Receiver

Receiver is an individual or individuals to whom the message is directed. The receiver always respond in some way and signals that response to the sender and the signal may take the form of  a spoken comment, a long sigh, a written message, a smile or some other action. Also ‘Bovee and Thill 1992’ states that even a lack of response is in a sense a form response. According to our own understanding this totally makes sense, take for example someone(sender) tells a joke and the other person(receiver) does not respond but just look at him or her without even laughing. This is simply a feedback that the joke intended to make the receiver laugh didn’t so in other words it was not funny hence the receiver didn’t respond by laughing and just looked at the sender, it was a boring joke.

Sender

A sender is an individual, group or organization that initiates the communication. Basically in all communication there should be the sender at the beginning of the process. The medium is used here as paramount in ensuring the receiver interpreters the message as intended by the sender.

Media (Singular Medium)

example of a medium; letter

Medium is a system, frequently encompassing multiple channels, that enables the creation and consumption of messages. It is generally described as transmission channels or tools used to store and deliver information from the sender to the receiver. Types of channels used to transmit these information include telephone lines, letters, television, spoken words etc. 

Text

In simple words text are sentences, words and paragraphs. They are a symbol that transmits some kind of a message. I would like to bring forth a definition I found somewhere online when I was doing a research and simply interpret it our way. It state that text refers to the original context of a particular piece of writing; that is the text of a work is that primal symbolic arrangement of letters as originally composed, apart from later alterations, deteriorations, commentary, translation, paratext, etc. Research source: http://en.wikipedia.org/wiki/Text_(literary_theory). So in our understanding we can put it is simple terms and say text are written words that conveys or translate a message from a sender to a receiver through  writing.