Prenatal Development and Neurulation

The period of prenatal development lasting from the end of the second week to the eighth week.

The period of prenatal development starting from the ninth week until birth.

The inner cell mass, a cluster of cells within the blastocyst, is the progenitor of the embryo.

The formation of the three germ layers: ectoderm, endoderm, and mesoderm.

The ectoderm gives rise to the nervous system, skin, and sensory organs.

The endoderm gives rise to the lining of the digestive and respiratory systems.

The mesoderm gives rise to muscles, bones, blood, and connective tissue.

The process of forming the neural tube, which will eventually become the brain and spinal cord.

The neural tube closes first in the cervical region, then anteriorly and posteriorly.

The oropharyngeal membrane is a thin membrane that separates the primitive oral cavity (stomodeum) from the foregut.

The mandibular arch forms the maxillary and mandibular processes.

The pharyngeal arches are responsible for the formation of structures in the head and neck.

The maxillary processes grow forward and upward, forming the upper lateral edge of the mouth.

The palate is formed by the fusion of the maxillary and frontonasal processes.

The primary palate is formed by the frontonasal process, and contains the incisors.

The secondary palate is formed by the lateral palatal growths of the maxillary processes.

The tooth germ is composed of three main elements: the enamel organ, the dental papilla, and the dental sacculus.

The enamel organ forms the enamel of the tooth.

The dental papilla forms the dentin and pulp of the tooth.

The dental sacculus forms the cementum, periodontal ligament, and alveolar bone.

The bud stage is the first stage of tooth development, characterized by a ball of epithelial cells.

The cap stage is the second stage of tooth development, characterized by the enamel organ forming a cap-like structure.

The bell stage is the third stage of tooth development, characterized by the enamel organ forming a bell-shaped structure.

The enamel knot is a cluster of cells in the enamel organ that acts as a signaling center for tooth development.

The enamel cord is a row of cells in the enamel organ that helps to shape the crown of the tooth.

The enamel niche is a hollow space in the enamel organ where ameloblasts begin to deposit enamel.

The presecretory stage is the first phase of ameloblast differentiation, where ameloblasts prepare to secrete enamel.

The secretory stage is the second phase of amelogenesis, where ameloblasts secrete the enamel matrix.

The maturation stage is the third phase of amelogenesis, where the enamel matrix undergoes further mineralization and maturation.

The ameloblasts secrete the enamel proteins enamelin and amelogenin, which play a role in enamel formation.

The dentino-enamel junction is the boundary between the dentin and enamel, formed by the interaction of ameloblasts and odontoblasts.

Tomes' process is a projection at the end of the ameloblast that helps to deposit enamel.

The peritubular dentin is the layer of dentin surrounding the dentinal tubules.

The intertubular dentin is the layer of dentin between the dentinal tubules.

The mantle dentin is the initial layer of dentin deposited at the dentino-enamel junction.

The circumpulpal dentin is the main layer of dentin surrounding the pulp.

The predentin is the unmineralized layer of dentin matrix that is deposited by odontoblasts.

The odontoblasts are specialized cells that produce dentin.

Korff's fibers are thick collagen fibers produced by subodontoblasts that are found in the mantle dentin.

The dental pulp is the soft tissue inside the tooth that contains blood vessels, nerves, and connective tissue.

The odontoblast zone is the layer of the dental pulp that contains odontoblasts.

The cell-free zone is a layer of the dental pulp that is relatively devoid of cells and is located beneath the odontoblast zone.

The cell-rich zone is a layer of the dental pulp that is densely packed with cells, including fibroblasts and undifferentiated mesenchymal cells.

The parietal nerve layer is a layer of the dental pulp that contains nerve fibers that innervate the odontoblasts.

Hertwig's epithelial root sheath is a temporary structure that guides the formation of the tooth root.

The cementoblasts are specialized cells that produce cementum.

The cementum is a layer of mineralized tissue that covers the root of the tooth.

Sharpey's fibers are collagen fibers that anchor the periodontal ligament to the cementum and alveolar bone.

The periodontal ligament is a fibrous connective tissue that surrounds the tooth root and connects it to the alveolar bone.

The alveolar bone is the bone that surrounds the tooth root and provides support.