Muscle Cells Essay

Skeletal Muscle Structure.The cells of skeletal muscles are long fiber-like structures. They contain many nuclei and are subdivided into smaller structures called myofibrils. Myofibrils are composed of 2 kinds of myofilaments. The thin filaments are made of 2 strands of the protein actin and one strand of a regulatory protein coiled together. The thick filaments are staggered arrays of myosin molecules.

Smooth muscle is one of three muscle fiber types found in animals. Unlike skeletal and cardiac muscle cells, smooth muscle cells are not striated, and have single nuclei. Smooth muscles are typically under control of the autonomic nervous system, and do not contract voluntarily. Smooth muscle contracts slowly,

types of muscle tissues : skeletal, cardiac, smooth. Each of these different tissues has the ability

23. This is a network of specialized cardiac muscle fibers that provide a path for each cycle

The condition rigor mortis develops several hours after death because of a lack of ATP. It is characterized by

What are the different levels of organization of a muscle down to myofilaments? What is a “sarcomere” and how are its proteins organized?

There are three main types of muscle tissue in the body: Skeletal muscle, smooth muscle and cardiac muscle. Firstly, skeletal muscle has a stripped appearance when it is examined under a microscope so it is sometimes known as striated/stripped muscle. Skeletal muscle is voluntary and this means that it is under conscious control. Secondly, there is smooth muscle which is an involuntary muscle that operates without any conscious control. This muscle is controlled by the nervous system. Smooth muscle can be found in the blood vessels and the walls of the digestive system and it helps to control digestion and blood pressure. Lastly, there is cardiac muscle which is located in in the wall of the heart. Cardiac muscle is involuntary and this means that it is not under conscious control. This is made up of a specialised type of tissue which is striated and it has its own blood supply. The contractions aid the pumping of blood through the blood vessels

The fibers in both cells are striated, and the fibers are long and each muscle cell is fused to one another. This is why so many nuclei are included. Also, the fibers are almost threadlike, with dark and light colored striations.

Serves as the cell 's skeleton. It is an interior protein system that gives the cytoplasm quality and adaptability. The cytoskeleton of all cells is made of microfilaments, halfway fibers, and microtubules. Muscle cells contain these cytoskeletal parts in addition to thick fibers. The fibers and microtubules of the cytoskeleton frame a dynamic system whose ceaseless rearrangement influences cell shape and capacity.

Muscles are made up of small fibres that contract making the whole muscle contract. There are three types of muscle fibre; Type 1, Type 2a and Type 2b. All individuals have a combination of all fibre types and their combination of fibre types is genetically determined. Different parts of the body have different combinations of fibre types.

Muscle tissue - Muscle cells are the contractive tissue of body that produce force and cause motion within internal organs. Muscle tissue is separated into three different categories: visceral or smooth muscle that are located in the inner linings of organs and skeletal

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.

Myofibrils are made up of long proteins that include myosin, titin, and actin while other proteins bind them together. These proteins are arranged into thin and thick filaments that are repetitive along the myofibril in sectors known as sarcomeres. The sliding of actin and myosin filaments along each other is when the muscle is contracting. Dark A-bands and light I-bands reappear along myofibrils. The alignment of myofibrils causes an appearance of the cell to look banded or striated. A myofibril is made up of lots of sarcomeres. As the sarcomeres contract individually the muscle cells and myofibrils shorten in length. The longitudinal section of skeletal muscle exhibits a unique pattern of alternating light and dark bands. The dark staining, A-bands possess a pale region in the middle called the H-zone. In the middle of the H-zone the M-line is found, that displays filamentous structures that can join the thick filaments. The light-staining bands also known as I-bands are divided by thin Z-line. These striated patterns appear because of the presence of myofibrils in the sarcoplasm (IUPUI, 2016).

There are the Smooth, the Skeletal, and the Cardiac muscular tissues. Smooth muscles are made of spindle-shaped cells.

2. What occurs in the muscle during this apparent lack of activity? Ca++ is being released from the sacroplasmic reticulum and filament movement is taking up slack.