How can I get the corresponding table header (th) from a table cell (td)?

Given the following table, how would I get the corresponding table header for each td element?

<table>
    <thead> 
        <tr>
            <th id="name">Name</th>
            <th id="address">Address</th>
        </tr>
    </thead> 
    <tbody>
        <tr>
            <td>Bob</td>
            <td>1 High Street</td>
        </tr>
    </tbody>
</table>

Given that I currently have any of the td elements available to me already, how could I find the corresponding th element?

var $td = IveGotThisCovered();
var $th = GetTableHeader($td);