Kortikaalkihte

Kortikaalkihte is a Finnish term that translates to "cortical bone" in English. This refers to the dense, hard outer layer of bone found in the skeleton of vertebrates. Cortical bone, also known as compact bone, forms the smooth, white external surface of most bones. It is characterized by its high mineral density, which provides strength and rigidity to the skeletal structure. This dense structure is crucial for supporting body weight, protecting internal organs, and facilitating movement.

Histologically, cortical bone is composed of repeating structural units called osteons, or Haversian systems. Each osteon consists of concentric layers of bone matrix (lamellae) surrounding a central Haversian canal, which contains blood vessels and nerves. These canals are interconnected by Volkmann's canals, allowing for nutrient and waste exchange throughout the bone. The mineral component of cortical bone is primarily hydroxyapatite, a calcium phosphate crystal, which gives bone its hardness, while collagen fibers provide tensile strength.

Cortical bone plays a significant role in bone metabolism, although it is less metabolically active than trabecular bone. It serves as a reservoir for calcium and phosphate, which can be released into the bloodstream when needed. The thickness and density of cortical bone can be influenced by factors such as age, mechanical stress, and hormonal status. For example, weight-bearing exercise can increase cortical bone density, while conditions like osteoporosis can lead to a significant loss of cortical bone mass, increasing fracture risk.