PLN 103 Lecture Notes - Calcitriol, Bone Density, Jaundice

• School: Ryerson University
• Department: Physiology
• Course: PLN 103
• Professor: Nick Bellissimo

Document Summary

Osteocytes (bone cells) within lacunae organized around blood vessels. Forms pathways for blood vessels (blood supply for bones) Consists of outer fibrous and inner cellular layers. Two thirds of bone matrix is calcium phosphate, ca3(po4) One third of bone matrix is protein fibers, collagen. Bone cells make up 2% of bone mass. Osteocytes 3 main things: matrix (less fluid then in other tissue types), canniculae extend from one osteo site to the next, helps with communication. Osteocytes, mature bone cells that maintain bone matrix. Found in been layers (lamellae) of matrix. Connect by cytoplasmic extensions through canaliculi in amllae. Two major functions: to maintain protein and mineral content of matrix, help repair damaged bone. Osteoblast are the immature bone cells that secrete matrix compounds. Osteoid is the matrix produced by osteoblasts but not yet calcified to form bone. Messenchymal (loose connective tissue) stem cells that divide to produce osteoblasts. Located in the endosteum, the inner layer of periosteum (membrane)