Concept explainers
Introduction:
Due to the presence of small vessels, it is hard to measure the pressure in the capillaries. These factors make it difficult to understand the mechanism of the capillary exchange. Thus, the theories of capillary exchange remain disputed. The stereomicroscope observation on the fingernail bed and eponychium has been the basis of study. The blood pressure of capillaries at the arterial end is about 32 mm Hg and 15 mm Hg and is found in the venous end. Due to their small narrow vessels, the blood pressure drops rapidly. The three routes in which the chemicals pass through capillary walls are the intercellular clefts between the endothelial cells, endothelial cell cytoplasm, and filtration pores of the fenestrated capillaries.
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Anatomy & Physiology: The Unity of Form and Function
- List the functions of the cardiovascular system.arrow_forwardDescribe the general structure of a capillaryarrow_forwardDescribe the mechanism of bulk flow in both directions within a fenestrated capillary. What are the names given to these two types of movements? Why do they happen on opposite sides of the capillary? What are the driving forces for each?arrow_forward
- Describe the structure of a capillary. Explain how this unique structure is suited to its function (the site of exchange of materials between blood and nearby cells).arrow_forwardCompare the structure of the three types of capillaries.Explain the various ways that materials pass throughcapillary walls.arrow_forwardList several specific substances that diffuse across capillarywalls.arrow_forward
- Describe a situation in which you can readily see the capillary beds opening and closing and give the physiological explanation for your observation.arrow_forwardList the three elements of the cardiovascular system.arrow_forwardWhat are the two main mechanisms by which capillary exchange takes place and the major type of compounds that are exchanged by these processes? Which parts of the blood are generally held back?arrow_forward
- Explain why water and dissolved substances leave the arteriolar end of a capillary and enter the venular end.arrow_forwardHydrostatic pressure forces plasma across capillary walls at venous end of capillary, and interstitial fluid enters arterial end of capillary by osmotic pressure. True or Falsearrow_forwardDescribe how the aorta and major elastic arteries allow for the continuous flow of blood and maintenance of pressure in the cardiovascular system even during ventricular diastole.arrow_forward
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