Laptop computers include the same components as their desktop cousins, but those components are squeezed into a much smaller space. Many of the parts that would be easy to find and replace in a desktop case or a tower are either hidden under an access panel, buried under the keyboard, or integrated into the motherboard.
The internal components are in different places in just about every make and model of laptop computer, so a universal roadmap is simply not possible. In most instances, you need specific instructions just to find your way around, let alone to remove and replace anything.
Don't try to get at the internal components of your laptop without the service manual or the procedures on the manufacturer's Web site. The manuals for most major laptop brands (available through their Web sites) include very detailed step-by-step procedures for finding and replacing what are often called Customer Replaceable Units (CRUs) or Field Replaceable Units (FRUs), such as the battery or a disk drive.
If you do have to perform your own emergency repairs on a laptop computer, it will probably be when you're away from your home base. You might want to keep a paper or CD copy of the service manual and a small screwdriver in your computer bag.