Suchergebnisse
Suchergebnisse:
30. Okt. 2023 · Learn about the different types of bones in the human skeletal system, their structure, functions and clinical relations. Kenhub provides articles, videos, quizzes and interactive quizzes to help you master anatomy.
- Development of the Skull
Embryological background. Lateral plate mesoderm found in...
- Development of the Skull
14. Juni 2024 · Learn about the structure and function of the human skeleton, the internal framework of bones and cartilages that supports, protects, and enables motion. Explore the axial, appendicular, and visceral subdivisions of the skeleton and their relation to the soft parts of the body.
- Overview
- Evolutionary origin and significance
- GeneratedCaptionsTabForHeroSec
The two principal components of bone are collagen and calcium phosphate, which distinguish it from other hard tissues such as chitin, enamel, and shell.
What are the major functions of bone tissue?
Bone tissue makes up the individual bones of the skeletons of vertebrates. The other roles of bone include structural support for the mechanical action of soft tissues, protection of soft organs and tissues, provision of a protective site for specialized tissues such as the blood-forming system (bone marrow), and a mineral reservoir.
Do bones contain calcium?
Bone contains 99 percent of the calcium in the body and can behave as an adequate buffer for maintaining a constant level of freely moving calcium in soft tissues, extracellular fluid, and blood.
Why is calcium important for bone health?
Bone is found only in vertebrates, and, among modern vertebrates, it is found only in bony fish and higher classes. Although ancestors of the cyclostomes and elasmobranchs had armoured headcases, which served largely a protective function and appear to have been true bone, modern cyclostomes have only an endoskeleton, or inner skeleton, of noncalcified cartilage and elasmobranchs a skeleton of calcified cartilage. Although a rigid endoskeleton performs obvious body supportive functions for land-living vertebrates, it is doubtful that bone offered any such mechanical advantage to the teleost (bony fish) in which it first appeared, for in a supporting aquatic environment great structural rigidity is not essential for maintaining body configuration. The sharks and rays are superb examples of mechanical engineering efficiency, and their perseverance from the Devonian Period attests to the suitability of their nonbony endoskeleton.
In modern vertebrates, true bone is found only in animals capable of controlling the osmotic and ionic composition of their internal fluid environment. Marine invertebrates exhibit interstitial fluid compositions essentially the same as that of the surrounding seawater. Early signs of regulability are seen in cyclostomes and elasmobranchs, but only at or above the level of true bone fishes does the composition of the internal body fluids become constant. The mechanisms involved in this regulation are numerous and complex and include both the kidney and the gills. Fresh and marine waters provide abundant calcium but only traces of phosphate; because relatively high levels of phosphate are characteristic of the body fluids of higher vertebrates, it seems likely that a large, readily available internal phosphate reservoir would confer significant independence of external environment on bony vertebrates. With the emergence of terrestrial forms, the availability of calcium regulation became equally significant. Along with the kidney and the various component glands of the endocrine system, bone has contributed to development of internal fluid homeostasis—the maintenance of a constant chemical composition. This was a necessary step for the emergence of terrestrial vertebrates. Furthermore, out of the buoyancy of water, structural rigidity of bone afforded mechanical advantages that are the most obvious features of the modern vertebrate skeleton.
Britannica Quiz
Human Bones Quiz
Learn about the structure, composition, and functions of bone, the rigid tissue that supports and protects the body. Explore the evolutionary origin and significance of bone in vertebrates and its role in internal fluid homeostasis.
e-Anatomy bietet einen hochwertigen Atlas der Anatomie und Bildgebung. Es ist das umfassendste Nachschlagewerk der Humananatomie, das im Internet, auf iOS- und Android-Geräten verfügbar ist. Detaillierte Ansichten aller anatomischen Regionen und in verschiedenen Modalitäten (CT, MRT, Röntgen), anatomische Diagramme und nuklearmedizinische ...
Vor 4 Tagen · Learn about the bones, joints, and skeletal anatomy of the human body with our interactive 3D models. Explore the skull, spine, ribs, pelvis, limbs, and more with detailed labels and cross-sections.
Zygote Scenes is a collection of scenes created by Zygote Media Group with annotations identifying anatomical landmarks. Hierarchy is a list of all the entities you have in your current scene. You can turn parts on and off using the check marks by each object or group of objects.
Learn about the bones, ligaments, cartilage, and functions of the skeleton. Find out how the skeleton is classified, protected, and produces blood cells.
