Foetal Development

Question 0

Neural/glial proliferation

Answer 0

Mass production of neuron sang glia from thickened layers surrounding neural tube

Question 1

What does foetal development of the nervous system involve?

Answer 1

Neural/glial proliferation
Migration
Organisation
Myelinisation

Question 2

Migration

Answer 2

Neurons move to areas of developing CNS/grey matter and developing PNS
Specialised glia assist migration
Occurs mainly 3-5months

Question 3

Organisation

Answer 3

• Ability of nervous system to work as an integrated whole
• aprox 6 months
• Increase in complexity of foetal movements as synapses are made
• includes the death of neurons, max number reached at 8 months

Question 4

Myelinisation

Answer 4

Laying down on myelin in both CNS & PNS
CNS occurs first
Begins in 2nd trimester, continues to adulthood

Question 5

Sensory abilities of the foetus

Answer 5

Start in embryological period and are Developed by 28 weeks

Question 6

Motor development of the foetus:

Answer 6

Spontaneous limb movement begins at ~10wk
Independent limb movement ~10-12 weeks
Hand and face movement ~12-13 weeks
Limb, head and torso movement ~12-16 weeks
16wk onward movements continue to increase in complexity

Question 7

Haematology: where does haematopoises occur

Answer 7

Initially in yolk sac
Liver 6-18 weeks
Bone marrow is main site from 30 weeks

Question 8

When does coagulability occur

Answer 8

From 12 weeks. Reduced because of reduced levels of vitamin k

Question 9

Outline foetal circulation

Answer 9

O2 blood in placenta > umbilical vein > ductus venosus > inferior VC > right atrium > foraman ovale > left atrium > Left ventricle > aorta > brain OR
MIXED O2 Right atrium > pulmonary trunk > ductus arteriosus > aorta
Mixed O2 Delivered to remaining tissue > umbilical artery > placenta

Question 10

Respiratory development sequence

Answer 10

• 6-18w Bronchial branching
• 16-19w primitive respiratory bronchioles develop
• 20-24w terminal bronchi develop distinction
• 24-26w terminal air sacs branch off and alveoli begin to develop
• 26-28w alveoli form clusters close to capillary networks
  28+ type 2 cells begin producing surfactant

Question 11

Renal development

Answer 11

8weeks: nephrons begin forming, all formed at 35-36w
Urogenital sinus develops in to bladder with ureters and mesonephric ducts attached and gives rise to urethra
Urine production starts at 9-10w

Question 12

GI tract

Answer 12

Foregut, midgut and hind gut develop in to various structures
Nutrient absorption and motility develop by mid pregnancy

Question 13

Three aspects of reproductive system?

Answer 13

Gonads
Reproductive tracts
External genitalia

Question 14

Gonad development

Answer 14

Testes are mature and produce testosterone by 8w

Ovaries mature and germ cells undergo mitosis then oogenesis by 4 months

Oogenesis halts at 7 months

Question 15

Differentiation of reproductive tracts

Answer 15

Testosterone stimulates mesonephric duct
MIH inhibits development of para mesonephric duct

Both produced my testes

Question 16

External genitalia

Answer 16

Testosterone stimulates male reproductive genitalia.

Question 17

Musculoskeletal system

Answer 17

Skeleton undergoes endochondrial ossification
Muscles continue to grow and mature
Movement detectable from 16-20w