Why don't phospholipid bilayers dissolve?
I just started learning about the structure and composition of cell's membrane and there is something that I fail to understand. The membrane is composed of a phospholipid bilayer. The phospholipid has a polar, hydrophilic head and a nonpolar, hydrophobic tail. My question: **Why doesn't the hydrophilic head dissolve in the extracellular fluid outside the cell?** I suppose that the extracellular fluid is watery, so how come that the water-loving head doesn't interact with the water from the extracellular fluid?