Homeostasis

By: Sarah Berger and Shay Dite

What is Homeostasis?

Homeostasis is the maintenance of a stable environment.

It prevents us from getting sick all the time. It keeps us warm in cold temperature. It maintains species. Homeostasis is necessary in the smallest

single cell organisms, to the biggest whale.

Why is Homeostasis Important?

Without it, waste wouldn’t be removed, Nutrients wouldn’t be delivered, Oxygen wouldn’t be received, Our temperature would be abnormal, pH levels wouldn’t regulate. Without homeostasis, nothing would live.

Cellular Homeostasis Cells maintain homeostasis. Cellular homeostasis means that everything in the cell is

working properly. The cell membrane is the main aspect to this conjecture. A membrane keeps the organelles safe and separate

from the external world. The stuff inside a cell is much different from the things

outside the cell. If a cell intakes something it shouldn’t it could very well

die.

Cellular Homeostasis (Cont.)

Sometimes cells have an unnecessary particle or molecule in them.

Sometimes there is a molecule they need right outside the membrane.

That is why cells use diffusion. It gets rid of the unwanted particles and intakes the wanted ones.

Cellular Homeostasis (Cont.)

Occasionally cells have too much water in them, if that occurs in excess, the cell can rupture and die.

Sometimes cells don’t have enough water. That is why the use osmosis –the passing of

water through a membrane. Osmosis and diffusion regulate the amount of

substances in a cell.

Hierarchy of Organization

The smallest thing able to function on its own is a cell, then:

Tissue Organ System Organism

Working Together

Cells work together to form tissues, which work together to form organs, to form systems, which work together to help maintain homeostasis in an organism.

Everything needs to work together and communicate in order to make life.

How Homeostasis Works:

There are receptors all over living things. Receptors monitor the condition of our

beings. They detect if we are cold or if we are getting too much light into our eyes.

Receptors can be our five senses, sight, taste, hearing, touch, and smell, or they can be internal sensory organs.

How it Works:

The receptors give the information to the control center.

The control center can be the brain or the nucleus.

It then tells the body what to do in response to the information received.

How it Works (Cont.):

The control center gives the effectors directions.

The effectors are the multiple organ systems we have.

The effectors then execute the order, in hopes of fixing the issue.

Additional Terms

Feedforward: term for what happens while waiting for a change.

Feedback: the actions made when a change has been discovered.

Negative Feedback loop: A way of communication to maintain homeostasis –receptors to the control center to the effectors. A negative feedback loop is basically what

homeostasis is.

Negative Feedback Loop

Without this process, homeostasis wouldn’t be existent.

An example is of heating a house: The thermometer (receptor) detects that

the house is cold. It gives that information to the thermostat

which tells the furnace to turn on.

Negative Feedback Loop

Here is an example in animals: A person walks from a dark room to a light-filled

room. The eye is in taking too much light (reception). The brain tells the pupils to shrink. The pupils shrink, letting the correct amount of

light into the eyes.

Negative Feedback Loop

Positive Feedback

In addition to negative feedback, it can be positive.

Positive feedback is when something doesn’t make a loop, but enhances the change.

When a baby is being born, the uterus is stretched. Instead of putting it back to its regular form, a positive feedback loop makes the uterus stretch farther.

Positive Feedback Loop

Homeostasis

Homeostasis can be disrupted by:A change in temperature

Internally and in the environmentLack of Oxygen PathogensToxinsChange in blood pressurePhysical and psychological distresses

Homeostatic Controls

There are two control systems for homeostasis.

They are intrinsic and extrinsic. Intrinsic are the controls inside an organ. Extrinsic are the controls outside an organ.

Body Systems

All the body systems work together to maintain homeostasis.

Some have more importance in maintaining things though.

The nervous system is probably the most important closely followed by the endocrine system.

The Nervous System

The nervous system controls the actions of the other systems.

It also detects changes in the body.

The Endocrine System

It secretes hormones which regulate many changes within the body.

Muscular System

The muscular system helps the body to move which can affect the heat.

It also helps maintain the structure of the organism.

Skeletal System

It maintains the body’s structure.

Muscles attach to it. The bones store

many minerals and are full of blood vessels.

Integumentary System

This system, the skin system acts like a cell membrane. It keeps unwanted things out and water in.

Respiratory System

This system gets oxygen to everything that needs it.

It also removes carbon dioxide from the body.

Digestive System

The digestive system intakes and absorbs nutrients for the whole body.

It gets rid of the unwanted waste.

Circulatory System

This system transports many things such as: Oxygen Carbon Dioxide Nutrients Hormones Waste

Excretory System

This system regulates the volume of liquids in the body.

Removes the waste from blood.

Reproductive System

The reproductive system maintains species.

If we couldn’t reproduce, species would die out and there would be no life.

Homeostasis

All the systems work together and do their own share in maintaining homeostasis.

It is probably one of the most complicated things in the entire world.

Somehow, mother nature, natural selection and evolution created the perfect balance of things.

Something no human or single cell could do consciously. It is just another world wonder.

Works Cited

BSCS Biology A Human Approach. Kendall Hunt Pub, 2007. Print.

Farabee, M. J. "ANIMAL ORGAN SYSTEMS." Estrella Mountain Community College. 18 May 2010. Web. 06 Dec. 2010. <http://www2.estrellamountain.edu/faculty/farabee/biobk/BioBookANIMORGSYS.html>.

"HomeostasisTutorial." Oklahoma City Community College. Web. 06 Dec. 2010. <http://www.occc.edu/biologylabs/Documents/Homeostasis/homeostasis_tutorial.htm>.