16 homeostasis Flashcards
define homeostasis
the maintenance of a constant internal environment
what does homeostasis ensure for cells in the body?
that they are in a stable environment that meets their needs and allows them to function normally despite any external or internal changes
what factors affect enzyme activity?
temperature
pH
inhibitors
activators
substrate concentration
why is it important to maintain a constant internal environment? (refer to enzymes)
makes sure enzyme controlled biological reactions take place at a constant/optimum rate
organisms that control their own internal environment are more…
independent of their environment
what does organisms being more independent of their environments lead to?
- greater geographical range so can colonise more habitats and ecosystems
- greater chance of finding food/shelter/mates
what must happen to all muscles for homeostasis to be achieved?
muscles have to be coordinated
what are the 5 control mechanisms?
- set point
- receptor
- controller
- effector
- feedback loop
define negative feedback
when there is an change from the set point, the opposite effect is instigated
what type of mechanism does the blood glucose regulation use?
negative feedback mechanism
what system does the blood glucose regulation involve?
endocrine system
what similarities do the hormones involved in the blood glucose regulation have?
- produced by glands and secreted into the blood
- carried in blood plasma to target cells
- complementary receptors only found on target cell
blood glucose concentration is strictly controlled within the range of…
80-100 mg 100cm^-3
what is the word for very low levels of glucose?
hypoglycaemia
what is the word for very high levels of glucose?
hyperglycaemia
what des hypoglycaemia mean?
vey low levels of glucose
what does hyperglycaemia mean?
very high levels of glucose
hyper and hypoglycaemia can both be…
fatal
what does the pancreas do?
controls glucose levels
what are the 4 reactions called during blood glucose concentration?
glycogenesis
glycogenolysis
gluconeogenesis
glycolysis
what is glycogenesis?
alpha glucose -> glycogen
what is glycogenolysis?
pyruvate + glycerol + amino acids -> glucose
what is gluconeogenesis?
glycogen -> alpha glucose