Lecture 16 Endocrine 1

Question 1

Endocrine Glands

Answer 1

secrete hormones; no ducts

Question 2

Hormone

Answer 2

chemical messenger, carried in blood
affect target cells
(ie. cells that have receptors for the hormone)

Question 3

Receptor

Answer 3

binds to hormone, required for response to the hormone

Question 4

Nervous System

Answer 4

fast response, short duration, secretes neurotransmitters, specific localized effects

Question 5

Endocrine System

Answer 5

slow response, longer duration, secretes hormones, widespread effects

Question 6

Neurotransmitters

Answer 6

affect a specific cell (the postsynaptic cell) at a synapse

Question 7

Hormones

Answer 7

affect target cells throughout the body

Question 8

neurohormones

Answer 8

hormones secreted by neurons

Question 9

paracrine substances

Answer 9

e.g. prostaglandins

exert local effects on neighboring cells

Question 10

lipophilic

Answer 10

lipid soluble
steroid hormones, thyroid hormones, eicosanoids
cross the plasma membrane
bind to intracellular (cytoplasmic) receptors

Question 11

lipophobic

Answer 11

water soluble
epinephrine (amino acid derivatives), insulin, antidiuretic hormone (peptides and proteins)
do not cross plasma membrane
bind to receptors on the PM

Question 12

Lipophilic hormones

Answer 12

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

Question 13

Lipophobic hormones

Answer 13

hormone binds to membrane receptor
hormone receptor binding activates a signal transduction pathway
activates enzymes within the cell
mostly metabolic effects

Question 14

Cyclic AMP second messenger system 1-3

Answer 14

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

Question 15

Cyclic AMP second messenger system 4-6

Answer 15

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

Question 16

Phospholipase-C (DAG-IP3) Second messenger system

Answer 16

(norepinephrine: a-adrenergic receptors)
G protein coupled receptor
activation of G protein activates phospholipase C enzyme in the cell membrane
phospholipase C cleaves a membrane phospholipid
forms 2 second messengers: diacylglycerol (DAG)
and inositol triphosphate (IP3)