Homeostasis

This lesson covers:

  1. What 'homeostasis' is
  2. The roles of receptors, coordination centres, and effectors 
  3. The differences between the nervous system and the endocrine system 
  4. What we mean by 'negative feedback'

What is homeostasis? 

Maintaining a constant external environment

Maintaining a stable internal environment despite changing conditions 

Changing an internal environment within the body

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Why does the body need to maintain optimal conditions?

For slow enzyme action and cell function

For optimal enzyme action and cell function

To kill pathogens

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Which of these are considered 'internal conditions'?

(Select all that apply)

Room temperature

Blood glucose concentration 

Blood pH

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True or false? Homeostasis ensure internal conditions stay exactly constant, they don't fluctuate at all. 

True

False

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Which of these are considered 'external conditions'?

(Select all that apply)

Blood oxygen concentration 

The amount of fluids you drink

Room temperature 

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effector / receptor


Homeostasis relies on automatic control systems. 


In what order are signals passed along the control system? 


 âž” coordination centre âž”

receptor
effector

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What is the role of a receptor? 

Interprets changes and organises a response 

Detects changes in the internal or external environment 

Carries out the response 

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What is the role of a coordination centre? 

Carries out the response 

Interprets changes and organises a response 

Detects changes in the internal or external environment 

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Where are the coordination centres located in the body?

(Select all that apply)

Brain

Muscles 

Spinal cord

Skin

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Name the two types of effectors and state what they do.

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Is the nervous system or the endocrine system faster acting? 

Nervous

Endocrine 

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Which system acts more generally across the body, the nervous system or the endocrine system? 

Endocrine 

Nervous

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Homeostasis relies on a system of , meaning whenever the levels of something get too high they're brought back down, and whenever the levels of something get too low, they're brought back up. 

negative
feedback

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If our body temperature gets too high, negative feedback will cause our temperature to:

It won't do anything 

Decrease back down

Increase further 

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Diagram illustrating negative feedback loop with arrows indicating the process around a human figure.

How does negative feedback work?

Any change in a system causes an action that amplifies the change

Any change in a system causes an action that reverses the change

Stops any changes from taking place

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