BMS 300 1st edition Lecture 32Outline of Last Lecture I. Interface between conductile and contractile-action potential in contractile cells 1. the channels (v-gated Na, Ca2+, K+)2. the effect >ca2+ induced calcium release >anatomy of the T-SA junction 3. the electrocardiogram >electrical currents in contractile myocardiumII. Autonomic modulation of the heart -anatomy of autonomic systems 1. CNS 2. PNS ganglia 3. target III. Parasympathetic innervation -vagus-cardiac ganglion -g-protein coupled receptor IV. Sympathetic innervationThese 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.Outline of Current Lecture V. Autonomic Regulation -generic 1. CNSPNStarget -parasympathetic branch 1. motor nucleus of the vagus 2. vagus nerve 3. cardial ganglion 4. pacemaker cells 5. acetylcholine 6. G-protein coupled receptor g2iVI. Sympathetic branch -spinal cord—intermediolateral gray column 1. T1-L32. sympathetic chain ganglia 3. postganglionic neuron to target VII. Role of nerephinophrine -G-protein coupled receptor -G (alpha) s1. increase in cAMP 2. affection HCN channels -Effection contractile cellsCurrent Lecture3 box model-start with the 3 box model from last time -in the PNS there is an autonomic ganglion which is clusters of neuronal cell bodies that send processes out and innervate the target-the target might be cardiac muscle, smooth muscle, or a gland -the neuron with the cell body in the CNS (1st box) is called the preganglionic autonomic neuron -the neuron in the second box is the postganglionic autonomic neuron -the pattern is always a 2 neuron chain to the target Parasympathetic innervation of the heart -start with a ice cream cone diagram with the brainstem and the spinal cord coming down from that -this is parasympathetic -there is a motor nucleus of cranial nerve 10 in the brain stem: the name is called the vagus which means the wonderer -the axons come out of the brainstem and in the periphery they enter the vagus nerve (preganglionic parasympathetic neurons)  output regions in the periphery -these neurons in cranial nerve 10 go to all different places but we are concerned with the innervation of the heart -there’s a region in the heart known as the cardiac ganglion -the postganglionic neuron goes out and innervates the SA and AV nodes -in the wall of the right side of the heart is the cardiac ganglion -the neurons in the cardiac ganglion are now receiving input from the preganglionic parasympathetic neurons whose cell bodies are all the way in the brain stem -the part in between the two is the cholinergic synapse: which means it releases acetycholine -the action potential will now be destined to innervate target (cardiomyocytes) -the cardiomyocytes that are targeted are the conductile cardiomyocytes of the SA and AV nodepacemaker cells **the autonomic nervous system is advising the pacemaker cells to slow down (rest and digest function) -whats happening on the synapse>we are working on target >the target is a conductile cardiomyocyte>the region of the postganglionic parasympathetic neuron is the output region which releases acetylcholine>the neurotransmitter is acetylcholine and the response is going to depend far less on the neurotransmitter then the receptor >in the postsynaptic cell there is a transmembrane protein which crosses the membrane 7 times >this category of proteins with its ligand binding domain on the outside is called g-protein coupled receptor >this particular receptor that binds Ach, is called a musclerlic receptor >the binding of the Ach leads to a conformational change down into the cytoplasmic side >there’s a sock shape structure that permits it to bind to the alpha subunit of the GTP binding protein >these come as a 3 subunit set >the binding of Ach binds to the GTP coupled receptor which changes the cytoplasmic region which then changes the GTP to GDP -the alpha subunit is to regulate Adenolyal cyclase -adenalcyclase is used to convert ATP to cyclic adenosine myophosphate (cAMP)-in the parasympathetic branch it reduces adenocyclase -when we talk about the pacemaker cells, the pacemaker cell activity has a ramp potential which is the result of activity the has HCN channels -this increases their permeability of sodium -in addition to affecting adenolycylcase theres now a potassium channel opened by the beta gamma subunits -this channels the same as a leak channel -2 things going on: >reduction to cAMP>we have opened more potassium channels which will lower the membrane resistance -we will need more HCN channels opened -the autonomic nervous system is influenced on both sides of the heart Adrenalin rush-we are looking at T1-T3 -there are neuronal cell bodies along the side: preganglionic sympathetic neurons -if we take a cross section of the spinal cord >there’s a region between T1 and T3 called the intermedial lateral grey column (column of neuronal cell bodies)-these axons come down across the ventral horn and come out the ventral root and formsynapses in the sympathetic chain ganglion -if we look at the spinal column we see that each one of the segments have the sympathetic chain ganglion -it then forms synapses onto the postganglionic sympathetic -which then goes to a conductile cardiomyocyte of the SA or AV node (pacemaker