BIOLOGY

• The skeleton is made up of bones, cartilage, ligaments, tendons, and joints.
• The carpals form the proximal row of wrist bones.
• The human body has 206 bones.
• The skull is made up of 22 bones, including the mandible and the cranium.
• The metacarpals form the distal row of wrist bones.
• Bones are hard structures that protect organs, support the body, store minerals, produce blood cells, and allow movement.
• The radius and ulna are the forearm bones that articulate with the carpals.
• The scapula, or shoulder blade, is a flat triangular-shaped bone located on either side of the upper back.
• Cartilage is a flexible connective tissue found at the ends of long bones to cushion them during movement.
• The humerus is the largest bone in the arm and forms the upper part of the limb.
• Bones are classified based on their shape (long, short, flat, irregular), location (axial or appendicular), and structure (compact or spongy).
• Compact bone has a dense outer layer called cortical bone and an inner layer called cancellous bone.
• Ligaments attach one bone to another and stabilize joints.
• The phalanges are the bones of the fingers and toes.
• The humerus is the long bone of the arm that connects to the glenoid cavity of the scapula at the shoulder joint.
• Compact bone forms the outer layer of most bones and provides strength and protection.
• The humerus is the largest bone in the arm and forms the upper arm.
• The clavicle, also known as the collarbone, is a thin, curved bone that extends from the sternum (breastbone) to the acromion process of the scapula.
• Synovial joints have two main types: hinge joints (e.g., elbow) and ball-and-socket joints (e.g., hip).
• The pelvic girdle consists of two hipbones joined by ligaments and fused together at the sacrum.
• The femur is the longest bone in the human body and makes up most of the thigh.
• Joints are points where two or more bones meet and allow movement.
• Red marrow produces blood cells, while yellow marrow stores fatty acids.
• Synovial fluid lubricates joints and reduces friction during movement.
• Osteoblasts produce new bone matrix by secreting collagen fibers and mineral salts into the extracellular space.
• The metacarpals are the five bones between the wrist and the digits of the hand.
• The patella is the kneecap located anteriorly over the knee joint.
• Spongy bone is found inside compact bone and contains red marrow where blood cells are produced.
• Cartilage is a flexible tissue that covers the ends of bones in synovial joints and helps absorb shock during movement.
• Long bones include the femur, tibia, fibula, radius, ulna, metacarpals, metatarsals, phalanges, and vertebrae.
• Flat bones include the skull, ribs, sternum, pelvis, and scapula.
• The fibula is the smaller of the two leg bones and runs horizontally along the outside edge of the lower leg.
• The tibia is the larger of the two leg bones and runs vertically down the center of the lower leg.
• Irregular bones do not fit into any other category and include the vertebral bodies, sacrum, coccyx, hyoid bone, and facial bones.
• Short bones have roughly equal length and width and are cube-shaped, such as those in the wrists and ankles.
• Bones have three main functions: support, protection, and storage.
• Irregular bones have complex shapes and include the vertebral bodies, sacrum, coccyx, and facial bones.
• Flat bones are thin and flat, providing protection to underlying organs or forming parts of the skull.
• Bones can be classified based on their shape (long, short, flat) and location (axial/appendicular).
• Axial skeleton includes the skull, mandible, hyoid bone, vertebral column, and thoracic cage.