Accept header vs Content-Type Header

I occasionally get confused between the Accept and the Content-Type Headers and this post is a way of clarifying the difference for myself. Let me summarize the difference to start with and then go onto a little bit of detail -
Accept and Content-type are both headers sent from a client(browser say) to a service.
Accept header is a way for a client to specify the media type of the response content it is expecting and Content-type is a way to specify the media type of request being sent from the client to the server.

To expand on this:

Accept header to quote the HTTP/1.1 RFC:

The Accept request-header field can be used to specify certain media types which are acceptable for the response. 

An example of an Accept header for a json request to a REST based service will be the following:

Accept: application/json

This is saying the response expected is a json content.

Content-Type to quote from the HTTP/1.1 RFC:

The Content-Type entity-header field indicates the media type of the entity-body sent to the recipient or, in the case of the HEAD method, the media type that would have been sent had the request been a GET.

As a sample if a json is being sent from a browser to a server, then the content type header would look like this:

Content-Type: application/json