GROWTH AND DEVELOPMENT . Growth  is natural increase of size of the body as a whole and of its separate parts. Its results from: 1. Multiplication of cells and     2. Increase in size of cells Development  means maturation of organs and system, acquisition of new skills and functions as well as ability to adaptation and assuming responsibilities Factors influencing growth and development ►   Genetic factors (e.g. short stature caused by achondroplasia)  ► Endocrine factors: Growth hormone, thyroid and sex hormones. ► Nutritional factors: Maternal and child nutrition during pregnancy and lactation. ►  Environmental factors and socio-economic status. ► Major congenital anomalies. ►  Chronic infections (e.g. Tuberculosis) and debilitating diseases. ►  Physical activity: Bed-ridden children do not grow normally STAGES OF HUMAN GROWTH AND DEVELOPMENT Prenatal: 1. Embryonic stage: First 12 week of gestation (1st trimester) or period of organogenesis. 2. Fetal stage: From 12th to 40th week of gestation. Period of rapid growth and development. Perinatal: From 20th week of fetal life to 28th day after delivery Postnatal: 1.       Neonatal period: First 4 weeks after birth. It is the most critical period during which the newborn adapts to extrauterine environment. It is mostly affected by: §  Prematurity & • Birth trauma §  Congenital anomalies &                 • Cross infections 2.       Infancy: from 1-12 months. Period of most rapid physical growth and mental development. It is mostly affected by: ·         Infectious diseases (immunizations are given during this period) ·         Nutritional disorders. 3.       Early childhood (toddler age or Preschool age): 1 – 4 years Period of weaning and exploration of outside world. Child is thus exposed to: ·         Accidents and household poisons (insecticides, potash, etc. ·         Nutritional disorders ·         Infections (particularly nursery acquired ones) 4.       Late childhood (school age): 5 – 12 years. Child is mostly exposed to: ·         Accidents and infections ·         Cardiac diseases (e.g. rheumatic fever and bacterial endocarditis) ·         Malignancies (leukemias, Lymphomas, etc.) ·         Psychological and emotional problems 5.       Adolescence (12 – 20 years): Is the passage from childhood to puberty and adulthood. The timing of start and the velocity of pubertal changes are highly variable from person to person. 1.       Early adolescence: 10- 14 years old 2.       Middle adolescence: 15-16 years old 3.       Late adolescence: 17-20 years old The adolescent is subjected to tremendous physical growth & maturation exposing him / her to: ·         Psychological and behavioral problems ·         Acne, and sex hormones-related problems ·         Rheumatic heart disease, diabetes mellitus, malignancies ·         Accidents