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Where does cholesterol that makes up steroid hormones come from?
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20% comes from denovo syn.
80% comes from cholesterol in blood bound to LDL |
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types of steroid hormones
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aldosterone
cortisol and corticosterone androgens estradiol progesterone |
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3 places that secrete steroid hormones
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adrenal cortex
gonads placenta |
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3 parts of adrenal cortex and what each one secretes
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1. zona glomerulosa secretes mineralocorticoids(aldosterone)
2.zona fasiculata secretes glucocorticoids (cortisol) and androgens 3. zona reticularis secretes glucocorticoid (cortisol) and androgens |
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2 types of gonads and what each secretes
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testes secretes testosterone
ovaries make estrogen and progesterone |
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what hormones does the placenta secrete?
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estrogen and progesterone
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What hormone are water soluable and transported in blood as free form?
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catecholamines and most peptides
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only 2 peptides that are proteins bound
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GH and insulin like growth factor
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what hormones are hydrophobic and bound to proteins to be transported in blood?
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all steroid hormones
thyroid hormones growth hormone insulin like growth factor |
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describe hydrophobic hormones transport in blood
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bound to proteins in blood. free form is the active form so hormones must dissociate from binding protien to be able to enter the cell and become active. most of steroid homones are in bound state with v. little free
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in what state are most steroid hormones in?
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bound state
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functions of bound hormone
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1.acts as reservoir of hormones and minimizes fluctuations in levels of homones in blood
2. extends half life of hormone bc only the free form of the hormone is metabolized |
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how are hormones inactivated?
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metabolism
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sites of hormone metabolism
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liver
kidney plasma |
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where are steroids broken down?
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liver by cytochrome p450
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what hormones are broken down in the plasma?
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catecholamines and peptides
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What 3 hormones are activated by metabolism?
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1. renin to angiotensin
2. T4 to T3 3. Testorsterone to dihydroxytestosterone and b-estradiol |
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after lipid soluble hormone is metabolised what happens?
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it gets put in aquesous form so that it does not diffuse across lipid bilayer. It is excreted out
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2 types of hormone receptors
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1.membrane bound
2.intracellular receptors |
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what hormones bind to membrane bound receptors?
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1. catecholamines
2.peptides causes signal transduction pathway that can activate/inactivate genes to change transcription/translation of proteins |
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What hormones bind to intracellular receptors?
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1. steroid hormones
2. thyroid hormones (lipid soluble hormones) bind to receptors in the cytoplasm and transported to nucleus. the hormone receptor binds to DNA and alters gene expression |
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3 ways hormone actions can integrate
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complementary actions
antagonistic actions permissive actions |
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example of complementary actions
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stress hormones
w/stress responses cortisol and epi help body with complementary actions |
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describe permissive action of hormones
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effect of one hormone requires the prescence of a second hormone
ex:thryroid hormone is required for beta adrenergic receptors that epi binds to |
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2 ways hormones are secreted
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pulses
cycles |
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2 types of cyclical releases of hormones
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1.circadian patterns like cortisol and GH are released at night
2. monthly cycles such as menstral cycle |
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control imputs for hormone secretion
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plasma conc of mineral ions or nutrients
neuronal control physical stimuli hormonal control (trophic) |
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example of how plasma conc of mineral ion/nutrients control hormone secretion
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insulin secretion regulated by plasma glucose
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3 hormones released by neuronal control
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oxytocin, epi, and insulin
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2 types of physical stimuli that affects release of hormones
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mechanoreceptors
light |
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trophic hormones
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hormone that stimulates release of another hormone
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where is pituitary?
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in sella turcica in sphenoid bone
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Posterior pituitary
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outgrowth of hypothalmus made of neuronal tissue
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anterior pituitary
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originates from Rathkes pouch in pharynx
cells release hormones |
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infundibulum
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connects hypthalmus and pituitary
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parts of hypothalmus
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median eminence
hypothalmic pituitary portal vessels |
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median eminece
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base of hypothalmus
this is where neurons meet the BV portion of the hypothalmus and where the neurons come to release the hormones |
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2 hormones releasesd by post. pituitary
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1.oxytocin
2.vasopressin (ADH) |
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oxytocin
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released by pp
octapeptide stimulates milk ejection and uterine contraction |
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vasopressin ADH
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released by pp
octapeptide regulated water reabsorbtion in collecting ducts |
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hypophysiotrophic hormones
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released from hypothalmus to regulate hormones from AP
GnRH GHRH SS TRH CRH Dopamine all are peptides except for dopamine all are neurotransmitters or neuromodulators |
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control of release of hypophysiotropic hormones
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the trophic neurons in the hypothalamus receive synaptic input from all areas of the NS. the synapses are excitary or inhibitory. various stimuli can excite hypothalmic nuclei and cause release of trophic hormones
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how are AP hormones released?
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hypophysiotropic hromones from hypothalmus released into portal vessels
the hypophysiotropic hormone bind to receptors on specific cells in AP called troph cells. causing release of hormones from AP |
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Describe release of ACTH from AP
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CRH release from hypothalmus
causes release of ACTH from AP which goes to adrenal cortex and causes the release of cortisol |
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Describe release of TSH from AP
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TRH is released from hypothalmus which causes AP to release TSH. TSH causes thyroid gland to release T3 and T4
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Describe release of FSH from AP
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GnRH is released from hypothalmus and that causes AP to release FSH which goes to the gonads to stimulate germ cell dev. and hormone release
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Describe release of LH from AP
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GnRH from hypothalmus causes AP to release LH which goes to gonads
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how is GH released from AP
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GHRH from hypothalmus causes GH increase. the GH causes the liver to release insulin like growth factor
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what inhibits prolactin release from AP?
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dopamine
dopamine is in nonpregnant people so they dont make milk |
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prolactin
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stimulates breast development and milk production
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How is GH release inhibited at AP?
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somatostatin released from hypothalmus decreased release of GH from AP
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what 2 places does GH act on?
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1. GH stimulates release of IGF from liver
2. GH directly stimulates protein synthesis and lipid and carb metabolism |
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negative feedback loop
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when hormones inhibit the release of releasing and trophic hormones to help dampen response. The neg feedback keeps hormone levels wi certain range
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3 ex of neg feedback loops
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CRH-ACTH-cortisol. the cortisol inhibits both ACTH and CRH release
TRH-TSH-thyroxine the thyroxine inhibits TSH and TRH release |
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4 categories of endocrine disorders
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1.hyposecretion
2.hypersecretion 3.hyporesponsiveness 4.hyperresponsiveness |
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primary hyposecretion
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abnormality at the gland due to either destruction of the gland or defects in hormone biosynthesis
ex:Type I diabletes and Hashmitos disease |
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secondary hyposecretion
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gland is normal but there is too little synthesis from pituitary or trophic hormone
ex: Kallmans syndrome where no GnRH is released so no LH/FSH can be released |
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primary hypersecretion
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usually due to hormone secreting cell tumor
ex: thyroid tumor |
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secondary hypersecretion
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gland is normal but there is too much stimulus from pituitary or trophic hormone
ex: Kushings where there is a tumor in AP which increase respone to ACTH which increases release of Cortisol |
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hyporesponsiveness
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hormone secretion is normal but target cell does not respond to hormone
ex Type II diabetes |
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3 reasons hyporesonsivness can occur
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1. lack of hormone receptors
2. receptor signal transduction coupling is abnormal 3. metabolic activation is abnormal |
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hyperresponsiveness
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up regulation of hormone receptors
ex. hyperresponse to epi with hyperthyroidism bc up regulation of beta adrenergic receptors |
