Embryology 1 (respiratory)

Question 1

Spermatogenesis creates

Answer 1

4 sperms (22+ X or Y)

Question 2

Oogenesis creates

Answer 2

1 ovum (22+x)

and 3 polar bodies

Question 3

Fertilisation

Answer 3

nucleus of sperm enters and fuses with the (pro)nucleus of ovum to give a diploid cell called the ZYGOTE

Question 4

Week 1 of the pre-embryonic phase (2 main facts)

Answer 4

zygote is formed - divides to form a blastocyst

moves through the uterine tube to reach the uterine cavity

Question 5

Mitochondrial diseases are inherited form the

Answer 5

mother

eg Leber’s hereditary optic. A neuropathy that leads to blindness

Question 6

Morula

Answer 6

solid ball of cells developed from the zygote

Question 7

As the number of cells in the morula increases - getting nutrition to the central core becomes difficult - therefore a cavity develops called the

Answer 7

blastocytic cavity

Question 8

cells accumulate at one end of the morula called the

Answer 8

inner cell mass

Question 9

The outer lining of the cells of the morula is the

Answer 9

trophoblast

Question 10

fertilisation occurs in the

Answer 10

Fallopian tube

Question 11

first cell division takes pace after

Answer 11

36 hours

Question 12

by day 5 or 6 the ……. is formed and is ready to enter into the …..

Answer 12

blastula

uterine cavity

Question 13

the diving zygote/ morula / blastocyst requires…… to move and reach the uterine cavity

Answer 13

healthy ciliated epithelium in the Fallopian tube

Question 14

Ectopic pregnancy can occur if

Answer 14

cilia function is abnormal

Question 15

At 7 days the blastocyst burrows into the

Answer 15

uterine wall

endometrium

Question 16

Chorion - what does it do?

3 facts

Answer 16

Implantation process (the chorionic villi)

forms part of the placenta in due course

secretes human chorionic gonadotropin (HCG)

Question 17

Decidua Basalis

Answer 17

part of the endometrium deep to the implanted conceptus

Question 18

Human chorionic gonadotropin secreted by the chorion is released to help

Answer 18

maintain the endometrium

Question 19

the cells of the inner cell mass turn into

Answer 19

epiblast and hypoblasts

into a flat disc called the bilaminar disc

Question 20

two cavities form from the bilaminar disc

Answer 20

amniotic cavity

yolk sac

Question 21

placenta main functions

Answer 21

foetal nutrition

transport of waste and gases

immune

Question 22

Events in week 3 of development

Answer 22

formation of germ layers (gastrulation)

formation of neural tube (neuralation)

development of somites

early development of the CVS

Question 23

primitive streak formed in the

Answer 23

midline of the epiblast

forms the axis of the embryo

Question 24

Inner cell mass of blastocyst develops into the

Answer 24

bilaminar disc

Question 25

bilaminar disc develops into the

Answer 25

primitive streak

Question 26

cells from the primitive streak invaginate to form the

Answer 26

hypoblast

Question 27

hypoblast forms the

Answer 27

endoderm

mesoderm

ectoderm

Question 28

Neuralation

Answer 28

formation of the neural tube

Question 29

three parts the mesoderm splits into

Answer 29

paraxial mesoderm

intermediate plate mesoderm

lateral plate mesoderm

Question 30

Teratogens

Answer 30

environmental factors that cause abnormal development

Question 31

Teratogen example

Answer 31

congenital rubella syndrome (getting German measles while pregnant)

Thalidomide (malformed limbs)

Question 32

Turners syndrome

Answer 32

45 chromosomes

single X

Question 33

Down’s syndromes

Answer 33

47 chromosomes

trisomy 21