02 02 2015 Exam 3 Receptor Characteristics Activation ligand binds o Based on shape and charge Specificity limited binding Affinity strength of binding Saturation activated Competition o Antagonist no response o Agonist response o Giving them signals that will either stop or activate a signaling pathway o As ways to alter communication Activation converts signal ligand messenger into response change in physiology o Signal transduction pathway Possible responses o Change in membrane o Ex phone call stranger change in entry of the house happens o Alter metabolism o Change contractile activity shape o Secrete Product receives one endocrine and releases another as a result o Change proliferation create one that looks exactly the same or differentiation change to being generic and change to be specific rate Locations types o Based on location where we find the receptor o 1 Intracellular within cytosol or nucleus inside the cell behind membrane barrier o 2 Membrane Bound sitting on surface of the cell Intracellular o W in nucleus or cytosol o Ligand needs to be able to come across barrier on its own nonpolar small to move across o FIGURE 5 4 o Nonpolar if endocrine does not like to be hanging out in polar environment Needs plasma binding protein Ex submarine us underwater versus us in air bubbles Binding protein amphipathic Doesn t matter where receptor is ligand whatever bound to receptor in nucleus Complex in nucleus interact with DNA cannot do outside in cytosol Result always alters DNA use up or down Membrane Bound FIGURE 5 5 o Always going to be an integral or transmembrane protein o Ligand polar no entry Only 1st in relay 2nd o Four categories 1 Receptor functions as ion channel Result in charge of distribution 2 Receptors Function as enzyme tyrosine kinase kinase is enzyme that does are equation 1 tyrosine amino acid Result cascade of phosphorylation s 3 Receptors interact with JAK kinase eq 1 Result synthesis of new proteins 4 Receptor interact with a G protein acting as middle man HETEROTRIMETRIC Most common Alpha Gamma Beta subunits 3 parts Alpha subunit with GTP Plasma membrane effector protein PMEP Two different 1 ion channel interacting with alpha subunit GTP transferred PMEP o ion channel opens 2 enzyme o ex adenylyl cyclase o FIGURE 5 6 Enzymatic function takes ATP and turns it into a circle type cAMP cAMP Activates a kinase and breaks down ATP ADP Pi Keys FIGURE 5 7 5 8 Amplification All responses FIGURE 5 9 o 1 Change the membrane doors and windows are altered o 2 Altered metabolism o 3 Changed shape microtubules being more present in cell o 4 Secretion o 5 Differentiation proliferation impacts DNA activity happening Not Limited to just one category can trigger all the results Receptor Activation Decrease o Messenger how can cell accomplish this by releasing compounds that breakdown particular signal Catabolize Ex block messages on phone text messages o Receptor Lower affinity harder for it to be able to bind lower down saturation Lower affinity by changing shape charge hide receptors endocytosis catabolize endocytosis bring it in in vesicles 2nd Messenger inactivate Increase more receptors more likelihood of interaction exocytosis anabolize o With receptors good at seeing communication does it for us in terms about components and background to physiology o Nervous System central peripheral outside CENTRAL brain and spinal cord Start at the smallest unit NEURON cell of nervous system Anatomy of Neuron rapid control system Central Peripheral In contrast to our endocrine syste o Cell body nucleus for communication DNA proteins being made o Processes Connection to other cells Perform input output FIGURE 6 1 1 Dendrites could have 400 000 about gathering information from other cells talk with other neurons so gather info from neurotransmitters environmental stimuli hit head puts pressure activates neurons more dendrites more communication with other cells Increase surface area why so many of them More receptors 2 Axon Nerve Fiber Some long 1 meter long can be of all size Examples of long o one neuron going entire length of leg o down spinal cord ALS long cells but don t provide enough stability Cell body to the effector depends on how far effector is from spinal cord to know how long axon is supposed to be Delivers information axon terminals Release neurotransmitters Collaterals times where axon cant expand to cover all area so it further influence of particular neuron for it communicate with other spaces o Myelin sheath covers axons not part of the neuron itself additional cell that associates and helps neuron be best neuron it can be it s a helper cell other cells Specialized extensions of plasma membrane insulates axon wrap around axon for insulation ex insulation of wire in house In PNS Schwann cells cover one axon In CNS Oligodendrocytes covers several spots on axon FIGURE 6 2 Breaks Nodes of Ranvier gives little opportunities to interact with interstitial fluid exposes axon to IF CNS composition o FIGURE 6 6 o Neurons glial cells neuroglia all other cells Physically and metabolically support neurons 90 of the cells but 50 of volume of CNS neurons are huge cells compared to other cells in your body o Types Oligodendrocyte see above Microglial little bit smaller macrophage like cell cells of immune system that go around and eat things that aren t supposed to be there like cleaner up cells immune system being present in CNS blood brain barrier makes things from our blood to enter the nervous system self protection system microglial cells Ependymal cells create boundary b w interstitial fluid cerebral spinal fluid CSF and the CNS regulate fluid that is in CSF space of brain and spinal cord Regulate composition of CSF environment Astrocytes of neuron o Remove K and neurotransmitters time period like a note then get ride of note once you re done completing task o Stimulates tight junctions in capillary wall BBB o Metabolic support glucose food and ammonia waste Neural Growth Signal system Generate and pass electrical messages like neurons Types of Neurons Type Info direction Parts in PNS Parts in CNS o Afferent from receptor Body most of Axon Small axon 1 10 o Efferent to effector Most of axon sm axon dend bo o Interneuron relay ALL 200K FIGURE 6 4 Synapse Types o Electrical fastest Via gap junctions o Chemical slower Generally need one way communication and chemical synapses are better at achieving that then the electrical ones so we have more of these Synapse unless
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