Embryology

Question 1

Gut Formation defects

Answer 1

No canal, atresia, stenosis

Question 2

Neuralation

Answer 2

Mesoderm cells under primitive streak –> notochord
Induces change in ectoderm –> neural plate
Neural plate dives into M then zips up –> neural tube
Differentiation –> neural crest cells

Question 3

Gestational Period, Fertilization age

Answer 3

Period from fertilization to birth: Fertilization + 38 weeks, or Last Period + 40 weeks

Question 4

Endoderm

Answer 4

Lining for GI system and glands, respiratory system

Question 5

Post natal development

Answer 5

Neonate > 1 month
Infant 1st year
Childhood 1-puberty
Puberty - women first period, men production of mature spermatozoea
Adolescence - maturation, reproduction
Adulthood - long bones fully formed, full maturity

Question 6

Embryonic prenatal phase (congenital malformations, 5 examples)

Answer 6

• Apoptosis
• Cell mitosis
• Cell migration
• Cell to cell interaction
• Transitional differentiation

Question 7

Mesoderm

Answer 7

Means-o-derm Cardiac system, muscular system

Question 8

Prenatal phases of development

Answer 8

1. Pre-implantation 1-6
2. Implantation 6-10
3. Post-implantation 10-birth

Question 9

Ectoderm

Answer 9

Attract-o-derm Skin, CNS, hair

Question 10

Phases of fetal development

Answer 10

Embryonic phase 4-7 weeks
Pseudo-glandular phase 7-16 weeks
Canicular phase 16-26 weeks
Terminal sac phase 26 weeks-birth

Question 11

Alveolar periods

Answer 11

Alveolar period I (32 weeks-birth) alveolar-capillary prepare for gas exchange; breathing in and out amniotic fluid; surfactant production; pulmonary circulation
Alveolar period II (birth-8 years) Until the age of 8, your number of alveoli will increase… from around 70 to 300-400! Leads to increase in lung size and rapid increase capillaries. Amniotic fluid is also removed. This

Question 12

Embryonic phase

Answer 12

4-7 weeks:
- gut canalization
- laryngo-tracheal groove
- division of trachea/esophagus –> sonic hedgehog
- defects - atresia
- development of bronchi + lung buds (primary, secondary, tertiary)
Mesenchyme –> bronchial smooth muscle, C rings

Question 13

Pseudo-glandular phase

Answer 13

7-16 weeks: Tertiary bronchi actively branch, beginning of early respiratory movements; all major elements have formed (terminal bronchiole, connective tissue, capillary)

Question 14

Canicular phase

Answer 14

16 - 26 weeks: Respiratory bronchioles branch into alveolar ducts, angiogenesis
Squamous epithelium, premies can survive b/c capable of gas exchange

Question 15

Terminal sac phase

Answer 15

26 weeks - birth:
Alveolar ducts expand into mesenchyme, mesoderm and vessels, alveolar septa formed; capillaries bulge into developing alveoli; blood/air barrier is established;
Epithelium type I and II cells, (surfactant)

Question 16

Oligohydramnios

Answer 16

Too little amniotic fluid, kidneys not developed, Potter’s syndrome. Severe lung hypoplasia

Question 17

Polyhydramnios

Answer 17

Too much amniotic fluid, atresia of the gut

Question 18

Problems with trachea and oesophague

Answer 18

Atresia of the gut/stomach/trachea/esophagus; fistula between trachea and esophagus

Question 19

Atresia

Answer 19

Failure to recanalize gut and trachea due to defective apoptosis –> Down’s, other genetic disorders

Question 20

Sonic hedhehog

Answer 20

Endoderm + mesoderm interaction during separation of trachea and esophagus, branching morphogenesis

Question 21

Surfactant

Answer 21

Mixture of phospholipied; forms a film over internal walls; counteract surface tension forces and facilitates expansion of terminal saccules; surfactant deficiency exists until last 4-6 weeks of pregnancy

Question 22

Necessary factors for lung development

Answer 22

• adequate space
• fetal breathing movements
• adequate amniotic fluid

Question 23

Atrial septal defect

Answer 23

Blood shunts from right atrium to left because don’t need blood to go to lungs; closes within 3 days of birth