These are not defined functions in the code. Magento abstracts the database calls this way. $this->getPasswordHash() is linked to the password_hash column in the database table. Here is the setWebsiteId() defined in a file. Most of the time that is an automagic function but it does basically what that bottom function does.
public function setWebsiteId($websiteId)
$this->_website = Mage::app()->getWebsite($websiteId);