Week 9 - lecture 3 Flashcards
Stages of lung development and weeks
Embryonic (3-8), Pseudo glandular (5-17), Canalicular (16-26), Saccular (24-38), Alveolar (36-38)
What develops at the embryonic and pseudo glandular stage?
Bronchi, Bronchioles, Terminal bronchioles
What develops at the canalicular stage?
Respiratory bronchioles
What develops at the saccular stage?
Alveolar ducts
What develops at the alveolar stage?
Alveolar sacs
How many alveoli do we have at birth?
20-70 million
How many alveoli do we have at 8 years of age?
300 million
Breathing rate at birth, 1 year, 5-6 years
40 / min, 30, 22 respectively
When is the respiratory tree fully developed?
8 years of age
Thermoregulation
The regulation of body heat
Why are infants colder than adults?
Their body surface area to mass ratio is lower, which means faster rate of heat dissipation
Why do infants have a low digestive enzyme count?
They haven’t needed to digest anything
What age do infants have a full set of deciduous teeth and how many?
30 months and 20 teeth
What does growth hormone do in the body?
Growth promoting effects from the hormone directly on target tissues, stimulates product of insulin like growth factor produced from the liver
What are the insulin like growth factors and what do they act on?
IGF1 - regulation of linear growth - long bone development, protein synthesis, increases cell proliferation
IGF2 - particularly important during the foetal period for organ creation and muscle differentiation
