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12 Cards in this Set
- Front
- Back
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What are arteries? |
Vessels that carry blood away from the heart and into arterioles |
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What are arterioles? |
Vessels that control blood flow from the arteries to the capillaries |
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What are capillaries? |
Vessels that link arterioles to veins |
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What are veins? |
Vessels that carry blood from capillaries back to the heart |
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What is the basic layer structure of arteries, arterioles and veins? |
1. Tough outer layer- resists pressure changes 2. Muscle layer- Contracts to control blood flow 3. Elastic layer- Helps maintain blood pressure by stretching and springing back 4. Thin inner endothelium- Smooth to prevent friction, thin to allow diffusion 5. Lumen- Central cavity through which blood flows |
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Explain the artery structure related to its function |
Transport blood rapidly under high pressure to tissues 1. Muscle layer thick compared to veins 2. Elastic layer thick compared to veins- Important blood pressure in arteries remains high Elastic wall stretches at each beat of heart Springs back when heart relaxes Maintains high blood pressure and smooths pressure surges 3. Thickness of wall is large to resist bursting of vessel under pressure 4. No valves because blood is under constant pressure |
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Explain the arteriole structure related to its function |
Arterioles carry blood under lower pressure from arteries to capillaries Control the flow of blood between the two 1. Muscle layer thicker than in arteries Contraction constricts the lumen which reduces flow of blood, more control 2. Elastic layer thinner than in arteries because blood pressure is lower |
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Explain the vein structure related to its function |
Transport blood slowly under low pressure to the heart 1. Muscle layer thin because veins carry blood away from tissues so their constriction/dilation cannot control flow of blood to tissues 2. Elastic layer thin because blood is under low pressure 3. Thickness of wall small because blood is under low pressure 4. Valves throughout to prevent backflow |
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Explain the capillary structure related to its function |
1. Walls only a lining layer so diffusion distance is short 2. Numerous and highly branched provides large surface area for diffusion 3. Narrow diameter so no cell is far from capillary 4. Lumen very narrow so red blood cells are squeezed flat against wall, bringing them closer to cells that need oxygen 5. Spaces between endothelial cells that allow white blood cells to escape |
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What is in tissue fluid? |
Water Glucose Amino acids Fatty acids Salts Oxygen |
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How is tissue fluid formed? |
1. Blood pumped by heart passes along arteries-arterioles-capillaries, much narrower, creating hydrostatic pressure 2. Hydrostatic pressure forces tissue fluid out of the blood plasma, squeezed out between endothelial cells 3. Hydrostatic forces only small molecules out of capillaries, leaving all cells and proteins in the blood 4. Hydrostatic pressure drops in the blood and water potential increases due to the proteins being left behind 5. Tissue fluid forced back into capillaries |
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Where does some of the tissue fluid go to? How is it moved? |
Pass through the lymphatic capillary that leads back to the heart
Hydrostatic pressure Contraction of body muscles |
