Flashcards in Lecture 32: Endocrine System Deck (15)
- Regulates internal environment by secreting hormones that travel through the bloodstream to target areas
Hormones are _____ _______ regulators:
- Long distance
Major endocrine glands include:
- Pituitary Gland
- Thyroid Gland
- Adrenaline Glands
Lil hormone pathway:
- Hormone secreting cell secretes hormone
- Hormone travels through blood stream
- Targets cells in one or more distant places in the body
- Chemical messengers produced in one location and transported to a second location (target cells) where they elicit an effect
Water-soluble hormones include...they are made....
- And stored inside the cell until required
Lipid-soluble hormones include.....
- Thyroid hormones
The difference between steroids and thyroid hormones...
- Steroids aren't made until required
- Thyroid hormones are stored and released when required
How do water soluble hormones have an effect on cells?
- Water soluble hormone recognises it's receptor protein
- Binds and changes receptor protein to change shape slightly
- This activates another protein inside the cell that is attached to the receptor protein
- Activates specific transporters
- Domino effect inside the cell
Give an example of a water soluble hormone having an effect on a cell:
- Epinephrine has multiple effects in mediating the body's response to short-term stress
- Epinephrine binds to receptors on the plasma membrane of liver cells
- This triggers the release of messenger molecules that activates enzymes and result in the release of glucose into the bloodstream
How do lipid-soluble hormones have an effect on a cell?
- Hydrophobic, lipid-soluble
- Easily goes through plasma membrane
- Once inside cell it can bind to specific receptor protein
- That receptor protein is always a transcription factor
- This binds to the promoter in the nucleus and makes mRNA
- Makes protein
Which has the quickest response: Water-soluble hormones or lipid-soluble hormones?
How do hormones have a specific effect on their specific target cell?
- Hormone = key
- Receptor = lock
- Specific matching system
- A hormone can only affect cells with specific receptors for that hormone
Regulation of target cell sensitivity:
- Sensitivity of a target cell depends on the number of receptors expressed for that hormone
- Receptors are constantly degraded and synthesized to ensure efficiency
- Provides a method to change receptor number when needed
- Synthesis > Degradation --> Up-regulation
- Synthesis Down-regulation