Notes in The Cardiac Pressure-Volume Cycle LECTURE 21

To Subscribe, use this Key

Status	Last Update	Fields
Published	01/07/2025	some ion channels are {{c1::voltage gated}} and some are {{c1::time}} dependent
Published	01/07/2025	what are the two main channels in cardiac action potential?- When do these 2 open?{{c1::inward rectifier K+ channels - opens when Vm goes below -…
Published	01/07/2025	1. action potential - baselinecell starts at {{c1::resting potentia}}l of {{c1::-70mV}}{{c1::inward rectifier K+}} channels open{{c1::K+ flo…
Published	01/07/2025	2. action potential - depolarisationfew {{c1::Na+}} channels open; {{c1::Na+ permeability}} increases so more {{c1::Na+ current}} flows…
Published	01/07/2025	3. action potential - repolarisationtwo {{c1::time-dependent}} events occur:{{c1::Na+}} channel inactivation (decrease in influx of {{c…
Published	01/07/2025	4. action potential - hyperpolaristion (in nerve/skeletal/smooth muscle cells)when Vm is less than {{c1::-60mV:}}inward rectifier {{c1::K+ channe…
Published	01/07/2025	how long does a ventricular myocyte AP last?{{c1::500 ms}}
Published	01/07/2025	VENTRICULAR MYOCYTE AP:phase 0 - {{c1::depolarisation}}{{c1::Na+}} channels open with positive feedback{{c1::Na+}} enters myocytephase …
Published	01/07/2025	when does contraction occur during skeletal muscle AP?during or after AP? Long or short refractory period?{{c1::following AP - refractory period}} so …
Published	01/07/2025	when does contraction occur in cardiac muscle AP?during or after AP? Long or short refractory period?{{c1::during AP - long refractory period}}so no {…
Published	01/07/2025	what are the characteristic features of pacemaker tissues (SA and AV nodes)?exhibit {{c1::spontaneous}} depolarisationno {{c1::inward K+ rec…
Published	01/07/2025	which phase is the pacemaker current and what is it called?{{c1::phase 4}}{{c1::if = funny current}}
Published	01/07/2025	what is characteristic of the SA and AV node in cardiac AP? (3)-phase 4: conducts which ions? overall more +ve or -ve?-phase 0: depolarisation due to?…
Published	01/07/2025	phases of nodal AP?{{c1::0 - depolarisation phase}}{{c1::3 - repolarisation phase}}{{c1::4 - pacemaker potential}}
Published	01/07/2025	if current:When does if increase?{{c1::increases upon hyperpolarisation - HCN channel example}}What is the role of if?makes {{c1::Sa node cells}}…
Published	01/07/2025	all sodium channels {{c1::conduct sodium}}, not all channels that conduct sodium are {{c1::sodium channels}}
Published	01/07/2025	there are {{c1::intercalated discs}} between {{c2::adjacent cardiac myocytes}}
Published	01/07/2025	what are the gap junctions joining cardiac myocytes?{{c1::desmosomes}} - structural - hold cells together{{c1::adherens junctions}} - anchor…
Published	01/07/2025	what are key features of intercalated discs?low {{c1::electrical resistance}}high {{c1::ion permeability}}allow {{c1::APs}} to pass easily from c…
Published	01/07/2025	what is syncytium?- where are these present?a {{c1::multinucleated}} celldue to {{c1::multiple cell fusions}}
Published	01/07/2025	are cardiac muscle cells syncytia?{{c1::no}} - they are separated by {{c1::intercalated discs}}allows {{c1::co-ordinated cardiac contraction}}
Published	01/07/2025	what are the two 'functional' syncytia?{{c1::atria}}{{c1::ventricles}}
Published	01/07/2025	21e4a3062da24d45be328d5e8d04cef7-ao-1
Published	01/07/2025	21e4a3062da24d45be328d5e8d04cef7-ao-2
Published	01/07/2025	21e4a3062da24d45be328d5e8d04cef7-ao-3
Published	01/07/2025	21e4a3062da24d45be328d5e8d04cef7-ao-4
Published	01/07/2025	21e4a3062da24d45be328d5e8d04cef7-ao-5
Published	01/07/2025	21e4a3062da24d45be328d5e8d04cef7-ao-6
Published	01/07/2025	why is the delay at the AV node important?{{c1::allows contraction of atria and filling of ventricles to be complete before heart muscles begin to con…
Published	01/07/2025	speed of av node conduction:the AV node is {{c1::the slowest conducting tissue in the heart by a factor of 10 (0.05 m/s)}}
Published	01/07/2025	velocity of AV node contraction is controlled by {{c1::autonomic nervous system}} which acts by {{c1::affecting phase 0 depolarisation}}- wh…
Published	01/07/2025	how does the sympathetic nervous sytem affect AV node contraction?- which hormone binds to which receptors?{{c1::noradrenaline binds to beta-1 recepto…
Published	01/07/2025	how does the vagal nerve affect AV node conduction?- which horome binds to which receptor?{{c1::ACh binds to muscarinic M2 receptors}}decreases {{c1::…
Published	01/07/2025	drugs which slow down AV node conduction{{c1::bisoprolol}} (beta-1){{c1::verapamil}} (L-type Ca2+ channels){{c1::digoxin}} (increa…
Published	01/07/2025	sarcomeres and starling's law- what increases the more you stretch a myocyte?- what does this lead to an increase of?{{c1::the more you stretch a myoc…
Published	01/07/2025	regulation of contractile force:- what happens to force and duration?- number of cross bridges increase or not?1. intrinsic regulation ({{c1::Starling…
Published	01/07/2025	what is diastasis?{{c1::phase between passive and active filling of ventricles - not much happens}}
Published	01/07/2025	what happens during active filling of ventricles?{{c1::atrial contraction}}
Published	01/07/2025	when do the sounds of the heartbeat happen?{{c1::first - when mitral valve closes}}{{c1::second - when aortic valve closes}}
Published	01/07/2025	what does the P wave on an ECG refer to?{{c1::atrial systole (electrical activity)}}
Published	01/07/2025	the QRS on an ECG refer to?{{c1::ventricular depolarisation (occurs just before systole)}}
Published	01/07/2025	what does the T wave represent on an ECG?{{c1::ventricular repolarisation}}
Published	01/07/2025	what happens to left ventricular volume during the cardiac cycle?in diastole{{c1:: volume increases}}during isovolumic contraction{{c1:: volume stays …
Published	01/07/2025	what are the three components of the troponin complex?what are the functions of these?{{c1::Tn-T: binds complex to tropomyosin}}{{c1::Tn-C: binds Ca2+…
Published	01/07/2025	what is creatine kinase?an enzyme which moves {{c1::high-energy phosphate from ATP in mitochondria to ADP in cytoplasm}}used as biomarker before {{c1:…
Published	01/07/2025	The following 3 are features characteristic of...:exhibit spontaneous depolarisationno inward K+ rectifier currenttherefore not stable at rest
Published	01/07/2025	During phase 4, what does the If channel conduct?
Published	01/07/2025	During phase 0, what is depolarisation due to?
Published	01/07/2025	What is the name of the phase between passive and acting filling where not much happens?
Published	01/07/2025	What part of the ECG refers to atrial systole?{{c1::P wave}}What part of the ECG refers to depolarisation?{{c1::QRS}}What part of the ECG refers to ve…
Published	01/07/2025	Which troponin complex binds complex to tropomyosin?{{c1::Tn-T}}Which troponin complex binds Ca2+ during excitation contraction coupling?{{c1::Tn-C}}W…
Published	01/07/2025	What is the name of the enzyme which moves high-energy phosphate from ATP in mitochondria to ADP in cytoplasm?
Published	01/07/2025	What do we call a multinucleated cell with multiple fusions?
Published	01/07/2025	20356ef3e50d45138e870ecedd604848-ao-1
Published	01/07/2025	4cda5ae8ac184feb97a8281405ee6b9e-ao-1
Published	01/07/2025	wiggers diagram - need to know this fully
Published	01/07/2025	markers of myocardial damage- what are cardiac specific markers?- what are cardiac selective enzymes?- what is used for early disgnosis?- what are som…
Published	01/07/2025	do all muscles have the three components of troponin complex?- yes or no?- what is Tn-C common to all?- what is Tn-T and Tn-I specific to?{{c1::no}}{{…
Published	01/07/2025	label the following:a = {{c1::isovolumic contraction}}b = {{c1::ejection}}c = {{c1::isovolumic relaxation}}d = {{c1::diastolic filling}}(watch a video…
Status	Last Update	Fields