Term
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Definition
-distribute blood to body organs
-pulmonary trunk and aorta |
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Term
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Definition
-first branches of arteries, slightly smaller.
-provide blood to capillaries |
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Term
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Definition
-barely the diameter of a single red blood cell
-form extensive branching networks
-chemical and gaseous exchange between the blood and interstitial fluid takes place across capillary walls.
-tissue cells rely on capillary diffusion to obtain nutrients and oxygen and to remove metabolic wastes
-the ONLY blood vessels whose walls permit exchange between blood and the interstitial fluid.
-diffusion distances are small, exchange occurs quickly |
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Term
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Definition
-blood moves out of the capillary network and first enters the venules
-smallest vessels of the venous system. |
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Term
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Definition
-Venules merge to combine veins.
-blood passes through small veins then medium and large veins before reaching the vena cava (in the systemic circuit) or the pulmonary veins (in the pulmonary circuit)
-collect blood from all tissues and return it to the heart |
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Term
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Definition
-innermost layer of blood vessels
-endothelial lining |
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Term
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Definition
-middle layer
-contains smooth muscle tissue
-thicker in arteries to resist pressure created by the heart as it forces blood into the arterial network |
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Term
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Definition
-forms sheath of connective tissue around the vessel
-anchors the vessel |
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Term
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Definition
-arterial smooth muscle under the control of the sympathetic division of the autonomic nervous system
-muscles in the vessel wall constricts |
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Term
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Definition
| -relaxation increases the diameter and its central opening (lumen) |
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Term
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Definition
| -interconnected network of capillaries |
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Term
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Definition
| -band of smooth muscle at the entrance of each capillary |
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Term
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Definition
| -blood flow within any capillary is intermittent rather than a steady stream because each capillary sphincter undergoes cycles of activity between contracting and relaxing each minute |
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Term
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Definition
| -tissue smooth muscle fibers respond to local changes in the concentration of chemicals and dissolved gases in interstitial fluid to allow for blood flow into the capillary sphincters |
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Term
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Definition
| -blood vessels provide alternate routes for blood flow by joining two tubes. |
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Term
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Definition
| -a vessel that connects an arteriole to a venule. |
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Term
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Definition
-in medium-sized veins
-prevent back-flow of blood returning to the heart |
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Term
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Definition
-largest pressure gradient found between the base of the aorta and the entrance to the right atrium
-averages about 100mmHg
-divided into arterial pressure, capillary pressure and venous pressure |
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Term
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Definition
-any force that opposes movement
-greatest pressure resistance is in the arterial network between arteries and arterioles (65 mmHg)
-peripheral resistance |
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Term
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Definition
-resistance of the blood vessels to blood flow
-most important factor in vascular resistance is friction between the blood and the vessel walls.
-the amount of friction depends on the length and diameter of the vessel.
-friction increases with length and decreasing vessel diameter |
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Term
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Definition
-the resistance to flow that results from interactions among molecules and suspended materials in a liquid.
-blood has a viscosity about 5 times that of water. |
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Term
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Definition
-reduced hematocrit due to inadequate production of hemoglobin, RBCs or both
-as a result blood viscosity and the oxygen-carrying capacity of the blood are reduced |
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Term
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Definition
| -high flow rates, irregular surfaces caused by injury or disease processes or sudden changes in vessel diameter upset smooth flow and increases resistance. |
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Term
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Definition
-highest in the aorta (120 mmHg)
-lowest in the venae cavae (2 mmHg) |
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Term
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Definition
| -the peak blood pressure measured during ventricular systole |
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Term
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Definition
| -the minimum pressure at the end of ventricular diastole |
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Term
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Definition
| -difference between systolic and diastolic blood pressure |
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Term
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Definition
| -pressure of blood within a capillary bed. |
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Term
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Definition
-continuous movement and exchange of water and solutes from the capillaries through the body tissues and back into the bloodstream
-important role in homeostasis
-4 functions
-maintain constant communication between plasma and interstitial fluid
-speed the distribution of nutrients, hormones, and dissolved gases throughout tissue
-assist movement of insoluble lipids and tissue proteins that cannot cross capillary walls
-flushing bacteria toxins and other chemical stimuli to lymphoid tissues and organs that function in providing immunity to disease |
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Term
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Definition
| -contractions of skeletal muscles near a vein compress it and help push blood toward the heart |
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Term
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Definition
-inhalation causes decreased pressure in the thoracic cavity and causes the inferior vena cava and right atrium to expand and fill with blood
-exhalation increases pressure in the thoracic cavity compresses the venae cavae, pushing blood into the right atrium |
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Term
| 3 factors that influence tissue blood flow |
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Definition
-cardiac output
-peripheral resistance
-blood pressure |
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