The need for communication systems Flashcards
Define cell signalling.
The way in which cells communicate with each other.
What are some conditions that must be maintained in all living organisms? (4)
Suitable temperature
Suitable pH
Aqueous environment that keeps the substrate and products in solution
Freedom from toxins and excess inhibition
Without the maintenance of certain conditions what will happen to the cells?
They will become inactive and die.
With changes in the external environment what are the stimulus and response?
Environmental change = stimulus
The way in which an animal changes it’s behaviour/physiology = the response
What environmental change causes a gradual response in an organism?
The seasonal changes.
Give an example of a gradual/seasonal change of an animal.
Arctic foxes
White coat in winter to camouflage with the snow.
Brown coat in the summer to camouflage with the grass.
What is the internal environment for cells?
The tissue fluid
What alters the environment for cells?
What they produce. Their substrates and toxins affect the environment around them.
What two things can affect the pH of the blood?
CO2 and lactic acid
The composition of the tissue fluid is maintained by what?
The blood
What does blood do to maintain the environment?
Flows through the body and transports substances to and from the cells.
Why must toxins and waster products be monitored closely?
So the cells have the substrates that they need and the body doesn’t excrete things that it needs and continue to contain things it doesn’t need.
What happens in cell signalling?
The first cell releases a chemical that is detected by a second cell. The second cell responds to the signal that the fist cell sent.
What are the two major forms of cell signalling?
Neural system
Hormonal system
What is the neural system?
An interconnected network of neurones that signal to each other across synapse junctions.
