Exocrine and Endocrine - Lecture Notes | BMS 360, Study notes of Biology

Download Exocrine and Endocrine - Lecture Notes | BMS 360 and more Study notes Biology in PDF only on Docsity! 23 January Gland secretes hormone → lumen → throughout the body (exocrine) Gland secretes hormone → interstitial fluid → cells (endocrine) Endocrine Neurotransmitters – short distance Hormones – long distance Paracrine – nearby cells Autocrine – self In cancer, cells can mutate to create growth substances that are autocrine – aids cancer’s independence Messenger binds to receptor Specificity – lock and key Subtypes Agonist – ligand that binds to receptor, generates cellular response Antagonist – prevents agonist from binding, inhibits action Homeostasis can be regulated at receptor level Downregulation – too much stimulation, number of receptors for cell decreased Upregulation – not enough stimulation, receptors increased Lipophilic messengers Ex: steroids, other hormones Enter cell, bind inside Passive diffusion (since it is lipophilic, can pass through cell membrane) Activates specific set of genes Signal amplification necessary – messengers only present in low concentrations Hydrophilic messengers Cannot pass through plasma membrane Ion-channel Binding → ion channel gated Substance (ion) flows down concentration gradient into cell E.g. Ca2+ Ions amplify signal – act as second messengers Enzyme Intrinsic section of receptor Protein inside cell is phosphorylated upon ligand binding (activation) JAK kinase Kinase activated, but is not intrinsic to receptor G-protein Trimeric (α, β, γ) G-protein activated by receptor binding α subunit dissociated to act on other proteins Cyclic AMP Important second messenger Adenylyl cyclase creates from ATP