Skeletal Muscle, Cardiac Muscle And Smooth Muscle

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,

-Sarcoplasmic Reticulum (SR) then releases Calcium which binds to troponin in the thin filament, exposing myosin-binding sites;

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

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?

DEVINE CE, SOMLYO AV & SOMLYO AP 1972, ‘Sarcoplasmic reticulum and excitation –contraction coupling in mammalian smooth muscles’, Journal of Cell Biology, vol. 52, no. 8, pp. 690-718

4. Rowing full speed is putting maximum demands on Jim's muscles. What metabolic process is providing most of the energy for Jim’s muscles at this point and why do Jim's muscles feel like they are burning? (5 points)

These muscle tissue cells specialised to contract and move parts of the body. It is also capable of responding to stimuli. There are three types of muscle in the body such as: skeletal, cardiac and smooth. Each muscle is created of muscle fibers that are capable of contracting and returning back to original state-relaxation. Contraction causes movement of the skeleton, soft tissue, blood or specific material. Skeletal muscle is attached to the bones of the skeleton. Some facial muscles are attached to the skin. They have direct control over them through nervous impulses from our brain sending messages to the muscle. Contractions can vary to produce fast, powerful movements. These muscles also have the ability to stretch and contract to return to original shape. Cardiac muscles are found in the chambers of the heart such as the atria and ventricles. It is under the control of the automatic nervous system; however, even without nervous input contractions can occur. It is completely different to all the other muscles. Smooth muscles are also known as involuntary due to our inability to control its movement. This muscle is usually found in the walls of hollow organs

Introduction: According to the “Human Physiology Laboratory Manual “,BIOL 282 ,page 31 , the reason of performing this experiment is to learn how the muscle contraction occurs based on the molecular level and what kind of factors are involved .As a matter of fact, skeletal muscles contain a lot of nuclei because of the cell fusion while being developed and are made of cylindrical cells that have myofibrils. The myofibrils contain sarcomeres and the

Martini, F. H., Nath, J. L., and Bartholomew, E. F. “Muscle Tissue.” Anatomy & Physiology. 9th

The body has many amazing systems within it. The muscular system is on of the systems that is the most intriguing. Type I, Type IIa, and Type IIb comprise the muscular fiber types within the human body. Type I or Slow-twitch fibers contain mitochondria. These mitochondria use the oxygen that is taken in to create adenosine triphosphate (ATP). ATP fuels muscle contraction. Type I fiber is considered to be aerobic due to the use of oxygen. The slow-twitch muscle fibers are also known as red fibers. This alias is due to the dark red appearance cause by the amount of myoglobin within the fiber. Slow-twitch fibers are the first within the body to be activated due to having a lower activation threshold. They create their own energy source which allows these fibers to sustain force for a longer period of time. The negative aspect is they are unable to create a large amount of force. If the fibers are unable to generate the amount of force that is needed then the fast-twitch fibers will be activated.

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).

Immunohistochemical analysis for smooth muscle actin (SMA) was done and the intensity of staining and staining location were considered.

Both of these muscles expand and contract as they have complex structures so it is essential how they do this. The cardiac muscle needs the contractions to occur in order to pump blood out of the atria and into the ventricles and round the circulatory system so the structure of this muscle shows the systole of the heart. The contractions of the skeletal muscle also depend on its structure. The binding and releasing of two strands of sarcomere is how the repeated pattern of contractions occurs. ATP is used to prepare myosin for binding to allow the contractions to happen. The skeletal and cardiac muscle also both has elasticity. The elasticity is used to restore the muscles back to their original lengths which enable them to resume back to their original length once they have contracted and been stretched.