Muscular System PDF

Muscular System Presented By: Rhian Jane F. Patacsil What is Muscle? A muscle is made of strong tissue that can contract in an orderly way All muscle tissues are made of cells that contract. When the cells of a muscle contract, the muscle tissues become shorter....

Muscular System Presented By: Rhian Jane F. Patacsil What is Muscle? A muscle is made of strong tissue that can contract in an orderly way All muscle tissues are made of cells that contract. When the cells of a muscle contract, the muscle tissues become shorter. The muscle tissues return to their original length when the cells relax. Shape of Muscle Circular Muscles - These muscles appear circular in shape and are normally sphincter muscles that surround an opening such as the mouth, surrounded by Obicularis Oris and Obicularis Oculi surrounding the eyes. Shape of Muscle Convergent Muscles- These are muscles where the origin (the attachment to a fixed bone, usually the proximal attachment) is wider than the point of insertion. This fiber arrangement allows for maximum force production. An example is Pectoralis Major. Convergent muscles are also sometimes known as triangular muscles. Shape of Muscle Parallel Muscles - have fibers that, as the name suggests, run parallel to each other and are sometimes called strap muscles. They are normally long muscles which cause large movements, and are not very strong but have good endurance. Shape of Muscle Fusiform Muscles - Sometimes, included in the parallel muscle group, these muscles are more spindle-shaped, with the muscle belly being wider than the origin and insertion. Examples are, Biceps Brachii and Psoas major. Shape of Muscle Pennate Muscles - have a large number of muscle fibers per unit and so are very strong, but tire easily. They can be divided into: 1. Unipennate: These muscles have their fibers arranged to insert in a diagonal direction onto the tendon, which allows great strength. Examples include the Lumbricals (deep hand muscles) and Extensor Digitorum Communis (wrist and finger extensor) Shape of Muscle 2. Bipennate: Bipennate muscles have two rows of muscle fibers, facing in opposite diagonal directions, with a central tendon, like a feather. This allows even greater power but less range of motion. An example is the Rectus Femoris Shape of Muscle 3. Multipennate: As the name suggests Multipennate muscles have multiple rows of diagonal fibers, with a central tendon that branches into two or more tendons. An example is the Deltoid muscle which has three sections, anterior, posterior, and middle. Skeletal Muscles There are well over 600 skeletal muscles in the human body, some of which are identified in Figure. Skeletal muscles vary considerably in size, from tiny muscles inside the middle ear to very large muscles in the upper leg. Structure of Skeletal Muscles Each skeletal muscle consists of hundreds or even thousands of skeletal muscle fibers. The fibers are bundled together and wrapped in connective tissue as shown Figure. The connective tissue supports and protects the delicate muscle cells and allows them to withstand the forces of contraction. It also provides pathways for nerves and blood vessels to reach the muscles. Skeletal muscles work hard to move body parts. They need a rich blood supply to provide them with nutrients and oxygen and to carry away their wastes Function-Movement Many of your muscles help you move. Most of these muscles attach to bones. These muscles make your skeleton move. When muscles contract, they move bones. This movement can be fast, such as when you run. The movement can also be slow, such as when you stretch. Functions-Stability Muscles that are attached to your bones support your body and help you keep your balance. Tendons attach muscles to the bones. Tendons work with muscles and keep your joints in place when your body moves. Tendons also help hold your body in a correct posture, or shape. Functions-Protection Muscles protect your body. They cover most of your skeleton. Muscles also cover most of the organs inside your body. Muscles are like a layer of padding. They surround your abdomen, chest, and back, and protect your internal organs. Functions-Temperature Regulation Your muscular system helps your body keep your internal temperature within a certain range. Have you ever felt cold and then started shivering? Shivering is muscles rapidly contracting. This changes chemical energy to thermal energy. The released thermal energy helps maintain your body's temperature. This is important because a human's body temperature must stay around 37°C in order for the body to function properly. Muscles also change chemical energy to thermal energy during exercise. This is why you feel warm after physical activity. Types of Mucsles Skeletal Muscles Muscle that attaches to bones is skeletal muscle. Skeletal muscles are also called voluntary muscles. Voluntary muscles are muscles that you can consciously control. Skeletal muscles work by pulling on bones. Muscles cannot push on bones. Instead, muscles work in pairs and move the body. For example, you can control whether or not you lift your leg. The contractions of skeletal muscles can be quick and powerful, such as when you run. However, contracting these muscles for a long time can tire them or make them cramp. Skeletal Muscles Your skeletal muscles can change throughout your lifetime. If you exercise, your muscle cells get larger. Then, your entire muscle becomes larger and stronger.  Cardiac Muscles Your heart is made of cardiac muscles, which are found only in the heart. A cardiac muscle is a type of involuntary muscle, which is muscle you cannot consciously control. As cardiac muscles contract and relax, they pump blood through your heart and through vessels throughout your body. Cardiac muscle cells have branches with discs at their ends. These discs send signals to other cardiac muscle cells. The signals cause all the cardiac muscle cells to contract at almost the same time. Smooth Muscles Smooth muscles line your blood vessels and many of your organs. Smooth muscles are involuntary muscles named for their smooth appearance. Contraction of smooth muscles helps move material through your body, such as food in your stomach. Smooth muscles also control the movement of blood through your vessels.  Thanks! CREDITS: This presentation template was created by Slidesgo, and includes icons by Flaticon, and infographics & images by Freepik QUIZ TIME! 1-5. Identify the shape of muscle below: