The Muscular System Leslie Ross p.7
Name of muscle
Shoulder
Deltoid- Is a large muscle responsible for lifting the arm and giving the shoulder its range of motion. It is locates in the uppermost part of the arm of the shoulder
Trapezius- locate in the back and is responsible for moving, rotating, and stabilizing the scapula and extending the head at the neck
Infraspinatus- is a thick triangular muscle that occupies much of the infraspinous fossa of the scapula
forearm
Arm
Bicep Brachii- movement of the elbow and shoulder
Brachioradialis- located forearm that flexes the forearm at the elbow
Flexor carpi radialis- is a muscle of the human forearm that acts to flex and abduct the hand
Pelvis
iliopsoas- a compound muscle which formed by the iliac and psoas major muscle, originates from the lumbar vertebral column and hip bone, and has its insertion on the femur
Thigh
Vastus Medialis- an extensor muscle located medially in the thigh that extends the knee
Vastus Lateralis- the largest and most powerful part of the quadriceps femoris, a muscle in the thigh
Semitendinosus- a long superficial muscle in the back of the thigh, lies posteromedially in the thigh, superficial to the semimembranosus
Sartorius- the longest muscle in the entire human body, it arises from the anterior superior iliac spine on the lateral edge of the hip bone
Gracilis- one on the muscles found in the groin, its starts at the external point of the ischioppubic ramus and extends down to the upper medial shaft of the tiba and it responsible for hip adduction and assists knew flexion
Semimembranosus- is the most medial of the three hamstring muscles
Bicep Femoris- is a double- headed muscle located on the back of thigh and it may be considered extensors of the thigh
Neck
Sternocleidomastoid- one of the largest and most superficial cervical muscles and the primary actions of the muscle are rotation of the head to the opposite and flexion of the neck
Thorax
Pectoralis major- a thick fan-shaped muscle contributing to the thoracobrachial motion, consists of a clavicular part and a sternal part, both converging to a flat tendon that inserts on the humerus
Serratus anterior- is a muscle that originates on the surface of the 1st to 8th ribs at the side of the chest
Leg
Tibialis Anterior- a muscle in humans that originates in the upper two-third of the lateral surface of the tibia and inserts into the medical cuneiform and first metatarsal bones of the foot
Soleus- the plantar flexor muscle of the ankle, it is capable of exerting powerful forces onto the ankle joints. It is located on the back of the lower leg and originates at the posterior aspect of the fibular head and the medial border of the tibial shaft
Fibularis longus- a muscle inside the outer area of the human leg which everts and flexes the ankle
Muscle Tissue & Major Functions
Skeletal Muscle Tissue- used to effect skeletal movement such as locomotion and to maintain posture
Cardiac Muscle Tissue- that is found in the heart and similar to both smooth and skeletal muscle tissue, that allows it to functions with fast buts sustained contractions, rapid conductions and coordinated movement
Smooth Muscle Tissue- allows for contractions and relaxation with great elasticity
Body Movement
Hyperextension- extension beyond 180
Rotation- movement of a bone around a longitudinal axis
Extension- movement that increases angle of joint
Flexion- movement that decrease angle of joint
Abduction- movement of limb away from midline
Adduction- movement of limb toward the midline
Circumduction- proximal end of a limb is stationary and the distal end moves in circle
Dorsiflexion- lifting the superior surface of foot towards shin
Plantar Flexion- pointing toe
Inversion- turn sole of foot medially
Physiology of Muscle Contraction
The sliding filament theory is the explanation for how muscles contract to produce force. The actin and myosin filaments within the sarcomeres of muscle fibers bind to create cross-bridges and slide past one another, creating a contraction. It explains how these cross-bridge are formed and the subsequent contraction of muscle
For a contraction to occur there must first be a stimulation of the muscle in the form of an impulse from a motor neuron. The motor end plate is the junction of the motor neurons axon and the muscle fibers it stimulates. An impulse reaches the muscle fibers of a motor unit , it stimulates a reaction in each sarcomere between the actin and myosin filaments . This reaction results in the start of a contraction and the sliding filament theory.
Muscle Tissue and Major Function
Skeletal Muscle Tissue- used to effect skeletal movement such as locomotion and maintain posture
Cardiac Muscle Tissue- specialized tissue that is found only in the heart. It had characteristics similar to both smooth and skeletal muscle tissue, as well as specialized properties, that allows it to functions with fast but sustained contractions, rapid conduction and coordinated movemne
Smooth muscle tissue- allows for contraction and relaxation with great elasticity
Eversion- turn sole of foot laterally
Major Functions
Structure and organization levels of the skeletal muscle
The endomysium is the connective tissue surrounding individual muscle fibers, and they're packed within a fascicle. Myofilaments are organized into sarcomeres, and they serve as the functional units of skeletal muscle
Respiration
The diaphragm is a dome-shaped muscle located below the lungs. When the diaphragm contracts, it pushes downward causing the chest cavity to get bigger. The lung then fill with air and the muscle relaxes , it pushes air out of the lung
When someone wants to breath more deeply, it requires help from other muscles, including those in the abdomen, back, and neck
Breathing involves the use of the diaphragm muscle
Posture
Good posture relies on strong, flexible muscles, stiff, weak, or tight muscles contribute to poor posture and misalignment of the body
Long-term bad posture leads to joint and muscle pain in the shoulders, back, neck, and elsewhere
Skeletal Muscle helps keep the body in the correct position when someone is sitting or standing. It is known as posture
Digestive
Food move through the digestive system with a wave-like motion called peristalsis. Muscles in the wall of the hollow organs contact and relax to cause this movement which pushes food through the esophagus into the stomach
The upper muscle in the stomach relaxes to allow food to enter, while the lower muscles mix food particles with stomach acid and enzymes
Smooth muscle in the gastrointestinal or GI tract stretches from the mouth to the anus