Layers of Frog

Ectoderm

Outer germ layer that develops into epidermis, neural tube, and neural crest.

Mesoderm

Middle germ layer that forms notochord, somites, urogenital system, and lateral plate mesoderm.

Endoderm

Inner germ layer that forms the primitive gut and associated structures.

Neural Tube

Structure that develops from the ectoderm to form the central nervous system.

Somites

Segments of paraxial mesoderm that develop into dermis, skeleton, and limb muscles.

Urogenital system

Develops from intermediate mesoderm and includes kidneys.

Chordamesoderm

Part of the mesoderm that develops into the notochord.

Extra-embryonic ectoderm

Layer responsible for forming the amnion.

Facial connective tissue

Developed from head mesenchyme, part of the mesoderm.

Lateral Plate Mesoderm

Mesoderm that splits into somatic and splanchnic mesoderm.

Germ Cells

Reproductive cells, which include oocytes and sperm.

Amnion

A membrane that develops from extra-embryonic ectoderm.

Primitive gut

Early structure that develops into the digestive and respiratory systems.

Neural Crest

Group of cells from the ectoderm that develop into the peripheral nervous system.

Extra-embryonic endoderm

Endoderm layer of the yolk sac.

Somatic Mesoderm

Parietal pleura, pericardium, parietal peritoneum

Splanchnic mesoderm

Heart, blood, blood vessels, visceral pleura, visceral peritoneum, mesenteries, visceral connective tissue, gonad stroma, yolk sac mesoderm

Prosencephalon

upper area of the embryo

Nasal Placodes (inner ectodermal)

ventral to prosencephalon

Olfactory receptors and axons of olfactory

located with nasal placodes

Pineal gland

located dorsal to prosencephalon

Optic cup

located posterior to prosencephalon

Sensory retina

thick part of optic cup

Pigmented Retina

thin part of optic cup

Lens placode

adjacent to optic cup

Mesencephalon

second layer posterior to prosencephalon

infundibulum

ventral to mesencephalon; source of posterior pituitary gland

posterior pituitary gland

located at the infundibulum

Auditory vesicle (inner ear)

posterior to the pituitary gland

Spinal cord

posterior to inner ear

Neural crest

dorsal to spinal cord

Rhombencephalon

dorsal to the mesencephalon

Metencephalon and Myelencephalon

divided parts of rhombencephalon

Foregut (endoderm)

cranial to prosencephalon

Mouth opening (stomodeal ectoderm)

below foregut

Pharynx

3rd layer (endodermal) posterior to prosencephalon

Liver rudiment

3rd layer (endodermal) ventral to prosencephalon

Duodenum

ventral to the liver rudiment

Midgut

below duodenum

Hindgut

ventral to midgut

Cloacal membrane to anus

more posterior to hindgut

Notochord

posterior to infundibulum

Subnotochordal rod (hypochord)

located in caudal regions of notochord

Pronephric duct

round vesicles on each side farthest from the spinal cord

Pronephric tubules

it is above pronephric ducts

Pronephric kidneys

composes of pronephric duct and tubules

Lateral plate mesoderm

ventral to pronephric kidney

Somatic and Splanchnic mesoderm

two divided parts of lateral plate mesoderm

Somatic mesoderm

outer layer of lateral plate mesoderm

Splanchnic mesoderm

inner layer of lateral plate mesoderm

Coelom

small spaces between the somatic and splanchnic mesoderm

Bulbus cordis

located posterior to the foregut; it is beneath the pharynx

Heart

near bulbus cordis

Endocardium and Myocardium

two layers of the heart

Endocardium (splanchnic mesoderm)

inner layer of the heart

Myocardium (splanchnic mesoderm)

outer and thick layer of the heart

Parietal pericardium (somatic mesoderm)

thin layer of cells enclosing the heart

Pericardial cavity

space between the eat and the parietal pericardium

Dorsal mesocardium

dorsal bridge of splanchnic mesoderm

First aortic arches

lie ventrolateral to the pharynx

Dorsal aorta

extend caudad and fade out at about the level of the midgut