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18 Cards in this Set

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Top crthe sum of itical Words
stimuli
Behavior
Homeostatisis
Negative Feedback
Positve Feedback
Chemical reaction
First descripative
Living things respond to conditions both in the world around them and in the world inside them: and the sum of their responses is called=behavior
Behaviior
Second descriptive
Behavior is subject to evolutionary forces
Third Descriptor
Hoemstatis is the maintenance of stable internal conditions and two feedback mechanisms are important in the maintance:NEGATIVE and POSTIVE feeedback
FOUR Descripitor
there exist a varity of physiolgical mechansisms in the human body to maintain homostasis and these include thermoregulaton and chemical regulation
Response to stimult
provides a reaction, the way a organism responds
behavior
internal or external
-behavior has also evolved through natural slection
-behavior have adoptive value and have the ability of determine productive success
external stimuli
Things that are from the outside issthat effect, smelling, hearing, seeing, tasting
internal stimulti
all organs remain style includes the use of blood plazma, tissue fluid, and intracellular fluid
homostatis
The homeostatic maintenance of internal bodily conditions within tolerable limits is one fundamental characteristic of living things. In order for an organism's life systems to function properly, the tissues and cells require appropriate conditions. Homeostasis depends on the dynamic action and interaction of a number of body systems.[1] Factors such as temperature, salinity, acidity, plus nutrient and waste balances all affect a complex organism's ability to sustain life.

With regard to any given life system parameter, an organism may be a conformer or a regulator. Regulators try to maintain the parameter at a constant level over possibly wide ambient environmental variations. On the other hand, conformers allow the environment to determine the parameter. For instance, endothermic animals maintain a constant body temperature, while ectothermic animals exhibit wide body temperature variation.

This is not to say that conformers don't have behavioural adaptations allowing them to exert some control over a given parameter. For instance, reptiles often rest on sun-heated rocks in the morning to raise their body temperature. Likewise, regulators' behaviors may contribute to their internal stability: The same sun-baked rock may host a ground squirrel, also basking in the morning sun.

An advantage of homeostatic regulation is that it allows an organism to function effectively in a broad range of environmental conditions. For example, ectotherms tend to become sluggish at low temperatures, while a co-located endotherm may be fully active. That thermal stability comes at a price since an automatic regulation system requires additional energy. One reason snakes may eat only once a week is that they use much less energy to maintain homeostasis
Negative feedback
Negative feedback mechanisms reduce or suppress the original stimulus, given the effector’s output. Most homeostatic control mechanisms require a negative feedback loop to keep conditions from exceeding tolerable limits. The purpose is to prevent sudden severe changes within a complex organism. There are hundreds of negative feedback mechanisms in the human body. Among the most important regulatory functions are: thermoregulation, osmoregulation, and glucoregulation. The kidneys contribute to homeostasis in four important ways: regulation of blood water levels, reabsorption of substances into the blood, maintenance of salt and ion levels in the blood, and excretion of urea and other wastes.

A negative feedback mechanism example is the typical home heating system. Its thermostat houses a thermometer, the receptor that senses when the temperature is too low. The control center, also housed in the thermostat, senses and responds to the thermometer when the temperature drops below a specified set point. Below that target level, the thermostat sends a message to the effector, the furnace. The furnace then produces heat, which warms the house. Once the thermostat senses a target level of heat has been reached, it will signal the furnace to turn off, thus maintaining a comfortable temperature - not too hot nor cold. [
Positive feedback
Positive feedback mechanisms are designed to accelerate or enhance the output created by a stimulus that has already been activated. Unlike negative feedback mechanisms that initiate to maintain or regulate physiological functions within a set and narrow range, the positive feedback mechanisms are designed to push levels out of normal ranges. To achieve this purpose, a series of events initiate a cascading process that builds to increase the effect of the stimulus. This process can be beneficial but is rarely used by the body due to risks of the acceleration becoming uncontrollable.

One bodily positive feedback example event is blood platelet accumulation which in turn causes blood clotting in response to a break or tear in the lining of blood vessels. Another example is the release of oxytocin to intensify the contractions that take place during childbirth.[2]

Positive feedback can also be harmful. An example being when you have a fever it causes a positive feedback within homeostasis that pushes the temperature continually higher. Body temperature can reach extremes of 113 degrees, at which cellular proteins denature, causing the active site in proteins to change, thus causing metabolism stop and ultimately resulting in death.
Thermoregulation
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when temperature surrounding is very different. This process is one aspect of homeostasis: a dynamic state of stability between an animal's internal environment and its external environment (the study of such processes in zoology has been called ecophysiology or physiological ecology). If the body is unable to maintain a normal temperature and it increases significantly above normal, a condition known as hyperthermia occurs. The opposite condition, when body temperature decreases below normal levels, is known as hypothermia.

Whereas an organism that thermoregulates is one that keeps its core body temperature within certain limits, a thermoconformer changes its body temperature with changes to the temperature outside of its body. It was not until the introduction of thermometers that any exact data on the temperature of animals could be obtained. It was then found that local differences were present, since heat production and heat loss vary considerably in different parts of the body, although the circulation of the blood tends to bring about a mean temperature of the internal parts. Hence it is important to determine the temperature of those parts which most nearly approaches to that of the internal organs. Also for such results to be comparable they must be made in the same situation. The rectum gives most accurately the temperature of internal parts, or in some cases of sex or species, the
Chemical regulaiton
the. The pancreas produces insluin and glucahos to control blood suger concentration. the lungs take in oxygen and give off carbod dioxide (this has an acidity effect on body fluids) Kidneys revove urea, and adjust the concentrations of water and a variety of Ions
conclusion
TEACh U that organsims must respond to both external and internal stimuli to survive
conclusin 2
all these responses togther make up an organisms behavior, which is subject to natural selection and evolutionary mechanisms
concluiosn3
teach u the definition of homestatis and the mechansims bh which it works
conclusion 4
teacher must demonstrate knowledge of examples of physilogical mechanisms present in the human body to maintain homeostatis