Embryology

Question 1

Phases of human development

Answer 1

0-3 weeks, pre-embryonic phase
4-8 weeks, embryonic phase
9-40 weeks, foetal phase

Question 2

Pre sperm cell

Answer 2

Spermatogonium

Question 3

Pre egg cell

Answer 3

Oogonium

Question 4

Zygote

Answer 4

Product of fertilisation

Question 5

Morula

Answer 5

Solid ball of cells

Question 6

Blastocyst

Answer 6

Group of cells with inner cell mass, blastocyst cavity and trophoblast outer lining of cells

Question 7

Cell division timings

Answer 7

Decrease as more divisions occur

Question 8

Abnormal cilia function

Answer 8

Can result in ectopic pregnancy

Question 9

When does placenta develop

Answer 9

Day 6

Question 10

Bilaminar disc

Answer 10

Shape the pre embryonic cells form

Question 11

Chorion

Answer 11

Trophoblast has villi to implant in epithelium. Secretes Human Chorionoic Godatrophin which is used in pregnancy tests

Question 12

Decidua basalis

Answer 12

Part of the endometrium deep to the implanted conceptus (with maternal blood vessels)

Question 13

Myometrium

Answer 13

Smooth muscle around uterus

Question 14

Bilaminar disc cavities

Answer 14

Amniotic above epiblasts, yolk sac below hypoblasts

Question 15

Allantoic cavity

Answer 15

Waste products

Question 16

Main functions of the placenta

Answer 16

Foetal nutrition, transport of waste and gases, immune

Question 17

Foetal part and surface of placenta

Answer 17

Smooth with foetal blood vessels and end of umbilical cord

Question 18

Maternal part of placenta

Answer 18

Decidua basalis of endometrium. Rough, with maternal blood vessels

Question 19

Placenta facts

Answer 19

Matures by 18-20 weeks. Weighs 1/6 of the foetus

Question 20

what happens in Week 3

Answer 20

Gastrulation (formation of germ layers), neuralation, development of somites and early development of cardiovascular system

Question 21

Primitive streak

Answer 21

Formed in midline of epiblast, forms axis

Question 22

Trilaminar disc formation

Answer 22

Epiblast cells migration and displace hypoblast, 3 germ layers formed: ectoderm, mesoderm, endoderm. Cells are now specialised

Question 23

Notochord formation

Answer 23

Ectoderm sinks down, separates a bit into a solid tube of cells

Question 24

Neural tube formation

Answer 24

Again ectoderm sinks to form neural plate, this folds to form neural tube

Question 25

Mesoderm separation

Answer 25

Into paraxial mesoderm, intermediate plate mesoderm, lateral plate mesoderm (which splits into a v)

Question 26

What does the paraxial mesoderm form

Answer 26

Somites

Question 27

What does the intermediate plate mesoderm form

Answer 27

Urogenital system (kidneys and reproductive)

Question 28

What does the lateral plate mesoderm form

Answer 28

Body cavity and coverings

Question 29

Somites

Answer 29

Ridges/segments in paraxial mesoderm

Question 30

Lateral folding of embryo

Answer 30

Ectoderm surrounds. Endoderm forms inner tube(gut). Lateral plate mesoderm forms squashed semicircular tube

Question 31

Head and tail fold when will they be formed

Answer 31

By week 6

Question 32

Further somite development into 3 categories

Answer 32

Dermatome(skin), myotome(muscle), sclerotome(bone)

Question 33

Dermatome- compartment of somite turns into

Answer 33

Dermis of skin

Question 34

Myotome, a somite section that turns into..

Answer 34

Muscles

Question 35

Sclerotome, a somite that turns into..

Answer 35

Bones including vertebrae

Question 36

What will ectoderm form

Answer 36

Epidermis of skin and neural tube (and notochord which forms the nucleus pulposes)

Question 37

What will endoderm form

Answer 37

Gut and respiratory

Question 38

What will mesoderm form

Answer 38

Dermis, muscles, bones, urogenital, peritoneum, pleura, body cavities

Question 39

Teratology

Answer 39

Study of when things go wrong in pregnancy

Question 40

Congenital rubella syndrome

Answer 40

German measles

Question 41

Risk of teratogenesis

Answer 41

1-2 low risk as death risk is high, 3-8 high sensitivity to teratogens, weeks 9-38 decreasing sensitivity to teratogens

Question 42

Diagnosis of prenatal malformations

Answer 42

Blood - AFP Ultrasound at 12 weeks Invasive eg Chorionoic sampling amniocentesis

Question 43

Diagnosis of postnatal malformations

Answer 43

Hip stability Testes descent Fingers and toes Hearing

Question 44

When does respiratory system start and end developing

Answer 44

Tracheal buds form in 4th week, lobes are formed at 8 weeks

Question 45

Foregut (oesophagus) buds to lungs

Answer 45

Laryngeal groove starts on ventral side which forms trachea from respiratory diverticulum then lung buds. Oesophagotracheal septum forms to separate them

Question 46

Where do lung buds invaginate

Answer 46

Pleural cavities (splanchnic mesoderm) laterally forming the 2 layers like a squashed balloon

Question 47

What forms the gut tube

Answer 47

Endoderm (foregut, midgut and hindgut) from embryo folding in week 3

Question 48

Tracheoeosophageal fistula

Answer 48

When the trachea and oesophagus are accidentally connected

Question 49

Atresia

Answer 49

An orifice or passage is abnormally closed or absent

Question 50

The initial gaps between the parietal and visceral pleura

Answer 50

Pleuroperitoneal canals between somatic mesoderm and visceral mesoderm

Question 51

What separates the pleural and pericardial cavities

Answer 51

Pleuropericardial folds

Question 52

Embryonic phase

Answer 52

0-7 weeks

Question 53

Pseudoglandular phase in respiratory

Answer 53

7-17 weeks, the pulmonary structures are all set up except those used for gas exchange

Question 54

Canalicular phase in respiratory

Answer 54

17-27 weeks, terminal bronchioles make tubes for respiratory part of lung and type 1/2 pnuemocytes are differentiated

Question 55

Saccular stage in respiratory

Answer 55

27-40 weeks, alveolar sacs are formed which divide and divide into alveoli

Question 56

Alveolar stage in respiratory

Answer 56

32 weeks to 8 years, alveoli form and enlarge and number of respiratory bronchioles increase

Question 57

RDS

Answer 57

Caused by lack of surfactant, a mixture of phospholipids and proteins

Question 58

Respiratory congenital conditions

Answer 58

Accessory lobes, lobe of azygous vein, agenesis of lung (missing lung)

Question 59

Hiatus hernia types

Answer 59

Sliding or paraesophageal/rolling (to the side)