Homeostasis and Animal Bodies What is homeostasis Processes
Homeostasis and Animal Bodies
What is homeostasis? �Processes that maintain an organism’s internal environment �Examples?
What is homeostasis �Processes are dynamic – body continually adjusting to internal and external changes versus
Why is homeostasis important? �Allows for optimal cell function �Ex. proteins denature if environment is too hot, too salty, too acidic, etc.
How does it work? �Feedback systems regulate internal conditions Negative feedback systems ▪ Counteract the effects of changes in internal environment Positive feedback systems ▪ Intensifies initial change in internal environment
Negative Feedback � Most important mechanism � Returns system to original condition � Contains 3 components: A sensor – senses condition A control center – compares condition to “set point” An effector – produces response to restore desired condition
Negative Feedback - Example
Positive Feedback �Relatively rare �Intensifies a change, but eventually stops �Ex. childbirth Contractions begin Cervix starts to open Hormones stimulate more and stronger contractions Cervix stretches even more More hormones released After delivery, positive feedback stops
Organization of Animal Bodies �All parts must work together �Coordination takes place at multiple levels Cells – building blocks of life Tissues – structurally similar cells that perform a similar function Organs – discrete structures made of at least two tissue types that perform complex functions Organ Systems – groups of 2 or more organs that work together to perform a common function
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