endocrinology Flashcards
what are endocrine organs
Glands
how do hormones travel
In the blood
how do target cells impart specificty
Via receptor expression
how is the endocrine system connected
Not connected
what are most hormones
Peptides (small proteins)
types of Peptide hormones
Releasing hormones
Insulin
Melatonin
variability of peptide hormones
Highly variable
what determines specificity of pepitide hormones
receptors on target cells
onset of hormones
SLow onset
duration of hormones
Long duration
size of peptide hormones
Lots of different sizes
what type of peptides are cleared quickly
smaller peptide hormones
synthesis of Peptide hormes
synth begins with transcription then traslation in the RER
Golgi is where it is prepared and packaged
What all can peptides act as
Neurotransmitters or hormones
what is a preprohormone
hormone right after the ribsome
What is a prohormone
From RER with folding to be packaged
when does a prohormone become a hormone
after final cleaving
where often is final cleaving of a prohormone done
in the secretory vesicle
why is packaging of peptide hormones important
Allows large release
also limits the feedback that would otherwise lead it to stop being produced.
what are lipid hormones derived from
Cholesterol
what determines what lipid steroid is produced
Enzymes
size of lipid hormones
Smaller
commonness of lipid hormones
Less common
where are cholesterol hormones gound
gonads
Adenyl cortex
Placenta
Vitamin D
steps of steroid synthesis
binding to receptor
Adenylyl cyclase activates to make cAMP
activates PKA
PKA phospholates proteins to make phosphoproteins
Phosphoproteins take Lipid Droplets from LDL to make free cholesterol
StAR goes to PBD in michondrium with P450 enzymes on inner membrain
shuttling between SER and MItochondria
Diffusion to blood
what takes Androstenedione to make testosterone
17beta-hydroxysteroid dehydrogenase
what takes Testosterone to make Estradiol
Aromatase
action of Cholesterol Esteras
Cleaves the ester bond
why make Cholesterol ester
makes it water soluble
action of StAR
binds to free cholesterol to put it into the mitochondria
where is cholesterol converted to steroids
In the mitochondria
storage of steroids
cannot be stored because lipid soluble
what does 17beta hydroxysteroid dehydrogenase do
takes the ketone group in androstenedione to an OH group in testosterone
what does Aromatase do
aromatizes testosterone to make estradiol
can you undo steps of the steroid biosynthetic path
no, most are unidirectional
what happens if their is an enzyme deficiet in the steps of steroid synthesis
bottlenecks and backs up
Mineralcorticoid si from what gland
Adenyl cortex
Roll of Mineralcorticoids
regulation of glucose
what are androgens
regulate male features
most common androgen
TEstosterone
what are Estrogens
regulate female features
most common estrogen
Estradiol
what type of hormone are mineralcorticoids
steroid
what are amines derived from
Tyrosine
what amines are lipid soluble in the thyroid
T3 and T4
what are amines in the nervous system
Catcholamines
where are catecholimines that are found in the Glads found
Andenyl medula
how are catecholamines trasmported
water solublie, so like a peptide
what are the catecholamines
Norepinephrine
Epinephrine
Dopamine
what are Eicosanoids
Lipids dervied from arachidonic acid
exams of eicosanoids
Prostaglandins
Prostacyclins
Thromboxanes
Leukotrienes
where all do eicosanoids act
Mostly local
odd place where eicosanoids can be made
in non-endo organs
what are leukotrienes
white blood cell made hormones
how are hormones secreted
In short bursts from upward signals
other in a cyclic fashion throughout the day
how is LH released
in a burst followed by Testosterone
exames of cyclic hormones
Growth hormone high at night
Cortisol high at the day
what can happen to a hormone ocne it circulates in the blood
Excted in urine or poop
Inactivated by metabolism
Binds to receptor on target cell
Activated by metabolsim to bind on target cells
what determines the secretion of a hormone
That wich is present in the blood
Neural impact
By another hormone
what helps bind lipid proteins in the blood
Binding proteins
where are binding proteins synthesized
In the liver
Roll of binding proteins
protect hormone from destruction in blood
negative of binding proteins
Less likely to bind to target though
do peptide and catecholamines enter cells
No, act of membrane proteins
G-coupled receptors
Metabotropic
ion channel receptors
Ionotropic
effect of peptides and catecholamines on the cell
Usually cause change in ions and protein phosphorylation (fast)
can also do gene transcription (Slow)
what hormones enter the cell
Steroids Thyroid hormones
action of Steroid and thyroid hormones
create a complex that binds to DNA
where is the hypothalamus
in the wal of the 3rd ventricle as part of the diencephalon region
in the stella turcica
how does the hypothalamus talk to the pituitary
via the infundibulum
what does the anterior pituitary come from
The hypophseal pouch off the gut
what does the posterior pituitary come from
Neurohypophyseal bud from neuroectoderm
what is the bottom of the hypothalmus
Median eminence
adenohypothesis is associated with what
the anterior pituitary and Raphke’s pouch
what does the posterior pituitary secrete
Oxytocin and vasopressin
Nuclei for the posterior pituitary
Supraoptic nuclei
Paraventricular nuclei
how does the posterior pituitary release its hormones
Synth in hypothalamus
carried down axon to posterior pituitary
released into blood stream
action of Oxytocin
S. muscle contraction
action of Vasopressin
REgulate blood Pressure
decreases urine output
how does the anterior pituitary work
neurons synth releasing hormones
Hormones travel down axon
releassing hormones realeased at the median eminence
travel down hypothalamohypophyseal portal vessel
release hormones there now
Action of Corticotropin-releasing horone
Stiulates secretion of ACTH
Action of Thyrotropin-releasing hormone
Stimulates secretion of TSH
Action of Growth Hormone-releasing hormone
Stimulates Secretion of GH
action of Somatostatin
Inhibits secretion of GH
Action of Gonadotropin releasing hormone
Stimulates secretion of LH and FSH
action of Dopamine
Inhibits secretion of prolactin
axis
PAth of a hormone from first step to getting to its target cells
POMC
Pro-opio-Melano-capsin
what can POMC be broken down into
lots of different stuff when placed within vesicles
what does FSH and LH act on
Gonads to do germ cell development and hormone secretion
what does GRowth hormone act on
Liver and otehr cells to secrete IGF-1
tissues for protein sysnth and carb/lipid metabolism
what does TSH act on
Thyoid to secrete thyoxine and triiodothyonine
what does Prolactin act on
breasts to make milk
what does ACTH act on
ADrenal cortex to secrete cortisol
short loop feedback
when hormones from the anterior pituitory feeback to the hypothalmus
long loop feedback
when hormones from 3rd endocrine glands provide feedback to the hypothalmus and the anterior pituitary
