Can you identify muscle structures

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See our privacy policy for additional details. Learn Site. Artery walls include smooth muscle that relaxes and contracts to move blood through the body 3. Get our awesome anatomy emails! About News Contact. All Rights Reserved. User Agreement Privacy Permissions. The cardiac muscle fibers are joined end to end by specialized junctional regions called the intercalated discs.

The intercalated discs provide anchorage for myofibrils and allow rapid spread of contractile stimuli between cells. Such rapid spread of contraction allows the cardiac muscles to act as a functional syncytium. The intercalated discs contain three types of membrane-to-membrane contact:. In addition to the contractile cells, there is a specialized system made up of modified muscle cells whose function is to generate the stimulus for heartbeat and conduct the impulse to various parts of the myocardium.

This system consists of sinoatrial node, atrioventricular node, bundle of His, and Purkinje fibers. How are fibers connected? Location and number of nuclei How are fibers connected? Morphology Location of muscle Answer:. Slides Please select whether to view the slides in study mode or quiz mode. In study mode, the images will contain labels and a description. In quiz mode, labels and description will be hidden.

Study Mode. With this dye, the A-bands are stained dark and the I-bands light. Since both cardiac muscle fibers and skeletal muscle fibers are striated, how would you differentiate between them in a histological slide? This is a section of the tongue. Begin by identifying groups of fasciculi cut in transverse section. Where are the nuclei located within a cell? Can you identify the endomysium and the perimysium? Where can capillaries be found? How does the location of capillaries in muscle differ from peripheral nerves?

As you zoom in on the image, note the abundance of capillaries in between the cardiac muscle cells. Why are so many capillaries necessary? Note how the cardiac muscle cells are striated, like skeletal muscle cells. However, unlike skeletal muscle, note how the end of each cells splits into branches. Other structural proteins are associated with the sarcomere but do not play a direct role in active force production. Titin, which is the largest known protein, helps align the thick filament and adds an elastic element to the sarcomere.

Titin is anchored at the M-Line, runs the length of myosin, and extends to the Z disc. The thin filaments also have a stabilizing protein, called nebulin, which spans the length of the thick filaments. Watch this video to learn more about macro- and microstructures of skeletal muscles. The arrangement and interactions between thin and thick filaments allows for the shortening of the sarcomeres which generates force.

It is important to note that while the sarcomere shortens, the individual proteins and filaments do not change length but simply slide next to each other. This process is known as the sliding filament model of muscle contraction Figure Tropomyosin winds around the chains of the actin filament and covers the myosin-binding sites to prevent actin from binding to myosin. The troponin-tropomyosin complex uses calcium ion binding to TnC to regulate when the myosin heads form cross-bridges to the actin filaments.

Cross-bridge formation and filament sliding will occur when calcium is present, and the signaling process leading to calcium release and muscle contraction is known as Excitation-Contraction Coupling.

Skeletal muscles contain connective tissue, blood vessels, and nerves. There are three layers of connective tissue: epimysium, perimysium, and endomysium. Skeletal muscle fibers are organized into groups called fascicles.

Blood vessels and nerves enter the connective tissue and branch in the cell. Muscles attach to bones directly or through tendons or aponeuroses. Skeletal muscles maintain posture, stabilize bones and joints, control internal movement, and generate heat. Skeletal muscle fibers are long, multinucleated cells. The membrane of the cell is the sarcolemma; the cytoplasm of the cell is the sarcoplasm. The sarcoplasmic reticulum SR is a form of endoplasmic reticulum. Muscle fibers are composed of myofibrils which are composed of sarcomeres linked in series.

Useful link Find out more about muscle cell types. Go to full glossary Add 0 items to collection. Download 0 items. Twitter Pinterest Facebook Instagram. Email Us. See our newsletters here. Would you like to take a short survey? This survey will open in a new tab and you can fill it out after your visit to the site. Yes No.