Physiology of Bone PDF
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Alexandria University
Nahed Elsokkary
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Summary
This document provides an overview of bone physiology, covering topics such as bone structure, formation processes, growth, and hormonal regulation. It details the functions of bone, emphasizing its role in supporting vital organs and its metabolic activities. The presentation also touches on bone remodeling and regulation.
Full Transcript
PHYSIOLOGY OF BONE By Ass. Prof. Nahed Elsokkary Assist. Prof. of Medical Physiology Faculty of Medicine Alexandria University PHYSIOLOGICAL FUNCTIONS OF BONE It protects and supports vital organs, Blood elements forma...
PHYSIOLOGY OF BONE By Ass. Prof. Nahed Elsokkary Assist. Prof. of Medical Physiology Faculty of Medicine Alexandria University PHYSIOLOGICAL FUNCTIONS OF BONE It protects and supports vital organs, Blood elements formation The metabolic functions of bone: Reservoir & Homeostasis of : Mineral (Ca++ & P04- - -) Growth Factor and Cytokine Fat reservoir. Endocrine Function: Bone controls metabolism of phosphate by osteocalcin. BONE STRUCTURE BONE FORMATION PROCESSES (OSSIFICATION OR OSTEOGENESIS) BY OSTEOBLASTS: (A) SYNTHESIS OF ORGANIC MATRIX (B) MATRIX MINERALIZATION (C) RESORPTION AND REFORMATION BONE GROWTH BONE GROWTH HORMONAL REGULATION OF BONE GROWTH Growth Hormone Thyroid Hormone ↑Bone length: proliferation Important for of cartilage in epiphyseal normal skeletal then calcium deposition growth ↑Bone thickness Estrogen & Testosterone ↑osteoblastic activity ↓ osteoclastic activity Stimulate the closure of epiphyseal plate (Growth plate) BONE REMODELLING Coordinated bone resorption and bone formation take place Bone remodeling units: both osteoclasts and osteoblasts. Importance : 1. Removal of old bone to form new bone. 2. Reshaping or replacement of bone 3. Maintenance of bone strength and mineral homeostasis. BONE GROWTH VERSUS REMODELING BONE REMODELLING REGULATION Factors affecting: a. Genetic Factors b. Mechanical Factors c. Vascular / Nerve Factors d. Nutritional Factors e. Toxic habits f. Growth Factors & Cytokines g. Hormonal Factors HORMONAL BONE MODELLING REGULATION Parathormone ↑ca+2 in blood By ↑activity of Calcitonin osteoclast ↓Ca+2 in blood By ↓ activity of osteoclast Active Vit D ↑Ca+2, in blood By ↑Ca+2 absorption from intesine ↑ activity of osteoblast ↑bone mineralization (ca+2 deposition)
