Notes in 111 LEC 11

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Published	11/08/2023	there are 3 electrically active (excitable) cardiac cells – {{c1::pacemaking}}, {{c1::conductive}}, {{c1::contractile}}
Published	11/08/2023	Pacemaking cells – {{c1::form nodes that generate rhythmic electrical signals in the form of periodically triggered AP}}
Published	11/08/2023	Conductive cells – {{c1::form bundles of electrically conductive tissue that facilitate the propagation of electrical signals across the heart}}
Published	11/08/2023	3 major pacemakers – {{c1::SA nod}}e, {{c1::AV node}}, {{c1::purkinje cells}}
Published	11/08/2023	SA – {{c1::major pacemaker which spontaneously fire AP (60-80/min)}} AV – {{c2::fire at a slower rate (40-60 AP/ min)}} → {{c1::overridden}} Purkinje …
Published	11/08/2023	Uncoupling pacemaker → {{c1::ectopic contractions}} (arrhythmia) → {{c1::inefficient cardiac activity}} → death
Published	11/08/2023	Cardiac action potentials are {{c1::different}} in shape and triggering time - APs are different in each {{c1::region}} of heart - Epicardium AP is {{…
Published	11/08/2023	Phases of the cardiac action potential (cAP) Phase 0 – {{c1::rapid depolarization}} Phase 1 – {{c1::initial/ early repolarization}} Phase 2 – {{c1::pl…
Published	11/08/2023	Phase 0 and 1 - {{c3::Na current (INa)}} -- {{c2::NaV1.5}} causes {{c1::initial largest depolarization}} (phase 0) - {{c3::Transient outward K current…
Published	11/08/2023	Phase 2 and 3 - {{c1::Ca current (ICa):}} {{c2::CaV1.2 activation}} → Ca influx → activates {{c2::Ryanodine receptors type 2 (RyR2)}} → {{c3::Ca relea…
Published	11/08/2023	Phase 4 - {{c1::inwardly rectifying K current (IK1)}} – voltage independent channels {{c2::(KIR2.1-3)}} keeps resting potential {{c4::negative}}- In a…
Published	11/08/2023	Depolarization – {{c1::electrical activation of heart}} Repolarization – {{c1::electrical deactivation of heart}}
Published	11/08/2023	{{c1::Atrial depolarization}} – {{c3::P}} {{c1::Ventricular depolarization}} – {{c3::QRS complex}} {{c2::Ventricular repolarization}} – {{c3::T}} {{c2…
Published	11/08/2023	Electrocardiography (ECG) - non-invasive technique - record heart {{c1::electrical activity}} (does not record {{c1::mechanical}} activity) - Lead II …
Published	11/08/2023	ventricular AP propagates through {{c1::gap junctions}} between {{c2::myocytes}} Gap junctions – {{c1::complexes made of connexin proteins}} that allo…
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Published	11/08/2023	1. AP in SA → electrical activity spreads to {{c1::left atrium}} and {{c1::AV node}} 2. produces {{c1::net difference in membrane potential}} pointing…
Published	11/08/2023	Tachycardia – {{c1::higher heart rate (> 90 BPM) observed after exercise}} Flutter – {{c1::heart rate of 200 – 300 BPM}} Atrial fibrillation – {{c1…
Published	11/08/2023	Causes of cardiac rhythm abnormalities
Published	11/08/2023	{{c1::elevated ST segment}} → {{c2::diffused ventricular AP}} → {{c3::infarction}} {{c1::lesser (biphasic) elevated ST segment}} → {{c2::diffused vent…
Published	11/08/2023	Mechanism by which Nav channel mutations → {{c1::hyperexcitability disorders}} 1. {{c1::Mutation}} → protons {{c2::leak}} through {{c3::VSD of closed …
Published	11/08/2023	Facts on the effect of mutations that increase late Na currents in heart - Increased Na current = hallmark of disease associate mutations of {{c1::Nav…
Published	11/08/2023	Long QT syndrome - {{c2::Prolonged AP}} because of {{c1::persistent Na current}} which causes a longer QT - {{c1::Type 1 QT syndrome}} affects {{c2::K…
Published	11/08/2023	{{c3::Brugada syndrome}} -- {{c1::reduced Na current}} causes {{c2::disproportionate shortening}} of {{c3::epicardial action potential}}
Published	11/09/2023	4518a76536584d97b569142cc07272bf-oa-1
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Published	11/09/2023	356500c674c94a6ebfb444be14c0a6a6-oa-1
Published	11/09/2023	052895bff4164da4a8f56f485bdc656b-oa-1
Published	11/09/2023	d61c9ccae49440f3ab534ac2a6fb32c4-oa-1
Published	11/09/2023	300425b44f7f41fcbf31eef6b5a79143-oa-1
Published	11/09/2023	eb090b7bfbac4901b2ebf6871a0c46c0-oa-1
Published	11/09/2023	0446cfb8fab44bec9b105be92896742f-oa-1
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