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The Muscular System
- 1. Charter College T.Miller– 7/2017 ~Muscles and Joints
- 2. • Muscles supportand maintain body posture through a low level of contraction • Skeletal muscles produce a substantial amount of heat when they contract
- 3. • Muscle functionsin the movement of body parts and does so by contraction and relaxation of muscle fibers. • Bones provide a place for muscles and supporting structures to attach. Because of the close association of the skeleton and muscles, the two systems are often referred to as one system called the musculoskeletal system.
- 4. • Skeletal • Attachesto the bones of the skeleton • Voluntary/striated • Operates under conscious control • Smooth • Called visceral muscle • Involuntary/not striated • Not under conscious control • Cardiac • Forms the wall of the heart • Involuntary
- 5. • Tendon • Attachesmuscles to bones • Point of Origin • Point of attachment of the muscle to the bone that is less movable • Point of Insertion • Point of attachment to the bone that it moves
- 6. • Ligaments arebands of fibrous tissue that connect bones or cartilages and serve to support and strengthen joints. The terms ligament and ligamentatum are used in naming the ligaments. • For example, ligamentum costo/clavicul/are or costoclavicular ligament is a ligament that expands from the first costal cartilage to the clavicle. • Movement tends to create friction between bone and adjacent structures. Bursae are sacs of fluid located in areas of friction, especially the joints. Bursae serve to reduce friction. • Inflammation of a bursa is called bursitis. Excision of a bursa is called a bursectomy, and a calculus (stone) in a bursa is a bursolith.
- 7. • Tendons arebands of strong fibrous tissue that attach the muscles to the bones. Tend/o and ten/o are combining forms that mean tendon. • Tendodynia is a word meaning pain in a tendon, as does the word tenalgia. Tendodynia may be caused by tendonitis, which means . Inflammation of a tendon
- 8. • The musclesare responsible for body movement and help form many of our internal organs. • My/o is the combining form meaning muscle. Myocarditis is a complex word meaning heart muscle inflammation, so myocardial means pertaining to the heart muscle. • Muscul/o is another combining form that also means muscle. • Any disease of a muscle is call myopathy. Myography is a recording of a muscle. This process records muscular contractions. The instrument used in myography is a myograph. In general, electromyography is used to record the response of
- 9. • Muscle tissuethat is attached to bone is generally voluntary, which means that it is controlled by the conscious part of the brain. Smooth involuntary muscle is located in the walls of hollow internal structures, such as the stomach and intestines. Cardiac muscle is also involuntary and forms the walls of the heart. • Skeletal muscle is composed of many muscle fibers, which, under the microscope, are found to be composed of many threadlike structures called myofibrils. These slender threads of muscle that alternate in light and dark bands that are called striations. Muscle tissue with striations is called striated muscle.
- 10. • Smooth involuntarymuscle is located in the walls of hollow internal structures, such as the stomach and intestines. • Internal organs of the body contain smooth (involuntary) muscle. Internal organs enclosed within a cavity, especially the abdominal organs, are called viscera. The combining form that means viscera is viscer/o.
- 11. • Smooth involuntarymuscle is located in the walls of hollow internal structures, such as the stomach and intestines. Cardiac muscle is also involuntary and forms the walls of the heart. • Cardiomegaly or megalocardia both mean enlargement of the heart. Note that although –megaly means enlarged, it gives the no indication of the cause of the enlargement. Two suffixes that distinguish the cause of enlargment are –trophy and –plasia. • In cardiac hypertrophy, the enlarged heart is caused by an increase in the size of existing cells. In contrast, an increase in the number of cells of a tissue or organ is called hyperplasia.
- 12. • Skeletal musclesexert force on tendons, which in turn pull on bones, producing movement. Most skeletal muscles are named on the basis of distinctive characteristics. For example, the biceps muscle is named for the number of origins (attachments) of the muscle to the bone. So, the biceps have two origins. • Other distinctive characteristics used in naming muscles are directions of the muscle fibers, location, size, and action. Muscle actions include flexion, extension, abduction, adduction, and others. • Flexion is the bending of a limb at a joint, and the muscles responsible are called flexors. Extension is a movement that brings members of a limb into a straight condition and the muscles involved in this type of movement are called extensors.
- 13. • Abduction isthe movement away from the midline of the body, and the responsible muscles are called abductors. Ab- is the prefix meaning away from. • Ad- is the prefix meaning toward, so adduction is the movement toward the midline of the body. The muscles responsible for this movement are called adductors.
- 14. • Buccinator • Locatedin fleshy part of cheek • Temporal • Located above and near the ear • Masseter • Located at the angle of the jaw • Raises the mandible and closes the jaw • Sternomastoid (sternocleidomastoid) • Extends from the sternum upward along the side of the neck to the mastoid process
- 15. • Trapezius • Triangular-shapedmuscle • Extends across the back of the shoulder • Covers back of neck • Inserts on clavicle and scapula • Latissimus Dorsi • Originates from vertebrae of lower back • Crosses lower half of thoracic region • Passes between humerus and scapula • Inserts on anterior surface of humerus • Forms the posterior border of the armpit
- 16. • Pectoralis Major •Large, fan-shaped muscle • Crosses the upper part of the front chest • Originates from sternum • Crosses over to humerus • Deltoid • Covers the shoulder joint • Originates from clavicle and scapula • Inserts on lateral side of the humerus
- 17. • Biceps Brachii •Muscle has two heads • Originates from scapula • Inserts on the radius • Triceps Brachii • Muscle has three heads • Originates from scapula and humerus • Inserts onto olecranon process of the ulna at the elbow
- 18. • Gluteus Maximus •Forms most of the fleshy part of the buttock • Originates from ilium and inserts in the femur • Gluteus Medius • Located above the upper outer quadrant of the gluteus maximus muscle • Originates from posterior part of ilium • Inserts in greater trochanter of the femur
- 19. • Quadriceps Femoris •Forms anterior part of the thigh • Help extend the thigh • Hamstring Muscles • Located in posterior part of the thigh • Help flex leg on the thigh • Help extend the thigh
- 20. • Gastrocnemius • Mainmuscle of the calf • Attaches to heel bone by way of Achilles tendon • Used to plantar flex foot and flex toes • Tibialis Anterior • Positioned on the front of the leg • Used to dorsiflex foot and turn foot inward
- 21. • Joint =articulation • Point at which two individual bones connect • Joints determine degree of movement • Movement ranges from free to limited • Suture = immovable joint • Purpose is to bind bones together
- 22. • Fibrous • Surfacesof bone fit closely together • Held together by fibrous connective tissue • Immovable joint • Example: Suture between the skull bones S T R U C T U R A L
- 23. • Cartilaginous • Bonesare connected by cartilage • Limited movement joint • Example: Symphysis • Joint between the pubic bones of the pelvis
- 24. • Synovial • Spacebetween the bones = joint cavity • Joint cavity lined with synovial membrane • Synovial membrane secretes synovial fluid • Bones are held together by ligaments • Free movement joint • Example = shoulder
- 25. F U NC T I O N A L Hinge - Allows a back and forth type motion - Example = elbow Ball-and-Socket - Allows movement in many directions around a central point - Example = shoulder joint and hip joint
- 26. • Flexion • Bendingmotion • Decreases angle between two bones • Extension • Straightening motion • Increases angle between two bones • Abduction • Movement of a bone away from midline of the body • Adduction • Movement of a bone toward midline of the body
- 27. • Supination • Actof turning the palm up or forward • Pronation • Act of turning the palm down or backward • Dorsiflexion • Narrows the angle between the leg and the top of the foot • Foot is bent backward, or upward, at the ankle
- 28. • Plantar Flexion •Increases angle between the leg and the top of the foot • Foot is bent downward at the ankle • Toes pointing downward, as in ballet dancing • Rotation • Turning of a bone on its own axis • Circumduction • Movement of an extremity around in a circular motion • Can be performed with ball-and-socket joints