Principles Of Homeostasis Flashcards
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
Vasoconstriction
Shivering
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
Vasodilation
Increased sweating
Lowering of body hair
Behaviour mechanism
