Lab Project: Model of a Working Human Limb

For the lab for this unit we were supposed to construct a working limb, complete with muscles and neurons causing muscles to contract. After much thought I decided to present an arm, using the elbow joint and the biceps and triceps muscles. My problem was that I could not figure out how I was going to create the bones. Finally I decided to use newspaper and masking tape, so all of the bones that you see in the photographs, the humerus, radius, and ulna, were constructed out of rolled up newspaper and masking tape. They turn out a lot better than I expected actually. Obviously the biceps help us to flex the forearm and the triceps helps us extend it.

List of parts an d supplies:

Bones

Newspaper

Masking tape

Muscles and Tendons

Red Cloth

Newspaper

Neuron

Pipe cleaners

Card Stock

Muscle Fiber

Pipe Cleaners

White fabric

Sodium-Potassium Pump

Card Stock

Sequins (Hearts=sodium ions, Snowflakes=potassium ions)

Pipe Cleaners

Muscle cell

Pipe Cleaners

Sequins

These are the supplies I used for the model. The masking tape and newspaper were almost gone by the time I finished.

For the muscles I used red cloth stuffed with newspaper and masking tape as tendons.

Creating the bones, you can see one of them beside me.

Bone model, I think the labels make it pretty easy to understand.

Cutting a dendrite out of card stock.

Twisting pipe cleaners into an axon.

I know this one begs for an explanation. Basically the hearts represent the sodium ions (Na+) and the snowflakes are potassium (K+). The photo above shows resting potential.

In this photo action potential is beginning. This is when depolarization occurs. The Na+ gates have opened and Na+ is moving into the axon.

Here the K+ gates are open and K+ is moving outside of the axon. The action potential is ending.

A model of a neuron, a nerve impulse is traveling down the myelinated axon.

A very lame looking muscle fiber with myofibrils *sigh*.

This photo shows the sacomeres relaxed...

..here they are contracted.

Basically my models show the bones and muscles of the arm and what happens inside those muscles. I actually learned a bit more about how the muscle works from putting this together. I was a little confused about muscle cells and this helped me to get a better feel for the parts of a muscle cell.