hormonal system Flashcards
what are endocrine glands
a group of specialised cells that work together to secrete hormones
what are hormones
chemical messengers
when are hormones secreted
when an endocrine gland is stimulated
why is a hormone called a first messenger
carries a chemical message the first part of the way, from the endocrine gland to a target cell
what happens when a hormone binds to a receptor
activates an enzyme in the cell membrane
what type of hormones have to bind to receptors on the plasma membrane of cells
peptide hormones
why cant peptide hormones enter a cell
not fat soluble so repelled by phospholipid bilayer
when an enzyme is activated by the binding of a protein what does this cause
production of a signalling molecule
what is a signalling molecule
sends signals to other parts of the body
what does the signalling molecule act as
secondary messenger
how does the signalling molecule act as a secondary messenger
carries the chemical message the second part of the journey, from the receptors to other parts of the cell
what does the secondary messenger activate
cascade of reactions inside of the cell
how do steroid hormones trigger a response
bind to receptors in the cell / in the nucleus
why can steroid hormones enter the plasma membrane
fat soluble
