We have the macrophage. Inside the macrophage we have the organelles, we have our nucleus and we have these green structures which are the lysosomes. They contain digestive enzymes that can hydrolyze and break down the things that the macrophages actually engulfed. So let's suppose we have some type of pathogen. Let's suppose a bacterial cell, as shown in red. And the macrophage finds our bacterial cell and engulfs that bacterial cell.