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By: Sophie Wilson
What is Homeostasis?Homeostasis are the changes in an organism
so that it can maintain a stable living environment for itself. Homeostasis is essential for the survival of all living things. Each part of a cell has functions and actions they must carry out to maintain homeostasis.
HomeostasisHomeostasis involves a series of mechanisms
that can sense and respond to changes in the exterior environment. For survival, the organisms must restore internal environment variables to an acceptable living rate.
Two systems that contribute to maintain homeostasis are the nervous system and the endocrine system.
Homeostasis Continued…To maintain homeostasis, unicellular
organism grow, respond to the changes in its internal and external environment, transform energy as well as reproduce! Homeostasis is needed to maintain balance in chemical and physical conditions.
AdaptationUnicellular organisms both include prokaryotes and
eukaryotes.Prokaryotes are very adaptable and can survive
almost everywhere due to the process of homeostasis.
Every organism must obtain certain amounts of different concentrates, food and water so that it may survive. Homeostasis allows organisms to change and use the resources in their environment whether it needs to make rapid or long term changes in its internal environment. However, sometimes the change in the environment can be so dramatized that the organism can not respond to the change so quickly and the entire population can become extinct. Take dinosaurs for example.
Working TogetherTo obtain homeostasis, different cells and
systems have to function together and communicate with eachother
Some cells are specialized to move, others to react to the environment, others to reproduce etc.
Just like in our previous explored investigations, cells form tissues, which from organs, which form organ systems which all play a role important to achieve homeostasis. Some organ systems important in homeostasis made up of organs and tissues and cells are the nervous and endocrine system. Everything is given a role using receptors.
Nervous SystemThe nervous system helps contribute to
homeostasis by:Controls activities within the organism,
responding to rapid changes needed in the internal environment due to changes in the external environment.
Nervous System also detects changes in the external environment so it can respond to these changes and make a stable living environment.
Endocrine SystemThe endocrine system helps maintain
homeostasis by:Responds to changes that require duration
and time rather than a rapid response.Endocrine System controls the stability of
nutrients by adjusting kidney function, controls environments volume, and lastly it controls electrolyte composition throughout the organism
What is Involved?Homeostasis consists of:Concentration of nutrientsAmount of water, food, salt, and other
various food substances.Amount of waste product and what is not
needed in the organism (what can be discarded)
Blood volumeBlood pressureTemperature
Why is Homeostasis Needed?Homeostasis is constantly being disrupted by
several factors such as:External:Heat, cold, lack of airPathogens and toxinsInternal:Blood TemperatureBlood PressureAmount of water, sugars, salts and other
substancesPhysical and mental stress
HomeostasisThe organism must be able to:1.Detect changes in the internal and external
environment2.Respond to these changes to make
appropriate adaptations to maintain homeostasis
Control SystemsIntrinsic Controls Extrinsic ControlsLocal Controls found in
organsMechanisms found
outside the organs.Achieved by nervous and
endocrine systems
Feed Back!Feed Forward Feed BackResponses made to
anticipate changeRefers to response after
change is made.Two types of feed back
are positive and negative
FeedbackNegative PositiveStimulus is reversedMost feedback systems
in the body are negativeUses for helping control
the organs and systems that need help to function regularly
Stimulus is intensifiedSeen during child birth:Stretch receptors send
signals to the brain and brain releases hormones into blood stream. The uterine contracts and the process ends with the decrease in stretch and birth of child
FeedbackThere are many elements composed in feedback loops
such as:1.Receptor- Structures that monitor and receive
impulses indicating change in the internal or external environment. This also consists of your five senses: taste, sight, touch, hear, smell.
2.Control Center- Determines the next action working within the organism. This is your brain.
3.Effector- Receives impulses from the control center and responds to it creating a balanced and stable environment making homeostasis achievable. This consists of muscles and things that make your body move and other characteristics throughout the body or organism.
Exploring ReceptorsWhen the body is performing an action, many
parts of small molecules send out chemical impulses and signals to other cells.
To receive these chemical signals a cell must have what is called a receptor which are mostly on the membrane but can sometimes be found in the cytoplasm
The chemical signals will work together to create change. For example, a series of impulses are necessary in pumping blood from the heart
Receptors include your five senses.
TemperatureThermo receptors can detect change in
temperature increase in the external and internal environment.
The brain will send out impulses to blood vessels and the sweat glands
Sweat is released which also causes a decrease in heat restoring normal body temperature
Homeostasis temperature controlhttp://www.southtexascollege.edu/nilsson/4_gb_lecturenotes_f/4_gb_16_anims_ho_j_spr2003.html
BiblyographyWorks Cited"Homeostasis - Credo Reference Topic." Credo Reference
Home. Web. 19 Nov. 2010. <http://www.credoreference.com/topic/homeostasis>.
"Homeostasis | Define Homeostasis at Dictionary.com." Dictionary.com | Find the Meanings and Definitions of Words at Dictionary.com. Web. 19 Nov. 2010. <http://dictionary.reference.com/browse/homeostasis>.
"Kids and Teens." AskColorado - Welcome! Web. 19 Nov. 2010. <http://www.askcolorado.org/k12/index.html>.
Miller, Jeffery. "Biology Investigation Resources." Biology. Wikispaces. Web. 19 Nov. 2010. <http://coloradoearthsystemsresearchcollaborative.wikispaces.com/Biology+Investigation+Resources>.
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