Growth and Development Flashcards
Growth refers to an increase in?
Size or number
Growth is what kind of phenomenon?
An anatomic one
Development refers to an increase in?
Complexity
Development is what kind of phenomenon?
Physiologic or behavioral
The head makes up what percentage of the body as a fetus, newborn, and adult?
50%, 25%, and 12% respectively
When is neural tissue done growing?
By 6-7 years of age
The curve for body growth takes what shape?
S-shaped
Describe the growth of lymphoid tissue?
Reaches 200% of adult size by age 10 then rapidly involutes
What happens during the first stage of the female growth spurt?
- Breast buds
- Early pubic hair
- Growth spurt begins
When does the second stage of the female growth spurt occur and what happens?
One year after the first stage
- Peak of height
- Noticeable breast development
- Auxillary hair
- Dark pubic hair
When does the third stage of the female growth spurt occur and what happens?
12-18 months following the second stage
- End of height spurt
- Menarche
- Broadening of hips
- Female weight distribution
What happens in the first stage of the male growth spurt?
Fat spurt and increase in size of testes and scrotum
When does the second stage of the male growth spurt begin and what happens?
About one year after the first stage
- Begin height spurt
- Loss of fat
- Dark pubic hair
- Growth of penis
When does the third stage of the male growth spurt occur and what happens?
12-18 months after the second stage
- Facial hair on lip
- Peak of height
When does the fourth stage of the male growth spurt begin and what happens?
15-24 months after the third stage
- Facial hair on chin
- End of height spurt
- Adult auxiliary/pubic hair
- Weight gain- muscle
The maxilla and mandible grow at what rate relative to the body? Which finishes growing first?
Grow faster than the body. The maxilla finishes growing first
Describe the growth curve in males relative to females
it is wider and taller
On average the female growth curve peaks how many years before males? On average males grow how many years longer?
2 years for both
What are the 4 experimental methods for measuring growth?
Vital staining, tetracycline staining, implants, and autoradiographs
Vital staining uses what?
Alizarin which stains newly forming bone
What does tetracycline do to teeth?
It will stain newly forming enamel
What 3 things cause hard tissue growth?
Hypertrophy, hyperplasia, secretion of ECM
Which is more important?
Hyperplasia
In hard tissue growth, what happens to ECM?
Mineralizes
How does soft tissue growth occur?
Mainly by hypertrophy and hyperplasia, ECM secretion is secondary
When hypertrophy and hyperplasia occur in all places at the same time this is?
Interstitial growth
At what point can interstitial growth no longer occur?
When tissue mineralizes
What are the major sites of interstitial growth?
base of skull and the long bones
In development of the chondrocranium, what is present at 8 weeks?
Solid bar of cartilage from the nose to the occiput
What is present at 12 weeks?
Intramembranous bone formation in the brain case and jaws, bone replaces cartilage
In intramembranous ossification, bone is formed in what kind of environment? How is bone formed?
Membranous, formed by secretion of bone directly into connective tissue
Endochondral ossification occurs in what type of environment?
Cartilagenous. Bone grows up into the cartilage and displaces it
What is a suture or syndesmosis?
Joint between two bones without cartilage and a fibrous layer between the bony tissues
Where is a suture or syndesmosis seen?
Cranial vault and face
What is a fontanel?
Like a suture but bigger
What is symphysis
A joint between two bones with membranous and cartilage tissue
Where is symphysis seen and what kind of ossification is it?
Endochondral, connects the two halves of the mandible
What is synchondrosis?
A joint between two bones with cartilage but no fiber
How is a synchondrosis formed and where is it seen?
Endochondral ossification, seen in the cranial base
What is synostosis?
Bone ceases to grow and the joints become fused
Most of the initial formation of the mandible is due to what kind of growth?
Intramembranous ossification
Where does the growth of the mandible occur?
Lateral and anterior to Meckel’s cartilage
What kind of growth is seen in the condyle and when does it fuse with the mandible?
Endochondral, it fuses with the mandible at 4 months
Growth of the cranial vault is due to what process? What causes the growth?
Intramembranous ossification, grows in response to brain growth
When does the cranial vault ossify?
9 weeks in utero
The bones of the cranial base are initially formed in?
Cartilage
What occurs simultaneously to growth of the cranial base?
Sphenoidal sinus growth
By what process does the maxilla grow? In what direction?
Intramembranous ossification. Grows away from the cranium, down and forward
What causes growth of the maxilla?
Growth of the nasocranial complex and soft tissue growth
The mandible grows in which direction but is translated?
Grows up and back but is translated down and forward
Where is the biggest growth of the mandible seen?
In the posterior aspect
At what age is the inter canine width and maxilla size established?
8 years old
When does the jaw stop growing?
It doesn’t, it is continuously remodeled
In terms of facial growth, what is determined by genetics?
Bone and cartilage
Describe Dr.Moss’s theory?
Soft tissue function defines form. Soft tissue sends signals to bone and cartilage and they respond accordingly
