Embryology Introduction (Exam 1)

Question 1

What are the three main developmental stages of an embryo

Answer 1

early development
embryonic
fetal

Question 2

When does the early developmental stage occur

Answer 2

day 0-2 weeks

Question 3

When does the embryonic period occr

Answer 3

3-8 weeks

Question 4

When does the fetal period occur

Answer 4

9 weeks- birth (38 weeks)

Question 5

What stage of development is an embryo at highest risk of malformation

Answer 5

embryonic

Question 6

What typically occurs to malformations that occur during the early developmental period

Answer 6

results in spontaneous abortion

prevents implantation and will not be viable

Question 7

What events will occur during early development

Answer 7

• fertilization
• implantation
• proliferation
• formation of trilaminar embryo
• formation of placenta
• determination of body axes

Question 8

What is the trilaminar embryo

Answer 8

When the embryo has formed its 3 primary layers from which all cells will divide from

Question 9

What stage of development is this seen in

Answer 9

early stage of development

Question 10

During which stage of development will all organs and body parts form

Answer 10

embryonic stage

Question 11

What makes the embryonic stage at increased risk for injury

Answer 11

due to a lot of organ formation and cell division there is increased risk for injury

Question 12

How will an embryo enter the embryonic period

Answer 12

as a trilaminar embryo

Question 13

What occurs during the fetal period of development

Answer 13

• finalization and maturation of organ development

- increase in length and weight

Question 14

How does weight development in a fetus

Answer 14

not uniform, greatest prior to birth

Question 15

How does length development in a fetus occur

Answer 15

uniformly

Question 16

What organs are susceptible to injury during the fetal period

Answer 16

brain
ears
teeth
palate
external genitalia
eyes

Question 17

What is NOT included in external genitalia

Answer 17

gonads, these develop inside then come down closer to birth

Question 18

What is a congenital anomaly

Answer 18

abnormalities that are present at birth

Question 19

What determines what undifferentiated cells will become

Answer 19

cell signaling

Question 20

What is induction

Answer 20

two tissues communicating with each other, one will induce the other to perform an action

Question 21

How does induction occur between notocord and ectoderm

Answer 21

notochord causes the ectoderm to thicken and form the neural plate, where the neural tube will ultimately form from

Question 22

What differentiates the different levels of the spinal chord

Answer 22

gene expression

Question 23

What are the stages of the cell cycle

Answer 23

G1
S
G2
M
G0
GTD

Question 24

What occurs during G1 phase

Answer 24

gap phase

DNA damage checkpoint prior to S phase

Question 25

What occurs during S Phase

Answer 25

Dna Synthesis

Question 26

What occurs during G2 phase

Answer 26

Gap phase 2, DNA checkpoint, unreplicated

Question 27

What is the M phase

Answer 27

Mitosis

Question 28

What is G0 phase

Answer 28

cells that are not actively dividing

Question 29

What is produced by mitosis and what will the products contain

Answer 29

2 daughter cells that have diploid genomes with identical DNA as the parent cell

Question 30

What is the DNA content of a diploid cell

Answer 30

46 chromosomes | -22 pairs of autosomal chromosomes and 1 pair of sex chromosomes

Question 31

What are the different terms of ploidy

Answer 31

Haploid | Diploid

Question 32

What is Haploid

Answer 32

cell has just one copy of maternal or paternal strands of DNA - just one strand of each chromosome

Question 33

What is Diploid

Answer 33

cell has both maternal and paternal strands | -2 chromosomes

Question 34

What is produced from meiosis

Answer 34

4 haploid cells that are genetically unique

Question 35

What are the steps of meiosis

Answer 35

``` Prophase I Metaphase I Telophase I Anaphase I Metaphase II Telophase II Anaphase II ```

Question 36

What occurs during Prophase I

Answer 36

the doubled DNA condenses into chromosomes, and crossing over occurs

Question 37

What is the process of crossing over called

Answer 37

pachytene

Question 38

What occurs during Metaphase I

Answer 38

chromosomes align at random in the center, mitotic spindle forms

Question 39

What occurs during Anaphase 1

Answer 39

The chromosomes are pulled apart to opposite poles

Question 40

What occurs during Telophase I produce

Answer 40

2 daughter cells that are haploid with unique genomes

Question 41

What occurs during Metaphase II

Answer 41

the chromosomes again line up inside the cells

Question 42

What occurs during Anaphase II

Answer 42

the chromosomes are pulled apart

Question 43

What is the results of Telophase II

Answer 43

4 haploid daughter cells with unique genomes

Question 44

What does meiosis result in males

Answer 44

4 spermatids

Question 45

What does meiosis result in females

Answer 45

one ovum and three polar bodies

Question 46

Why do polar bodies occur

Answer 46

during division, the ovum gets majority of the cytoplasm

Question 47

What are the 4 clinically significant types of congenital anomalis:

Answer 47

malformations dysplasia deformation disruptions

Question 48

What are malformations

Answer 48

occur during organogenesis; results in abnormal structure

Question 49

There can be "deleterious" malformations called what

Answer 49

anatomical variations

Question 50

What are disruptions

Answer 50

result from external influences that cause alterations of completely formed structures or organs

Question 51

What are deformations

Answer 51

abnormal structure resulting from mechanical forces

Question 52

What is dysplasia

Answer 52

abnormal organization of cells into tissue

Question 53

What is an example of anatomical variation

Answer 53

three headed biceps

Question 54

What is an example of disruptions

Answer 54

strangulation by an amniotic band

Question 55

What is an example of deformation

Answer 55

club feet

Question 56

What is an example of dysplasia

Answer 56

sacrococcygeal teratoma

Question 57

What are the three main causes of congenital anomalies

Answer 57

Genetics Environmental factors Unknown/Multifactorial

Question 58

How much does genetics contribute to congenital anomalies

Answer 58

30%

Question 59

How much does environmental factors contribute to congenital anomalies

Answer 59

15%

Question 60

How much does unknown/multifactorial factors contribute to congenital anomalies

Answer 60

55%

Question 61

In North America, how many infant deaths are attributed to congenital malformations

Answer 61

20%

Question 62

What is agenesis

Answer 62

absence of an organ

Question 63

What is aplasia

Answer 63

cells to form an organ never formed

Question 64

What is association

Answer 64

anomalies occurring together without a determined cause

Question 65

What is atresia

Answer 65

absence of an opening or lumen

Question 66

What is hyperplasia

Answer 66

overgrowth of an organ

Question 67

What is hypoplasia

Answer 67

underdevelopment of an organ

Question 68

What is syndrome

Answer 68

a group of anomalies, occurring together with a common cause

Question 69

What is teratogen

Answer 69

substance affecting migration, proliferation, or interaction of cells; results in congenital anomalies

Question 70

What cells is meiosis limited to

Answer 70

gamete forming cells

Question 71

What are the two significant stages of meiosis I

Answer 71

Pachytene | Metaphase

Question 72

What occurs during Pachytene

Answer 72

crossing over event that results in unique genetic combinations

Question 73

What occurs during Metaphase I

Answer 73

maternal and paternal chromosomes align randomly