Flashcards in Lecture 16 Endocrine 1 Deck (16)
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1
Endocrine Glands
secrete hormones; no ducts
2
Hormone
chemical messenger, carried in blood
affect target cells
(ie. cells that have receptors for the hormone)
3
Receptor
binds to hormone, required for response to the hormone
4
Nervous System
fast response, short duration, secretes neurotransmitters, specific localized effects
5
Endocrine System
slow response, longer duration, secretes hormones, widespread effects
6
Neurotransmitters
affect a specific cell (the postsynaptic cell) at a synapse
7
Hormones
affect target cells throughout the body
8
neurohormones
hormones secreted by neurons
9
paracrine substances
e.g. prostaglandins
exert local effects on neighboring cells
10
lipophilic
lipid soluble
steroid hormones, thyroid hormones, eicosanoids
cross the plasma membrane
bind to intracellular (cytoplasmic) receptors
11
lipophobic
water soluble
epinephrine (amino acid derivatives), insulin, antidiuretic hormone (peptides and proteins)
do not cross plasma membrane
bind to receptors on the PM
12
Lipophilic hormones
hormone binds to cytoplasmic receptor
diffuses through membrane
intracellular hormone-receptor complex -> binds to DNA, acts as transcription factor
->regulates transcription of specific genes->mRNA->protein synthesis ->metabolic and developmental effects
alters production of proteins, activates or represses 1 or more genes
13
Lipophobic hormones
hormone binds to membrane receptor
hormone receptor binding activates a signal transduction pathway
activates enzymes within the cell
mostly metabolic effects
14
Cyclic AMP second messenger system 1-3
e.g. epinephrine :B-adrenergic receptors
1. Hormone Binds to receptor
2.G protein associated with receptor is activated
3. activated G protein activates adenylyl cyclase in the plasma membrane
15
Cyclic AMP second messenger system 4-6
4. adenylyl cyclase converts ATP to cyclic AMP (cAMP)
5.Cyclic AMP acts as secondary messenger, activated protein kinase enzyme in the cell
6. Protein kinase activates other enzymes via phosphorylation
->amplification of cellular response
16
