Protein Channel- they'll allow these outside extracellular ions into the cell. And normally, these sodium ions wouldn't be able to pass through the cell membrane just by themselves.
Carbohydrate- function as adhesion and address loci for cells. The Fluid Mosaic Model describes membranes as a fluid lipid bilayer with floating proteins and carbohydrates.
Phospholipid- This basic cellular structure acts as a barrier to protect the cell against various environmental insults and more importantly, enables multiple cellular processes to occur in subcellular compartments.
Polar Head- The heads (the phospho part) are polar while the tails (the lipid part) are non-polar. The heads, which form the outer and inner linings, are "hydrophilic" (water loving) while the tails that face the interior of the cell membrane are "hydrophobic" (water fearing).
Nonpolar Tail- These hydrophobic tails do not allow polar molecules to pass through. Thus, for molecules to pass through channels are formed by proteins.