Notes in 4. Regulation of Stroke Volume and Heart Rate

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Published	02/10/2024	Sympathetic regulation of heart rate involves sympathetic nerves releasing {{c1::adrenaline}} and adrenal medulla releasing {{c1::noradrenaline}} that…
Published	02/10/2024	The {{c1::slope}} of the pacemaker potential is {{c2::increased}} due to sympathetic regulation which leads to increased heart rate.
Published	02/10/2024	Parasympathetic regulation of heart rate involves vagus nerves releasing {{c1::ACh}} that act on {{c2::muscarinic}} receptors…
Published	02/10/2024	The {{c1::slope}} of the pacemaker potential is {{c2::decreased}} due to parasympathetic regulation which leads to reduced he…
Published	02/10/2024	{{c1::Starling’s}} Law states that the {{c2::energy of contraction is proportional to the initial length of the cardiac muscle fibre.}}…
Published	02/10/2024	{{c1::Preload}}, i.e. the initial stretching of the myocytes, is affected by the {{c2::end diastolic volume}}
Published	02/10/2024	{{c1::Preload}} can be defined as {{c2::the initial stretching of the cardiac myocytes prior to contraction. In other words, how full the ventricle is…
Published	02/10/2024	What is the relationship between venous return and stroke volume?{{c1::Increased venous return leads to a rise in EDV, and therefore there is a higher…
Published	02/10/2024	{{c1::Afterload}} is {{c2::the load against which the muscle tries to contract. In other words, how difficult it is for the heart to pump out the bloo…
Published	02/10/2024	High {{c1::Total Peripheral Resistance (TPR)}} increases the aortic/arterial pressure which increases the {{c2::Afterload}}, therefore decreasing the …
Published	02/10/2024	{{c1::Total Peripheral Resistance (TPR)}} describes {{c2::how easy it is for blood to flow through the arterioles. This depends on the length of arter…
Published	02/10/2024	Why does stroke volume go down if there is an increase in total peripheral resistance?({{c1::An increase in total peripheral resistance means that the…
Published	02/10/2024	Sympathetic innervation (noradrenaline and adrenaline acting on B1 receptors) to myocytes increases {{c1::contractility}} and {{c1::hea…
Published	02/10/2024	How does sympathetic innervation (norandrenaline and adrenaline acting on B1 receptors) to myocytes causes an inotropic effect (i.e. increas…
Published	02/10/2024	{{c1::Inotropic}} is a term that describes {{c2::an increase in contractility}}{{c1::Chronotropic}} is a term that describes {{c2::an increase in&nbsp…
Published	02/10/2024	How does sympathetic innervation to myocytes cause a stronger but shorter contraction?[1] Stronger because of {{c1::increased cross-bridges betwe…
Published	02/10/2024	Parasympathetic innervation to the heart has little to no effect on {{c1::contractility}} but it affects the {{c1::heart rate}}. This is because the {…
Published	02/10/2024	{{c1::Venules and Veins}} are capacitance vessels that affect {{c2::preload}} by affecting the return of blood to the heart
Published	02/10/2024	{{c1::Arterioles}} are resistance vessels that affect {{c2::afterload}} by controlling the radius/diameter.
Published	02/10/2024	{{c1::Contractility}} is a term that describes {{c2::how strong a contraction is produced for any given preload or afterload. It is affected by the sy…
Published	02/10/2024	Stroke volume is affected by the {{c1::sympathetic system (contractility)}}, {{c1::preload}}, and {{c1::afterload}}.
Published	02/10/2024	Heart rate is determined by the pacemaker cells of the sinoatrial node but can be affected by both the {{c1::sympathetic}} and {{c1::parasympathetic}}…
Published	02/10/2024	Increasing heart rate above 140/150 causes a small increase in cardiac output, but then stroke volume starts decreasing. Why?[1] {{c1::The shortened&n…
Published	02/10/2024	Control of Cardiac Output (increases 4-6 time during exercise. How?)[1] {{c1::An increase in Heart rate}} [2] {{c1::An increase in Contractility}…
Published	02/10/2024	During exercise, {{c1::contractility}} goes up via increased {{c2::sympathetic tone}} which then alters {{c3::inotropic state}} and shortens {{c3::sys…
Published	02/10/2024	During exercise, {{c1::heart rate}} goes up due to decreased {{c2::vagal}} tone and increased {{c2::sympathetic}} tone.
Published	02/10/2024	During exercise, {{c1::venous return}} goes up due to {{c2::venoconstriction}} and {{c2::skeletal/respiratory pumps}}, which maintains the preload.
Published	02/10/2024	During exercise, {{c1::total peripheral resistance}} falls due to {{c2::arteriolar dilation}} in muscle, skin, and heart, which reduces the afterload,…
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