Hormones and Endocrine System Flashcards
How do cells communicate?
Through chemical signals, known as ligands
Autocrine Signaling
A cell secretes a hormone or a chemical substance that binds to the receptors on the same cell, leading to functional changes in the cell
Paracrine Signaling
Allows cells to communicate with each other by releasing signalling molecules that bind to and activate surrounding cells
How are hormones secreted?
By the endocrine glands, directly into the bloodstream
3 Main types of hormones
Proteins
Amines
Lipids
Protein hormones - examples
Insulin
Glucagon
Amine hormone - example
Adrenaline
Steroid hormones - examples
Cortisol, oestrogen and progesterone
Action of Lipid-soluble hormones
Pass through the target cell membrane
Bind to an intracellular receptor
Hormone-receptor complex binds to DNA to turn specific genes on or off
Action of Water-soluble hormones
Bind to receptors
Receptor protein activated a signal transduction pathway
Series of trelay molecules transmits the signal
Cell response occurs
Mechanisms controlling the release of hormones
Specific metabolite
Another hormone in the blood
Stimulation of neurons
What functions does the thyroid regulate?
Heart rate
Muscle tone
Bioenergetics
Digestive and reproductive functions
What are hormone levels controlled by?
Negative feedback
