Early Embryology and Development

The fertilized egg formed by the union of two gametes (sex cells).

The process where a zygote divides into multiple cells to form a blastula.

The process of forming the endodermal tube during early embryonic development

The process of forming the ectodermal neural tube from early embryonic development

The three main layers (Ectoderm, Endoderm, and Mesoderm) of cells in early embryos that develop into tissues and organs.

A method of reproduction where embryos develop in eggs laid outside the mother's body.

A method of reproduction where embryos develop inside the mother's body.

Cells that migrate to different parts of the body and differentiate into various cell types in vertebrates.

Bone cells that break down old bone.

Bone cells that build new bone.

Mature bone cells, maintaining bone matrix.

Dense bone tissue, formed of osteons.

Bone tissue with a lattice-like structure (trabeculae).

Lattice-like structures in spongy bone; maximize strength

The tubular shaft of a long bone.

The wider, end part of a long bone.

Bone development from cartilage.

Bone development directly from mesenchyme.

The hardest connective tissue in the body, made of collagen fibers embedded in a mineralized ground substance (hydroxyapatite).

Connective tissue that is hard but pliant, made primarily of chondroitin sulfate proteoglycans and collagen. There are hyaline, fibrocartilage, and elastic types.

Most common type of cartilage, with short, dispersed collagen fibers and abundant proteoglycans. Found in joints and embryonic bones.

Cartilage with thick collagen bundles, providing high tensile strength. Found in areas with high stress, like intervertebral discs.

Cartilage with elastic fibers, collagen, and proteoglycans. Flexible and resilient, found in ears and the epiglottis.

Cells that produce cartilage matrix.

A protein that provides a soft framework in bone, contributing to its flexibility.

A mineral in bone that contributes to its strength and hardness.

The diaphragm, a muscle that separates the chest and abdomen, develops from the fusion of two embryonic structures: the pleuroperitoneal membrane and the transverse septum.

The vertebral column, the backbone of vertebrates, develops from segmented clusters of cells called sclerotomes, which surround the notochord.

Pharyngeal arches, segmental structures in the pharynx, are remarkably conserved throughout vertebrate evolution, playing a crucial role in the development of various structures, including jaws and neck supports.

Metamorphosis is a dramatic change from a larval stage to an adult form, often involving significant physical and physiological transformations. It is commonly observed in amphibians, insects, and some fish.

Ontogeny is the continuous development of an organism from fertilization to adulthood. It is a long process that encompasses both embryonic and post-embryonic stages.

The initial site of bone formation within the diaphysis (shaft) of a long bone, where cartilage is replaced by bone.

A layer of hyaline cartilage located at the ends of long bones responsible for longitudinal bone growth. It contributes to lengthening the bone.

A type of growth pattern where an organism reaches a specific size and stops growing at maturity, often due to the ossification of growth plates.

A region of bone formation that develops in the epiphysis (ends) of long bones, contributing to the overall shape and strength.

A thin layer of hyaline cartilage that covers the ends of bones in joints, allowing smooth movement and reducing friction.

Undifferentiated cells with the potential to develop into a variety of cell types, including bone cells. They play a key role in intramembranous ossification.

The unmineralized, organic matrix of bone tissue, composed primarily of collagen fibers. It is secreted by osteoblasts and later mineralized.

The main body cavity in animals that forms from the mesoderm. In vertebrates, it becomes subdivided into various cavities.

A body cavity in vertebrates that surrounds the lungs and abdominal organs. In amniotes, it eventually separates into pleural and peritoneal cavities.