中胚层产生肌肉等structures. The other answers are derived from the ectoderm or endoderm.

Many of the glandular structures—both exocrine and endocrine—arise from endoderm. In particular, both the thyroid and parathyroid glands bud off from the pharyngeal mucosa, which of course is endodermal in character. Of course, like all tissues, there are mesodermal components of the gland in the way of connective tissues and blood vessels. The response indicating a mesodermal component invites you to make a wrong selection because you could remember that there are mesodermal-derived tissues everywhere, but you could not specifically recall the origin of the thyroid tissue, itself.

The correct answer is cytoderm.

There are three major germ layers formed during gastrulation: the ectoderm, mesoderm, and endoderm. Major structures form from these germ layers over the course of embryogenesis and development.

Gastrulation is the formation of the three layers of the embryo: ectoderm, endoderm, and mesoderm. The endoderm gives rise to the lining of the digestive system and respiratory system. A defect in these tissues suggests a problem of that germ layer during development. The ectoderm gives rise to the nervous system and epidermis. The mesoderm gives rise to the muscle and skeletal systems.

三个胚胎胚芽层外胚层,mesoderm, and endoderm. The mesoderm gives rise to bone, muscle, the urinary system, and the kidneys. Ectoderm develops into the nervous system, dermis, hair, nails, eyes, and ears. The endoderm develops into the lining of internal organs, such as the lungs and the gastrointestinal tract. The notochord is not an embryonic layer and, like the kidneys, arises from the mesoderm.

The process of gastrulation generates the three primary germ layers (ectoderm, endoderm, mesoderm). This is one of the most important steps of development.

The eight-cell stage signals the beginning of compaction, during which the cells of the blastula adhere to each other and prepare for further divisions. The epiblast and hypoblast are generated before gastrulation, but after implantation. Differentiation occurs long after the primary germ layers are formed.

The correct answer is the ectoderm. The ectoderm is responsible for generating nervous tissue and glial cells, among other features.

Ectoderm differntiates into the epidermis, nervous system, eye lens, and hair.

Mesoderm differentiates into muscle, cardiac and skeletal systems, blood, and spleen.

Endoderm differentiates into the lining of internal organs, like the digestive tract and respiratory tract.

胚胎外胚层的外层,which gives rise to the external ectoderm and the neuroectoderm. The neuroectoderm can further be divided into the neural crest and the neural tube. The neural crest migrates from the neural tube early in development. While both external ectoderm and the neural tube form an epithelial layer, the neural crest does not and is actually a highly migratory cell lineage. Furthermore, the neural crest is required for innervation of endodermal organs (forming the enteric nervous system), craniofacial features, innervation of the diaphragm for breathing, and many more critical features. Due to its structural and migratory properties, and its importance in development, the neural crest is often referred to as the "fourth germ layer."

Cardiomyocytes refer to cardiac muscle cells, while hepatocytes are liver cells. Beta cells are found in the pancreas and secrete insulin.

The ectoderm gives rise to the nervous system, epidermis, lens of the eye, and the inner ear.

The lungs are derived from the endoderm. Most epithelial linings are located toward the superficial regions of the body, and arise from the ectoderm. The linings of the respiratory and digestive tracts, however, are embedded deep within the body and are derived from the endoderm.

The endoderm gives rise to most of the internal organs, including the lining of the digestive tract, the liver and pancreas, and the respiratory system.

Muscles and bones are derived from the mesoderm.