Experiment essays

Experiment essays Introduction: The purpose of this lab included a review of muscle types. Specifically there are three types of muscle types, smooth, skeletal and cardiac. In this lab we will be specifically focusing on skeletal muscle. Skeletal muscles are made up of thousands of muscle fibers. These fibers are made of thick and thin filaments. The thick filaments are composed entirely of the protein myosin. The thin filaments are composed of actin. The thick filaments can be found in the middle of each sarcomere; entire array of thick and thin filaments between Z lines. The thin filaments are at the end of each sarcomere. The thin filaments are connected to an interconnecting proteins known as the Z line. The thick filaments are arranged in parallel arrangement producing dark bands known as A bands. The thin I band produces the light band. This variation of light band and dark band produce a striped look under a microscope and thus result in the muscle being called striated. The lab also focuses on the mechanism of skeletal muscle contraction. Skeletal muscle contraction is controlled by the nervous system. In a nutshell, skeletal muscle contraction begins with -95mv resting potential. Influx of sodium ions is caused by a stimulus and leads to depolarization and then an action potential is reached. Then the resting potential of the fiber is restored by an outflow of potassium ions. Also, we will be defining and understanding subthreshold, threshold, submaximal, maximal, supramaximal in regards to muscle twitching. Finally we will be demonstrating summation, tetanus and fatigue on the dissected muscle. Materials and Methods: The materials in this lab include the frog leg, transducer, Transbridge Amplifier, Harvard Stimulator, Wire. The methods for this experiment including the dissection, neural stimulation, direct stimulation, summation, tetanus, and the operation of the Harvard Stimulator can be found on page ...