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A snapshot of the summary - Complete Biology for Cambridge IGCSE®
2 organisation and maintenance of organisms
2.45 homeostasis: maintaining a steady state
What is the difference between internal and external enviroment of the body?Internal: the body has mechanisms to keep the conditions around the cells constant
External: the conditions continuously change.
Name 7 organs which are involved in homeostasis and name their function.(HeSKiLILC)
1 heart (transport of blood and pressure to form tissue fluid)
2 skin (heat exchange)
3 kidneys (
regulatelevels of water and salt and remove ureaand other wastes)
4 lungs (exchange carbon dioxide and oxygen)
intestens(supply food and water)
6 liver (regulate solutes in blood and remove poison)
7 cells (change the composition of the tissue fluid/when doing their functions)
What is the principle of homeostasis?The external enviroment has varying conditions, which may be experienced by the body. Homeostatic systems even out these variations so the tissue fluid surrounds working cells with constant / Ideal conditions.
2.46 control of body temperature
Why must your body temperature be controlled?Because many biological and physical processes are affected by temperature.
Name 4 processes in your body that are affected by temperature.1 enzymes
2 cell mebranes (more fragile as higher temperature)
3 diffusion rates (increased by higher temperature)
4 blood (thicker by lower temperature)
What are birds or mammals called that are able to maintain a constant body temperature by generating heat internally?Endotherms
2.46.1 role of the skin
What is the role of the skin?It is the main organ concerned with heat loss and heat conservation.
Why does skin have so many different sense organs?The skin needs to sense the conditions of the external enviroment.
Name 5 different types of sensory cellsmechanoreceptors, thermoreceptors, proprioceptors, pain receptors, and chemoreceptors
2.46.2 control of blood glucose level
Name 3 hormones which influence the glucose level in your blood.1 insulin (when blood sugar is too high)
2 glucagon (when blood sugar is too low)
3 adreline (to make your blood sugar raise quickly)