Please enable JavaScript.
Coggle requires JavaScript to display documents.
1.21.5.11 - Fetal Respiratory Development - Coggle Diagram
1.21.5.11 - Fetal Respiratory Development
germ layers
mesoderm
kidneys, liver, gonads, bones, heart, blood cells
endoderm
lining of the digestive tract and the respiratory system
ectoderm
epidermis (skin) nervous system and pigment cells
embryonic endoderm
two tubes within the body
digestive tube
liver
gallbladder
pancreas
respiratory tube
bifurcates into two lungs
formation of lung buds
process of branching morphogenesis
many genes involved
lungs kidneys, mammary glans
highly influences surrounding mesenchymal tissue
A. formation of laryngotracheal groove
buds into main bronchi
B. further budding may be unequal
e.g. three right lobes, two left lobes
C. final septation distinguishes pharynx form larynx and trachea from oesophagus
local mesenchyme
regional specificity of mesenchyme determines differentiation
in the neck, mesenchyme grows straight = trachea
in the thorax, mesenchyme branches = bronchi and lungs
left lobe vs right lobe
left = tracheal mesenchyme = straight bronchi
right = retained lung mesenchyme = branched bronchi
branching at the foregut
forms the respiratory diverticulum
formation of the trachea and lung buds
trachea develops as outgrowth of foregut at repiratory diverticulu
lung buds form and continue budding
at vary between speices
most lung development is in utero
highly sensitive to surrounding tissue
at birth, lungs work but are immature
stages of lung development
canalicular
saccular
psudoglandular
alveolar
embryonic
in all species, lung development continues postnatally
long time in litter bearing species
factors affecting lung development
intruterine space
fetal breathing movements
intrathoracic space
lung liquid production
affect = underdeveloped lungs
can manifest as exercise intolerance
neonatal support may be needed
hormones increasing surfactant
catecholamines
thyroid hormones
glucocorticoids
conditions
polyhydramnios
excess amniotic fluid during pregnancy
oligohydramnios
deficient amniotic fluid during pregnancy
glucocorticoids
reduce the work of breathing
increas elastin content
thinning of alveolar wall and intersitial tissue
differentiation of type II pneumocytes
help lung inflation and prevent collapse
increase surfactant production
increase enzymes responsible for phospholipid synthesis
increase lung fluid
increase pulmonary beta adrenoreceptors
icrease enzymes responsible for phospholipid synthesis
prepare lungs for new environment
increase antioxidant enzymes
surfactant
function
allow alveolar cells to touch without sticking together
composition
90% phospholipid
10% protein
reduce the surface tension to have air filled lungs open
17 out of 24 lung bud divisions occur in utero
no surfactant = respiratory distress syndrome
glucocorticoids mature the lung
lung liquid production
lungs secrete liquid into the lung cavity
helps to inflate lungs
helps lungs grow
no secretion = no development
fetal breathing movements
denervation of diaphragm = lung hypoplasia
late gestation develops respiratory muscles and matures alveoli
causes movement of water
important for lung growth
intra-uterine space
fetal lungs need adequate spcae
lack of amniotic fluid = uterine compression
leads to pulmonary hypoplasia
intra-thoracic space
need for sufficient space
abdominal contents enter the thorax
compression of lungs = hindrance of growth