feedback mechanisms – Flashcards
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what are the types of feedback mechanisms?
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positive and negative
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why do organisms use feedback mechanisms?
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to either maintain or amplify important chemical systems
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how do organisms regulate complex systems through chemical interactions?
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through feedback mechanisms
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what happens in a negative feedback mechanism?
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there is a stimulus, a signal is sent, a response, and the stimulus is decreased
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what happens in a positive feedback mechanism?
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there is a stimulus, a signal is sent, a response, and the stimulus is increased
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stimulus:
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a trigger
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signal:
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message sent
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response:
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reaction to the signal/message
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what mechanism is most useful for amplifying a condition that is advantageous for the organism?
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positive feedback mechanism, because it promotes the condition
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what mechanism is most useful for stopping a condition that is detrimental or limiting a condition to specified levels?
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negative feedback mechanism, because it stops a detrimental condition
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thermoregulation:
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a process/cycle that keeps the temperature close to homeostasis
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what portion of the brain contains sensors that monitor body temperature?
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the hypothalamus
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what are two mechanisms the body uses to cool itself?
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sweat glands increase sweat production, and blood vessels in skin dilate to radiate heat
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what are two mechanisms the body uses to warm itself?
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muscles generate heat by shivering, and blood vessels in skin constrict to reduce heat loss
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when your hot and your body sweats and dilates blood vessels what type of mechanism is this?
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positive, because the response increases until the normal body temperature returns
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when your cold and your body generates heat by shivering and constricting blood vessels what type of mechanism is this?
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positive because the response increases until the normal body temperature returns
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would a positive feedback loop ever be helpful in maintaining homeostasis?
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no, because it pushes you away from homeostasis
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what a single negative feedback loop ever be helpful in maintaining homeostasis?
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no, because you need multiple feedback loops
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is childbirth an example of a positive or negative feedback system?
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positive because the stimulus increases until the child is born
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what does the common phrase, "a vicious cycle" mean?
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its when the response continues the response
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is lactation in mammals a positive or negative feedback system?
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positive, because the oxytocin pathway will continue to be activated until the baby stops suckling
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what can alterations in our feedback loops lead to?
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diabetes
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homeostasis:
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an internal stable environment
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ectotherms:
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the internal temperature equals the external temperature
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endotherms:
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the internal temperature is constant
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is fruit ripening an example of a positive or negative feedback loop?
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positive, because the fruit that become ripened produce and give off more of that gas/ethylene, then the ethylene gas is amplified and the fruit spoils faster
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when are positive feedback loops used?
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when you want to do something quickly
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where is glucose in your body?
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the blood, cells and liver
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what two hormones help with blood glucose regulation?
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insulin and glucagon
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what organ regulates blood glucose?
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the pancreas
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what are the two cells found in the pancreas?
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Beta cells and Alpha cells
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what do beta cells do?
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produce insulin
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what do alpha cells do?
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produce glucagon
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why do the blood glucose levels usually rise three times a day?
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because you eat three meals a day; breakfast, lunch and dinner
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what rises at the same time as the insulin level?
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blood level
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what is wrong when you have type 2 diabetes?
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you've consumed too much glucose throughout your life and not exercised much, so your cells don't recognize insulin resulting in the insulin not synthesizing
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what pattern do you see with diabetes worldwide?
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3% of the world population has diabetes, mainly north America, and 90-95% of that 3% has type 2 diabetes
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what is wrong when you have type 1 diabetes?
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it results from the autoimmune destruction of the insulin-producing beta cells in the pancreas and this lack of insulin leads to increased blood and urine glucose.
