Lesson OverviewLesson Overview Homeostasis and CellsHomeostasis and Cells
7.4 Homeostasis 7.4 Homeostasis and Cellsand Cells
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The Cell as an Organism
Homeostasis – maintenance of a relatively constant internal physical and chemical conditions
How do individual cells maintain homeostasis?
To maintain homeostasis, unicellular organisms grow, respond to the environment, transform energy, and reproduce.
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Multicellular Life
How do the cells of multicellular organisms work together to maintain homeostasis?
The cells of multicellular organisms become specialized for particular tasks and communicate with one another to maintain homeostasis.
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Multicellular Life
The cells of multicellular organisms are interdependent, and like the members of a successful baseball team, they work together.
In baseball, players take on a particular role, such as pitcher, catcher, infielder, or outfielder. Messages and signals are sent and understood by teammates and coaches to play the game effectively.
Cells in a multicellular organism work the same way. The cells of multicellular organisms become specialized for particular tasks and communicate with one another in order to maintain homeostasis.
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Example - Specialized Animal Cells
Particles of dust, smoke, and bacteria are part of even the cleanest air.
Specialized animal cells act like street sweepers to keep the particles out of the lungs.
These cells are full of mitochondria, which provide a steady supply of the ATP that powers the cilia on their upper surfaces.
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Example - Specialized Plant Cells
Pollen grains are highly specialized cells that are tiny and light, with thick cell walls to protect the cell’s contents.
Pine pollen grains have two tiny wings that enable the slightest breeze to carry them great distances.
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Levels of Organization
The specialized cells of multicellular organisms are organized into tissues, then into organs, and finally into organ systems.
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Levels of Organization
A tissue is a group of similar cells that performs a particular function.
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Levels of Organization
Organ – groups of tissues that work together
Each type of tissue performs an essential task to help the organ function.
In most cases, an organ completes a series of specialized tasks.
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Organ system - a group of organs that work together to perform a specific function
For example, the stomach, pancreas, and intestines work together as the digestive system.
Levels of Organization
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Levels of Organization
The organization of the body’s cells into tissues, organs, and organ systems creates a division of labor among those cells that allows the organism to maintain homeostasis.