Session 2 Terminology

Question 1

Define Bilaminar disc

Answer 1

The Epiblast and hypoblast. Derived from the embryoblast. This will later become the trilaminar disk with the formation of the primitive streak.

Question 2

Define Ectoderm

Answer 2

The outermost layer of the trilaminar disc

Question 3

Define Endoderm

Answer 3

The bottom layer of the trilaminar disc

Question 4

Define Germ layer

Answer 4

A layer from which other developed tissues originated from

Question 5

Define Doral Surface

Answer 5

The outermost surface during early development

Question 6

Define Ventral Surface

Answer 6

The innermost surface during early development

Question 7

Define Mesoderm

Answer 7

The middle layer of the trilaminar disc

Question 8

Define Primitive Streak

Answer 8

A groove that develops on the dorsal surface of the Epiblast that determines front/back and left/right of the embryo via molecular signals

Question 9

Define Gastrulation

Answer 9

The reorganisation of the germ layers into the ectoderm, mesoderm and endoderm

Question 10

Define Trilaminar Disc

Answer 10

The three germ layers. Ectoderm, mesoderm and endoderm.

Question 11

List ectodermal derivatives

Answer 11

• Skin
• Skin derivates (Hair, nails, lens and cornea of eye, mouth and anus lining)
• Brain and spinal cord
• Peripheral nerves
• Retina and iris of eye

Question 12

List mesodermal derivatives

Answer 12

• Smooth, skeletal and cardiac muscle
• Connective tissue
• Bone
• Cartilage
• Blood and blood vessels
• Urinary system

Question 13

List endodermal derivatives

Answer 13

Lining of the digestive tract

• Glands associated with digestion (E.g. liver, pancreas)
• Other gut derivates (E.g. lungs)