Lecture 2 Flashcards
What are the three stages of prenatal growth? and weeks?
- fertilized egg or zygote (first 2 weeks)
- Embryo (weeks 2-8)
- Fetus (weeks 9-40)
What happens in stage 1 of prenatal growth?
- egg or zygote is fertilized
- doubles in size every 24hrs
- rapid cell division
- Differentiation of multiple cell layers
What are the three layers of the Gastrula?
- 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
What are the two different types of twins?
identical (monozygotic) - splitting of fertilized ovum
Fraternal (dizygotic) - 2 eggs & 2 sperm
What happens in stage two of prenatal growth?
Embryo (2-8 weeks)
- rapid growth
- differentiation of stem cell tissues
- basic anatomical and physiological features
what is totipotent and pluripotent?
2 different types of stem cells
what are the male and female chromosomes?
male = XY Female = XX
What happens if Y gene is inactive? What is DSD?
- 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
What is stage 3 of prenatal growth?
- fertilized egg or zygote (first 2 weeks)
- Embryo (weeks 2-8)
- Fetus (weeks 9-40)
What is a low birth weight?
below 2.5kg
What is pre term?
birth 37 weeks and before
What are some direct and indirect factors that affect birth weight?
direct - smoking, alcohol, ethnicity
indirect - maternal age , socioeconomic status
Prenatal loss - what are the chances of conception? What is the rate of spontaneous abortion of fertilized eggs?
- chances of conception 25-30%
- spontaneous abortion of fertilized eggs 35%
What % will have congenital malformations?
which are also chromosomal abnormalities - XXYY XXY XYY
1%
What was thalidomide used for
used to treat morning sickness
How does low birth weight = TII diabetes (diabetes mellitus)??
Low birth weight = stunted growth of pancreas = decrease in beta cells = decrease capacity to produce insulin = pancreatic exhaustion and diabetes
What happens (risks) to a heavy/high birth weight for date baby?
full term and heavy/ high birth weight for date = increase risk of hyperinsulinemia (high insulin output) = pancreatic exhaustion and diabetes
What is anthropometry? examples
a technique for taking measurements of the body and parts of the body
eg. body size, weight, height
What are skinfolds used for?
measure body fat around the body
How do you work out BMI?
weight divided by height (m2)
11.7 divide 0.85 squared = BMI - 16.2
What age do males and females increase height until?
males increase until age 20
females peak 16-18
What is a method for measuring skeletal maturation ?
Gruelich-pyle (GP)
- method using x-ray and comparing to a standard plate
eg - wrist and hand bones
How do you work out skeletal age (SA) is advanced or delayed to chronological age (CA) ??
SA divided by CA
if ratio is above 1.0 = advanced
if below 1.0 = delayed
Is someone with a CA 10.5yrs ; SA 12.3yrs delayed or advanced?
Indicates maturity is advanced/ early
True or false - An increase in height is usually accompanied by an increase in weight ? - justify answer
true - increase in height means an increase in bone mass which means an increase in weight
Describe the shape of a BMI that occurs across a lifespan
increases for most and the slowly declines in the elderly
What are the advantages to using a longitudinal study compared to a cross sectional study?
longitudinal studies someone more than just once therefore can track status and rate of progress
what are 3 skeletal maturity indicators?
- initial appearance of bone centres
- definition and characterisation
- fusion of epiphysis and diaphysis
what are the percentile cut offs for children BMI?
<5th percentile = underweight
5th - 85th = healthy
85-95 = overweight
95+ = 0bese
when would the major morphological changes occur and when would functional defects and minot morphological changes occur?
major morphological defects would occur in the embryo stage (2-8 weeks)
functional and minor morphological would occur in fatal period (9-38 weeks)
why do males tend to be taller than females?
females hit puberty earlier therefore males have an extra two years to grow
