muscular system

• Cardiac muscles are striated muscles found in the walls of the heart and are responsible for pumping blood.
• The contraction process involves sliding filaments, which shorten the muscle fiber and generate force.
• Muscles contract when stimulated by nerve impulses from motor neurons.
• Skeletal muscles are attached to bones by tendons, allowing movement at joints.
• Muscle fibers have long cylindrical cells with many nuclei at their ends.
• Muscle fibers are long, thin, syncytial cells.
• Skeletal muscles are attached to bones by tendons.
• Muscles provide movement at joints and play an important role in body language and communication.
• The skeletal muscle is the most abundant tissue in the body, accounting for about half of its weight.
• Muscle tissue is striated and can contract very rapidly.
• The pectoralis major is a skeletal muscle responsible for flexion, adduction, and medial rotation of the arm.
• Smooth muscle is found in hollow organs such as blood vessels, digestive tract, uterus, bladder, and iris of eye.
• There are two types of bone tissue: compact (cortical) bone and spongy ( cancellous ) bone.
• Each fiber has multiple nuclei located near the cell membrane.
• Osteocytes are mature cells that make up the majority of bone tissue.
• Bone marrow is the soft tissue inside bones where red blood cells are produced.
• Compact bone consists of osteons arranged parallel to one another with concentric lamellae surrounding central canal containing blood vessels and nerves.
• Bone marrow is located inside bones and produces red blood cells, white blood cells, and platelets.
• Skeletal muscle is composed of long cylindrical cells with multiple nuclei and myofibrils containing actin and myosin filaments.
• Compact bone has a dense structure with osteons arranged parallel to long axis of bone.
• Skeletal muscle is voluntary and under conscious control, while smooth and cardiac muscle are involuntary and not under conscious control.
• Cardiac muscle is found only in heart walls and has unique properties that allow it to function continuously without fatigue or rest.
• The deltoid is a triangular-shaped skeletal muscle located on top of the shoulder.
• Compact bone is dense and hard, while spongy bone contains spaces filled with fatty tissue or yellow marrow.
• Bone marrow contains red bone marrow which produces RBC's and WBC's
• Red bone marrow produces red blood cells, white blood cells, and platelets.
• Spongy bone is less dense than compact bone and consists of trabeculae or plates of bone arranged like a honeycomb.
• Yellow bone marrow stores lipids and fats.
• There are two types of bone tissue: compact (dense) bone and spongy (cancellous) bone.
• The structure of a given joint is directly correlated to its degree of movement
• Major functions of the skeletal system

  • Support: Rigid, strong bone is well suited for bearing weight and is the major supporting tissue of the body. Cartilage provides firm yet flexible support within certain structures, such as the nose, external ear, thoracic cage, and trachea. Ligaments are strong bands of fibrous connective tissue that attach to bones and hold them together.
  • Protection: Bone is hard and protects the organs it surrounds. For example, the skull encloses and protects the brain, and the vertebrae surround the spinal cord. The rib cage protects the heart, lungs, and other organs of the thorax.
• Sitting, standing, walking, picking up a pencil, and taking a breath all involve the skeletal system
• Without the skeletal system, there would be no rigid framework to support the soft tissues of the body and no system of joints and levers to allow the body to move
• The term skeleton is derived from a Greek word meaning dried. The skeletal system consists of dynamic, living tissues that are able to grow, detect pain stimuli, adapt to stress, and undergo repair after injury
• A joint, or an articulation, is a place where two bones come together. Many joints are movable, although some of them allow only limited movement; others allow no apparent movement
• Skeletal muscles attach to bones by tendons. Contraction of the skeletal muscles moves the bones, producing body movements. Joints allow movement between bones. Smooth cartilage covers the ends of bones within some joints, allowing the bones to move freely. Ligaments allow some movement between bones but prevent excessive movement
• Some minerals in the blood, principally calcium and phosphorus, are stored in bone. Adipose tissue is also stored within bone cavities. Red bone marrow in many bones produces blood cells and platelets
• Minerals released from bone into the blood


  Minerals are released from bone into the blood
• Lipids stored in bone cavities

  If needed, lipids are released into the blood and used by other tissues as a source of energy
• Blood cell production


  Many bones contain cavities filled with red bone marrow, which produces blood cells and platelets