Muscle Anatomy and Physiology Model Building

Hello everyone! Today we are going to discuss muscle anatomy as well as the anatomy and physiology of the neuromuscular junction. 

First up is the skeletal muscle anatomy, as can be seen in the illustrations below. The first picture shows the muscle in its entirety while the second depicts a zoomed-in view of the myofibril. 

As you can see, each part of the muscle anatomy is composed of bundles of fibers that work together. This is a very general description, however, it can be broken down to the parts labeled above.

Next is the anatomy and physiology of the neuromuscular junction. In basic understanding, the neuromuscular junction is where a motor neuron can transmit a signal to the muscle fiber, which then causes the muscle to contract. Just like in the muscle, there are multiple components to this junction. 

To begin with, calcium enters the neuron through the voltage-gated calcium channel. This begins a process that results in the secretion of a neurotransmitter, acetylcholine, from the axon terminal. The acetylcholine travels across the synapse until it is intercepted by the acetylcholine receptors within the muscle cell membrane. The acetylcholine causes sodium ions to passe through the neurotransmitter-gated channel in the acetylcholine receptors, and into the muscle cell. Once it has done its job, the acetylcholine is broken down by an enzyme called acetylcholinesterase. This prevents the muscle from overcontracting. As the sodium ion passes through the neurotransmitter-gated channel, it depolarizes and excites the muscle cell membrane upon entrance. The muscle then contracts due to this impulse, and the neuromuscular junction has served its purpose, for the time being.

To make this model, I used styrofoam, a funnel, and "I Love Lucy"'s Vitameatavegamin candies.

Check out a video of the neuromuscular junction model here: http://youtu.be/Vt8lekZoBUI.

Thanks for joining me in this lesson about muscle anatomy and physiology!