Lecture 2

Question 1

What are the three stages of prenatal growth? and weeks?

Answer 1

1. fertilized egg or zygote (first 2 weeks)
2. Embryo (weeks 2-8)
3. Fetus (weeks 9-40)

Question 2

What happens in stage 1 of prenatal growth?

Answer 2

• egg or zygote is fertilized
• doubles in size every 24hrs
• rapid cell division
• Differentiation of multiple cell layers

Question 3

What are the three layers of the Gastrula?

Answer 3

• Endoderm = which becomes gastro intestinal tract, respiratory tract and endocrine glands
• Mesoderm = becomes muscle, mesenchyme, connective tissue, gonads and other organ tissue
• Ectoderm = predominantly skin

Question 4

What are the two different types of twins?

Answer 4

identical (monozygotic) - splitting of fertilized ovum

Fraternal (dizygotic) - 2 eggs & 2 sperm

Question 5

What happens in stage two of prenatal growth?

Answer 5

Embryo (2-8 weeks)

• rapid growth
• differentiation of stem cell tissues
• basic anatomical and physiological features

Question 6

what is totipotent and pluripotent?

Answer 6

2 different types of stem cells

Question 7

what are the male and female chromosomes?

Answer 7

male = XY
Female = XX

Question 8

What happens if Y gene is inactive? What is DSD?

Answer 8

• embryo will continue to develop as female
• which makes you a pseudohermaphrodite
• have genetic material as male but hasn’t developed into a male

DSD = different sexual development

Question 9

What is stage 3 of prenatal growth?

Answer 9

1. fertilized egg or zygote (first 2 weeks)
2. Embryo (weeks 2-8)
3. Fetus (weeks 9-40)

Question 10

What is a low birth weight?

Answer 10

below 2.5kg

Question 11

What is pre term?

Answer 11

birth 37 weeks and before

Question 12

What are some direct and indirect factors that affect birth weight?

Answer 12

direct - smoking, alcohol, ethnicity

indirect - maternal age , socioeconomic status

Question 13

Prenatal loss - what are the chances of conception? What is the rate of spontaneous abortion of fertilized eggs?

Answer 13

• chances of conception 25-30%

- spontaneous abortion of fertilized eggs 35%

Question 14

What % will have congenital malformations?

which are also chromosomal abnormalities - XXYY XXY XYY

Answer 14

1%

Question 15

What was thalidomide used for

Answer 15

used to treat morning sickness

Question 16

How does low birth weight = TII diabetes (diabetes mellitus)??

Answer 16

Low birth weight = stunted growth of pancreas = decrease in beta cells = decrease capacity to produce insulin = pancreatic exhaustion and diabetes

Question 17

What happens (risks) to a heavy/high birth weight for date baby?

Answer 17

full term and heavy/ high birth weight for date = increase risk of hyperinsulinemia (high insulin output) = pancreatic exhaustion and diabetes

Question 18

What is anthropometry? examples

Answer 18

a technique for taking measurements of the body and parts of the body

eg. body size, weight, height

Question 19

What are skinfolds used for?

Answer 19

measure body fat around the body

Question 20

How do you work out BMI?

Answer 20

weight divided by height (m2)

11.7 divide 0.85 squared = BMI - 16.2

Question 21

What age do males and females increase height until?

Answer 21

males increase until age 20

females peak 16-18

Question 22

What is a method for measuring skeletal maturation ?

Answer 22

Gruelich-pyle (GP)
- method using x-ray and comparing to a standard plate
eg - wrist and hand bones

Question 23

How do you work out skeletal age (SA) is advanced or delayed to chronological age (CA) ??

Answer 23

SA divided by CA
if ratio is above 1.0 = advanced
if below 1.0 = delayed

Question 24

Is someone with a CA 10.5yrs ; SA 12.3yrs delayed or advanced?

Answer 24

Indicates maturity is advanced/ early

Question 25

True or false - An increase in height is usually accompanied by an increase in weight ? - justify answer

Answer 25

true - increase in height means an increase in bone mass which means an increase in weight

Question 26

Describe the shape of a BMI that occurs across a lifespan

Answer 26

increases for most and the slowly declines in the elderly

Question 27

What are the advantages to using a longitudinal study compared to a cross sectional study?

Answer 27

longitudinal studies someone more than just once therefore can track status and rate of progress

Question 28

what are 3 skeletal maturity indicators?

Answer 28

1. initial appearance of bone centres
2. definition and characterisation
3. fusion of epiphysis and diaphysis

Question 29

what are the percentile cut offs for children BMI?

Answer 29

<5th percentile = underweight
5th - 85th = healthy
85-95 = overweight
95+ = 0bese

Question 30

when would the major morphological changes occur and when would functional defects and minot morphological changes occur?

Answer 30

major morphological defects would occur in the embryo stage (2-8 weeks)

functional and minor morphological would occur in fatal period (9-38 weeks)

Question 31

why do males tend to be taller than females?

Answer 31

females hit puberty earlier therefore males have an extra two years to grow