Insert code into blog post by referencing it rather than directly entering it. (Use for Adsense)

When typing on a blog post, I would like to insert code for Adsense or another code using a short-name that references the code rather than pasting the code directly into my blog post. Is there an easy way to do this?

For example, I would like to define a short-name like this:

"dogphoto" = "<img src="http://www.news.cornell.edu/stories/Sept05/dog.jpg" />"

Then I could merely reference the short-name for the code by typing this:

"I love dogs. I love all dogs. Here is a photo of a Dog. {dogphoto}. Isn't that dog cute?"

The resulting HTML would be this:

"I love dogs. I love all dogs. Here is a photo of a Dog. <img src="http://www.news.cornell.edu/stories/Sept05/dog.jpg" />. Isn't that dog cute?"

I presume this could be done by including a text file. A Wordpress plugin (MiniManager) does this by allowing users to "name" a mini-block of code and then call that code in the blog post by referencing it.

Is there a way to do this in Drupal? If so, it would be a time-saver for repetitive blocks of code that need to be entered when writing a blog post or page. It could be used to insert Adsense ads, Yahoo Ads, a disclaimer at the end of the post, etc.

Thanks in advance for any suggestions.