Science 6

• Musculoskeletal System is composed of the skeletal and muscular systems
• The skeletal system is the framework of the human body
• A human adult has 206 bones in their body
• A newborn has more bones than adults
• The bones of a newborn's skull are separated and have small spaces in between
• As the baby grows, the spaces in the skull fuse together and form one skull bone
• A cartilage is a firm and flexible tissue that is softer than bones
• Only a small percentage of cartilage remains in bones, and they are normally found between two bones. Some bones remain as cartilage, such as the nose bridge and ear.
• The Axial Skeleton is represented by the bones and cartilages of the head, neck, and trunk.
• The Appendicular Skeleton is represented by the bones of the upper limbs (arms, forearms, and hands) and lower limbs (thighs, legs, and feet)
• The Axial Skeleton and the Appendicular Skeleton are connected to the upper limbs (collar bones and shoulder blade) and to the lower limbs (hip bones)
• Ligament connects two bones
• A Tendon connects the bones and muscles
• Joint is a point where two bones meet and are connected together by a ligament
• Synovial joint allows movement between bones
• Fibrous joint has no movable parts
• Cartilaginous joint has some limited movement
• The skull has immovable joints, which are the sutures.
• Slightly movable joints may be found in the back bone or vertebral joint
• A synovial joint is freely moveable joint that can rotate, bend, stretch, twist, slide, hinge, glide or pivot
• Hinge joint allow flexion/extension and are found in the knee and elbow joints
• Pivot joint allows one bone to rotate around another, it can be found in the top of the neck
• Saddle Joint allows flexion, extension, abduction and adduction. An example is the thumb joint
• Ball-and-Socket Joints allow flexion, extension, abduction, adduction, and rotation. It can be found in the shoulder and hip
• Condyloid joints are found in the wrist and fingers. They also allow flexion, extension, adduction and abduction
• Gliding joints enable bones to glide and are found in bones of the feet
• Contraction happens when the muscle fiber becomes shorter and thicker
• Relaxation happens when the muscle fiber returns to its original form
• Skeletal Muscles is a muscle attached to the bones. It moves through conscious effort.
• Cardiac muscles are involuntary muscles that make up the heart walls. The cardiac muscle contracts rhythmically without any control from the brain or nervous system.
• Smooth muscles are involuntary muscles that line hollow organs such as stomach, intestines, uterus, bladder, etc. These muscles contract slowly and rhythmically.
• The immovable end of the skeletal muscle is called origin