Ameloblasts are cell

Cell (biology)

The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

s, present only during tooth development, that deposit tooth enamel

Tooth enamel

Tooth enamel, along with dentin, cementum, and dental pulp is one of the four major tissues that make up the tooth in vertebrates. It is the hardest and most highly mineralized substance in the human body. Tooth enamel is also found in the dermal denticles of sharks...

, the hard outermost layer of the tooth that forms the chewing surface.

Ameloblasts are cell

Cell (biology)

The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

s which secrete the enamel

Tooth enamel

Tooth enamel, along with dentin, cementum, and dental pulp is one of the four major tissues that make up the tooth in vertebrates. It is the hardest and most highly mineralized substance in the human body. Tooth enamel is also found in the dermal denticles of sharks...

 proteins enamelin

Enamelin

Enamelin was described in older literature as an EDTA soluble enamel protein. It accounts for the organic portion of enamel, which represents 4% of enamel's mass. It turned out in recent research to be albumin derived from blood contamination....

 and amelogenin

Amelogenin

Amelogenin is a protein found in developing tooth enamel, and it belongs to a family of extracellular matrix proteins. Developing enamel contains about 30% protein, and 90% of this is amelogenins...

 which will later mineralize to form enamel on teeth, the hardest substance in the human body. Each Ameloblast is approximately 4 micrometers in diameter, 40 micrometers in length and has a hexagonal cross section. The secretory end of the ameloblast ends in a six-sided pyramid-like projection known as the Tomes' process

Tomes' process

Tomes' processes are a histologic landmark identified on an ameloblast, cells involved in the production of tooth enamel. During the synthesis of enamel, the ameloblast moves away from the enamel, forming a projection surrounded by the developing enamel...

. The angulation of the Tomes' process is significant in the orientation of enamel rods.
Ameloblasts are derived from oral epithelium

Epithelium

Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands. Functions of epithelial cells include secretion, selective...

 tissue of ectoderm

Ectoderm

The "ectoderm" is one of the three primary germ cell layers in the very early embryo. The other two layers are the mesoderm and endoderm , with the ectoderm as the most exterior layer...

al origin. Their differentiation from preameloblasts is a result of signaling from the ectomesenchymal

Mesenchyme

Mesenchyme, or mesenchymal connective tissue, is a type of undifferentiated loose connective tissue that is derived mostly from mesoderm, although some are derived from other germ layers; e.g. some mesenchyme is derived from neural crest cells and thus originates from the ectoderm...

 cells of the dental papilla

Dental papilla

The dental papilla is a condensation of ectomesenchymal cells called odontoblasts, seen in histologic sections of a developing tooth. It lies below a cellular aggregation known as the enamel organ. The dental papilla appears after 8-10 weeks intra uteral life...

. The ameloblasts will only become fully functional after the first layer of dentine has been formed by odontoblasts. Ameloblasts control ionic and organic compositions of enamel. They adjust their secretory and resorptive activities to maintain favorable conditions for biomineralization.

The murine ALC cell line is of ameloblastic origin.

Life cycle of ameloblasts

The life cycle of ameloblasts consists of six stages :

1. Morphogenic stage
2. Organizing stage
3. Formative (secretory) stage (Tome's processes appear in secretory stage)
4. Maturative stage
5. Protective stage
6. Desmolytic stage

See also

• Ameloblastoma
  Ameloblastoma
  Ameloblastoma is a rare, benign tumor of odontogenic epithelium much more commonly appearing in the lower jaw than the upper jaw. It was recognized in 1827 by Cusack...
  
  
• Ameloblastin
  Ameloblastin
  Ameloblastin, also known as amelin, is a gene-specific protein found in tooth enamel. Although less than 5% of enamel consists of protein, ameloblastins comprise 5%-10% of all enamel protein. This protein is formed by ameloblasts during the early secretory to late maturation stages of amelogenesis...