embryology

Question 1

define embryology

Answer 1

the study of embryos and their development

Question 2

pre embryonic stage

Answer 2

first 2 weeks

Question 3

when is the developing human referred to as en embryo

Answer 3

weeks 3-8

Question 4

the pre embryonic and embryonic stage are characterized by

Answer 4

cell division, migration , and differentiation

Question 5

when is a human referred to as a fetus

Answer 5

from the 9th week of gestation until birth

Question 6

when are all organ systems structure ?

Answer 6

by week 9

Question 7

define gastrulation

Answer 7

cellular rearrangement which involved migration, invagination, and differentiation of the epiblast

Question 8

during gastrulation the 2 cell layers become

Answer 8

3 germ cell layers and the bodily axes in the mature adult are created

Question 9

mesoderm

Answer 9

notochord
musculoskeletal system
muscular layer of stomach
circulatory system

Question 10

ectoderm

Answer 10

epidermis of skin
cornea and lens of eye
nervous system

Question 11

when do dermatomyotomes originate

Answer 11

3rd week of embryogenesis

Question 12

after day 20 the mesoderm differentiates into

Answer 12

44 pairs of semite’s and then change into 31 sets of spinal nerves

Question 13

dorsal portion of somites

Answer 13

comes from dermis , as limbs grow the dermis i stretched and moved down the limb

Question 14

ventral portion of somites

Answer 14

consists of sclerotome, the precursor to the ribs and vertabrae

Question 15

during the 4th week of development , the upper limbs buds appear as elevations of

Answer 15

C5-T1 segments if the anterolateral body wall

Question 16

the lower limb buds grow

Answer 16

laterally from the broader bases formed by the L2-S2 segments

Question 17

flex urges occur where

Answer 17

gaps develop between the precursors of the long bones

Question 18

by the end of the 7th week the proximal parts of the upper and lower limbs

Answer 18

undergo a 90 degree torsion around their long axes but in opposite directions
elbows go caudally and knee cranially

Question 19

what is the precursor structures of the limbs

Answer 19

limb buds

Question 20

syndactyly

Answer 20

represents fusion of two or more digits

Question 21

polydactyly

Answer 21

extra digits , typically occurs bilaterally

Question 22

macrodactyly

Answer 22

enlarged digits

Question 23

adactyly

Answer 23

absence of digits

Question 24

ectrodactyly

Answer 24

“lobster-claw deformity” typically missing middle digit and occurs unilaterally

Question 25

amelia

Answer 25

complete a sense of one or more extremities

Question 26

meromelia

Answer 26

partial absence of one or more extremities

Question 27

phocomelia

Answer 27

shortened lower extremities

Question 28

following gastrulation , rudiments of the CNS develop from the ectoderm in the process of

Answer 28

neurulation

Question 29

what vitamin is important to the healthy development of the neural tube and preventing neural tube defects?

Answer 29

folate one of the vitamin b

Question 30

the neural plate border separates thh

Answer 30

ectoderm from the neural plate

Question 31

What is a disorder which two sides of the vertebral arches fail to fuse during development, resulting in an open vertebral canal

Answer 31

spina bifida

Question 32

Spina bifida occulta

Answer 32

occurs when there is a defect in the vertebral arch of L5 or S1
10% of ppl
pt is asymptomatic with a tuft of hair

Question 33

meningocele

Answer 33

large outpouching of the meninges that contains cerebrospinal fluid

Question 34

myelomeningocele

Answer 34

large outpuching of the meninges that is a portion of the spinal cord

Question 35

anencephaly

Answer 35

absence of a major portion of the brain, skull, and scalp
fetal neural tube defect
folic acid
failure of neural tube to close at the base of the skull