Absence of Typical Haversian System from the Compact Bone of Some Reptile and Bird Species
📝 Abstract
Background and Objective: Mammalian compact bone is composed mostly of Haversian system. Although there are many studies describing the typical Haversian system in mammals, there are few studies conducted on bones from non-mammalian species. The objective of the current study was to investigate the existence of the typical Haversian system in compact bones from reptiles and birds. Materials and Methods: Femora were collected from geckos, Nile monitors, sparrows, ducks and geese. Samples were then, fixed in 10% paraformaldehyde and embedded in paraffin. Paraffin sections were stained with hematoxylin and eosin or Von Kossa and then examined using light microscopy. Results: The current study showed different histological structures of compact bones from studied species and an absence of the typical Haversian system seen in mammals. The compact bone of geckos was mostly avascular, while Nile monitor bone was highly vascular. Sparrow bone showed one side vascular and the other side avascular. The vascularity was represented by primary vascular canals surrounded by a few irregularly arranged osteocytes inside their lacunae forming primary osteons. Bone tissue from ducks and geese were similar and were composed mostly of dense Haversian tissue, while some areas had primary osteons. Conclusion: The compact bone microstructure in some reptile and bird species lack the typical Haversian system described in mammals. This will be of a great importance in developing a better understanding of long bone anatomy and physiology in different species.
💡 Analysis
Background and Objective: Mammalian compact bone is composed mostly of Haversian system. Although there are many studies describing the typical Haversian system in mammals, there are few studies conducted on bones from non-mammalian species. The objective of the current study was to investigate the existence of the typical Haversian system in compact bones from reptiles and birds. Materials and Methods: Femora were collected from geckos, Nile monitors, sparrows, ducks and geese. Samples were then, fixed in 10% paraformaldehyde and embedded in paraffin. Paraffin sections were stained with hematoxylin and eosin or Von Kossa and then examined using light microscopy. Results: The current study showed different histological structures of compact bones from studied species and an absence of the typical Haversian system seen in mammals. The compact bone of geckos was mostly avascular, while Nile monitor bone was highly vascular. Sparrow bone showed one side vascular and the other side avascular. The vascularity was represented by primary vascular canals surrounded by a few irregularly arranged osteocytes inside their lacunae forming primary osteons. Bone tissue from ducks and geese were similar and were composed mostly of dense Haversian tissue, while some areas had primary osteons. Conclusion: The compact bone microstructure in some reptile and bird species lack the typical Haversian system described in mammals. This will be of a great importance in developing a better understanding of long bone anatomy and physiology in different species.
📄 Content
OPEN ACCESS Asian Journal of Biological Sciences ISSN 1996-3351 DOI: 10.3923/ajbs.2017. Research Article Absence of Typical Haversian System from the Compact Bone of Some Reptile and Bird Species 1Yasser Ahmed, 2Mohamed Abdelsabourv Khalaf and 1Fatma Khalil 1Department of Histology, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt 2Department of Anatomy and Embryology, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt Abstract Background and Objective: Mammalian compact bone is composed mostly of Haversian system. Although there are many studies describing the typical Haversian system in mammals, there are few studies conducted on bones from non-mammalian species. The objective of the current study was to investigate the existence of the typical Haversian system in compact bones from reptiles and birds. Materials and Methods: Femora were collected from geckos, Nile monitors, sparrows, ducks and geese. Samples were then, fixed in 10% paraformaldehyde and embedded in paraffin. Paraffin sections were stained with hematoxylin and eosin or Von Kossa and then examined using light microscopy. Results: The current study showed different histological structures of compact bones from studied species and an absence of the typical Haversian system seen in mammals. The compact bone of geckos was mostly avascular, while Nile monitor bone was highly vascular. Sparrow bone showed one side vascular and the other side avascular. The vascularity was represented by primary vascular canals surrounded by a few irregularly arranged osteocytes inside their lacunae forming primary osteons. Bone tissue from ducks and geese were similar and were composed mostly of dense Haversian tissue, while some areas had primary osteons. Conclusion: The compact bone microstructure in some reptile and bird species lack the typical Haversian system described in mammals. This will be of a great importance in developing a better understanding of long bone anatomy and physiology in different species. Key words: Haversian system, compact bone, geckos, Nile monitors, sparrows, ducks, geese, histology Received: Accepted: Published: Citation: Yasser Ahmed, Mohamed Abdelsabourv Khalaf and Fatma Khalil, 2017. Absence of typical Haversian system from the compact bone of some reptile and bird species. Asian J. Biol. Sci., CC: CC-CC. Corresponding Author: Yasser Ahmed, Department of Histology, Faculty of Veterinary Medicine, South Valley University, Qena, Egypt Tel: +20965211223/+201098782129 Fax: +20965211223 Copyright: © 2017 Yasser Ahmed et al. This is an open access article distributed under the terms of the creative commons attribution License, which permitsunrestricted use, distribution and reproduction in any medium, provided the original author and source are credited. Competing Interest: The authors have declared that no competing interest exists. Data Availability: All relevant data are within the paper and its supporting information files. Asian J. Biol. Sci., 2017 INTRODUCTION The shaft of compact bone in mammals is composed of similar units known as Haversian System (HS). An early study showed that although long bones may be used for the same purposes, their Haversian system structure and arrangement are different from species to species, from bone to bone and even from side to side of the same bone1. The typical mammalian HS is composed of vascular canals (Haversian canals) containing blood vessels and nerves and surrounded by different types of bone lamellae. Concentric lamellae are found around the Haversian canals, periosteal lamellae are close to periosteum, endosteal lamellae are close to the endosteum and circumferential lamellae between them2. The Haversian canals with surrounding lamellae are commonly called Secondary Osteons (SO), which form onan earlier formed and smaller Primary Osteons (PO). The PO has no or a few lamellae smoothly merge with the surrounding bone tissue3. While bone lamellae of the SO are separated from surrounding bone tissue by a darkly stained cement line of bone matrix4,5. According to its placement, the HS is subclassified into irregular, endosteal and dense types3. The irregular type consists of a few SO irregularly distributed through the bone tissue. The endosteal type has SO only close to the endosteal surface, while the dense type holds numerous SO distributed in all parts of the bone3. The compact bone histological structure was recently used to differentiate between bone fragments from different animal species5-8 and from human and non-human sources9. Although there are large numbers of histological studies of compact bone of mammals2-13, there is very little literature on bone from reptiles and birds14. The current study aimed to investigate the existence of the typical HS in the compact bone of the femur from 2 non-mammalian gropus; reptiles (geckos and Nile monitors) and birds (sparrows, ducks and geese). MATERIALS AND METHODS The current study started
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