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Flashcards in Principles Of Homeostasis Deck (11)
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What is homeostasis

The maintenance of an internal environment within restricted limits in organisms


What is the internal environment made up of

Tissue fluids, that bathe each cell, supplying nutrients and removing wastes to


Why is homeostasis important

For enzymes that control biochemical reactions within cells and other proteins are sensitive to changes in pH and temperature; by any changes to these factors reduces the rate of reaction of enzymes or may even prevent them from working all together


Why is homeostasis important in terms of blood glucose

If blood glucose conc is too high the water potential of blood is reduced to a point where water molecules diffuse out of cells into blood by osmosis

If blood glucose conc is too low, cells are unable to carry out normal activities because there isn’t enough glucose for respiration to provide energy

A constant blood glucose conc also ensures a reliable source of glucose for respiration by cells


What are the series of stages that are involved in controlling any self regulating system

Optimum point - the point at which the system operates best, this is monitored by...

Receptor - which detects any deviation from the optimum point and informs the ...

Coordinator - which coordinates info from receptors and send instructions to the appropriate....

Effector - often a muscle or gland, which brings about the changes needed to return the system to the optimum point. This return to normality creates...

Feedback mechanism - by which a receptor responds to a stimulus created by the change to the system brought about by the effector


What’s negative feedback

The mechanism That restores levels back to normal


When does positive feedback occur

When a deviation from an optimum causes changes that result in an even greater deviation from the normal


How do ectotherms control
Body temp

Exposing themselves to the sun

Taking shelter

Gaining warmth from ground


How do endotherms gain heat in a cold environment



Raising of hair

Increased metabolic rate

Decrease in sweating

Behavioural mechanisms


What do fluctuations from the optimum temp mean

Enzymes function less efficiently, the enzyme may denature and cease to function all together. A constant temp means that reactions occur at a predictable and constant rate


How do endotherms lose heat in a hot environment


Increased sweating

Lowering of body hair

Behaviour mechanism