Cortical and cancellous are two types of bone tissue; the osteoblast, osteoclast, and osteocyte bone cells are responsible for growing, shaping, and maintenance of bones; the osteocytes from the calcium/protein matrix of bones.
Overall, the bones of the body are an organ made up of bone tissue, bone marrow, blood vessels, epithelium, and nerves. The strength of bone comes from the bone matrix, which has both organic and inorganic components. The inorganic component of bone is a salt that is similar to hydroxyapatite (Ca10[PO4]6[OH]2). The organic components include collagen, glycoproteins, and other peptides.
There are two types of bone tissue include cortical and cancellous bone. Both are biologically identical but differ in the arrangement of their microstructure. Cortical bone is a compact bone that forms the extremely hard exterior. Cancellous bone is a trabecular and spongy bone that fills the interior.
The inorganic calcium/protein matrix of bones is formed by the living cells of bone tissue, osteocytes. Osteocytes are involved in the reabsorption of bone tissue. The mineralized matrix of bone tissue has an organic component mainly made of collagen, and an inorganic component of bone mineral made up of various salts. Other bone cells which are osteoblasts help in the creation and mineralization of bone tissue.
Deficiencies in diet, especially the amount of calcium intake can lead to lifelong diseases such as osteoporosis and low bone density. The lack of calcium in a person’s diet leads to a weaker matrix being produced. Osteoporosis can also be caused by other risk factors such as gender, the menopause and vitamin D deficiency.
Practice Questions
Khan Academy
https://jackwestin.com/khan-academy-mcat/disorders-of-the-skeletal-system-and-bone-remodeling
MCAT Official Prep (AAMC)
Online Flashcards Biology Question 24
Biology Question Pack, Vol. 2 Passage 13 Question 86
Biology Question Pack, Vol. 2 Passage 13 Question 90
Practice Exam 3 B/B Section Passage 10 Question 56
Key Points
• The bones of the body are an organ made up of bone tissue, bone marrow, blood vessels, epithelium, and nerves.
• The strength of bone comes from the bone matrix, which has both organic (collagen, glycoproteins, and other peptides) and inorganic components.
• The calcium/protein matrix of bones are formed by the living cells of bone tissue, osteocytes.
• Two types of bone tissue include cortical and cancellous bone; cortical bone is a compact bone that forms the extremely hard exterior while cancellous bone is a trabecular and spongy bone that fills the interior.
• Three types of bone cells include osteoblasts, osteocytes, and osteoclasts; osteoblasts create and mineralize bone; osteocytes and osteoclasts reabsorb bone tissue.
• Deficiencies in calcium can lead to osteoporosis.
Key Terms
osteoblast: a mononuclear cell from which bone develops
osteocytes: a star-shaped type of bone cell that is found in the cells of mature bone
bone matrix: the organic and inorganic matrix that makes up bone
bone marrow: the spongy tissue inside bones which contains stem cells
collagen: the main structural protein in various connective tissues
glycoprotein: a class of proteins that have carbohydrate groups attached to the polypeptide chain
cortical bone: a compact bone that forms the extremely hard exterior.
cancellous bone: a spongy bone that fills the interior
