Growth And Development Flashcards
What is growth?
Increase in size (and mass)
Positive changes in size over a period of time
Increase in size and number of cells- increase in size and weight
What is development?
Specialisation, organisation and maturation
What is human growth and development?
Complex and dynamic physiological process
Involved changes in stature, body proportion, and composition
What is maturation?
Universal sequence of biological events occurring in the body/brain that permit psychological functions to appear (provided infant is healthy and live in an environment containing people and objects)
What are the 9 human life stages (in order)?
1) sperm/egg
2) fertilisation
3) zygote
4) blastocyst (hollow ball of cells)
5) embryo
6) fetus
7) child
8) adolescent
9) adult
What are the 3 germ layers of the embryonic disc?
Ectoderm
Mesoderm
Endoderm
What are the 5 stages of Embryonic development?
1) fertilisation
2) cleavage
3) gastrulation
4) neurulation
5) organogenesis
What is fertilisation?
Day 1
Moment when the ovum (egg) and the sperm join together- form a zygote (fertilised egg)
What is cleavage?
Week 1-2
Mitotic cell division of fertilised egg- produces blastocyst (hollow ball of cells)
What is gastrulation?
Week 3
Extensive cell movement
3 germ layers develop
3 layered embryo has primitive gut
What is neurulation?
Week 3-4
Notochord develops- followed by neural plays from ectoderm layer
Neural plates fold inwards upon itself to form neural tube- develop into spinal cord and brain- forms CNS
Phollic acid is required for the formation of the spinal cord
What is organogenesis?
Week 3-8
Internal organs (and tissues) develop from all 3 germ layers
What are the components of the endoderm (internal layer)?
Lung cells
Thyroid cells
Pancreatic cells
Lining of the gut
Lining of the respiratory system
What are the components of the mesoderm (middle layer)?
Cardiac muscle
Skeletal muscle cells
Tubule cell of kidney
RBC
Smooth muscle (in gut)
What are the components of the ectoderm (external layer)?
Skin cells of epidermis
Neurones of the brain
Pigment cells
When does most growth take place?
Birth- 2 years
Adolescence (puberty)
What is child development ?
Biological, psychological and emotional changes that occur in human beings between birth and the end if adolescence
Individual progressed from dependency to increasing autonomy
Continual process
What is a cephalocaudal trend?
Growth proceeds from head to toe
What is the proximodistal trend?
Growth in an inward to outward pattern (centre of body to the Peripheral)
What is the function of thyroxine?
Secreted from thyroid gland
Normal brain development and overall rate of growth
What is the function of adrenal androgen
Secreted from adrenal gland
Involved in some changes at puberty eg development of secondary sex characteristics in girls
What is the function of testosterone?
Testes
Formation of male genitalia prenatally
Triggers sequence of changes in primary/secondary sex characteristics in males (at puberty)
What is the function of estradiol?
Ovaries
Development in menstrual cycle and breast
What is the function of growth hormones/activating hormones?
Pituitary gland
Rate of physical maturation
Signals other glands to activate them to secrete hormones
