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Name the parts of this bone:
What is Fibrodysplasia Ossificans Progessiva (FOP)?
–Disease that occurs
when lymphocytes produce BMP-4 protein
•This is a protein
that triggers bone formation
How does Bone
–1-physical action of
muscles pulling on bones stimulates osteoblasts-building bone
–2- release of calcitonin which inhibits osteoclast activity
Name the classification of bones and an example of each.
1. Long bones - femur
2. Short bones - carpals & tarsals
3. Irregular - vertebrae - sacrum
4. Flat - scapula
5. Sesmoid - patella
What are the 2 types of bone categories?
1. Compact bone - 80%
2. Spongy bone - short, flat, irregular bones - epiphysis of long bones
Describe Intramembranous Ossification
1. Sheets of messenchyme tissue - osteoblasts form and start making bone tissue, they group together to secrete bone matrix.
2. Ca+ is deposited into the matrix and calcification begins - forming spikes called trabiculae.
3. The trapped osteoblasts become osteocytes
4. Trabeculae fuse together to become spongy bone.
Flat bones, facial bones, sternum are made this way.
Describe Endochondral Ossification
1. Messenchyme cells gather in shape of future bone
2. Chondroblasts - move into the messenchyme & begin forming cartilage in the shape of the future bone
3. Starts in diaphysis - chondrocytes grow and burst changing the pH of matrix - which begins to harden - forming bone.
4. As cartilage disintegrates bone is formed solid so osteoclasts move in to hollow out the center
5. At the same time the outer edge of bone model - osteoblasts are forming bone
6. In the epiphysis - osteoblasts invade cartilage on the end and begin forming trabeculae which forms spongy bone.
Osteoperosis results from
too much osteoclast activity
What happens when there is too much Ca++ in the ECF?
Calcitonin (CTH) increases osteoblast activity and inhibits osteoclast activity - PTH is inhibited
Ca++ is deposited into skeletal system
What happens when there is not enough Ca++ in the ECF
Thyroid secretes Parathyroid Hormone (PTH) increasing osteoclasts - ultimately increasing Ca++ in ECF
Regulation of growth
• Growth Hormone Releasing Hormone (GHRH) to the:
• anterior pituitary-which releases:
• GH-growth hormone
•The level of growth hormone can result in disease.
• Pre-growth plate closure
• Post growth plate closure
Anatomy & Physiology Lecture