embryology week four

Question 1

week four

Answer 1

folding of the embryo, germ layer derivatives

Question 2

how is general body form established?

Answer 2

by the folding of the flat trilaminar embryonic disc into a cylindrical embryo

Question 3

sides of the complex folding process

Answer 3

fold in a medial direction

Question 4

head & tail regions of the complex folding process

Answer 4

fold under due to the rapid expansion of the brain and lengthening of spinal cord

Question 5

what is the result of folding?

Answer 5

embryo becomes a tadpole shape (shape of comma or letter c)

Question 6

primitive gut

Answer 6

cylindrical folding of the embryo encloses a tubular part of the yolk sac

Question 7

germ layer derivative: ectoderm

Answer 7

neural plate:
brain & spinal cord
epidermis, hair, nails, skin glands
sensory nerve cells and ganglia
facial bones

Question 8

germ layer derivative: endoderm

Answer 8

lining of inner tube in embryo:
epithelial lining & glands of the gastrointestinal & respiratory tracts

Question 9

germ layer derivative: mesoderm (notochord)

Answer 9

jelly-like inner core of vertebral disk
nucleus pulpous of intervertebral disks

Question 10

germ layer derivative: mesoderm (intermediate mesoderm)

Answer 10

kidneys and gonads

Question 11

germ layer derivative: mesoderm (lateral plate mesoderm)

Answer 11

wall of the digestive & respiratory tubes, heart & blood vessels, dermis of the ventral body region- connective tissue of the limbs (bones, joints, ligaments)

Question 12

3 segments of somite derivatives

Answer 12

sclerotome, dermatome, myotome

Question 13

sclerotome

Answer 13

(hard piece) cells migrate medially, gather around the notochord and neural tube, and become the vertebrae and ribs

Question 14

dermatome

Answer 14

(skin piece) cells migrate to more superficial layers and become the dermis of the skin on the dorsum of the body

Question 15

myotome

Answer 15

(muscle piece) remaining cells form the trunk and limb musculature