5.1.1: The need for communication systems Flashcards
If environment change is the stimulus, what is the response?
The organism changes its behavior or physiology.
The arctic fox has a thicker white coat in the winter and a thinner grey/brown coat in the summer. Explain why this is a beneficial adaptation.
- The change in the coat provides greater insulation and camouflage in the winter, ensuring the animal can survive.
- Yet in the summer, the animal does not overheat.
Many cells and tissues are not exposed to the external environment, what are they protected by?
Epithelial tissues and organs such as skin or bark.
In many organisms, what are the internal tissue fluids bathed in?
Tissue fluid, this is the environment of the cells.
How do the activities of cells alter their environment? (tissue fluid)
- The cells undergo their own metabolic activity and as they use up substrates, products are created.
- Some of these compounds may be unwanted or toxic and move out if the cells into the tissue fluid - altering the environment.
What happens if carbon dioxide is allowed to build up in the tissue fluid outside of the cells?
(example of a stimulus)
It will alter the pH of the tissue fluid and could disrupt the action of enzymes and other proteins.
The accumulation of excess waste or toxins in this internal environment acts as a stimulus to cause the removal of the waste product. What happens as a result of carbon dioxide building up in the tissue fluid?
-This reduction in pH of the blood stimulates greater breathing activity that expels the carbon dioxide from the body.
How can the build-up of waste products in the tissue fluid also act directly on the cells?
- The cells could respond by reducing their activity so that less waste is produced.
- However, this may not be good for the whole organism.
How is the composition of the tissue fluid maintained by the blood?
- Blood flows throughout the body and transports substances to and from cells.
- Any waste toxins accumulating in the tissue fluid are likely to enter the blood and be carried away.
Waste toxins are carried away in the blood, how is the accumulation of waste products in the blood prevented?
They must be removed from the body by excretion.
Why is it important that the concentrations of waste products and other substances in the blood are monitored closely?
- So that the body does not excrete any useful substance but removes enough of the waste product to maintain good health.
- It ensures that all of the cells in the body are supplied with the substrates they need.
Multicellular organisms are more efficient than single-celled organisms because Its cells are differentiated. Why is a good communication system required?
- The cells that monitor the blood may be in a different part of the body well away from the source of the waste product.
- They may also be some distance away from the tissue or organ specialised to remove the waste from the body.
- A good communication system is required to ensure that these parts of the body work together efficiently.
A good communication system will…
- cover the whole body
- enable cells to communicate with each other
- enable specific communication
- enable rapid communication
- enable both short term and long term responses
WDescribe the process of cell signalling.
One cell releases a chemical that is detected by another cell. The second cell responds to the signal released by the first cell.
What are the two major systems of communication that work by cell signalling?
Hormonal and neuronal systems.
