5.4 HORMONES Flashcards
1
Q
Define hormone
A
- Chemical signals released/transported in the bloodstream that act as messengers
2
Q
State the *two** types of hormones
A
- peptide/protein hormones
- steriod (lipid) hormones
3
Q
State the difference between endocrine and exocrine glands
A
- Endocrine glands release their hormones (protein or steriod) into the bloodstream
- Exocrine glands have a duct that carriers their hormones away
4
Q
Define first messenger
A
- A protein hormone that binds to a receptor on plasma cell surface membrane and activates the second messenger
5
Q
Define second messenger
A
- A signalling molecule which stimulates** a change in activity of a cell
6
Q
State the first messenger in adrenaline release
A
- Adrenaline
7
Q
State the second messenger in adrenaline release
A
- Cyclic AMP (cAMP)
8
Q
Describe the route of protein/peptide hormones
A
- From adrenal medulla it attaches to complementary receptor of glycoprotein in plasma cell membrane of target cell
- G protein attached to receptor becomes activated
- Activated G protein now activates the enzyme adenyl cyclase
- Activated adenyl cylases converts ATP to cAMP
- cAMP acts directly on channel protein or initates a cascade of enzyme-controlled reactions
9
Q
Describe the route of steriod (lipid) hormones
A
- From adrenal cortex through plasma cell membrane of target cell
- Steroid hormone binds with specific receptor in cytoplasm
- Receptor-steroid compex forms, enters nucleus
- Binds to promoter region of a gene which increases production of mRNA
10
Q
State why protein hormones are unable to enter cells
A
- Not lipid soluble
- Polar
11
Q
State why steriod hormones can enter cells
A
- Lipid soluble
- Nonpolar
12
Q
Draw the two types of adrenal glands
A
- Adrenal cortex
- Adrenal medulla
13
Q
State the type of hormone secreted by the adrenal medulla
A
- Protein/peptide hormones
14
Q
State the type of hormone secreted by the adrenal cortex
A
- Steroid/lipid hormones
15
Q
Draw the structure of the adrenal cortex
A
- Zona glomerulosa
- Zona fasciculata
- Zona reticularis
- (GFR)