BIOB34H3 Lecture Notes - Endocrine Gland, Thyroid, Pituitary Gland
Document Summary
Chemical messengers secreted directly into the blood stream by specialized calls known as endocrine glands/cells can be transported to distant targets because they are carried in the blood stream. Salivary, sweat, mammary glands) do not secrete hormones. Hormones can have effects over minutes, hours, days, weeks, months. Even at a low concentration, there is still an effect (nanomolar 10^-9 to picomolar 10^- Binds to a receptor to cause a response. Effect on tissue depends on type of tissue and stage of development (baby to teenager to. They are degraded to inactive metabolites by enzymes (often in the liver and kidneys) excreted in urine and bile (from the liver) Half life: amount of time rewuired to decrease the concentration of hormone in the adult) circulation by half. 3 chemical classes of hormones amine hormones. Amine hormones are derived from tryptophan or tyrosine. Small molecules which have a half life of seconds needs to be continuously secreted for long duration of action.