General Embryology

Question 1

down syndrome is known as

Answer 1

trisomy 21

Question 2

features of a down syndrome kid?

Answer 2

1. macroglossia (protruding tongue)
2. missing teeth
3. delayed eruption
4. periodontal issues
5. hypoplastic maxilla
6. facial clefts.

Question 3

examples of autosomal dominant diseases

Answer 3

cleidocranial dysostosis, achondroplasia, osteogenesis imperfecta and dentinogenisis imperfecta

Question 4

dentinogenesis imperfecta arises from mutation of which gene?

Answer 4

sialophosphoprotein gene

Question 5

examples of autosomal recessive diseases

Answer 5

chondroectodermal dysplasia, cystic fibrosis and cleft palate.

Question 6

first month ( 4 weeks ) after fertilization

Answer 6

proliferation and differentiation of cells. severe perturbation can cause the embryo to be lost

Question 7

second month (8 weeks)

Answer 7

congential diseases can be formed

Question 8

what are congential disease causing chemical ?

Answer 8

teratogens ( drugs, radiation, smoking and alcohol )

Question 9

what happens after fertilization ?

Answer 9

cells differentiate and make up a ball of cells called morula

Question 10

what is blastula?

Answer 10

when the morula is filled with fluid, it forms into an empty fluid filled ball called as blastula.

Question 11

two cell types in blastocyst?

Answer 11

embryoblast and trophoblast cells?

Question 12

function of embryoblast?

Answer 12

forms embryo proper

Question 13

functions of trophoblast?

Answer 13

makes up the placenta

Question 14

what happens in 2 week?

Answer 14

the EMBRYOBLAST makes up the bilaminar layers. the ectoderm and endoderm

Question 15

ectoderm makes up the?

Answer 15

amniotic cavity (columnar)

Question 16

endoderm makes up the?

Answer 16

roof of the secondary yolk sac (cubiodal)

Question 17

what happens in 3 weeks?

Answer 17

trilaminar layer forms.

Question 18

what does ectoderm forms in 3 weeks?

Answer 18

the primitive streak in the midline

Question 19

rostral end of primitive streak has

Answer 19

primitive node

Question 20

how is mesoderm formed?

Answer 20

the cells of ectoderm differentiate and depress into the primitive streak and start forming the mesoderm

Question 21

rostral end of the embryo has?

Answer 21

the prochordal plate

Question 22

caudal end of embryo has?

Answer 22

cecal plate

Question 23

how is notochord formed?

Answer 23

the cells of ectoderm move in a circular way. they dont divide and sit in the middle section and thus forms the notochord

Question 24

the area next to notochord is called?

Answer 24

par axial mesoderm

Question 25

somites are?

Answer 25

segments of par axial mesoderm

Question 26

sclerotome?

Answer 26

makes up the vertebrae and their disk

Question 27

myotome ?

Answer 27

makes up the muscle mass

Question 28

dermatome ?

Answer 28

connective tissues

Question 29

the two planes in which the embryo folds?

Answer 29

rostrocaudal axis and lateral axis

Question 30

the head fold is primitive for the formation of ?

Answer 30

stomatodeum/ oral cavity

Question 31

stomatoduem is seperated from the gut by?

Answer 31

buccopharyngeal membrane

Question 32

4th week?

Answer 32

the thickening of the ectoderm makes up the neural plates.

Question 33

neural folds?

Answer 33

neural plates raises making up margins called neural fold

Question 34

neural groove?

Answer 34

depression between the neural folds

Question 35

neural crest?

Answer 35

groups of cells made by the neural tube, DIVIDE at the neural fold and they move towards different parts of the body. originate from ectoderm

Question 36

layers of mesoderm?

Answer 36

1. paraxial mesoderm 2. intermediate mesoderm 3. lateral plate mesoderm

Question 37

ectomesenchyma cells

Answer 37

connective tissue formed when neural crest comes and sits on the mesoderm only FOUND IN HEAD AND NECK

Question 38

treachers collins syndrome

Answer 38

neural crest cells fail to migrate to the head and neck area and thus have undeveloped head and neck areas, and oral cavity except enamel and some part of dentin

Question 39

what happens in treachers collins syndrome?

Answer 39

micrognathia hearing loss slanted eyes mandibulo facial dysostosis

Question 40

derivatives of Neural crest *

Answer 40

1. cranial and sensory ganglion and nerves 2. adrenal medulla 3. ectomesenchyme of bones and skull 3. PDL 4. alveolar bone . 5. dentin

Question 41

derivates of intermediate layer

Answer 41

1.urogenital system

Question 42

derivates of surfaces of ectoderm

Answer 42

1. epidermis 2. hair 3. nails 4. cutaneous gland 5. mammary gland 6. anterior pituitary gland 7. parenchyma of salivary glands 8. enamel of teeth 9. lens 10. inner ear

Question 43

derivatives of neuroectoderm/ neural tube

Answer 43

1. posterior pituitary 2. pineal body 3. retina 4. central nervous system

Question 44

derivatives of paraxial mesoderm

Answer 44

1. muscles of trunk 2. skeleton (except of skull) 3. dermis of skin 4. connective tissues (mesenchyme)

Question 45

derivatives of lateral plate

Answer 45

1. connective tissues (mesenchyme) 2. muscles of viscera 3. serous membrane of pleura 4. pericardium and peritoneum 5. blood and lymph cells 6. cardiovascular and lymphatic system 7. spleen 8. adrenal cortex

Question 46

derivatives of endoderm

Answer 46

1. epithelium components of trachea, bronchi and lungs 2. epithelium of urinary bladder, pancreas, liver, urachus, gastrointestinal tract 3. epithelium components of pharynx, parathyroid, thyroid, tympanic cavity, pharyngotympanic tube, tonsils