Unit 2 Flashcards
What are the 4 major types of studies
Case study, cross sectional, longitudinal and mixed cross sectional and longitudinal
what are the other names for a mixed cross sectional and longitudinal study
cross-sequential or mixed longitudinal
What is a Case study
a research design that focuses on one person or one event
What are case studies useful for
when there is a need to obtain an in-depth appreciation of an issue, event or phenomenon of interest, in its natural real-life context
What is a cross-sectional design
a measure of individuals at a given age only once in the sample. It acts as a snapshot at the age sex or specific group. Provides information on the status of the individuals and there can be variability within the sample group
What is a longitudinal design
a repeated measurement of the same group of individuals over a long period of time. provides information on status and change over time including rate of change in growth and maturation
what is the difference between the two types of mixed longitudinal designs
one design has no overlap between ages in various cohorts and the other has overlap within the cohorts
What features are the same in both types of mixed longitudinal designs
both have same start and end times among cohorts, both have different start and end ages across cohorts and both require individuals to be measured repeatedly
What are the pros and cons of a longitudinal study
takes 20-25 years
costs lots of money
requires a long term research team
commitment of participants for long periods
technology changes over time
Pros and cons of cross-sectional design
short term study
less money
shorter commitment
technology more stable
must be careful with sample size calculation
only provides information on status
pros and cons of mixed longitudinal
recruit participants at different starting ages
measure each group for 4 years
overlap ages
more practical length
we can only speculate that we would see similar results in a true longitudinal design
What are measurements taken of in these types of studies
dimensions, preformance or level of activity
what devices are used to record data in these types of experiements
ultrasounds, scales, calipers, ergometers, accelerometers and tape measures along with other equipment
what underlying processes may you be observing in these types of studies
stages of maturity or patterns of activity
What is the use of an ultrasound in prenatal growth assessment
fetal number
fetal age
fetal position
identify deformities
identify sex at about 12 weeks
How does a ultrasound work
- high frequency sound waves are sent through the abdomen through the device
- the waves are reflected back towards the transducer
- the transducer detects the distances travelled by the waves
- the sound waves are converted into a video or photo format
Why is the onset of pregnancy difficult to measure
a healthy sperm can live inside a women’s body for 2-5 days, sperm must reach a released egg and fertilize it which can take about 24 hours and then the fertilized egg will travel through the fallopian tube entering the uterus which can take another 3-4 days`
When is the period of the egg
the first 2 weeks after fertilization
When is the period of the embryo
after the first two weeks, the cells implant themselves into the wall of the uterus beginning the period of the embryo through 8 weeks
when is the period of the fetus
9 weeks until 40 weeks or birth
Features of the embryo at 5 weeks
-cells have burrowed into the wall of the uterus
-measures approximately 2mm
-the foundations for all major organs are in place
-the baby is indie an amniotic sac
features of fetus at 9 weeks
-The head has straightened out and more fully developed
-the ears are continuing to grow
-toes are visible
-all of the babies essential organs have begun to develop
-size of macoroni
features of fetus at 9 weeks
-The head has straightened out and more fully developed
-the ears are continuing to grow
-toes are visible
-all of the babies essential organs have begun to develop
-size of macaroni
Features of fetus at 11 weeks
-heart is formed and pumping
-brain is still developing
-nerves and muscles are starting to work now
-size of brussels sprout
Features of fetus at 14 weeks
-sex becomes apparent
-head is getting rounder
-almost 3.5in long or the size of a nectarine
features of a fetus at 18 weeks
-yawn
-hiccupping
-swallowing
-the size of baby shampoo or 8.33in
features of a fetus at 22 weeks
-eyelids fused shut still but eyes start moving
-tear ducts are forming
-eye brows form
-baby becomes more responsive to external stimli
-size of an avacado
features of a fetus at 30 weeks
-hands are now formed and finger nails are growing
-baby is grabbing their feet
-kicking
-hair growth
-size of cabbage
features of a fetus at 40 weeks
-measures about 22.2in on average
-weighs abut 7.6lbs
-lungs are the last organ to finish developing
-size of watermelon
Most premature baby ever to survive
Amilla at 22 weeks
25cm
0.62lbs
smallest baby ever to survive
saybie at 23 weeks
0.5lbs
Are there risks if the baby is overdue
the baby may appear abnormally thin as a result of not receiving sufficient nutrition at the end of the pregnancy
-function of placenta decreases giving fewer nutrients and less oxygen
What are somatic cells
the cells in the body other than sperm and egg cells
What is required for normal somatic growth
Integrated function of money of the hormonal, metabolic and other growth factors
What are the three most common measurements done for newborn babies
weight, length and head circumference
What is the ponderal Index
measurement similar to BMI used for low birth weight babies
What is an anthropometric measurment
set of standardized techniques to systematically measure the body and its segments
What are essential features for anthropometric measurments
defined landmarks, specific positions and appropriate instruments
Head circumference
important from birth to age 3-4, measures brain growth, to find measurement tape measure is placed around the head just above the eye brows
expected Infant Length growth
1 inch per month for the first 6 months of life and then 0.5 in for the next 6 months of life
Factors affecting an infants height/weight/length
whether the baby was born prematurely or past their due date and if it was a single or multiple babies
Factors affecting infant growth
genetics, diet and activity level
What is the most important thing about a childs growth
That it maintains a health growth trend rather than measurements compared to other individuals
Standing Height
an anthropometric measurement that requires standard instuction such as head, shoulders and butt against the wall while looking straight forward
Sitting Height
an anthropometric measure that allows decomposing of stature and can be connected to disease and nutrition levels
-allows us to see torso length, thigh length and shin length
Waist circumference
an anthropometric measure that assess obesity-related health risk. its preformed while standing around someones waist at their belly button during exhale
Skinfolds
an anthropometric measure that indicates subcutaneous adipose tissue and change in growth and maturation. can be taken from 12 sites most commonly the triceps or subscapular area
What can you calculate with subscapular skin folds
Body density and composition
-% fat
-fat weight
-fat-free weight
-body weight goals
Assumptions made when preforming skinfolds
double fold of skin and adipose tissue with no muscle
challenges when preforming skinfolds
inter-rater reliability - two different people may preform it two different ways
also painful if preformed incorrectly
Value of preforming skinfolds
inexpensive, easy, identify direction of change
Anthropometric data assumptions
accurate and reliable data
standardized techniques
training of the researchers
Anthropometric data measurement errors
Intra-rater variability (consistent individually)
Inter-rater variability (consistent between individuals)
instrument variability
Systemic errors in anthropometric data
consistent over/under measuring, leads to directional error
Technical errors of meaurement
instrument or user error
participant variation errors
physiology (muscle tension or sweat interfering with measuring
temperament, cooperation, anxiety
gender size differences
minimal difference pre-adolescence, early adolescence females have size advantage until males surpass females
How can body size be measured
mass or stature
What does body weight measurements include
bones, fat, organs
body height meausrement
linear measurement from plantar surface to vertex of the skull including feet legs trunk neck and skull
Changes in weight through the day
heaviest at the end of the day due to nutrition, hydration and physical activity that occured throughout the day
Changes in height through the day
tallest in the morning, vertebral disks unload over not and compress during the day causing a difference of about a cm
what does the ration between weight and height indicate
nutritional status in pre-adolescence, growth spurt in adolescence, obesity and health in adults
what does the ratio between height and stature indicate
the portion of height accounted for by the trunk of leg
what does the ratio between hip and shoulder width indicate
changes to the body often due to athletics and is most apparent during adolescence
what is the technical name for hip to shoulder ratio
bicristal breadth to biacromial breadth
The center for disease control and prevention growth charts
a reference for how children grew during a period in the US
The WHO growth charts
contain data from breastfed babies, recommended for babies under 2
