HOMEOSTASIS

Your body at work! Some jobs that the human body performs are easy to see! Example: when you run or text on your cell phone, you can see your body at work

BEHIND THE SCENES Your body’s systems are working constantly to do something that is difficult to see, such as maintaining a controlled, stable internal environment. This stable environment is called HOMEOSTASIS

Break it down!

non-living example One way to understand homeostasis is to look at a non-living example that automatically keeps conditions within a certain range. Example: Home air conditioning system

FEEDBACK LOOPS Homeostasis: It’s the process and ability of an organism to maintain equilibrium or balance within itself. You experience homeostasis in your daily activities such as drinking, eating, etc. There are two different ways homeostasis is maintained. One is called a NEGATIVE FEEBACK LOOP and the other is called the POSITIVE FEEDBACK LOOP

NEGATIVE FEEDBACK LOOP Your body most frequently uses a negative feedback loop, that is , your body experiences a change and it does something to neutralize that change. MOST COMMON FEEDBACK LOOP! The body produces a response that is the opposite of the stimulus

NEGATIVE FEEDBACK LOOP example Body temperature Your body wants to stay in its optimal temperature range. If the body temperature changes, the hypothalamus in the brain sends a message to the skin

NEGATIVE FEEDBACK LOOP example The skin responds in many ways such as producing sweat (if you’re hot)

NEGATIVE FEEDBACK LOOP example Or raising body hairs creating “goose bumps” and shivering (if you are cold)

Negative feedback loop example #2 Hydration Your body needs a lot of water to carry on its processes. If your body is low on water, it signals you to drink by giving you a thirst sensation and making your lips dry and chapped. When you’ve had enough water and your water is in balance, your thirst dissipates (goes away). Proper hydration requires a balance of water

Positive feedback loop The positive feedback loop isn’t as common and it might be a bit more difficult to understand. The body detects a change and instead of neutralizing the change, the body works to increase the change. The body produces a response that increases the stimulus.

Positive feedback example Blood Clotting If you have an injury and start to bleed, your body starts to build a clot. Once your body notices it’s building a clot, it works faster and faster until the bleeding stops. The clotting process, which is the reaction to the change in the body, accelerates

Positive feedback example #2 Uterine Contractions http://www.johnwiley.net.au/highered/interactions/media/Foundations/content/Fou ndations/homeo4a/bot.htm

CHECKING FOR UNDERSTANDING #1 Sweating and shivering are ways the body attempts to cool off and heat up to maintain a constant temperature.  True. Sweat is evaporated which cools our body. Shivering causes our muscles to move which warms up the body.

CHECKING FOR UNDERSTANDING #2 The only purpose of breathing is to cool off the body. False. While panting can help a dog or cat cool their body, another purpose of breathing is to take in oxygen and release carbon dioxide. If the lungs cannot exchange these gases, the body will die.

CHECKING FOR UNDERSTANDING #3 When you are thirsty, it's okay to ignore the urge to drink fluids.  False. The need to quench your thirst is your body's way of demanding more water. If you ignore the urge to drink, your body will not be able to maintain homeostasis and can become ill or injured.

CHECKING FOR UNDERSTANDING #4 The brain sends triggers to different parts of the body to maintain homeostasis True. The brain triggers the body to sweat when it's hot, create goose bumps or shiver when it's cold, or to drink fluids when it needs water. There are many other ways the brain helps maintain homeostasis. These are just a few examples.