Axial mesodermis located in the midline and forms the notochord.
Paraxial mesodermformssomites.Somites are divided into sclerotomes
(bone formation), myotomes (muscle precursors), and dermatomes
(precursor of dermis).
Intermediate mesodermgives rise to components of the genitourinary system.
Lateral plate mesodermforms bones and connective tissue of the limbs
and limb girdles (somatic layer,also known as somatopleure) and the
smooth muscle lining viscera and the serosae of body cavities (splanch-
nic layer, also known assplanchnopleure).
Intermediate mesoderm is not foundin the head region, and the lateral
plate mesoderm is not dividedinto layers there.
High-Yield Facts 3Epithelium of skin (superficial epidermis layer)
Ectodermal All nervous tissue: formed by neuroectoderm:
Derivatives Brain and spinal cord (neural tube)
Peripheral nerves and other neural crest derivatives
The gastrointestinal tract
Organs that form as buds from
Epithelial the endodermal tube:
Endodermal linings of: Pharyngeal gland derivatives*
Derivatives Respiratory system
Digestive organs (liver, pancreas)
Terminal part of urogenital systems
Hypoblast Endoderm: Gametes migrate to gonads
All connective General connective tissue
tissue† Cartilage and bone
Mesodermal Blood cells (red and white)
Derivatives All muscle types: Cardiac, skeletal, smooth
Body cavities
Some organs:
Epithelial linings of: Cardiovascular system
Reproductive and urinary
systems (most parts)*Pharyngeal derivatives: palatine tonsils, thymus, thyroid, parathyroids.†
Some connective tissue in the head are derived from neural crest.
GERM LAYER DERIVATIVES