4.1 Cell Communications

• Cells communicate with each other through direct contact
• Cells of multi-cellular organisms (like humans) often maintain physical contact with each other
• Some unicellular organisms live in colonies and make contact with each other in the colony
• Cells can send chemical signals into nearby cells
• Cell membrane and cell wall modifications allow for communication to occur between nearby cells
• Cells can communicate over long or short distances
• Cells use chemical signals to communicate over long & short distances
• The cell receiving the signal is known as the target cell
• Cells send out signals, Target cell is within a short distance of the signal, Often used to communicate with cells of the same type

  Short Distance Communication
• Long Distance Communication


  Target cell is not near the cell sending out the signal, Signal travels a long distance to reach the target cell, Often used to communicate with cells of different types
• Immune/Healthy cells often communicate through cell-to-cell contact
• The cells of multi-celled organisms must communicate with one another to coordinate the activities of the organism as a whole.
• There are 3 stages of cell communication: reception, transduction, and response
• Reception: Detection of the signal coming from outside the cell
• Transduction: Converting the signal to a form that can produce a response
• Response: Specific cellular response to the signal received