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level: 16.1 Principles of homoeostasis

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level questions: 16.1 Principles of homoeostasis

QuestionAnswer
Homeostatis meaning- Changes in ur external enviro. can affect your internal enviro. - blood + tissue that surrounds cells - Hom. involves control systems that keep ur internal enviro. constant (within certain limits) - Keeping ur internal envio. stable is vital for cells to function normally + to stop them being damaged
The importance of homeostasis- Temperature - pH - Glucose
Temperature- If bod temp to high enzymes may denature - Breaks H bonds that no longer hold 3d shape - Site of AS changed, no longer works as catalyst - Makes metabolic reactions less efficient - If bod temp too low enzyme activity happens at their op temp
pH- If blood pH too high or low enzymes become denatured - Breaks H bonds that no longer hold 3d shape - Site AS changed, no longer works as catalyst - Makes metabolic reactions less efficient - Highest rate of enzyme activity happens at their op temp (pH 7) - But some enzymes work best at other pHs
Glucose- If blood glucose conc. is too high water potential of blood is reduced to a point where water mols diffuse out of cells into blood by osmosis - This cause cells to shrivel up + die - If blood glucose conc. is to low, cells unable to carry out normal activities coz there inst enough glucose for respiration to provide energy
Control mechanisms- The optimum point - Receptor - Coordinator - Effector - Feedback mechanism
The optimum point- The point at which the system operates best - This is monitored by receptors
Receptor- Detects any deviation for the optimum point (like a stimulus) - Informs the coordinator
Coordinator- Which coordinators info fro rectors and sends instructions to an appropriate effector
Effector- Often a muscle or gland - Brings abut changes needed to return the system to the optimum point - This return normality creates a feedback mechanism
Feedback mechanism- Where a receptor responds to a stimulus created by the change to the system brought about by the effector
Control mechanism- Negative feedback - Positive feedback
Negative feedback- System that returns a factor to the norm after a deviation from the norm
Positive feedback- Occurs when a deviation from an optimum causes changes that result in an even greater deviation from the normal
Coordination of control mechanism- Control systems normally have many receptor + effectors - This allows them to have separate mechanisms that each produce a + movement towards the optimum - This allows a greater degree of control of the particular factor being regulated - Having separated mechanism that controls departures in different directions form the original state is a general feature of homeostasis - It is important to ensure that info provided by receptors is analysed by the coordinator before action is taken