Mechanisms Of Disease During Embryogenesis

Question 1

What are the two main periods of human development?

Answer 1

Embryonic and fetal

Question 2

When is the embryonic period and what happens in it?

Answer 2

Fertilisation -> week 8

When most of the organogenesis happens

Question 3

When is the fetal period and what happens in it?

Answer 3

Week 8-> birth

Growth and modelling of organs

Question 4

When does cleavage happen?

Answer 4

When zygote is moving from the site of fertilisation to the uterus

Question 5

What is another name for the 16-cell zygote?

Answer 5

Morula

Question 6

What is compaction?

Answer 6

The trophoblast secretes fluid inside, forming a blastocoele that pushes the inner cell mass to one side
-> inner cell mass splits into the hypoblast and the epiblast

Question 7

In the morula, which cells are polar and what are their poles called?

Answer 7

Trophoblast cells have an apical and a basolateral surface

Inner cell mass are apolar

Question 8

What is the blastocoele?

Answer 8

Fluid filled space secreted by trophoblast

Question 9

What is the blastocyst?

Answer 9

Thing formed when the trophoblast has secreted the blastocoele and pushed the inner cell mass to the side

Question 10

What does the inner cell mass split into?

Answer 10

Hypoblast and epiblast

Question 11

Which part of the epiblast is touching the blastocoele?

Answer 11

Hypoblast

Question 12

What happens once the embryo is fully implanted?

Answer 12

Formation of the bilaminar germ disk

Question 13

What is gastrulation?

Answer 13

Differentiation from two layers of cells to three

Question 14

What is another name for the hypoblast?

Answer 14

Primitive endoderm

Question 15

What is the primitive endoderm displaced by in gastrulation?

Answer 15

Involuting cells that become the definitive endoderm and mesoderm

Question 16

Where does the primitive groove form and what does it do?

Answer 16

One end of the epiblast and moves along the epiblast, displacing the hypoblast

Question 17

What happens when the primitive streak reaches the other end of the epiblast?

Answer 17

It regresses

Question 18

Where does the mesoderm form?

Answer 18

Between the epi and hypoblast

Question 19

What does the hypoblast form?

Answer 19

Endoderm

Question 20

What does the epiblast form?

Answer 20

Ectoderm

Question 21

How is the notochord formed?

Answer 21

Primitive streak regression

Question 22

What is the notochord?

Answer 22

A rod of cells that secrete molecules extracellularly that instruct the exoderm on top of it to become neural tissue

Question 23

What forms the neural plate?

Answer 23

Notochord secretions

Question 24

What forms the neural tube?

Answer 24

Folding of the neural plate

Question 25

Where is the neural tube found?

Answer 25

Buried in the embryo (covered by surface ectoderm)

Question 26

Where does neural tube formation start?

Answer 26

In the middle and moves out towards the edges

Question 27

What does the ectoderm form?

Answer 27

Specification of the CNS

Question 28

What does the mesoderm organise into?

Answer 28

Blocks called somites

Question 29

What are somites precursors to?

Answer 29

Muscles and bones etc

Question 30

What does folding of the embryo form?

Answer 30

Umbilical cord

Question 31

What is happening at the same time as neurulation and somitogenesis?

Answer 31

Gut formation and body folding

Question 32

What model does the embryo folding follow?

Answer 32

Cloth purse model

Question 33

What happens in embyronic folding?

Answer 33

Septum and heart move from the margin to the centre | Yolk sac, allantois and stalk make the umbilical cord

Question 34

What delimits the gut tube?

Answer 34

Prochordal and cloacal plates

Question 35

What happens in organogenesis?

Answer 35

``` Differentiation of somitic derivitives Development of sensory organs Limb formation Formation of facial structures Formation of genital structures ```

Question 36

What are the stages of development from egg -> adult?

Answer 36

``` Egg Fertilisation Cleavage Gastrulation Neurulation and somitogenesis Organogenesis Adult ```

Question 37

Which limbs develop first?

Answer 37

Forelimbs

Question 38

What is the establishment pattern of limb formation?

Answer 38

Proximodistal, anterior-posterior, dorsal-ventral

Question 39

What are the desirable characteristics of a model organism?

Answer 39

``` Relevance/representitive Accessibilty/availibility Experimental manipulation Genetics Cost/space ```

Question 40

What are specific gene mutations?

Answer 40

Cases when mutation in one particular gene will be enough to display a characteristic defect

Question 41

What are chromosomal anomalies?

Answer 41

Whole chromosomal rearrangements responsible for a disease

Question 42

What is an example of a chromosomal abormality?

Answer 42

Trisomy 21- downs syndrome

Question 43

What is a polygenic disorder?

Answer 43

When several different genes are simultaneously affected, causing disease

Question 44

What are environmental factors?

Answer 44

Deleterious influence of the environment on a particular process