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23 Cards in this Set
- Front
- Back
Capillary |
smallest of blood vessles, which connect arterioles and venules, these walls are composed of only a single layer if cells so lipids and oxygen can pass through |
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diffusion |
movement of particles from high concentration to low concentration: passive transport |
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peripheral circulation |
blood flow to upper and lower extremities and the dermis |
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cardiovascular functions |
rtransport metabolic substances to tissue, transport metabolic end products to organs to dispose of, transport endocrines from the organs that secret them to their target tissue |
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arterioles function |
control the flow to individual vascular beds |
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capillaries function |
exchange materials between blood and interstitial fluid |
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lymphatics function |
collect fluid and their substances from tissue and return it to the circulation |
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peripheral pulses |
confirmation that extremities of the body and dermis are receiving oxygenated blood and nutrients |
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sinoatrial node |
pacemaker of heart, controls heart rate |
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conduction system |
composed of av node, bundle of his, bundle branches an purkinje fibers |
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heart block |
electrical defect of heart, impulses from sa node are impeded or blocked so av node becomes pacemaker but at a slower rate |
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complete heart block |
atria beat at normal rate but ventricles at a slower rate, leads to poor pumping efficiency, these patients are candidates for a pacemaker |
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venous return |
the blood flowing from the veins ino the right atrium each minute |
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Preload |
the initial stretching of the cardiac myocytes prior to contraction. related to sarcomere length at end of diastole |
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sacomere |
the basic unit of a muscle |
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myofibrils |
composed of repeating sections of sarcomeres, which appear as dark an light bands |
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afterload |
the load that the heart must eject blood against, closely related to aortic pressure |
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inotropy |
contractility, changes are caused by intrinsic cellular mechanisms that regulate the interation between actin and myosin independent of sarcomere length |
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effects of gravity |
venous pooling will reduce cardiac output |
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spontaneous respiration |
decreased intra-thoratic pressure results in a decreased right atrial pressure which enhances venous return |
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mechanical ventilation |
increased intra-thoratic pressure during positive pressure lung inflation causes increased right atrial pressure which decreases venous return |
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valsalva maneuver |
causes a large increase in intra-thoratic pressure which impedes venous return to the right atrium |
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cardiac index |
CO/BSA normal- 2.6-4.2 mid left heart failure- less than 2.5 shock- less than 1.8 |