BIOL 320 1st Edition Lecture 1 Outline of Current Lecture I Endocrinology II Endocrine Glands and Organs III IV V VI cAMP 2nd Messenger System Plasma Membrane Receptors 2nd Messenger System Direct Gene Activation Specificity Current Lecture I II Endocrinology slide 9 a Definition chemical communication between cells over distances b Endocrine system is similar to the nervous system slide 10 i Both communicate with body nervous system is faster ii Nerve travels down axon to the synapse endocrine gland releases hormone which travels in bloodstream to the target organ Endocrine Glands and Organs slide 11 a Pancreas 99 exocrine 1 endocrine tissue releases insulin and glucagon antagonists i Diabetes too much glucose in blood stream ii Insulin moves glucose and amino acids out of blood and into tissues so the body can use the glucose to make ATP or store it as glycogen in muscles lowers blood glucose iii Glucagon raises blood glucose levels iv Without pancreas and insulin everyone would comatose and die b Important Terms slide 12 i Autocrine cell produces a chemical that acts on itself ii Paracrine cell produces a chemical that acts on neighbor cells iii Exocrine hormone exits gland or tissue via a duct iv Endocrine gland or tissue releases hormone directly into bloodstream or lymph which then travels to the target organ These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute III Hormones slide 13 a 3 main groups i Steroid hormone cholesterol based produced by gonads adrenal cortex lipid soluble 1 Steroid hormones act on receptors inside the cell 2 Ex Testosterone responsible for all secondary sex characteristics of males ii Protein hormone water soluble amino acid chains 1 Act on receptors in the plasma membrane iii Biogenic amine water soluble subgroup of protein hormones except modified 1 Act on receptors in the plasma membrane IV cAMP 2nd Messenger System slide 15 a Hormones have specific receptors when hormone binds to receptor it activates a G protein b G protein activates Adenylate cyclase which converts ATP into cAMP second messenger c cAMP activates protein kinase which causes target cell to have a hormonal response i Ex of hormones that use this ACTH FSH LSH TSH glucagon parathyroid d Usually G protein is stimulatory however it can be an inhibitory protein slide 17 i Ex Growth hormone something has to make you stop growing Plasma Membrane Receptors 2nd Messenger System slide 18 19 a PIP2 calcium signaling mechanism involves a G protein b Phospholipase splits PIP2 into two 2nd messengers DAG and IP3 c DAG is equivalent to cAMP both activate protein kinase d IP3 triggers Ca2 release which can bind to calmodulin i Release of extracellular Ca2 stroke volume and cardiac output Direct Gene Activation slide 20 a Steroid and thyroid hormones TH acts like a steroid hormone even though it s an amino acid b Hormone binds to intracellular receptor and moves into nucleus to find specific DNA sequence c Binding initiates transcription into mRNA leaves cell goes to ribosome for protein synthesis V VI VII Specificity slide 21 a Definition hormones only bind to cells containing specific receptors or target cells i Ex ACTH only acts on Adrenal Cortex b 3 factors regulate target cell activation i Hormone levels ii of receptors on target organ iii Affinity of hormone for receptors c Receptor Dynamics i Up regulation low hormone levels cause cells to up regulate receptors 1 More receptors means more hormone in the blood 2 Allow a given hormone to have a larger effect ii Down regulation cells down regulate receptors when elevated hormones in blood 1 Ex Body destroys insulin receptors when a person has Type 2 Diabetes