Role of capillaries
exchange material between blood and interstitial fluid
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| Term | Definition |
|---|---|
| Role of capillaries | exchange material between blood and interstitial fluid |
| Intercellular clefts | water-filled space at junctions between cells |
| Types of capillaries | continuous, fenestrated, sinusoidal |
| Continuous capillary | endothelial cells form uninterrupted tube, surrounded by membrane - most tissues |
| Fenestrated capillary | fenestrae (pores) penetrate endothelial lining, surrounded by membrane - endocrine glands, choroid plexus, GI tract, kidneys |
| Sinusoids | discontinuous capillaries, flat and irregular shape, no surrounding membrane - liver, bone marrow, spleen |
| Precapillary sphincter | at entrance of capillary, ring of smooth muscle - alters blood flow |
| Metarteriole | - connects arterioles to venules - contains smooth muscle cells - regulates flow w/ diameter |
| F = P/R | P = pressure difference (mmHg) F = Flow (mL/min) R = resistance to flow (mmHg/mL/min) |
| What determines resistance to blood flow | Viscosity, length of BV, diameter of BV |
| Functions of cardiovascular system | - deliver oxygen/nutrients, remove waste - chemical signaling w/ hormones - thermoregulation (body temp) - inflammatory |
| Component of the cardio system | blood, blood vessels, heart |
| Arteries vs. veins | Arteries: blood away from heart vein: blood towards heart |
| Interatrial septum | separates left/right atria |
| Interventricular septum | separates left/right ventricles |
| Pulmonary circulation | - blood to and from gas exchanges surfaces of the lungs - blood entering lungs = deoxygenated - oxygen diffuses from lung tissue to blood - blood leaving lungs = oxygenated |
| Systemic circulation | - blood to and from rest of body - blood entering tissues = oxygenated blood - oxygen diffuses from blood to tissues - blood leaving tissues = poorly oxygenated |
| Series flow | blood must pass through pulmonary and systemic circuits |
| Pericardium and its functions | fibrous sac around heart - stabilizes heart in thoracic activity - protection - secrete pericardial fluid to reduce friction - limit overfilled chambers |
| 3 layers of the pericardium | fibrous, parietal, visceral |
| Pericarditis | inflamed pericardium |
| cardiac tamponade | compression of heart due to accumulated pericardial fluid (decreases ventricular filling) |
| T/F: the right ventricular wall is thicker than the left | false |
| Components of the heart wall | Epicardium, myocardium, endocardium |
| 2 types of cardiac muscle cells | myocyte: "Y", striated, one nucleus, many mitochondria intercalated disk: where desmosomes and gap junctions lie |
| Why are the heart muscles arranged spirally | when muscle contracts/shortens, wringing effect is produced and pushes blood upwards towards exit if arteries |
| 4 valves of the heart | pulmonary, aortic (semilunar), left AV (mitral), right AV (tricuspid) |
| T/F: blood flow is bidirectional through the heart | False |
| T/F: energy is not used to open and close the valves of the heart | True, they work due to pressure gradients |
| AV valves | - prevent backflow of blood into atria when ventricles contract made of: cusps, chordae tendinea, papillary muscles |
| Chordae tendinea | extend from leaflet to papillary muscle |
| Papillary muscle | - cone shaped |