Week 4: Physical Growth Flashcards
Distance curve
Plots the average size (weight or height) of a sample of children at each age and indicates typical yearly progress toward maturity.
What are centile marks on a distance curve
Centile marks on a distance curve represent specific percentiles that indicate how a child’s measurements (such as weight or height) compare to the general population at each age. They provide a way to assess whether a child’s growth is within the typical range for their age group.
-Centile lines (often shown as a series of curves) are drawn at specific percentiles, such as 2nd, 5th, 10th, 25th, 50th, 75th, 90th, 95th, and 97th.
-The 50th centile represents the median or average value, meaning 50% of children fall below this mark and 50% above it.
Important thing is that a child’s growth should steadily track a centile line if they are suddenly deviate that could be a sign that something is wrong.
Velocity Curves
A velocity curve: Plots the average amount of growth at each yearly interval and reveals the exact timing of growth spurts.
e.g. 1st year see a lot of growth then at 12 for girls and 14 for boys is another period of rapid growth (due to hormonal changes)
Changes in body proportions
Cephalocaudal growth trend is clear i.e. at 2 months the head makes up about 50% of total length and this reduces as the child grows i.e. the body and limbs starting growing more rapidly than the head
Skeletal Growth (what is the skeleton like when the baby is an embryo and how does growth continue across childhood… when does it stop?)
-Skeletal age provides the best estimate
of a child’s physical maturity.
-Embryonic Skeleton is initially comprised of soft, pliable tissue called cartilage. From the 6th week of pregnancy, cartilage cells begin to harden into bone
-The epiphysis (pl. epiphyses) is a vital growth centre that appears just prior to birth. Growth plates or epiphysial plates continue to produce cartilage cells throughout childhood and sit at either end of each long bone. After the growth plates disappear, no further bone- in length – is possible
If you looked at two images one of a 2 1/2 year old’s hand and one of a 14 1/2 year olds hand what would you see in terms of skeletal growth?
You would see big gaps between the finger bones in the x-ray of the toddler as this is where the cartilage growth plates are (won’t show up on the x-ray as they are not bone).
The teenager will not have big gaps as their finger skeletons would have finished growing the epiphysis/ growth plates would have disappeared.
What is Epiphyseal fusion? What is recent research showing about this aspect of skeletal growth?
-This is when growth plates thin and disappear i.e. when the bone is finished growing the epiphyseal plates disappear in a process known as epiphyseal fusion
-Research is showing that this fusion is happening earlier for children than it used to , i.e. there is a new normal for how fast children are growing
Open the slides and look at the gross motor development milestones table for early-middle childhood…. pick and-think about a motor activity pertaining to one of the age groups break it down into it’s component parts i.e. what do you need to be able to do?
Example -> Pedal and steers tricycle (present from about 3-4 years old)
-Moving legs separately in sequence, bending legs -> will become automated
-Planning where to go in order to steer, hold attention – gaze (cognitive)
-Balancing on seat
-Think about where body is in space (Proprioception)
-Gripping the handlebars, holding arms in front
-Multi-tasking, coordination of different processes
Are there gender differences in gross motor development? Why are they likely to exist?
-Differences in motor skills between boys and girls increase with age
-Sex differences in physical capacity remain small throughout childhood
-Difference in motor skills that emerges is not likely due to physical capacity then but rather social/ cognitive factors. Example: bodys at 12 are able to throw a ball much further than girls. This is likely because boys are encouraged to throw balls and be sporty. They practice these skills and it becomes automated. Girls on the other hand are not as encouraged and significantly have less financial banking / positive societal influences for being invovled in sports and so don’t have as much motivation or practice throwing the ball so naturally are worse despite no physical difference in their capacity for the movement.
What is the pituitary gland? What key things does it influence?
-Small pea- sized gland at the base of the brain regulated by the hypothalamus
-Directly releases growth hormone throughout the life and this acts on body tissue from birth onwards stimulating growth and cell regeneration note = does not cause growth in the central nervous system or genitals
-Encourages release of other hormones from other areas (often referred at the ‘master gland’)
estrogens from the ovaries
testosterone from the testes
androgens from the adrenal cortex
thyroxine from the thyroid
The hypothalamus monitors hormone levels and adjusts pituitary activity based on feedback from the body.
(good flowchart for this in the slides)
What happens if a child lacks growth hormone?
-Unlikely to exceed 1.3 meters
UNLESS
-Treated with growth hormone injections
Brain development numbers i.e. what percentage of it’s adult weight is the brain at birth, age 2 and age 6.. what can we infer from this pattern?
At birth: a child’s brain ≈ 30% of its adult weight
* By age 2: a child’s brain ≈ 70% of its adult weight
* By age 6: a child’s brain ≈ 90% of its adult weight
Inference = Huge growth in brain weight in first two years of life -> likely due to large number of connections that are forming/ synapses. Dendrites grow at very fast rate to form connections/ synapses with other neurons
What is the role of genes/ environment in brain development?
Genes provide the blueprint for brain development, but experience plays a crucial role in shaping the brain’s architecture beyond that.
“The brain’s circuitry must rely on experience to customize connections to serve the needs of the individual.” This follows a “use it or lose it” principle. A vast number of neural connections form in the first few years of life, but if these circuits are not regularly activated, they are pruned. On the other hand, frequent use strengthens these connections, allowing more complex circuits to build upon the basic framework, leading to further refinement.
Other environmental influences include:
Nutrition: Protein, healthy fats (especially omega-3s), iron, zinc, and vitamins (B-complex, D, and E) support brain cell formation, synaptic connectivity, and neurotransmitter function. Poor nutrition, particularly in early childhood, can impair cognitive development and processing speed.
Social interactions: Caregiver interactions shape brain wiring. Responsive caregiving—through eye contact, talking, and physical touch—strengthens neural connections related to emotion regulation, language, and social cognition. On the other hand, neglect or lack of interaction can lead to fewer synaptic connections, particularly in areas like the prefrontal cortex, affecting emotional control and cognitive flexibility.
