embryology

Question 1

development of the limbs begins at what week?

Answer 1

end of the fourth week

Question 2

upper limb bud appears by

Answer 2

day 24

Question 3

upper limb patterns regulated by which genes?

Answer 3

homeobox genes (HOX)

Question 4

limb buds elongate by proliferation of

Answer 4

mesenchyme

Question 5

apex of each limp bud is the

Answer 5

ectoderm

Question 6

apex limb bud ectoderm thickens to form

Answer 6

apical ectodermal ridge

Question 7

role of the apical ectodermal ridge

Answer 7

inductive influence of limb mesenchyme to form blood vessels and cartilage

Question 8

by what weeks has the mesenchymal tissue in the hand plates condensed to form digital rays?

Answer 8

end of the 6th week

Question 9

during which week does the digital foot plates form

Answer 9

7th week

Question 10

interdigital apoptosis is mediated by

Answer 10

bone morphogenetic proteins

Question 11

cartilaginous precursors of limb bones develop by..

Answer 11

chondrification

Question 12

chondrification of the limb bones occurs within and by what week?

Answer 12

mesoderm in the 6th weel

Question 13

primary ossification centres appear by which weeks in the limbs?

Answer 13

8-12 weeks

Question 14

all limb bones bar the clavicle develop by

Answer 14

endochondrial ossification

Question 15

the clavicle forms by

Answer 15

membranous

Question 16

which way does the limbs rotate in development

Answer 16

90 degrees laterally

Question 17

lower limbs rotate by which direction in development

Answer 17

90 degrees medially

Question 18

which week does peripheral nerves grow?

Answer 18

5th week

Question 19

total absence of limb is called

Answer 19

amelia

Question 20

partial limb absence is called

Answer 20

meromelia

Question 21

long bone absence is called

Answer 21

phocomelia

Question 22

all parts present but small is called

Answer 22

micromelia

Question 23

presence of more than 5 digits is called

Answer 23

polydactyly

Question 24

fusion of digit bones is called

Answer 24

osseous syndactyly

Question 25

webbed fingers is called

Answer 25

cutaneous syndactyly

Question 26

thalidomide causes

Answer 26

meromelia

Question 27

congenital club foot is called

Answer 27

talipes equinovarus

Question 28

most common birth defect is

Answer 28

congenital heart defects

Question 29

greatest risk time period for teratogens

Answer 29

week 3 and 11

Question 30

functional and growth defects are more likely to occur after how many weeks?

Answer 30

12

Question 31

rubella triad

Answer 31

sensorineural deafness, eye abnormalities, congenital heart disease

Question 32

cervical kidneys are called

Answer 32

pronephros

Question 33

thoracolumbar kidneys are called

Answer 33

mesonephros

Question 34

pelvic functional kidneys are called

Answer 34

metanephros

Question 35

cloaca divides to from

Answer 35

rectum and urogenital sinus

Question 36

mesonephric duct drains into the

Answer 36

urogenital sinus

Question 37

urogenital sinus forms the

Answer 37

urinary bladder and the urethra

Question 38

at week 6 the mesonephros forms

Answer 38

genital ridge

Question 39

weeks cells germ cells migrate from where to form

Answer 39

the yolk sac to form primitive sex cords

Question 40

primitive sex cords consist of

Answer 40

mesenchyme of the genital ridges and germ cells from the yolk sac

Question 41

mesonephric duct in men forms

Answer 41

epididymis, vas deferens and seminal vesicle

Question 42

paramesonephric duct in men

Answer 42

degenerates

Question 43

urogenital sinus in men forms

Answer 43

bladder, urethra, and prostate

Question 44

in females the mesonephric duct

Answer 44

degenerates

Question 45

in females the paramesonephric duct

Answer 45

forms the fallopian tube, uterus, cervix and part of the vagina

Question 46

the urogenital sinus in females forms

Answer 46

bladder and lower part of the vagina

Question 47

SRY gene encodes for

Answer 47

testis determining factor

Question 48

in men Sertoli cells secrete what

Answer 48

Mullerian inhibiting substance that stimulates paramesonephric duct degeneration

Question 49

interstitial cells of Leydig are formed from

Answer 49

mesenchyme

Question 50

caudal end of the paramesonephric duct becomes

Answer 50

uterus, and superior part of the vagina

Question 51

descent of testis and ovaries begins

Answer 51

week 7

Question 52

testis enter scrotum week

Answer 52

39

Question 53

a heavily indented uterus is called

Answer 53

bicornuate uterus

Question 54

a slightly ridged uterus is called

Answer 54

arcuate uterus

Question 55

two cervixes and two uteruses is called

Answer 55

complete duplication

Question 56

one cervix but two uteruses is called

Answer 56

septate uterus