Dermal bone: Difference between revisions

General Information
Latin	os dermale
Greek
TA98
TA2
FMA
Details
System	Skeletal system
Artery
Vein
Nerve
Lymphatic drainage
Precursor	Mesenchyme
Function
Identifiers
Clinical significance
Notes

Latest revision as of 17:39, 11 December 2024

Type of bone that forms in the skin

Dermal bone is a type of bone that forms directly within the dermis of the skin, without a cartilaginous precursor. This type of bone is distinct from endochondral bone, which forms from a cartilage template. Dermal bones are primarily found in the exoskeletons of vertebrates, such as the bony plates of turtles, the scales of fish, and the osteoderms of some reptiles.

Formation[edit]

Dermal bone formation is a process known as intramembranous ossification. During this process, mesenchymal stem cells within the dermis differentiate directly into osteoblasts, which are bone-forming cells. These osteoblasts secrete osteoid, an unmineralized bone matrix, which then becomes mineralized to form mature bone.

Functions[edit]

Dermal bones serve various functions depending on their location and the species in which they are found. Common functions include:

Protection: Dermal bones often form protective armor, such as the bony plates in the shells of turtles or the scales of certain fish.
Support: In some species, dermal bones provide structural support, as seen in the skulls of vertebrates where they contribute to the cranial structure.
Mineral storage: Like other bones, dermal bones can serve as reservoirs for minerals such as calcium and phosphorus.

Examples in Vertebrates[edit]

Fish: Many fish have dermal bones in the form of scales, which provide protection and reduce water resistance.
Amphibians: Some amphibians, like the axolotl, have dermal bones that contribute to their cranial structure.
Reptiles: Reptiles such as crocodiles and turtles have extensive dermal bone structures, including osteoderms and shells.
Mammals: In mammals, dermal bones are less common but can be found in the form of antlers and some cranial bones.

Evolutionary Significance[edit]

Dermal bones are considered to be one of the earliest forms of bone to evolve in vertebrates. They are thought to have originated as a form of external armor in early jawless fish, providing protection from predators and environmental hazards. Over time, the role and complexity of dermal bones have evolved, contributing to the diverse array of vertebrate forms seen today.

Also see[edit]

@@ Line 1: / Line 1: @@
-'''Dermal bone''' refers to a type of bone tissue that forms in the dermal layer of the skin in some vertebrates, particularly in fish and some reptiles. Unlike endochondral bone, which develops from a cartilaginous precursor, dermal bone is formed directly within the skin.
+{{Short description|Type of bone that forms in the skin}}
+{{Infobox bone
+| Name = Dermal bone
+| Latin = os dermale
+| Image =
+| Caption =
+| Precursor = [[Mesenchyme]]
+| System = [[Skeletal system]]
+}}
-== Structure and Characteristics ==
+'''Dermal bone''' is a type of [[bone]] that forms directly within the [[dermis]] of the skin, without a cartilaginous precursor. This type of bone is distinct from [[endochondral bone]], which forms from a cartilage template. Dermal bones are primarily found in the [[exoskeleton]]s of vertebrates, such as the bony plates of [[turtles]], the scales of [[fish]], and the [[osteoderm]]s of some reptiles.
-Dermal bone is characterized by its unique structure and location:
-* '''Origin''': Dermal bone originates from specialized cells within the dermis of the skin. These cells, known as osteoblasts, produce bone matrix directly.
-* '''Composition''': The composition of dermal bone may vary, but it often consists of a dense matrix of collagen fibers embedded with calcium phosphate or hydroxyapatite crystals. This composition gives it strength and rigidity.
+==Formation==
+Dermal bone formation is a process known as [[intramembranous ossification]]. During this process, [[mesenchymal stem cells]] within the dermis differentiate directly into [[osteoblasts]], which are bone-forming cells. These osteoblasts secrete [[osteoid]], an unmineralized bone matrix, which then becomes mineralized to form mature bone.
-* '''Function''': Dermal bone serves several functions, including providing structural support, protection, and aiding in buoyancy for aquatic species. In fish, for example, it forms the armor-like scales that protect against predators.
+==Functions==
+Dermal bones serve various functions depending on their location and the species in which they are found. Common functions include:
-== Evolutionary Significance ==
+* '''[[Protection]]''': Dermal bones often form protective armor, such as the bony plates in the shells of turtles or the scales of certain fish.
-The presence of dermal bone is an important characteristic in the study of vertebrate evolution. It is considered an ancestral feature in certain groups of vertebrates and has evolved in various forms to serve different purposes, such as defense, camouflage, and structural support.
+* '''[[Support]]''': In some species, dermal bones provide structural support, as seen in the [[skull]]s of vertebrates where they contribute to the cranial structure.
+* '''[[Mineral storage]]''': Like other bones, dermal bones can serve as reservoirs for minerals such as calcium and phosphorus.
-== Comparative Anatomy ==
+==Examples in Vertebrates==
-Dermal bone can vary greatly in its appearance and distribution among different species. In some, it may form extensive bony plates or scales, while in others, it may be limited to specific regions of the body.
-== Research and Study ==
+* '''[[Fish]]''': Many fish have dermal bones in the form of scales, which provide protection and reduce water resistance.
-Dermal bone is a subject of interest in the fields of comparative anatomy, paleontology, and evolutionary biology. It provides insights into the evolutionary history and adaptations of vertebrates.
+* '''[[Amphibians]]''': Some amphibians, like the [[axolotl]], have dermal bones that contribute to their cranial structure.
+* '''[[Reptiles]]''': Reptiles such as [[crocodiles]] and [[turtles]] have extensive dermal bone structures, including osteoderms and shells.
+* '''[[Mammals]]''': In mammals, dermal bones are less common but can be found in the form of antlers and some cranial bones.
-== Summary ==
+==Evolutionary Significance==
-A dermal bone or investing bone or membrane bone is a bony structure derived from intramembranous ossification forming components of the vertebrate skeleton including much of the skull, jaws, gill covers, shoulder girdle and fin spines rays (lepidotrichia), and the shell (of tortoises and turtles). In contrast to endochondral bone, dermal bone does not form from cartilage that then calcifies, and it is often ornamented.
+Dermal bones are considered to be one of the earliest forms of bone to evolve in vertebrates. They are thought to have originated as a form of external armor in early jawless fish, providing protection from predators and environmental hazards. Over time, the role and complexity of dermal bones have evolved, contributing to the diverse array of vertebrate forms seen today.
-{{stub}}
+==Also see==
+* [[Endochondral ossification]]
+* [[Intramembranous ossification]]
+* [[Osteoblast]]
+* [[Osteoclast]]
+* [[Bone remodeling]]
+{{Skeletal system}}
+[[Category:Bone]]
+[[Category:Skeletal system]]
 [[Category:Anatomy]]
-[[Category:Bone]]
+[[Category:Vertebrate anatomy]]
-[[Category:Evolutionary Biology]]