Neurodevelopment

Question 1

What are the 3 stages of Prenatal Development?

Answer 1

1. pre-embryonic stage (zygote)
2. embryonic stage (embryo)
3. fetal stage (fetus)

Question 2

What occurs in the pre-embryonic stage?

Answer 2

fertilisation of ovum by sperm

Question 3

What days are the pre-embryonic stage from?

Answer 3

day 0 to 14

Question 4

What occurs in the embryonic stage?

Answer 4

zygote implants in uterus

Question 5

what days are the embryonic stage from?

Answer 5

day 15 to end of 8th week

Question 6

what days are the fetal stage (fetus)

Answer 6

from end of 8th week until birth (38-42 weeks = full term)

Question 7

what is developed in the embryonic stage?

Answer 7

all tissues/ organs formed

Question 8

what 3 things happen to the cells in the embryonic stage?

Answer 8

1. cell proliferation - division
2. cell migration - movement
3. cell differentiation (become more specialised)

Question 9

what do the cells differentiate into in the embryonic stage?

Answer 9

• embryonic disk – 3 layers of cells
• neural tube formation: cephalic to caudal

Question 10

what are the 3 layers of cells in the embryonic disk?

Answer 10

1. endoderm
2. mesoderm
3. ectoderm

Question 11

What does the endoderm (bottom layer) make up?

Answer 11

gut, liver, pancreas & respiratory systems

Question 12

What does the mesoderm (middle layer) make up?

Answer 12

muscles, skeleton, excretory & circulatory systems

Question 13

What does the ectoderm (top layer) make up?

Answer 13

sensory organs, hair, skin, nails & whole NS (CNS & PNS)

Question 14

What are the different neural tube defects?

Answer 14

• ancephaly
• craniorachischisis
• open spina bifida
• closed spina bifida
• encephalocele
• iniencephaly

Question 15

What are the different parts of the neural tube which can cause defects if injured?

Answer 15

• cranial neuropore
• middle
• caudal neuropore
• somite
• neural groove
• neural fold

Question 16

What can disruptions during the pre-embryonic & the embryonic periods cause?

Answer 16

impact upon development of neural tube = neural tube defects (NTD)

Question 17

What happens in weeks 13-24 of fetal development?

Answer 17

• neurogenesis
• most neurons by 24 week
• major regions of brain develop
• eyes sensitive to light, reacts to sound

Question 18

What happens in weeks 25-38/40

Answer 18

• size increases, lungs mature, CNS matures
• rapid brain development

Question 19

What is a teratogen?

Answer 19

substance / condition that can disturb the development of the embryo (toxic substance)

Question 20

Why is the prenatal period a sensitive period?

Answer 20

limited time in which a part of the body / behaviour is biologically prepared to develop rapidly
- period of organ differentiation –> cells becoming specialised

Question 21

what is a neonate?

Answer 21

first 4 weeks after birth

Question 22

full term

Answer 22

from 37 weeks

Question 23

what is still developing in neonates?

Answer 23

• myelination
• synpatogenesis

Question 24

what is defined as ‘extremely premature’?

Answer 24

from 23-28 weeks

Question 25

what is defined as ‘very pre-term’?

Answer 25

28-32 weeks

Question 26

what is defined as ‘moderately pre-term’?

Answer 26

32-36 weeks

Question 27

what is defined as ‘late pre-term’?

Answer 27

36-37 weeks

Question 28

low birth weight

Answer 28

<2500g

Question 29

What do ‘extremely pre-term’ babies have an increased risk ok?

Answer 29

developmental problems due to being born with immature respiration / CNS