Term
| Cardiac muscles contract? |
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Definition
| Independently and spontaneously |
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Term
| What is the order of electrical conduction in the heart? |
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Definition
| Sino-atrial node (SA node), atrioventricular node (AV node), atrioventricular bundle (AV bundle or Bundle of His), right and left branches, Purkinje Fibres |
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Term
| What do the ECG waves mean? |
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Definition
P wave= atrial depolarization
QRS complex=ventricular depolarization
T wave= ventricular repolarization |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| Passive filling of the ventricles. Semi-lunar valves are closed. Atrial contraction pushes the rest of the blood into the ventricles. The Atrioventricular valves close (i.e. the Bicuspid and Tricuspid valves) |
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Term
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Definition
| Ventricles contract (beginning at the apex) and push the semi-lunar valves open. The atrioventricular valves remain closed and this means the atria are passively filling. |
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Term
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Definition
| The semi-lunar valves close to prevent back flow. The atrioventricular valves open and allow blood to start moving into the ventricles. |
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Term
| Mechanical Heart Activities |
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Definition
| Mid-to-late-Diastole--Systole--Early Diastole |
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Term
| Why do the sounds "lub" and "dup" occur? |
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Definition
"lub"=atrioventricular valves closing.
"dup"=semi-lunar valves closing |
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Term
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Definition
| SV x HR=volume of blood pumped per minute |
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Term
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Definition
| Heart rate is controlled by extrinsic factors e.g. the SA node, hormones, and the autonomic nervous system. The VAGUS nerve is attached to the SA node. When the parasympathetic system fires quickly the SA node fires less quickly. When the sympathetic system fires quickly the SA node increases firing. The HR is also controlled by extrinsic factors e.g. temperature, potassium levels (too much and you die), and arterial stretch. HR is, "how many beats per minute." |
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Term
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Definition
| EDV-ESV=the volume of blood pumped out of each ventricle per heart beat |
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Term
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Definition
| Is decreased by the sympathetic nervous system as the sympathetic system increases myocardium contractability (which, allows more blood to pumped out each heartbeat). Hormones also decrease ESV (leave less blood in ventricles after a heartbeat). |
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Term
| Diastolic Arterial Pressure |
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Definition
| Is the lowest pressure and is distinguished as the pressure "when the sound goes away" while taking BP |
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Term
| Systolic Arterial Pressure |
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Definition
| Is the first noise you hear when taking a persons BP. It is the highest pressure. |
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Term
| How do you increase Blood Pressure in the short term? |
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Definition
| Increase HR, SV, venous return (through venoconstriction, TPR |
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Term
| Total Peripheral Resistance (TPR) |
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Definition
| The total resistance of blood flow in the SYSTEMIC circulation. TPR is increased by the size of the arteriole, blood viscosity, and blood vessel length |
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Term
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Definition
| Controlled by hormones not the nervous system. Is constriction of a vein. |
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Term
| Vasoconstriction vs. vasodilation |
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Definition
| Vasoconstriction is constriction (contraction) of blood vessels. Increases BP. Vasodilation is a relaxation of smooth muscle, widening the blood vessel. |
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Term
| Chronic Changes to Blood Pressure? |
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Definition
| Arteriole stiffness in old age, blood viscosity, and blood vessel length in obesity) |
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Term
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Definition
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Term
| Hormonal response to low arterial oxygen? |
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Definition
| Release of erythropoietin from the kidney in response to too little oxygen in the body for it to function properly. Erythropoietin stimulates bone marrow to produce more erythrocytes |
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