Session 12 - Embryology

Question 1

What is embryology

Answer 1

Progression from a single cell to a baby in 9 months

Question 2

What do the fimbriae do

Answer 2

Their movements helps move the egg from the ovary into the Fallopian tube

Question 3

Why can the uterus reverse its contractions

Answer 3

To assist the movement of sperm

Question 4

Why must the opening of the cervix remain closed during pregnancy

Answer 4

So the bay doesn’t fall out. This is a cause of recurrent miscarriages

Question 5

What is spermatogenesis

Answer 5

The production of 4 spermatids from a spermatogonium

Question 6

What is produced in oogenesis

Answer 6

I big egg and 3 polar bodies

Question 7

Why is the egg cell so big

Answer 7

It contains lots of food to be able to survive 12 weeks before it’s supplied nutrients via the placenta

Question 8

When does meiosis II occur during oogenesis

Answer 8

After fertilisation

Question 9

When does meiosis I occur in oogenesis

Answer 9

In puberty just priori to ovulation

Question 10

What happens to the number of germ cells in females are they age

Answer 10

They reduce dramatically

Question 11

Why does the number of germ cells in females reduce

Answer 11

Many die or contribute to producing a big egg

Question 12

What helps the movement of the egg through the Fallopian tube

Answer 12

Contractions by the Fallopian tube

Question 13

How do sperm know which Fallopian tube to travel down

Answer 13

Thermotaxis

Question 14

True or false; cilia in the Fallopian tube assist the movement of sperm

Answer 14

False, they help the movement of the egg and so waft in the opposite direction to sperm making it harder

Question 15

What is capacitation of spermatids

Answer 15

When chemicals in the reproductive tract cause the heads of the sperm to change so that they swim faster. This then makes them capable to fertilise the egg

Question 16

What is the layer of cells covering the egg called

Answer 16

Corona radiata

Question 17

What is the outer layer of the egg called

Answer 17

Zona pellucida

Question 18

What happens when sperm burrow into the zona pellucida

Answer 18

They bind to sperm receptors triggering acrosomes to release digestive enzymes

Question 19

What happens to the zona pellucida once a sperm enters the egg

Answer 19

It hardens stopping other sperm entering

Question 20

What happens to the female genetic information once the egg is fertilised

Answer 20

It completes meiosis II and then forms a pronucleus

Question 21

What bring the 2 pronuclei together in fertilisation

Answer 21

Microtubules

Question 22

Where does fertilisation occur

Answer 22

Ampullary region of the Fallopian tube

Question 23

How long are sperm viable for

Answer 23

5 days

Question 24

How long are secondary oocytes viable for

Answer 24

12-24 hours

Question 25

When are antibodies against sperm produced

Answer 25

When they have contact with blood

Question 26

What does seminal fluid do

Answer 26

Helps the survival of sperm, contains immunosuppressants, increases likelihood of implantation

Question 27

What s the embryonic age

Answer 27

Time since fertilisation

Question 28

What is the gestational age

Answer 28

Time since last menstruation (embryonic age minus 2 weeks)

Question 29

What is the germinal Stage

Answer 29

Time from fertilisation to end of 2nd week

Question 30

What is the embryonic period

Answer 30

Time from 3rd to 8th week

Question 31

What is the foetal period

Answer 31

Time from 9th week to birth

Question 32

what is a zygote

Answer 32

fertilised ovum

Question 33

what is a morula

Answer 33

a cluster of 32 cells

Question 34

what will the trophoblast become

Answer 34

the placenta

Question 35

what is the function of the zona pellucida

Answer 35

stops implantation occurring in the wrong place and prevents the ball of eggs becoming too large as theres limited food

Question 36

true or false; the morula and blastocyst undergo both aerobic and anaerobic respiration

Answer 36

true

Question 37

what is histotrophic nutrition

Answer 37

nutrition provided to the embryo not from maternal blood

Question 38

how long does the embryo undergo histotrophic nutrition

Answer 38

for the first 12 weeks

Question 39

what is haemotrophic nutrition

Answer 39

nutrition provided by the mothers blood

Question 40

what does the morula differentiate into

Answer 40

an outer and inner cell mass

Question 41

when does the embryo develop into a blastocyst

Answer 41

when a blastocyst cavity form

Question 42

where does the embryo normally implant

Answer 42

superior posterior wall of uterine cavity

Question 43

what day does implantation occur

Answer 43

day 6

Question 44

what is an ectopic pregnancy

Answer 44

when implantation occurs at an abnormal site

Question 45

what is placenta previa

Answer 45

when implantation occurs at the internal os and so the placenta blocks the babys exit

Question 46

what does the outer cell mass differentiate into

Answer 46

trophoblast

Question 47

what does the inner cell mass differentiate into

Answer 47

embryoblast

Question 48

what does the trophoblast develop into

Answer 48

cytotrophoblast and synctiotrophoblast

Question 49

when does the trophoblast begin to differentiate

Answer 49

as it burrows into the endometrium wall

Question 50

what does the embryoblast develop into

Answer 50

bilaminar disc

Question 51

what are the 2 layer of the bilaminar disc

Answer 51

epiblast and hypoblast

Question 52

what develops between the cytotrophoblast and the epiblast

Answer 52

amniotic cavity

Question 53

What do cells from the hypoblast form

Answer 53

the yolk sac

Question 54

what membrane covers the yolk sac

Answer 54

exocoelomic membrane

Question 55

true or false the growth of the bilaminar disk is faster than the syncytiotrophoblast and cytotrophoblast

Answer 55

false - its actually the other way round

Question 56

what is the name of the small holes that form in the syncytiotrophoblast

Answer 56

lacunae

Question 57

what is the extra embryonic mesoderm

Answer 57

the new cells that form between the yolk sac and cytotrophoblast

Question 58

what happens to the extraembryonic membrane

Answer 58

a cavity forms creating the chorionic cavity

Question 59

what joins the bilaminar disk to the cytotrophoblast

Answer 59

connecting stalk

Question 60

during which period is there the greatest risk of congenital malformation

Answer 60

embryonic stage

Question 61

what is teratogensis

Answer 61

congenital malformation

Question 62

what stage occurs in the 3rd weed of development

Answer 62

gastrulation

Question 63

what occurs in gastrulation

Answer 63

the bilaminar disk is converted into a trilaminar disc

Question 64

what occurs at the primitive streak

Answer 64

cells from the epiblast migrate here and invaginate into the bilaminar disk forming a new layer

Question 65

what are names of the 3 layers of the trilaminar disc

Answer 65

ectoderm, mesoderm and endoderm

Question 66

what does the ectoderm develop into

Answer 66

brain and epidermis

Question 67

what does the mesoderm develop into

Answer 67

muscle, cartilage, bone and heart

Question 68

what does endoderm develop into

Answer 68

epitheial lining, respiratory tract

Question 69

what occurs at the primitive node

Answer 69

ciliated cells waft signals for leftsidedness to the left

Question 70

what occurs after gastrulation

Answer 70

neurulation

Question 71

what drive neurulation

Answer 71

the notochord

Question 72

what does the notochord do

Answer 72

convert the overlying ectoderm into neuroectoderm by releasing signals for these cells to differentiate to become thicker forming the neural plate

Question 73

how does the neural tube form

Answer 73

edges of the neural plate curl up to form the neural groove and then eventually the neural tube

Question 74

what does the following mesoderm develop into following the neural tube formation

Answer 74

somites

Question 75

what step occurs after neurulation

Answer 75

segmentation

Question 76

at what day do somites start to develop

Answer 76

day 20

Question 77

how many pairs of somites do you develop

Answer 77

31

Question 78

what do somites degrade and differentiate into

Answer 78

dermatome, myotome and sclerotome

Question 79

what is dermatome the precursor of

Answer 79

skin

Question 80

what is myotome the precursor of

Answer 80

muscle

Question 81

what is sclerotome the precursor for

Answer 81

bone

Question 82

what will the buccopharyngeal membrane develop into

Answer 82

mouth

Question 83

what will the cloacal membrane develop into

Answer 83

anus

Question 84

what will the intraembryonic coelom develop into

Answer 84

the serous membranes

Question 85

what stage occurs after segmentation

Answer 85

folding

Question 86

what type of folding occurs first?

Answer 86

cephalocaudal folding

Question 87

what drive cephalocaudal folding

Answer 87

growth of the neutral tube

Question 88

what type of folding occurs second

Answer 88

lateral folding

Question 89

what drives lateral folding

Answer 89

growth of somites