Amine hormones (Tyrosine derivatives) • Produced by the adrenal gland, the hypothalamus and the anterior pituitary gland • Very short duration of action – act as neurotransmitters as well as hormones
Steroid hormones • All derivatives of cholesterol • Insoluble in water – travel in plasma bound to plasma proteins • Longer-acting and act INSIDE the cell • Stress, sexuality, SEX
Steroid hormones • Steroid hormones pass through the cell membrane easily and act on the inside of the cell • May bind to receptors in cytoplasm OR nucleus • Steroid hormones alter DNA transcription: they act as ‘transcription factors’…
Peptide and protein hormones • Soluble in plasma but cannot cross the lipid membrane • Act on cell surface receptors • Binding with the receptor leads to activtion of a ‘second messenger’ cascade
H.1.4: Outline the relationship between the hypothalamus and the pituitary gland
How does the hypothalamus orchestrate the autonomic nervous/endocrine system?
Negative feedback is essential to hypothalamo-pituitary-hormonal control • Hormones whose secretion is regulated by the hypothalamus and pituitary gland regulate their own release through negative feedback. • The hormone produced by a peripheral glad will bind to receptors in the hypothalamus and pituitary and inhibit release of ‘tropic’ hormones’