embryology

Question 1

what is gametogenesis?

Answer 1

formation of gametes

Question 2

what is a gamete

Answer 2

haploid cells

23 chromosomes

Question 3

what does gametogenesis involve

Answer 3

mitosis then meiosis

Question 4

what is Spermatogenesis

Answer 4

formation of male gametes

Question 5

how long does Spermatogenesis take

Answer 5

64 days

Question 6

what is oogenesis

Answer 6

formation of female gametes

Question 7

when is oogenesis halted and restarted

Answer 7

halted at prophase

meiosis restarts at puberty

Question 8

what is nondisjunction

Answer 8

failure of sister chromatids to separate during cell division

Question 9

what is trisomy 21

Answer 9

down syndrome

Question 10

what can nondisjunction in meiosis cause

Answer 10

trisomy

Question 11

what is fertilisation

Answer 11

fusion of sperm and oocyte to form a zygote

Question 12

what is a zygote

Answer 12

diploid single cell that will develop into an embryo

Question 13

what is cleavage

Answer 13

mitotic cell division of the zygote

Question 14

what is formed during cleavage

Answer 14

morula

Question 15

why is there no increase in size during cleavage

Answer 15

because of the presence of the zona pellucida

Question 16

what is gastrulation?

Answer 16

formation of the three primary germ layers

Question 17

what are the three primary germ layers

Answer 17

ectoderm
mesoderm
endoderm

Question 18

what is established during gastrulation

Answer 18

body axes

Question 19

where does fertilisation occur

Answer 19

ampulla

Question 20

what does sperm bind to in fertilisation

Answer 20

zona pellucida

Question 21

what is released by the head of sperm when attached to the ZP

Answer 21

acrosomal enzymes

Question 22

what happens to the oocyte once the membranes of the sperm and the oocyte have fused

Answer 22

completes meiosis 2

releases cortical granules

Question 23

what occurs when the morula undergoes compaction

Answer 23

cells become closely associated with each other by forming cell junctions to maximise space

Question 24

what is formed when fluid enters through the zona pellucida

Answer 24

the blastocyst cavity

Question 25

what is the outer layer of a blastocyst called

Answer 25

trophoblast layer

Question 26

what do cells form when they group together in a blastocyst

Answer 26

inner cell mass

Question 27

why does the blastocyst break free of the ZP

Answer 27

it is restrictive, and to implant

Question 28

when does implantation usually occur

Answer 28

day 6

Question 29

when is a bilaminar embryo formed

Answer 29

day 8

Question 30

what are the two layers that the trophoblast splits into

Answer 30

cytotrophoblast | syncytiotrophoblast

Question 31

what is the syncytiotrophoblast

Answer 31

outer multinucleate layer

Question 32

what is the cytotrophoblast

Answer 32

inner mononucleate layer

Question 33

what two layers does the inner cell mass split into

Answer 33

epiblast | hypoblast

Question 34

what is the small cavity in the epiblast known as

Answer 34

the amniotic cavity

Question 35

what layer penetrates the uterine lining

Answer 35

syncytiotrophoblast

Question 36

how is the heusers membrane formed and when

Answer 36

day 9 | cells from the hypoblast cover the cytotrophoblast

Question 37

what does heusers membrane line

Answer 37

the primitive yolk sac

Question 38

what forms in the synctiotrophoblast

Answer 38

trophoblastic lacunae

Question 39

what is ectopic pregnancy

Answer 39

when implamtation occurs outwith the uterus

Question 40

when does the primitive streak form

Answer 40

day 15

Question 41

where does the primitive streak appear

Answer 41

the midline of the epiblast layer

Question 42

what is at the cranial end of the primitive streak

Answer 42

primitive pit/node

Question 43

when does gastrulation occur

Answer 43

day 16

Question 44

how are the 3 primary germ, layers formed?

Answer 44

epibklast cells move through the primitive streak

Question 45

fate of the ectoderm?

Answer 45

skin | nervous system

Question 46

fate of the endoderm?

Answer 46

lining of gut tubes, respiratory tract, bladder, urethra

Question 47

what are the three regions of the mesoderm

Answer 47

paraxial intermediate lateral plate

Question 48

what two parts make up the lateral plate mesoderm

Answer 48

somatic and visceral

Question 49

fate of the paraxial mesoderm

Answer 49

axial skeleton skeletal muscle dermis of the back

Question 50

fate of the intermediate mesoderm

Answer 50

urogenital systems

Question 51

somatic lateral plate mesoderms fate?

Answer 51

dermis lining of body wall limbs

Question 52

visceral lateral plate mesoderms fate?

Answer 52

CVS smooth muscle mesothelium