Homeostasis

The Human Body Compared to a

Fish Tank

Conditions in the tank must be kept constant, or the same, in order for the fish to stay healthy and survive

Fish Tank

In order for the fish to survive the fish tanks must maintain:

warm temperature: ~78 degrees Fahrenheit

high nutrient level: food for the fish, plants and bacteria

high oxygen (O2) level and low carbon dioxide (CO2) level:for the fish to “breath”

low nitrogen-waste level: poisonous for the fish

How do we maintain stable conditions in a tank?

• Heater : temperature• Feeding the fish daily : nutrient levels• Air pump : oxygen• Filters : removes waste• Plants : carbon dioxide• Cleaning the tank : removes waste

Specific systems and organs in your body have Specific systems and organs in your body have specific roles in maintaining homeostasisspecific roles in maintaining homeostasis

Job

• O2 levels up and CO2 levels down

• Nutrient levels up so you have energy

• Waste levels down

• Temperature constant

Main System Responsible Primary Organ Responsible

• Respiratory system• lungs

• Digestive system • small intestine

• Excretory system• kidneys

• Integumentary and nervous system • skin and brain

Fishbowl Human Body

Function

Glass tankBarrier- keep certain things inside and certain things outside

Air pump Keep O2 level stable: high

Filter Keeps waste level stable: low

Heater Keep temperature stable

Feeder Keep nutrient level stable: high

Integumentary (Skin)

Respiratory (Lungs)

Excretory (Kidneys)

NervousIntegumentary

Muscles

Digestive system

Stimulus and ResponseStimulus and Response

Why animals and plants do what they do OR

A fancy way of saying cause and effect in science.

What is a stimulus?What is a stimulus?

Stimulus: any change in an organism’s environment that causes to the organism to react. It is a fancy way of saying “cause”.

Stimulus – singular Stimuli – plural

Example: You are hot and begin to sweat.

What is a response?What is a response?

Response: how the organism reacts to a stimulus and results in a change in behavior. It is a fancy way of saying “effect”.

Example: Getting a drink when you are thirsty.

There are two types of stimuli:There are two types of stimuli:

External Stimuliand

Internal Stimuli

What is an external stimulus?What is an external stimulus?

External stimulus: a stimulus that comes from outside an organism.

Examples: 1. You feel cold so you put on a jacket.2. A snake lunges at a rabbit so the rabbit runs away.3. A dog feels hot so it goes to lay in the shade.

What is an internal stimulus?What is an internal stimulus?

Internal stimulus: a stimulus that comes from inside an organism.

Examples: 1. You feel hungry so you eat some food.2. A cat feels thirsty so it drinks water.3. You feel sick and vomit.

Which organ system is responsible? Which organ system is responsible?

• One of the jobs of your nervous system is to sense changes in the environment (stimuli) and respond to them.

Examples of homeostasisExamples of homeostasis

Stimulus: your stomach is empty and your body needs fuel

Response: your stomach growls

Examples of homeostasisExamples of homeostasis

Stimulus: bright lightResponse: your pupils get smaller

Examples of homeostasisExamples of homeostasis

Can you think of anymore?Brainstorm with your table and fill in the chart

with examples 5-7

Exit Ticket

Explain homeostasis in exactly ten words

NO MORENO LESS10 words!

Really, exactly ten words