We have the cell membrane, and just like anything else can travel across any other cell membrane, these cells can also actually transport things across the cell membrane. Now, the final method by which we can exchange nutrients and waste products is via the process of pinocytosis. So this is simply when some type of molecule approaches the membrane of the cell, the cell essentially invaginates, and it takes in that nutrients into our body and it creates a vesicle inside the cytoplasm that contains that nutrient. So these are the four ways by which there can be an exchange of nutrients and waste products inside the capillary, between the lumen of the capillary and the surrounding cells, tissues and organs of our body. So these are the three different blood vessels found inside our body. Arteries are very elastic.