Growth and Development Flashcards
What is growth?
Positive change in size, often over a period of time.
What is development?
The process of growth to maturity.
What are the life stages?
- Infancy: birth to 1 year.
- Early childhood: 1-6 years.
- Late childhood: 6-12 years.
- Adolescence: 12-20 years.
- Early adulthood: 20-40 years.
- Middle adulthood: 40-65 years.
- Late adulthood: 65 years.
- Death.
What factors affect growth and development?
1) . Prenatal and birth factors.
2) . Genetic/chromosomal factors –> inherited.
3) . Racial factors.
4) . Endocrine system.
5) .Drugs.
6) . Illness - children grow slower during illness.
7) . Nutrition.
8) . Environment.
9) . Stress.
What are the developmental stages of embryology?
1) . Fertilisation.
2) . Cleavage.
3) . Gastrulation.
4) . Neurulation.
5) . Organogenesis.
What is the stage of fertilisation?
Day 1.
- Sperm and ovum join together to form a zygote.
What is the stage of cleavage?
Week 1-2.
- Mitotic cell division of the fertilised egg which produces the blastocyst, a hollow ball of cells.
What is the stage of gastrulation?
Week 3.
- Cell movement in which 3 layers develop –> 3 layered embryo.
What is the stage of neurulation?
Week 3-4.
- Neural plate fold in upon itself to form the neural tube –> this will form the brain and spinal cord.
What is the stage of organogenesis?
Weeks 3-8.
- The internal organs develop from the ectodern, endoderm and mesoderm.
What are the 3 germ layers that develop during the gastrulation stage?
1) . Ectoderm –> outside layer.
2) , Endoderm –> inside layer.
3) . Mesoderm –> middle layer.
What do the 3 germ layers produce?
1) . Ectoderm
- Skin cells of epidermis.
- Neuron of brain.
- Pigment cell.
2) . Endoderm
- Lung cell (alveolar cell).
- Thyroid cell.
- Pancreatic cell.
3) . Mesoderm
- Cardiac muscle.
- Skeletal muscle cells.
- Tubule cell of the kidney.
- red blood cells.
What are the 4 types of growth and development?
1) . Physical: body growth.
2) . Mental: mind development.
3) . Emotional: feelings.
4) . Social: interactions and relationships with others.
When do the 4 types of development occur?
In each stage of growth and development.
What is human physical growth?
Increase in size/number of cells –> increase in overall size.
When does most rapid growth take place?
In utero –> first 2 years of life and adolescence.
How is growth measured?
- Weight.
- Length.
- Head circumference.
- Skinfold thickness.
How does the growth velocity change in the first 2 years?
Growth velocity is high, but falls from over 200 to 90mm/year.
How does the growth velocity change 12 to 14 years?
Sharp increase in growth velocity from 70 to 100mm/year.
What are the main hormones responsible for the 2 growth spurts?
Growth hormone
- sex hormones (testosterone, oestrogen) are responsible for the adolescence growth spurt.
What are the 2 growth trends?
- Cephalocaudal.
- Proximodistal.
What is the cephalocaudal trend in growth?
- Grow from head down.
- Head and chest grow first before legs.
What is the proximodistal trend in growth?
- Center of the body grows outward.
- Arms and legs grow before hands.
What gland/hormones are important in growth?
1) . Thyroid –> thyroxine.
2) . Adrenal –> adrenal androgen.
3) . Testes –> testosterone.
4) . Ovaries –> Estradiol.
5) . Pituitary –> growth hormone + activating hormones.
How does thyroxine affect growth?
Normal brain development and overall rate of growth.
How does adrenal androgen affect growth?
Involved in some changes at puberty –>
- particularly the development of secondary sex characteristics in girls.
How does testosterone affect growth?
- Formation of male genitals.
- Triggers changes in primary/secondary sex characteristics at puberty in males.
How does estradiol affect growth?
Development of menstrual cycle and breasts in girls.
How does the growth hormone + activating hormone affect growth?
- Rate of physical maturation.
- Signals other glands activating to secrete hormones.
What is experience-expectant growth in the brain?
- Ordinary experiences “expected” by brain to grow normally.
What is experience-dependent growth in the brain?
- Specific experience, varies widely.
