Muscle Fiber Distribution

Abstract: In this experiment the measurements of skeletal muscle fibers of the rabbit are in millimeters. The average length for the three muscle fibers after adding the solution A which contained only 0.25% ATP in distilled water was 20 mm. The average length for the three muscle fibers after adding the solution C which contained 0.5M KCl and 0.001M MgCl2 in distilled water was 1.77 mm and the average length for the three muscle fibers after adding the solution B which contained 0.25 % ATP and 0.5 M KCl with 0.001 M Mgcl2 in water was 1.77 mm.

In a normal human being the heart correctly functions by the blood first entering through the right atrium from the superior and inferior vena cava. This blood flow continues through the right atrioventricular valve into the right ventricle. The right ventricle contracts forcing the pulmonary valve to open leading blood flow through the pulmonary valve and into the pulmonary trunk. Blood is then distributed from the right and left pulmonary arteries to the lungs, where carbon dioxide is unloaded and oxygen is loaded into the blood. The blood is returned from the lungs to the left

Rationale, Significance and Hypothesis. An extrinsic factor, which exerts a dominant influence on skeletal muscle fiber phenotype, is the nervous system. Buller et al. (1960) elegantly demonstrated the plastic nature of skeletal muscle fibers in response to changes in innervation type. Later, Lφmo and Westgaard (Lφmo and Westgaard, 1974; Westgaard and Lφmo, 1988) demonstrated that depolarization of muscle with specific patterns and frequencies of electrical activity are sufficient to cause changes in mature muscle fiber phenotypes. However, how myofibrillar gene expression and structural organization is affected by the frequency of impulses during activity, the amount of activity over time, or other characteristics of patterned activity is essentially unknown. To answer these questions will require the isolation and study of subsets of muscle-specific proteins in relation to different electrical activation patterns in vivo, an issue that cannot be easily addressed in preparations currently used in the study of muscle development and maintenance. However, using novel in vivo approaches can, in part, circumvent this difficulty.

Each type of muscle fiber has a different power output. These fibers are fast-twitch, and slow-twitch muscle fibers. Fast-twitch fibers are used for explosive movements that are sustained for a short amount of time. While slow-twitch fibers are used for periods of time when movement is sustained for a long period. Slow-twitch fibers utilize aerobic beta-oxidation for energy. This means this type of muscle fiber uses fatty acids for energy and requires oxygen to break them down. This breakdown takes place within the mitochondria. Fast-twitch fibers get energy from anaerobic glycolysis. Meaning this fiber utilizes the breakdown of glucose without oxygen. Humans are born with these fibers in different proportions than others. Genetics determines the amount of each fiber a person will have, and these pre-genetically determined number of fibers will remain constant throughout a person’s life. Due to the different capabilities of each fiber, the amount of slow and fast-twitch fibers can determine the person’s capability. Therefore, those who have more fast-twitch fibers will jump higher than those with more slow-twitch fibers of the same stature. (BSC 228,

Individual muscles are made up of individual muscle fibers and these fibers can be further organized into a motor unit grouped within each muscle. A motor unit is simply a bundle of grouped muscle fibers. When you want to move the brain instantaneously sends a signal or impulse through the spinal cord that reaches the motor unit. Muscle fibers are cells like the basic building block of the muscle. There are a few different types of muscle fibers, each are designed for a specific type of muscle activity. Some muscle fibers are good for endurance exercises, other work best for the short bursts. Each muscle fiber is a single cell. Each cell consists of a structure.

The heart consists into three layers in which are endocardium, the myocardium, and the epicardium. The endocardium is the inner layer of the heart (chambers and valves). The myocardium is the middle muscular layer which is responsible for heart contraction. The epicardium is the outside layer of the heart

The heart is a very strong muscle that has one major job. The heart’s job is to pump blood throughout the entire body. The heart is made up of 4 chambers, and 4 valves. There is the right and left atrium, and a right and left ventricle. The atriums are the superior chambers, and the ventricles are inferior chambers. The left ventricle is the most important, because that is where the blood travels through to go to the aorta, and eventually the rest of the body (Taylor 2015).

Both the right and left atrium contract causing blood to flow though the two valves, and then into the left ventricle. The left ventricle pumps blood into the systemic circulation through the aorta. This systemic circulation system is much bigger than the pulmonary circulation system, which is why the left ventricle is so big. The blood on the left side of the heart is oxygenated. It becomes oxygenated when the deoxygenated blood passes through the right atrium and then flows into the left ventricle. It is then pumped along the pulmonary artery into the lungs where it is oxygenated. It then travels through the pulmonary veins back into the heart. It enters through the left atrium and then travels to the left ventricle. This process is repeated over and over again, to make blood continuously flow through the heart, lungs and body. This process ensures that there is always enough oxygen for the body to work

Oxygen and nutrients the body requires for function are pumped around this complex network of blood vessels by the heart. At roughly the size of a human fist, the heart is a four-chambered muscle and performs two functions of circulation simultaneously and continuously. Systemic and pulmonary circulation. The heart is made up from three separate layers of cardiac tissue; the outer layer called the pericardium, which is a double sac-like outer covering with serous fluid inside to keep the middle layer, the myocardium from adhering to the outer layer. This middle layer of the heart is the heart muscle which is thicker on the left side, to aid with the pressure needed to sustain systemic circulation. The inner layer of the heart is the endocardium. It’s lining is smooth to help prevent the blood which circulates around the inside of the heart from clotting. The heart is the human body’s in-built pacemaker, and the electrical signals sent through the it cause the heart to contract and relax. This process is triggered by the autonomic nervous system and the contraction and relaxing cycle is

The cardiovascular system, however, would not be able to effectively complete these functions without help from what is sometimes referred to as the body’s hardest-working organ- the heart. Approximately the size of a fist, the heart is contains four chambers (the uppermost are called the atria and the lowermost are called the ventricles) and four valves. Additionally, the heart is surrounded by the pericardium, a structure that serves to protect the heart, keep the heart stabilized in the chest, and

The Right Atrium, as it is called, receives blood from the upper and lower body through the superior vena cava and the inferior vena cava, respectively, and from the heart muscle itself through the coronary sinus. The right atrium is the larger of the two atria, having very thin walls. The right atrium opens into the right ventricle through the right atrioventicular valve(tricuspid), which only allows the blood to flow from the atria into the ventricle, but not in the reverse direction. The right ventricle pumps the blood to the lungs to be reoxygenated. The left atrium receives blood from the lungs via the four pulmonary veins. It is smaller than the right atrium, but has thicker walls. The valve between the left atrium and the left ventricle, the left atrioventicular valve(bicuspid), is smaller than the tricuspid. It opens into the left ventricle and again is a one way valve. The left ventricle pumps the blood throughout the body. It is the Aorta, the largest artery in the body, which originates from the left ventricle.

The heart and great vessels are roughly in the middle of the thorax, being surrounded laterally and posteriorly by the lungs and anteriorly by the sternum and the central part of the thoracic cage. The heart acts a twofold, self-modifying suction and pressure pump, the parts of which work in union to push blood to all parts of the body. The right half of the heart (right heart) gets ineffectively oxygenated (venous) blood from the body via the SVC and IVC and pumps it through the pulmonary trunk to the lungs for oxygenation. The left half of the heart (left heart) gets well-oxygenated (arterial) blood from the lungs via the pulmonary veins and pushes it into the aorta for circulation to the body (Fig.1) (Moore and Dalley, 2006).

has to work harder pumping blood to the rest of the body. Blood in our

We have learned that the heart is a complex muscle that pumps blood throughout the body for the purposes of tissue oxygenation and gas exchange (waste removal). We must now discuss the four separate chambers of the heart through which this blood flows through. To start, the two upper, or superior chambers are known as the atria, and the two lower, or inferior chambers are known as the ventricles. These four chambers can further be separated into left and right half’s. Each half contains a superior pumping chamber – the atria, and an inferior pumping chamber – the ventricles. Each of these chambers have an important and specific job to perform during the circulatory process.

From my high school Human Anatomy and Physiology class, I vaguely remember the structure of the human heart. The human heart is fairly simple at a non-cellular level. Your heart contains a right and left atrium, and directly under those, a left and right ventricle. These are the four chambers of the human heart. Your heart also has two main exiting arteries: the pulmonary trunk which exits from the right ventricle and the aorta which exists from the left ventricle. The pulmonary trunk carries “dirty”, deoxygenated blood from the right ventricle to the two lungs to become oxygenated in a system called the pulmonary circuit. This oxygenated blood is then carried back to the left atrium by the pulmonary veins. The aorta carries this freshly oxygenated blood to the entire body in a system called the systemic circuit. The inferior vena cava and superior vena cava are major arteries leading into the heart, carrying the “dirty” blood to be cleaned. (See figure one). I know of these parts, however I want to know how these parts are able to function together as the body ages.