Endocrine System Flashcards
What is an endocrine gland?
gland that secrets hormones directly into blood (capillaires running through gland), no ducts
What is an exocrine gland?
gland that secretes mols into a duct that carries mols to where they are used
What system do endocrine glands use to transport their signals?
blood system
What is an example of an exocrine gland?
salivary gland secrete saliva into a duct that flows into the mouth
How are target cells for a hormone normally grouped?
In target tissues
What are the 2 types of hormone?
protein and peptide hormones and derivatives of amino acids (e.g. adrenaline, insulin and glucagon). Steroid hormones (e.g. sex hormones)
How do the 2 types of hormone work differently?
proteins not soluble in phospholipid membrane: don’t enter cell, steroid can pass through membrane and enter to have direct effect on DNA in nucleus
What is adrenaline?
amino acid derivative, no enter target cell, bind to receptor on membrane which is associated with enzyme on inner surface of membrane: adenyl cyclase
What is adenyl cyclase?
enzymes associated with receptor for many hormones, including adrenaline, found on inside surface of membrane
What is the first messenger?
hormone that transmits a signal around the body: adrenaline
What is the second messenger?
transmits signal inside cell: cAMP
What happens when adenyl cyclase is activated?
converts ATP to cyclic AMP (cAMP), cAMP then causes effect inside cell by activating enzyme action
Where are the adrenal glands found?
anterior (just above) the kidneys, one of each side of body, each had a medulla and cortex region
Where is the adrenal medulla? What does it do?
Found in centre of gland, cells in medulla manufacture and release adrenaline in response to stress like pain or shock
Why are the effects of adrenaline widespread?
most cells have adrenaline receptors
