Term
| Cardiac Output (CO) is defined as |
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Definition
the volume of blood ejected by each ventricle per unit of time;
Normally 5L/min @ rest |
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Term
| Cardiac output formula (CO) |
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Definition
| Heart rate * Stroke volume |
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Term
| Cardiac Output to ____,____ and _____ |
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Definition
Brain 13%;
Cardiac Muscle 4%;
Kidneys 20-25% |
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Term
| Heart rate is normally ___ bpm and the stroke volume (SV) is usually... |
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Definition
80bpm; the same for both ventricles but CO usually refers to the left ventricle;
Normally 70-80 ML/per system; the CO is usuallt 5-6 L/min |
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Term
| Stroke volume is affected by |
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Definition
| venous return, the peripheral resistance and the autonomic nervous system |
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Term
| If the heart rate increases 90/min, |
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Definition
| the cadiac output increases proportionally |
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Term
| If the heart rate increases from 90-140/min, |
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Definition
| the CO remains the same becuase the stroke volume decreases in proportion to the increase in the heart rate due to the fact that ventricles have less time to fill during diastole. |
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Term
If heart rate increases over 140/min,
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Definition
| the CO decreases because the stroke volume decreases faster than the increase in the heart rate |
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Term
| Starling's Law of the Heart |
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Definition
If all other factors remain constant, the SV is determined by the force of the contraction;
the heart will automatically eject all the blood that enters it over a broad range of volume...
bc of the nature of striated and cardiac muscle, which has a force of contraction is proportional to the degree to which it was stretched up to a LIMIT!! |
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Term
| the strength of contraction increases in proportion to the |
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Definition
| length of the ventrical muscle fibers, which implies that all the extra blood resulting from increased venous return is pumped out |
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Term
| the quality of blood in the ventricle just prior to their contraction determines the |
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Definition
initial length of the ventricular muscle fibers,
aka End-Diastolic Volume,
which in turn, determines the PRE-LOAD that is defined as the degree of TENSION of the muscle when it begins to contract |
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Term
| According to the Starling's law, any change in the venous return |
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Definition
has a direct effect on the SV and therefore in the CO;
increase in venous return causes an increase
in the strength of the contraction which causes
an increas in the stroke volume and cardiac output;
Similar results, but indirectly, are obtained by increasing the blood pressure |
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Term
| Increased blood pressure, ______ the resistance which _________ the SV which causes an _______ in the End-Diastolic Volume which ________ the strangth of myocardial contraction which _______ the SV. |
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Definition
| increases; decreases; increases; increases; increases |
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Term
| After the inital adjustment by the Starling Law, other factors begin to regulate the |
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Definition
| strength of the contraction and thus the cardiac output |
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Term
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Definition
| regulation of strength of cardiac contraction in response to influences that do not depend of fiber strength or length |
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Term
Cardiac Valve regulate blood flow from;
how many directions does flow in |
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Definition
atria to ventricle(cuspid valves);
ventricle to great arteries(semi-lunar);
Flow in ONE direction |
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Term
| What causes heart sounds and what is responsible for the normal Lub-Dup sound? |
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Definition
Closure of the heart valves are responsible for the heart sound;
Lub-closure of the cuspid valve(atria-ventricle)
Dub-closure of semi-lunar valve(ventricle-greater artery) |
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Term
| Leaflets of the valves are |
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Definition
| connective tissues covered with endothelial tissue |
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Term
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Definition
| the division between the cusps |
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Term
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Definition
| elastic cords inserted into the papillary mucles composed of myocardial tissue that contracts simultaneously with the ventricles assuring their proper closure during ventricular contraction reventing blood reflux |
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Term
The cuspid valve have thier ventricular surface
anchored to |
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Definition
the ventricul wall by way of the chordea tendinae;
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Term
Cardiac cycle: Diastole and Systole
both spontanteously generated by |
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Definition
Systole: force that drives blood out of the heart
Diastole: the period of time when the hear refills with blood;
an action potential in the sinus node(S-A node) |
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Term
| The action potential in the SA node the spontaneously generated systolic and diastolic contractions |
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Definition
| travels through both atria and reaches the a-v node, bundle of his, bundle branches, purkinje fibers and all cardiac fibers |
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Term
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Definition
| The opening and closing of valves that are determined by the pressure gradient across them |
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Term
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Definition
Contraction Phase (I)
Ejection Phase (II) |
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Term
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Definition
Relaxation Phase (III)
Filling Phase (IV) |
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Term
| P wave; QRS Complex; T wave |
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Definition
atrial depolarization right before atrial contraction;
ventricle contraction;
repolarization of ventricle |
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Term
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Definition
sensors that respond to distance of artery wall as a result of increase in pressure by sending impulses to the cardiac center(medulla oblongata) specifically the cardioinhibitor center which is activated triggering parasympathetic stimulus;
decreased HR & Cardiace Contraction
decreased CO
decreased BP |
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Term
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Definition
Baroreceptors not stimulated
No Parasym Discharge
Symp acts through cardioaccelerator center |
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Term
| 2 Baroreceptors are basically |
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Definition
nervous endings located in the aorta and carotid areteries;
Aortic Sinus
Carotid Sinus |
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Term
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Definition
| a Barorecpetors located in the aortic arch and innervated by the vagus |
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Term
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Definition
| a Baroreceptor located at the bifurcation of each common carotid innervated by the carotid sinus nerves of hering |
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Term
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Definition
sensors which don't respond to variations in the pressure but to the concentrations of oxygen and carbon dioxide in the blood;
located neat the aortic and carotid sinuses aka caortid and aortic bodies |
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Term
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Definition
| are immediately rostral to the bifurcation of each common carotid artery |
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Term
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Definition
| are scattered in the tissue between the aorta and pulmonary arteries |
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Term
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Definition
increases cardiac output but it is thought to be the result of direct stimulus of the medulla oblongata;
limited to the carotid and aortic bodies, the heart action is decreased or unchanged. |
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Term
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Definition
this value adjusts the cardiac output to the individual person's body size by representing blood flow relative to a square meter of body surface area;
the normal adult range is 2.5 to 4.2L/min/m^2 |
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Term
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Definition
| CO(l/min)/ Body Surface(m^2) |
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Term
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Definition
| Height(cm) * Weight(kg)/3600 |
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Term
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Definition
is the amount of blood that passes a given point in the circulation in a given period of time;
Bllos flow(Q)=^P/R
^P-pressure gradient (p1-p2)
R-resistance(PRU-peripheral resistance unit) |
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Term
| The Heart has a specialized system for |
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Definition
generating rhythmical impulses to trigger contraction of the heart muscle;
conducting these impulses quickly throughout the heart |
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Term
3 Membrane ion channels
playing an important role in causing the voltage changes of the action potential |
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Definition
fast sodium channels
slow calcium-sodium channels
potassium channel |
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