Lecture 1- Principles and central control Flashcards
Target cells impart… via receptor expression
specificity
3 classes of hormones
- peptides
- steroids
- amines
… hormones are the most common type and they are small proteins. They are highly variable and they can be made and stored.
peptide
Why bother with packaging and storing of peptide hormones?
- prevent from degradation
- reduce effects of hormone on cell thats making it
- can be released in large quantities when needed
… hormones are lipid soluble, NOT water soluble. They are all derived from cholesterol and are not variable.
steroid
3 largest sources of steroid hormones
placenta
adrenal cortex
gonads
… facilitates intracellular transport of cholesterol by binding to cholesterol and transporting it through the watery cytoplasm to the mitochondria where it crosses both outer and inner membranes
StAR (steroid acute regulatory protein)
synthesis of steroid is usually stimulated by…. which causes the next steps
- activate a …
- activate ….
- increase…
- activate… which stimulates activity of…
- release … from intracellular stores
peptide hormones
G protein coupled receptor
adenyl cyclase
cAMP
PKA/ cholesterol esterases
cholesterol
Cholesterol is converted to steroids by … in the mitochondria. These enzymes add… or cleave…
and then steroids are shuttled to the … for further modification
P450 enzymes
O-H
C-C
SER
precursor of amine hormones is…
tyrosine
… hormones have the most widespread effects on the body
amine
steroid hormones and thyroid hormones (which are amines) are both … soluble
lipid
peptide hormones and catecholamines (norepi, epi, dopa) are … soluble
water
norepi and epi are synthesized in the….
adrenal medulla
dopa is synthesiszed in the
hypothalamus
A 4th class of hormones is…. which are lipids derived from…. and are locally acting
eicosanoids
arachidonic acid
Some eicosanoids are… , … , … and …
prostaglandins
prostacyclins
thromboxanes
leukotrienes
do peptide hormones and catecholamines need binding carrier proteins?
no because they are hydrophilic and can readily dissolve in the plasma. but they can use they to reduce the chance of degradation/clearance
… hormones use binding carrier proteins
lipophilic (steroid and thyroid hormones)
hormones in the blood have 4 fates
- excreted in urine or feces
- inactivated by metabolism
- activated by metabolism
- goto target cell and produce response
the amount of hormone circulating in the blood at any one time is a function of what has been …combined with the rate of…
synthesized/secreted
clearance
the effects of a hormone depends on the following 3 factors
- how much is secreted
- how quickly its cleared from the blood
- receptor expression on target
receptors for peptides and catecholamines are on….
These hormones are too … or too… to pass through membrane
cell surface in plasma membrane
large
lipophobic
2 possible responses to peptides and catecholamines
- ionotropic
2. metabotropic
do peptides and catecholamines need to use a 2nd messenger system?
yes
the hypothalamus forms the floor of the … and surrounds the…
diencephalon
3rd ventricle
The…. is the hollow stalk of tissue that connects the posterior pituitary gland to the base of median eminence of the hypothalamus
infundibulum
The… or… develops from an outpocketing of the oral ectoderm that pinches off the roof of the mouth and lies above the palate
anterior pituitary gland
adenohypophysis
The…. or… buds off of the floor of the hypothalamus and is suspended below the brain by the infundibulum
posterior pituitary gland
neurohypophysis
2 hormones of the posterior pituitary
oxytocin
vasopressin
2 hormones released from the posterior pituitary (that are synthesized in the hypothalamus)
oxytocin
vasopressin (ADH)
the posterior pituitary contains axon terminals of 2 hypothalamic nuclei… and..
supraoptic
paraventricular
… inhibits secretion of GH
Somatostatin
… inhibits the secretion of prolactin
dopamine
… stimulates secretion of ACTH
CRH
… stimulates the secretion of TSH
TRH
… stimulates the secretion of GH
GHRH
…stimulates the secretion of LH and FSH
GnRH