the first breath Flashcards
what are the stages of lung development
- embryonic
- pseudoglandular
- cannalicular
- saccular
- alveolar
when is the embryonic phase of lung development
0-5 weeks
when is the pseudoglandular phase of lung development
5-17 weeks
when is the cannalicular phase of lung development
16-25 weeks
when is the saccular phase of lung development
25 weeks - term
where do the first 4 stages of lung development happen
the womb
how do babies get oxygen
from the mothers blood through the placenta
what are a babies lungs like before they are born
they are filled with fluid
what happens in the embryonic stage of lung development
- a lung bud develops from the foregut
- the bud separates into 2
- later on the lungs separate from the gut
- the two buds form the right and left lung
what happens in the pseudoglandular phase of lung development
- each lung bud keeps dividing (upto 20 times)
- form 3 buds on the right side (upper, middle, and lower lobes of the right lung
- form 2 buds on left side (upper and lower lobes of the left lung)
- by 16 weeks have all of their main airways (bronchi) and smaller airways (bronchioles)
- cells that will eventually become the tiny air sacs (alveoli) start to appear at the end of these smaller airways, like buds on trees
what happens in the cannalicular phase of lung development
- start to develop the areas where air sacs and blood vessels will form, at the end of the smallest airways.
- air sacs needed to get oxygen into their blood when they breathe outside the womb
- cells that will become air sacs carry on developing after birth
- capillaries grow close to these cells
what happens in the saccular phase of lung development
- the end of the smallest airways ( saccules) grow
- eventually develop into early alveoli (air sacs).
- the walls of these saccules get thinner to make more room for air in lungs
- a mixture of fats and proteins begin to form – surfactants - help make sure the air sacs expand more easily and won’t collapse at the end of each breath out
what happens in the alveolar phase of lung development
- the first air sacs (alveoli) develop
- more surfactants are produced as the lungs carry on developing.
- lungs develop and grow to enable oxygen to get into the blood.
- prepares lungs to breathe outside the womb
how long does a babys first breath take
can take up to 30 seconds after birth
what does a babys first breath sound like
sounds like a gasp as the baby reacts to sudden changes in temperature and environment
what happens to the lungs when a baby takes its first breath
the blood vessels around the lungs get wider and the blood flows to the lungs to collect oxygen
the fluid drains and the lungs begin to inflate and work on their own
what changes occur in the lungs after the first breath (4)
- increased oxygen in lungs - causes decrease in blood flow resistance to the lungs
- blood flow resistance of the baby’s blood vessels increases.
- fluid drains or is absorbed from the respiratory system
- lungs inflate and begin working on their own - moving oxygen into the bloodstream and removing carbon dioxide by breathing out (exhalation)
what is the respiratory diverticulum
an out-pocketing that appears in the proximal part of the primitive gut tube (the foregut)
what are the changes in the structure of the respiratory diverticulum
initially, it is continuous with the foregut - not functionally suitable
a longitudinal ridge forms called the tracheoesophageal septum - this makes the two structures compatible with life.
what does the respiratory diverticulum divide into
two buds - form the left and right primary bronchi
what do primary bronchi do
they multiply to give rise to secondary and tertiary bronchi
what is the lung bud
an outgrowth of the foregut portion of the digestive tract, and it turns into lower respiratory tract structures such as the larynx, trachea, and lungs
what are pneumocytes
the cells that line the alveoli and comprise of the majority of the inner surface of the lungs
there are 2 types:
type 1 & type 2
what are type 2 pneumocytes responsible for
secretion of pulmonary surfactant - reduces surface tension in the alveoli
