Homeostasis Flashcards
Homeostasis
Physiological control system that maintain constant internal environment
What 3 factors effect homeostasis
Temp, pH, glucose
Temperature control
Metabolism, enzymes have an optimum, too hot- denature, too cold- rate slows
pH control
Metabolism, enzymes have and optimum, too acidic, too alkali- rate deacreases
Glucose control
Needed for respiration- respiratory substrate, too much- decreases water potential of blood, water will move out my osmosis- cells shrivel up
Negative feedback
Receptors detect a change away from the normal and effectors activate mechanisms to return it to the normal
Why have a negative feedback
Control and regulation e.g blood temp, pH, glucose, water potential, separate negative feedback systems gives you more control
Positive feedback
A response that results in the effectors amplifying the change away from the normal ‘more produces more’
Why have positive feedback systems
Rapid changes and responses e.g Na+ channels threshold- depolarisation, blood clotting
Glycogenesis
Glucose to glycogen e.g insulin
Glycogenolysis
Splitting glycogen to glucose e.g glucose adrenaline
Gluconeogenesis
Making new glucose from non carbs e.g glucagon
Where is glucagon secreted
Alpha cells in the islets of langerhan in the pancreas
Where is adrenaline secreted
Adrenal gland
Where is insulin secreted
Beta cells in the islets of langerhans in pancreas
(Glucagon) When blood glucose is…
Low
(Adrenaline) when blood Glucose is….
Low
(Insulin) when blood glucose is…
High
(Glucagon) effect on blood glucose
Increase
(Adrenaline) effects on blood glucose
Increase
(Insulin) effect on blood glucose
Liver + muscles
(Glucagon) Mechanisms
Decrease rate respiration, glycogenolysis glyconeogenesis
(Adrenaline) mechanisms
Activates- glyconeogenesis, secretion of glucagon
Inhibits- glycogenesis, secretion of insulin
(Insulin) mechanisms
Increase rate respiration, glycogenesis, increase liver and muscle cells permeability to glucose
