Muscle Contraction Lab Report

There are three phases for muscle cell contraction: initiation of action potential in the sarcolemma, excitation-contraction coupling, and contraction, sliding of the myofilaments. ATP and calcium ions are two essential elements for muscle contraction. When ATP attaches to the myosin head, it gets hydrolyzed to ADP and Pi. Calcium ions bind to the troponin molecules and help expose the binding sites of actin filaments to allow for the attachment of the myosin heads. After the sliding of the myofilaments occurs, a new ATP is required to unbind the cross bridge between the actin and myosin filaments. To test the response of muscle fiber to the addition of ATP and/or salts (KCl and MgCl2), we conducted an experiment in which we added salts only, ATP only, and/or salts and ATP. Since ATP is the essential
element for muscle contraction, we hypothesized that adding ATP or ATP and salts will make the muscle contract, but adding salts only will not make it contracts. There are two types of muscle contraction: isometric, in which the muscle does not shorten, and isotonic, in which the muscle shortens.
Muscle tension is affected by different factors; such as the frequency of the stimulation. With a single stimulus, a muscle twitch is formed; muscle twitch consists of three phases: latent, contraction, and relaxation. Wave summation occurs when another stimulus is applied to a muscle before a full relaxation period, after the first stimulus. On the other hand, treppe occurs when another stimulus is applied right after the relaxation period of the first stimulus. With an increase in the frequency of stimulation, incomplete tetanus occurs in which the contraction and relaxation periods become very short. With even faster frequency of stimulation, complete tetanus occurs in which there is no relaxation periods and the contractions blend to form a continuous total contraction wave. Endocrine system consists of many glands that release hormones into the body to help maintain its homeostasis. The major endocrine glands are: pituitary gland, thyroid gland, parathyroid glands, adrenal glands, pancreas, the gonads, thymus, and pineal
gland. Respiratory system provides the oxygen needed by the body and eliminates the carbon dioxide, which is the body’s waste, through breathing. In order to measure tidal volume, which is the amount of air with normal inhalation and expiration at resting conditions, expiratory reverse volume, which is the maximum amount of air that can be exhaled after a normal exhalation, and vital capacity, which is the greatest amount of air that can be exhaled after a maximum inhalation, we conducted an experiment using spirometer. In the digestion process, specific hydrolytic enzymes are required to breakdown specific substrate molecules. Salivary amylase is required for carbohydrate digestion. Trypsin is required for protein digestion. While, lipase is required for fat digestion.