Week 4 - Introduction to embryology

Question 1

Embryology

Answer 1

The study of development of an embryo from the state of fertilisation to the fetal stage

Question 2

3 stages of life before birth

Answer 2

Preimplantation stage (w1)

Embryonic stage (organogenesis) (W2-8)

Fetal stage (9-38)

Question 3

Oocyte

Answer 3

Another word for an egg

Question 4

Process where embryo proliferates

Answer 4

Cleavage

Question 5

What happens to the size of embryo as it travels down the fallopian tube

Answer 5

Stays the same

Question 6

What is the narrowest part of the fallopian tube

Answer 6

Isthmus

Question 7

Name of tough peptidoglycan coat around the embryo

Answer 7

Zona pellucida

Question 8

What happens to pronuclei upon formation of a zygote

Answer 8

One contains paternal
One contains maternal

Two combine to form embryonic genome

Question 9

What is embryo called when it contains 16 cells

Answer 9

Morula

Question 10

In what structure can the first sign of cellular differentiation be seen

Answer 10

Blastocyst

Question 11

What does the ICM go on to develop

Answer 11

Embryo

Question 12

What are the outer cells called in the blastocyst and what do they contribute to

Answer 12

Trophoblasts - placenta

Question 13

What happens when blastocyst enters the uterine cavity

Answer 13

Fluid enters via the zona pellucida forming the blastocyst cavity

Question 14

Why does blastocyst need to impant

Answer 14

It runs out of nutrients

Question 15

What causes ‘hatching’ of blastocyst

Answer 15

ICM continue to proliferate AND fluid fills up. Fluid bursts through the zone pellucida

Question 16

Decidualisation

Answer 16

Morphological change to cells of endometrium in preparation for and during pregnancy

Question 17

What happens to trophoblast cells upon making contact with endometrium

Answer 17

They differentiate and form the bilaminar disc

Question 18

What is the bilaminar disc make up of

Answer 18

Hypoblast

Epiblast

Question 19

What is the invasive layer of cells called and what does it do at the end of week 2

Answer 19

Synctiotrophoblast starts to communicate with maternal side of placenta. This enables diffusion of O2, waste and nutrients via blood supply

Question 20

What is a urinal chemical marker used to detect pregnancy

Answer 20

Human chorionic gonadotrophin (HcG)

Question 21

What is an ectopic pregnancy

Answer 21

Implantation in the wrong place e.g uterine tube, peritoneal cavity, surface of ovary

Question 22

What can cause ectopic pregnancy

Answer 22

Slow transit through uterine tube
Premature hatching

Question 23

Why do ectopic pregnancies not develop

Answer 23

They can’t produce a fully developed placenta

Question 24

Amnion fetal membrane

Answer 24

Lines the amniotic cavity which protects the developing embryo

Question 25

Chorion cavity membrane

Answer 25

Lines a structure called the chorionic cavity AND forms the fetal component of the placenta

Question 26

Yolk sack

Answer 26

Continuous with hypoblast of the bilaminar disc.

Involved in nutrient transfer in w2-3 disappears at w20

Blood cell formation and formation of the gut

Question 27

Allantois

Answer 27

Outgrowth of yolk sac

Contributes to umbilical arteries and connects to the fetal bladder

Question 28

Process that happens during week 3

Answer 28

Gastrulation

Question 29

What is gastrulation

Answer 29

Formation of trilaminar embryo (ectoderm, mesoderm, endoderm) from the bilaminar epiblast

Question 30

Describe the movement of cells during gastrulation

Answer 30

Epiblast cells move in at the primative streak forming the future ectoderm, the mesoderm and the endoderm

Question 31

Examples of structures produced from ectoderm

Answer 31

Epidermis of skin
Cornea and lens of eye

Question 32

Examples of structures from mesodern

Answer 32

Skeletal system
Muscular system

Question 33

Examples of structures formed from endoderm

Answer 33

Epithelial lining of digestive tract

Lining of urethra