These terms are all related to the skeletal system and bone biology. Here’s a breakdown of what each one is, where it’s found (if applicable), and what it does:

• Metaphysis: The flared ends of long bones where growth occurs in children. (Location: Ends of long bones like femur, tibia, etc.)
• Haversian canal: Microscopic canals within compact bone that house blood vessels and nerves. (Location: Throughout compact bone)
• Volkmann’s canals: Canals that connect Haversian canals to the periosteum (bone membrane) and allow blood vessels and nerves to enter bone. (Location: Throughout compact bone)
• Red bone marrow: Soft tissue found in the center of most bones, responsible for producing red blood cells, white blood cells, and platelets. (Location: Primarily in spongy bone)
• Yellow bone marrow: Fatty tissue found in the center of some bones, used for energy storage. (Location: Can replace red bone marrow in some bones with age)
• Hydroxyapatite: The main mineral component of bone, giving it hardness and strength. (Location: Throughout bone)
• Epiphyseal plate: A cartilage plate at the ends of long bones in children where bone growth occurs. (Location: Ends of long bones until adulthood)
• Epiphysis: The rounded ends of long bones. (Location: Ends of long bones)
• Diaphysis: The shaft of a long bone. (Location: Main portion of a long bone)
• Interstitial growth: Cartilage growth within the epiphyseal plate, pushing the ends of bones further apart during childhood.
• Appositional Growth: Bone formation on the outer surface of the diaphysis and inner surfaces of the epiphyses, making bones thicker.
• Endochondral ossification: The process by which bone replaces cartilage, such as in the epiphyseal plate.
• Intramembranous ossification: The process by which bone forms directly from membranes, such as in the flat bones of the skull.
• Osteon: The basic unit of mature bone, containing a Haversian canal surrounded by concentric rings of lamellae (bone layers).
• Canaliculi: Tiny canals radiating from Haversian canals, allowing nutrients and waste to reach osteocytes (bone cells) trapped within bone.
• Nutrient foramen: An opening in the diaphysis that allows blood vessels and nerves to enter the bone. (Location: Shaft of long bone)
• Osteocytes, blasts, clasts: Bone cells: osteocytes are mature bone cells that maintain bone tissue; osteoblasts are cells that build new bone; osteoclasts are cells that break down bone tissue.
• PTH (Parathyroid hormone): A hormone that regulates blood calcium levels by stimulating the release of calcium from bones and increasing calcium absorption from the intestines.
• Calcitonin: A hormone that lowers blood calcium levels by inhibiting the release of calcium from bones and decreasing calcium absorption from the intestines.
• Vitamin D is synthesized by: Skin exposure to sunlight.