Musculoskeletal System (locomotor system) Sai Prasad Pydi • provides the body with movement, stability, shape, and support • Framework for your muscles and other soft tissues Muscular system Movement production, joint stabilization, maintaining posture, body heat production Storage of carbohydrates in the form of glycogen Skeletal system Mechanical basis for movements, providing framework for the body, vital organs protection, blood cells production, storage of minerals storage of minerals (e.g., calcium) and hematopoiesis Interesting Facts The skeleton makes up almost one-fifth of a healthy body’s weight. It also protects certain organs, such as the delicate brain inside the skull. Bones are reservoirs of important minerals, especially calcium, and also make new cells for the blood. Bone is an active tissue, and even though it is about 22 per cent water, it has an extremely strong yet lightweight and flexible structure. A similar frame made of high-technology composite materials could not match the skeleton’s weight, strength, and durability. It’s as strong as steel but light as aluminum. It can repair itself if damaged and can remodel its bones to thicken and strengthen them in areas of extra stress, when persons do extreme sports. How musculoskeletal system works? ➢ Nerves sends a message to activate your skeletal muscles. ➢ Muscle fibers contract (tense up) in response to the message. ➢ Activated muscles pulls on the tendon. Tendons attach muscles to bones. ➢ The tendon pulls the bone, making it move. ➢ To relax the muscle, nervous system sends another message. It triggers the muscles to relax/deactivate. ➢ The relaxed muscle releases tension, moving the bone to a resting position •Cartilage: connective tissue, •cartilage cushions bones inside your joints, along your spine and in your ribcage. • Firm, rubbery cartilage protects bones from rubbing against each other. •nose, ears, pelvis and lungs. •Joints: Bones come together to form joints. Some joints have a large range of motion, such as the ball-and-socket shoulder joint. Other joints, like the knee, allow bones to move back and forth but not rotate. •Ligaments: Made of tough collagen fibers, ligaments connect bones and help stabilize joints. https://my.clevelandclinic.org/health/articles/12254-musculoskeletal-system-normal-structure--function#:~:text=Your%20musculoskeletal%20system%20includes%20bones,problems%20with%20movement%20and%20function. What is cartilage? • Strong, flexible connective tissue that protects your joints and bones. • Acts as a shock absorber throughout your body. Absorbing shock Reducing friction Supporting structures in your body HC- It lines your joints and caps the ends of your bones slippery and smooth Present at the ends of bones that form joints, Between your ribs, nasal passages. FC- least flexible, tough cartilage made of thick fibers Present in meniscus in your knee, in disks between the vertebrae. EC-flexible cartilage, supports parts of your body that need to bend and move to function chondrocytes Joints consist of the following: •Cartilage. •Synovial membrane. The synovial membrane secretes a clear, sticky fluid (synovial fluid) around the joint to lubricate it. •Ligaments. Strong ligaments (tough, elastic bands of connective tissue) surround the joint to give support and limit the joint's movement. Ligaments connect bones together. •Tendons. Tendons (another type of tough connective tissue) on each side of a joint attach to muscles that control movement of the joint. Tendons connect muscles to bones. •Bursas. Fluid-filled sacs, called bursas, between bones, ligaments, or other nearby structures. They help cushion the friction in a joint. •Synovial fluid. A clear, sticky fluid secreted by the synovial membrane. •Meniscus. This is a curved part of cartilage in the knees and other joints. Ligament more than 900 ligaments that help connect bones, joints and organs Ligaments are like cords made of connective tissue, elastic fibers that are somewhat stretchy, and collagen, a protein that binds tissues in animals. •Bones: •all shapes and sizes •support your body, protect organs & tissues •store calcium and fat and produce blood cells. •They work with muscles, tendons, ligaments and other connective tissues to help you move. •Axial skeleton (80 bones ), vertebral column bones of the head thoracic cage •Appendicular skeleton (126 bones) shoulder and pelvic girdle, the upper and lower extremities 8 Total- 22 14 There are two types of bone tissue: compact & spongy https://open.oregonstate.education/aandp/chapter/6-3-bone- • osteoblasts - are bone cells with a single nucleus that make and mineralize bone matrix. They make a protein mixture that is composed primarily of collagen and creates the organic part of the matrix. They also release calcium and phosphate ions that form mineral crystals within the matrix. In addition, they produce hormones that play a role in the mineralization of the matrix. • osteocytes - are mainly inactive bone cells that form from osteoblasts that have become entrapped within their own bone matrix. Osteocytes help regulate the formation and breakdown of bone tissue. They have multiple cell projections that are thought to be involved in communication with other bone cells. • osteoclasts - are bone cells with multiple nuclei that resorb bone tissue and break down bone. They dissolve the minerals in bone and release them into the blood. • osteogenic cells - are undifferentiated stem cells. They are the only bone cells that can divide. https://humanbiology.pressbooks.tru.ca/chapter/13-4-structure-of-bone/ MUSCULAR SYSTEM The muscular system allows the body to move voluntarily, and involuntary (circulatory system and digestive system). Muscle contraction relies on energy delivery to the muscle. Muscle, like the liver, can store the energy from glucose as glycogen. But unlike the liver, muscles use up all of their own stored energy and do not export it to other organs in the body. Muscle is not as susceptible to low levels of blood glucose as the brain because it will readily use alternate fuels such as fatty acids and protein to produce cellular energy. Function Muscles make up the bulk of the body and account for > 1/3 of its weight.!! 1.Producing movement a. Bones of the Skeletal system b. Food through Digestive system c. Blood through the Circulatory system d. Fluids through the Excretory system 2.Maintaining posture 3.Stabilizing joints 4.Generating heat. 3/4th 5.Protect inner organs Types of Body Movements •Origin - attached to the immovable or less movable bone. •Insertion - attached to the movable bone, when the muscle contracts, the insertion moves toward the origin. •Flexion. decrease the angle of the joint and brings two bones closer together •Extension. Extension is the opposite of flexion. •Rotation. Rotation is movement of a bone around a longitudinal axis •Abduction. Abduction is moving the limb away from the midline •Adduction. Adduction is the opposite of abduction •Circumduction. Circumduction is a combination of flexion, extension, abduction, and adduction commonly seen in ball-and-socket joints •Elevation/ Depression 600 Skeletal Muscle Skeletal muscle tissue is composed of long cells called muscle fibres that have a striated appearance. Sarcolemma (Cell membrane ) 10-100 muscle fibers Transverse tubules (Action potential ) Sarcoplasmic reticulum (ER) Myofibril (organ) – Myo-filaments https://nurseslabs.com/muscular-system-anatomy-physiology/ Skeletal muscle cells are multinucleate. •Sarcolemma. Many oval nuclei can be seen just beneath the plasma membrane, which is called the sarcolemma in muscle cells. •Myofibrils. The nuclei are pushed aside by long ribbonlike organelles, the myofibrils, which nearly fill the cytoplasm. •Light and dark bands. Alternating dark and light bands along the length of the perfectly aligned myofibrils give the muscle cell as a whole its striped appearance. •Sarcomeres. The myofibrils are actually chains of tiny contractile units called sarcomeres, which are aligned end to end like boxcars in a train along the length of the myofibrils. •Myofilaments. There are two types of threadlike protein myofilaments within each of our “boxcar” sarcomeres. •Circular. The pattern is circular when the fascicles are arranged in concentric rings. •Convergent. the fascicles converge toward a single insertion tendon; such a muscle is triangular or fanshaped. •Parallel. In a parallel arrangement, the length of the fascicles run parallel to the long axis of the muscle. •Pennate. In a pennate pattern, short fascicles attach obliquely to a central tendon •unipennate; •bipennate •multipennate. – moves food through digestive organs – empties liquid from the bladder – controls width of the blood vessels Heart walls heart walls have three layers: •Endocardium: Inner layer •thin •it serves as a barrier between cardiac muscles and the bloodstream •makes up the lining of the chambers and valves of the heart •Myocardium: Muscular middle layer. •Scaffolding for heart chambers •Contraction and relaxation •Conducting electro-stimuli •thickest layer in the heart wall •Epicardium: Protective outer layer. •providing signals for proper heart formation and maturation within the embryo
