What Is the Activity System?

The motor system consists of three organs: bone, joints and skeletal muscle. Bone is joined together in different forms to form bone. The basic form of the human body is formed, and it provides muscle attachment. Under the innervation of the muscle, the muscle contracts, pulling the bone to which it is attached, and using the movable bone connection as a pivot, it generates lever movement.

The generalized motion system consists of

Motion system

Not only is the bone hard and elastic, it has a compression resistance of about 15 kg / mm ² and the same tensile strength. These physical properties are determined by its chemical composition. Bone tissue

The surface of bone is affected by factors such as the attachment and traction of tendons, muscles, ligaments, and the passage of blood vessels and nerves. Various morphological signs have been formed. Some signs can be clearly seen or touched from the body surface, becoming clinical diagnosis and Judgement during treatment

Motor system bones

The body's support is made up of bones connected by joints and ligaments. Used for muscle attachment and leverage during exercise. The shape and structure of bones are adapted to the tasks they perform in sports. It can be divided into: Spinal skeleton. Consists of skull, vertebra, ribs and sternum. The skulls are interconnected to form the skull. There is a vertebra in each somite, which is short and has many protrusions, which are connected to each other to form a spine, which is the main axis of the body. The vertebrae of the neck, chest, waist, sacrum, and tail are called cervical, thoracic, lumbar, sacrum, and coccyx, respectively. The sacrum is combined into a sacrum, which is conducive to receiving the force that pushes the body forward from the hind limbs. The ribs, sternum and thoracic spine form the thorax. Forelimb bones. There are scapula, humerus, radius, ulna, carpal, metacarpal and knuckle. The scapula is a flat bone located at the front of the thoracic wall and has a wide area for muscle attachment. The humerus is a long tubular bone located in the upper arm. The radius and ulna are juxtaposed on the forearm and are also tubular long bones. The carpal bones are a group of short bones that are stitched together in two rows to participate in the formation of the carpal joint. The metacarpal bone is a long tubular bone. The phalanges include phalanges and sesamoids. hind limb bones. There are hip, femur, sacrum, tibia, fibula, sacrum, sacrum and toe bone. The hip bone is a flat bone, which is a combination of the sacrum, pubic bone, and ischium. It has a wide area for muscle attachment. The left and right hip bones join with the sacrum to form the pelvis. The femur is a long tubular bone located in the thigh. The sacrum is located in the knee joint and is the sesamoid. The tibia is located in the lower leg and is a tubular long bone. The fibula is slender, juxtaposed with the tibia and attached to the tibia. The sacrum is a group of short bones that are divided into three rows and joined together to form the sacroiliac joint. The metatarsal and phalangeal bones are the same as the metacarpal and phalangeal bones, respectively.

joint

exercise system

Interboned structure. Some joints have simple structures, and the fibrous or cartilage tissues between bones are tightly connected, and they cannot move between each other. Some joint structures are more complex, bones and bones are connected by joint capsules and ligaments, and can move with each other. The outer layer of the joint capsule is a fibrous membrane; the inner layer is a synovial membrane that secretes synovial fluid to reduce friction (Figure 1). Synovial joints can be classified according to the shape and movement of the articular surface: slidable flat joints, such as wrist and palm joints; uniaxial joints that can be used for extension and flexion, such as elbow joints; uniaxial joints that can be used for rotational movement, such as Atlantoaxial joints; biaxial joints that can be used for extension, flexion, adduction, and abduction; multiaxial joints that can be used for extension, flexion, adduction, abduction, orbit, and rotation, such as the hip joint. The joints of the extremities are mostly uniaxial joints that perform flexion and extension. The shoulder and hip joints are structurally multi-axis joints. Most of the head joints cannot move, but the temporomandibular joint can perform extension and flexion and sliding movements. The connection of the spine is special. The vertebral arches of the vertebrae are connected by a synovial joint, and the vertebral bodies are connected by fibrocartilage.

Motor system muscles

exercise system

The muscles involved in the motor system are striated muscles. They are contractile tissues of the motor system. They can use joints as the fulcrum to move the bones attached to them. Running and pushing the body are the main forms of exercise. The muscles related to this are mainly the spine muscles, which mainly act on the spine and the skull. Some of its muscles have the function of raising heads, stabilizing interspinous joints, and transmitting the forces from the posterior thigh, thereby pushing the body forward. The various muscles distributed in the forelegs and hindlimbs each have different motor functions and play a coordination and mutual aid role. Such as the large number of forelimbs, the larger left and right ventral serratus muscles have a suspending effect and can cushion vibrations. The brachiocephalic muscle has the function of lifting the forelegs forward. The gluteal femoris muscles of the hind limbs are quite developed and are the main force for pushing the body forward. The middle part of the muscle structure is called the muscular abdomen, which is composed of muscle fibers, which can contract and relax; the two ends are tendons and belong to fibrous tissue. The strength of muscle contraction is proportional to the number of muscle fibers, and the shortening is proportional to the length of muscle fibers. Muscle fibers can generally shorten their original length by 1/3 to 1/2. Muscle fibers are filled with sarcoplasmic reticulum, mitochondria, muscle glycogen, and neatly arranged myofibrils. Myofibrils are composed of thick muscle filaments and thin muscle filaments that appear staggered in the dark and bright bands under the electron microscope. The thick muscle filaments located in the dark zone contain myosin; the thin muscle filaments contain actin, with one segment located in the bright zone and the other extending into the dark zone and staggered between the thick muscle filaments (Figure 2). When nerve impulses are transmitted, adenosine triphosphatase of thick myofilaments is activated to decompose adenosine triphosphate to generate energy; and myosin and actin are combined to form an actin complex, and thin myofilaments All pulled into the dark zone, forming myofibrillar contractions. When the nerve impulse stops, it presents a series of activities in the opposite direction. Any movement is the result of a group of muscles acting together under the unified control of the nerves. During the rest of the animal, the muscles are in a tense state, maintaining the body's posture and balance. During exercise, muscles contract and develop tension. The ability of muscles to work for a longer period of time depends on the availability of energy and oxygen sufficient to ensure that mitochondria in muscle fibers produce adenosine triphosphate, and the elimination of metabolites. Energy comes from the oxidation of fat, glucose and muscle glycogen. In addition, muscle fibers also have the function of storing energy.

Motor system movement mechanism

Running means that when the limb ends are lifted from the ground, the speed lever with the elbow joint as the fulcrum and the power arm smaller than the heavy arm is used. After the limbs reach the ground, the body advances, using the labor-saving lever that takes the limbs as the fulcrum and the force arm is greater than the heavy arm. For example, the movement of the forelimbs first contracts with the flexors of the shoulder, elbow, wrist, and interphalangeal joints. These joints flex, and the extremities lift up from the ground. Then, as the extensors contract, these joints stretch; At the same time, as the body moved forward, the forelimbs took a step forward and the limbs landed. After that, the extensors of these joints (including the flexors of the wrist and interphalangeal joints) contract, and the related joints stretch, pushing the body forward. The movement of the hind limbs is basically performed by the related joints of the hind limbs, such as the hip joint, knee joint, sacroiliac joint, and interphalangeal joint and their muscles, to push the body forward. In the process of the limbs moving alternately to push the body forward, when the hind limbs support the body, the back of the body rises and the center of gravity moves forward; when the forelegs support the body, the front of the body rises and the center of gravity moves backward. As a result, the body shows continuous fluctuations ^[1] .