How hormones work HBS 3A. Hormones change the function of cells Hormones enter cells and then change...
-
Upload
hubert-oliver -
Category
Documents
-
view
212 -
download
0
Transcript of How hormones work HBS 3A. Hormones change the function of cells Hormones enter cells and then change...
How hormones work
HBS 3A
Hormones change the function of cells
Hormones enter cells and then change the metabolic activity by one of three ways
• Activating certain genes in a nucleus so the cell starts making a particular protein – this could be an enzyme or a structural component
• Changing the shape of an enzyme to activate or inactivate it (turn it on or off)
• Changing the rate of protein production (in the nucleus or at the ribosomes) so changing the amount of enzyme or other proteins present
Enzyme amplification
• Each hormone activates thousands of enzymes
• The hormone triggers a number of reactions at each stage of the metabolic pathway it affects – setting of a cascade of reactions
• A very small amount of hormone can result in large changes or effects
Hormone clearance
• Some hormones are broken down by enzymes in the target cells
• Many hormones are broken down by the liver or kidneys
• Most broken down hormones are excreted by the kidneys
Types of hormones
The main types of hormones are • Steroid eg cortisol, aldosterone, oestrogen,
progesterone, testosterone• Amine eg adrenaline, noradrenaline, thyroxine, • Peptide eg growth hormone, LH, FSH, ACTH,
TSH, prolactin, ADH, oxytocin, insulin, glucagon, calcitonin, parathyroid hormone, hypothalamus releasing factors
Hormone action
Steroid hormones pass through cell membranes and act directly on the nucleus
Hormone action 1
Non- Steroid hormones can not pass directly through cell membranes and act by secondary messengers