L3 Growth Changes in Humans Flashcards
What are the different processes that occur to convert the fertilized oocyte to multicellular human ? ( 6 )
- Cell division
- Cell migration
- Cell differentiation
- Cell rearrangement
- Growth
- Apoptosis
What is the effect of birth on the development ?
Birth is merely a dramatic event during development resulting in change in the environment.
From intra to extra-uterine
When most of the developmental changes are completed?
Most developmental changes are complete by the age of 25.
What are the post-natal growth periods ? (5 )
- Infancy ( first year )
- Childhood ( 2 - 12/13 years )
- Puberty (12-15 women / +1 men )
- Adolescents ( 11-19 )
- Adulthood (19 and above )
What does the First 4 weeks ( month ) of Infancy is called ?
Neonatal or new born period
What are the main features of infancy period ?
- Body grows as whole
* length increase by 1.5X
* weight increase by 3X - At the end of 1 year, 6-8 primary (deciduous) teeth will be erupted
What are the main features of childhood ?
- Primary (deciduous) teeth continue to appear
- Secondary (permanent) teeth start to replace the primary
- Active bone formation + ossification
- Prepubertal growth spurt
What are the main features of puberty?
- Development of sex characteristics.
2. Capability of sexual reproduction
When the puberty period ends in males and females ?
In females :Puberty ends by first menstrual flow.
In males : puberty ends when mature sperms are produced.
What are the main characteristics of adolescents period ?
- Ability to reproduce is fully attained.
- Rapid physical and sexual maturation.
- Extend from pubertal development until attainment of physical, mental and emotional maturity.
- General growth rate decreases at the end of this period, EXCEPT Growth of male genitalia, female breast which continue to grow
What are the main features of adulthood?
- Ossification & growth are virtually completed during early adulthood (21-25)
- Developmental changes are slow after early adulthood
What is the cause of Cellular Hyperplasia (Multiplicative growth) ?
Protein and DNA synthesis leading to increase in cell number by mitotic division
Give example of hyperplacia ?
Type- I alveolar cells during childhood
What are the determinate tissue and indeterminate tissue ? ( all of these are examples of hyperplacia )
Determinate :
- Kidney
- Neurons
- Skeletal muscles
- Cardiac muscle
- Alveoli
- Intestinal villi
Indeterminate :
- Liver acinus
- Ovarian follicles
- Thyroid follicles
- Endocrine
- Exocrine
- RBC
What is the cause of hypertrophy ( auxetic growth ) ?
Synthesis of protein and cellular materials leading to increase in cell size and growth of the tissue but without mitotic cell division.
Give example of hypertrophy ?
Neurons hypertrophy in postnatal development
What is ( what is the cause of ) Accretionary growth ?
Growth due to increase in intercellular material like the growth of bone and cartilage
What is Appositional growth ? What is an example ?
It is the addition of both ( new cells + ECM ) on the tissue by a layer of dividing cells
Example :
- the growth of bone by the external periosteum layer