Lifespan Development 1 Flashcards
Define lifespan development
Age related changes that occur from birth through a persons life into, and during, old age
What are 6 stages of lifespan development?
Infancy = Birth - 2 years Childhood= 2-10 years Adolescence= 10-20 years Early adulthood= 20-40 years Middle age/ Young old = 40-65 years Older age= 65+ years then old old
Describe prenatal development
1st trimester = embryological and foetal development. Major organ systems begin being laid down as endoderm-mesoderm-ectoderm
2nd trimester= organ and organ systems are developed. Body shape + proportions change. Baby looks human like by 6 months.
3rd trimester= rapid foetal growth and deposition of adipose tissue. Major organ systems function at start of this trimester.
Organ development
After 1 week - Placenta develops
2 weeks = Brain and spinal cord
3 weeks= Heart and foetal circulation
4 weeks= Lungs
What is critical time period?
Where different organs are at risk if exposed to something. The changes are irreversible.
Anything mother exposed to goes to the foetus through placenta
Foetal circulation adaptations
Umbilical vein- from placenta to liver or ductus venosus
Ductus venosus- from umbilical vein to inferior vena cava
Foramen ovale- blood from RA to LA
Ductus arteriosus- Passes blood from pulmonary artery to aorta
Umbilical artery- Blood from foetus to placenta as an aortic branch
FOETAL CIRCULATION
Foetal capillaries and mother’s blood mixes in placenta
Blood carried through umbilical vein to liver or the ductus venosus
Ductus venosus carries blood from umbilical vein to IVC
Blood becomes slightly oxygenated
SVC and IVC expel blood into RA
Blood flows through RV, and pulmonary artery to both lungs.
Baby alveoli filled with fluid
HYPOXIC PULMONARY VASOCONSTRICTION- air sacs constricts arterioles.
Hugh pulmonary artery pressure, high resistance in lungs and high pressure in R side of heart
RA pressure higher than LA so blood flows through foramen ovale into LA
Pulmonary veins take blood to LA too
LA to LV
Blood flows through aorta
Some blood from pulmonary arteries went through ductus arteriosus to aorta down pressure gradient
Aorta branches to umbilical artery carry blood back to placenta (which is low resistance)
So in foetus- pressure high in lungs and low in placenta
Describe immediate changes after birth
Baby takes first breath and lungs expand
Blood rushes into pulmonary system and oxygen levels rise
Oxygen causes Ductus arteriosus to close + takes 24 hrs to close. Blood fully directed to lungs.
Pressure rises in LA so foramen ovale closes (if not, then hole in heart)
Cord gets clamped after birth- ductus venosus closes up as lack of blood from placenta causes closure
No more umbilical vein or umbilical artery
NOT SIMPLY SMALL ADULTS
Humans are born immature
Humans not fully formed
Body systems need to develop through infancy, childhood and adolescence
WHAT IS RESPIRATORY SYSTEM LIKE IN CHILDREN?
The rib cage is soft and cartilaginous (firms at three yrs)
Poorly developed,open intercostal muscles and less type one muscle fibres
Angle of insertion of diaphragm is horizontal not domed
Preferential nasal breathers
Airways diameters small and increased airway resistance + WOB, so high pulse rate and breathing rate
Less cartilaginous support in airways so can collapse?
Poorly developed cilia so don’t waft as well
About 150 million alveoli at birth (300 million as adult)
No collateral ventilation at birth
Higher resting metabolic rate and higher O2 requirements.
MSK system in infants
Babies born with 300 bones- will fuse later to 206 bones
Bones are soft and cartilaginous - ossify over time
Muscle fibres small and watery
Body fat laid down until 9-12 month old
NEUROLOGICAL SYSTEM IN INFANCY
Brain is 1/4 of total body weight at birth - floppy neck and head
Lower centres of brain mostly developed
Normal exhibition of flexural tone (curled up)
Possess primitive reflexes (eg, routing)
All neurones and nerves present from birth
Transient exuberance- dendrite growth in brain to form pathways
Facts about physical growth
At birth = 1/3 of adult height
Growth in 3 phases- rapid as infant, then slow as child and slows even more in adolescence
Body parts grow at different rates eg, bones, muscles ,hands
Weight increases before height
What can influence growth and development?
GENETIC OR ENVIRONMENTAL
GENETIC- determines gender, race and physical status
ENVIRONMENT- Growth and development by family, religion, culture, climate, school, community and nutrition
A poor nourished child = more prone to infection and won’t attain potential height
Factors affecting physical growth
Traits + characteristics inherited at birth
Single or multiple births
Physical and mental health of mother during pregnancy
Abnormal or normal delivery
Conditions of care at delivery
Care of baby and mother
Child’s nutrition after birth
