KIN 292 1nd Edition Lecture 11 Outline of Last Lecture I Finishing Chapter 4 Outline of Current Lecture I 5 1 Mechanisms of Intercellular Communication II 5 2 Chemical Messengers Current Lecture These are the notes from Professor Starnes lecture of Clinical Human Physiology These come from the slideshows provided by the professor and include extra notes and explanations Highlighted or bolded information are things that I believe to be information that is important to look over multiple times The notes in red are my personal additions and quotes of Professor Starnes from the class lecture 5 1 Mechanisms of Intercellular Communication https video search yahoo com video play ylt A0LEV7i 2dNUc1cAHX8nnIlQ ylu X3oDMTB0N25ndmVnBHNlYwNzYwRjb2xvA2J mMQR2dGlkA1lIUzAwNF8x p cool hand luke quotes tnr 21 vid 8375B9EE765FCD6E09138375B9EE765FCD6E091 3 l 37 turl http 3A 2F 2Fts3 mm bing net 2Fth 3Fid 3DUN 608010985515519515 26pid 3D15 1 sigi 11r4gc95u rurl https 3A 2F 2Fwww youtube com 2Fwatch 3Fv 3Dmu1LaU2b Uk sigr 11bdo97e6 tt b tit failure to communicate sigt 10mnf2cnp back https 3A 2F 2Fsearch yahoo com 2Fyhs 2Fsearch 3Fp 3Dcool 2Bhand 2Bluke 2Bquotes 26ei 3DUTF 8 26hsimp 3Dyhs 001 26hspart 3Dmozilla sigb 131m99cc3 hspart mozilla hsimp yhs 001 Our body requires communication among its 10 trillion cells in order to function properly General mechanisms a lot less than 10 trillion Direct or Indirect Figure 5 1 Types of intercellular communication 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 Gap junctions Link the cytosol of two adjacent cells Particle movement between cells acts as a signal Common in smooth and cardiac muscle Connexons are formed by specialized plasma membrane proteins Paracrine Communication is shown here where target cell is very near the Secretory or Source cell 5 2 Chemical Messengers All messengers are ligands definition a molecule that binds to a receptor The messenger is produced by the source cell The messenger is released often by secretion The messenger travels to the target cell Target cell has receptors specific for the messenger i e bind only to messenger ligand Binding of the messenger to the receptor triggers a target cell response Communication is indirect Figure 5 2 Three Functional classes of chemical messengers Paracrines A subclass is Autocrine where source and target are the same cell Neurotransmitter Hormone Discovery 5 1 Histamine Antihistamines and Allergies Histamine is a paracrine chemical messenger causing allergic reactions and inflammation Inflammation results from increased blood flow to affected area redness and leak of fluid from blood vessels into tissue swelling https video search yahoo com video play ylt A2KLqIJ2mtNUGBsAGnf7w8QF ylu X3oDMTBzc2M2MjdyBH NlYwNzcgRzbGsDdmlkBHZ0aWQDBGdwb3MDMTE p antihistamines allergic reactions vid 97742055a93ddcc2b8f759ca989ae3af l 1 3A27 turl h ttp 3A 2F 2Fts2 mm bing net 2Fth 3Fid 3DVN 608053814927429409 26pid 3D15 1 rurl https 3A 2F 2Fwww youtube com 2Fwatch 3Fv 3Dy3bOgdvV M tit Allergy 3D Medical Animation c 9 sigr 11bdg4k9o sigt 10ss3h7cv sigi 11r74vq3k age 1211556725 fr2 p 3As 2Cv 3Av hsimp yhs 001 hspart mozilla tt b Antihistamines are drugs that block the histamine receptors on target cells Benadryl and Dramamine are examples What is a common side effect of these drugs Drowsiness These drugs block histamine receptors throughout the body including those in the brain involved in mental alertness More specific blockers also called antagonists need to be developed that target only the affected tissues Learn more about other famous histamine antagonists such as Tagamet and Zantac in Discovery box on page 127 Chemical Classification of Messengers All messengers are ligands Ligand definition a molecule as an antibody hormone or drug that binds to a receptor Chemical descriptions of the 5 chemical classes covered in previous chapters o Lipophobic hydrophilic ligand Cannot cross cell membrane Receptors are on the cell membrane General actions include Enzyme activation and Membrane permeability changes o Lipophilic hydrophobic ligand Easily goes through cell membrane Receptors have intracellular location General action is via gene activation Figure 5 7 Transport of messengers in blood Synthesis and Release of Chemical Messengers Hydrophilic messenger Synthesis is independent of demand Stored in vesicles of the source until needed Release rate depends on exocytosis rate Exocytosis described in Chapter 4 next slide Relatively short half life length of time to decrease in concentration by half Hydrophobic messenger Synthesized on demand Can t be stored because they will leak out Immediate release from source Release rate depends on synthesis Need carrier proteins to move through plasma Relatively long half life Figure 4 22 Exocytosis Only lipophobic hydrophilic substances can be retained in secretory vesicles Chemical Classification of Messengers Amino acids Lipophobic Target cell receptors on the cell membrane Synthesized within a neuron Stored in vesicles until needed Only four amino acids function as messengers Glutamate aspartate glycine GABA Amines Most are lipophobic except thyroid hormones Target receptors on the cell membrane Made or derived from an amino acid Contains an amine group Examples Catecholamines Dopamine norepinephrine ephinephrine Made from tyrosine next slide Thyroid hormones Made from two tyrosine amino acids Histamine Made from histidine Serotonin Made from tryptophan Figure 5 3 Catecholamine synthesis Produced from tyrosine in the cytosol of the source The amine produced is determined by which enzymes are present in the source cell Stored in vesicles of the source Released by exocytosis Chemical Classification of Messengers Peptide and protein messengers Most abundant type of ligand Lipophobic Target receptors on the cell membrane Made of chains of amino acids Peptide ligand 50 amino acids Protein ligand 50 amino acids Figure 5 4a Peptide synthesis and release Formed by cleaving larger proteins Stored in secretory vesicles Released by exocytosis Figure 5 5 Steroids Synthetic pathway Lipophilic Synthesized on demand All derived from cholesterol All function as hormones Figure 5 6 Eicosanoid synthesis Lipophilic Intracellular target receptors Most are derived from arachidonic acid a cell membrane phospholipid Synthesized on demand