Communication and Homeostasis Flashcards
What do all living things need to keep constant within their cells?
Conditions (cells rely on the activity of enzymes)
What are examples of conditions that they need to keep constant?
-Temperature
-pH
-Concentration of substance and enzyme
-Aqueous environment
-Freedom from toxins and excess inhibitors
What is the external environment?
The air,soil or water surrounding an organism
How does the external environment change over time?
-Slow Changes:seasonal temperatures
-Rapid Changes:Day/Night temperatures
Most cells of multicellular organisms are not exposed to the external environment. What are they exposed to instead?
The internal environment
What is the internal environment for most multicellular organisms?
Tissue Fluid
What also happens to the internal environment?
It changes over time
What must happen if an organism is to keep conditions within the cell constant?
It must react to these changes in the external and internal environments
What must it do to react to these changes in the internal and external environments?
Detect the changes and then alter its behaviour or physiology
How is the change detected?
By receptors
What causes it to alter its behaviour of physiology?
Effectors
What are the two types of communications?
Nervous or hormonal
What is in between the receptor and the effector?
Coordination centre-Brain and Spinal Chord
What must happen for a stimulus to cause a response?
Communication between the cells that detect the stimulus and those that bring about the response
What are the two ways that cell signalling (cell to cell communication) can be achieved?
-Neuronal System
-Endocrine System
