the first breath

Question 1

what are the stages of lung development

Answer 1

1. embryonic
2. pseudoglandular
3. cannalicular
4. saccular
5. alveolar

Question 2

when is the embryonic phase of lung development

Answer 2

0-5 weeks

Question 3

when is the pseudoglandular phase of lung development

Answer 3

5-17 weeks

Question 4

when is the cannalicular phase of lung development

Answer 4

16-25 weeks

Question 5

when is the saccular phase of lung development

Answer 5

25 weeks - term

Question 6

where do the first 4 stages of lung development happen

Answer 6

the womb

Question 7

how do babies get oxygen

Answer 7

from the mothers blood through the placenta

Question 8

what are a babies lungs like before they are born

Answer 8

they are filled with fluid

Question 9

what happens in the embryonic stage of lung development

Answer 9

• 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

Question 10

what happens in the pseudoglandular phase of lung development

Answer 10

• 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

Question 11

what happens in the cannalicular phase of lung development

Answer 11

• 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

Question 12

what happens in the saccular phase of lung development

Answer 12

• 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

Question 13

what happens in the alveolar phase of lung development

Answer 13

• 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

Question 14

how long does a babys first breath take

Answer 14

can take up to 30 seconds after birth

Question 15

what does a babys first breath sound like

Answer 15

sounds like a gasp as the baby reacts to sudden changes in temperature and environment

Question 16

what happens to the lungs when a baby takes its first breath

Answer 16

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

Question 17

what changes occur in the lungs after the first breath (4)

Answer 17

1. increased oxygen in lungs - causes decrease in blood flow resistance to the lungs
2. blood flow resistance of the baby’s blood vessels increases.
3. fluid drains or is absorbed from the respiratory system
4. lungs inflate and begin working on their own - moving oxygen into the bloodstream and removing carbon dioxide by breathing out (exhalation)

Question 18

what is the respiratory diverticulum

Answer 18

an out-pocketing that appears in the proximal part of the primitive gut tube (the foregut)

Question 19

what are the changes in the structure of the respiratory diverticulum

Answer 19

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.

Question 20

what does the respiratory diverticulum divide into

Answer 20

two buds - form the left and right primary bronchi

Question 21

what do primary bronchi do

Answer 21

they multiply to give rise to secondary and tertiary bronchi

Question 22

what is the lung bud

Answer 22

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

Question 23

what are pneumocytes

Answer 23

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

Question 24

what are type 2 pneumocytes responsible for

Answer 24

secretion of pulmonary surfactant - reduces surface tension in the alveoli

Question 25

structure of type 2 pneumocytes

Answer 25

cuboidal in shape and possess many granules (for storing surfactant components)

Question 26

what are type 1 pneumocytes responsible for

Answer 26

involved in the process of gas exchange between the alveoli and the capillaries

Question 27

structure of type 1 pneumocytes

Answer 27

squamous (flattened) in shape and extremely thin (~ 0.15µm) – minimising diffusion distance for respiratory gases

Question 28

impact of premature babies on lung disease

Answer 28

• higher risk of developing lung problems
• because their lungs aren’t fully grown
• more likely to get infections

Question 29

lung related diseased caused by premature birth

Answer 29

• newborn respiratory distress syndrome
• lung scarring
• bronchopulmonary dysplasia
• bronchiolitis

Question 30

what is Newborn respiratory distress syndrome (NRDS)

Answer 30

happens when a baby’s lungs are not fully developed and cannot provide enough oxygen, causing breathing difficulties

Question 31

what is lung scarring

Answer 31

babies born prematurely may need a ventilator to breathe properly but ventilation can lead to scarring of the lungs

Question 32

what is bronchopulmonary dysplasia

Answer 32

a form of chronic lung disease

affects premature babies who need oxygen therapy

the lungs and the airways (bronchi) are damaged, causing tissue destruction (dysplasia) in the tiny air sacs of the lung (alveoli)

Question 33

what is bronchiolitis

Answer 33

an infection of the respiratory tract.

bronchioles get infected with a virus.

They swell and fill with mucus, which can make breathing hard.