a) Lamellae : concentric rings of ECM that consist of mineral salts, which give bone the hardness, and collagen fibres which give bone its strength. b) Lacunae : are small spaces between lamellae that contain mature bone cells cal led Osteocytes. c) Canaliculi : project from the lacunae providing routes for nutrients to reach the osteocytes and for waste removal.
d) Central Canal (Haversian Canal): contains blood vessels and nerves.
ii. Spongy bone
This type of bone lacks Osteons. It consists of columns of bone called trabeculae which contain lamellae, osteocytes, lacunae, and canaliculi. The spaces between trabeculae are filled with red bone marrow.
E. Liquid:
i. Blood : a CT with a liquid ECM called Blood Plasma, a yellow fluid made mostly of water and dissolved substances (nutrients, wastes, enzymes, proteins, hormones, etc.). RBCs (erythrocytes), WBCs (leukocytes), and platelets (thrombocytes). RBCs transport O2 to body cells and remove CO2. WBCs are involved in phagocytosis, immunity, and allergic reactions. Platelets are part of the clotting process.
ii. Lymph
Extracellular fluid that flows in lymphatic vessels. It is CT and consists of several types of cells in a clear liquid ECM similar to blood plasma but with much less protein.
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