Respiratory (FA) Flashcards
where do the lungs develop from? when?
respiratory diverticulum makes lung bud at wk 4
during which weeks is a TEF most possible?
wks 4-7 (the embryonic stage of lung devpt)
when is the fetus capable of respiration
wk 25
when are the lungs (finally) done developing?
wk 95,888,178
justtt kidding.. at 8 years!
what develops at each stage? embryonic (wk 4-7) pseudoglandular (wk 5-17) Cannalicular ( wk 16-25) Saccular (26-birth) Alveolar (wk 36-8 yrs)
embryonic phase (7wk)- 3iary bronchi psuedoglandular phase (17 wk)- terminal bronchioles (w/ little capillaries) cannalicular phase (25 wk) - respiratory bronchi/alveolar ducts w/ prominent capillaries **baby can breathe!** saccular phase (birth)- terminal sacs (1ary alveolar septae) alveolar phase (8yr) - adult alveoli
whats the change in pulmonary vascular resistance upon birth? why?
Pulmonary vascular resistance goes down because the baby is now breathing air not fluid, lower resistance.
pulmonary hypoplasia most commonly caused by what (2) things?
(1) congenital diaphragmatic hernia
(2) bilateral renal agenesis
club cells
type
actions
NONciliated, low columnar/cuboidal
(1) reserve cells
(2) secretory cells- secrete component of surfactant
(3) detox
type I pneumocyte
type
action
thin squamous cell
- line alveoli, permit gas exchange
type II pneumocyte
type
action
cuboidal
(1) secrete surfactant
(2) reserve cells – can become type I pneumocyte if needed, so proliferate during lung damage
what does surfactant do?
surfactant decreases alveolar surface tension
(1) increases compliance
(2) decreases lung recoil
(3) prevents collapse
what is surfactant made of?
lecithin mix, primarily DPPC (dipalmitoylphosphatidylcholine)
when does surfactant production BEGIN? when are there MATURE levels of surfactant?
wk 26 begins
wk 35 mature levels
what are risk factors for NRDS?
- prematurity
- c section
- maternal diabetes (high fetal insulin)
what are the complications of NRDS?
- PDA
- necrotizing enterocolitis
how do you treat NRDS?
how would you NOT treat NRDS and why?
treat: give mom steroids before/during birth, give baby surfactant
do NOT give baby O2. this will cause “ribs”= “retinopathy of premarity, intraventricular hemorrhage, bronchopulmonary dysplasia”
whats in the conducting zone of the lung?
nose/pharynx –> terminal bronchioles
what part of the respiratory tract has the lowest resistance? why?
terminal bronchioles
b/c there are MANY of them in parallel
what in the respiratory zone of the lung?
respiratory bronchioles—> alveoli
what kind of cells are in the trachea and bronchioles?
ciliated, psuedostratified, columnar, goblet cells club cells smooth muscle cartilage
what kind of cells are in the terminal bronchioles
transition from ciliated columnar cells to ciliated cuboidal cells
club cells
smooth muscle
what kind of cells are in the respiratory bronchiles
cuboidal cells (notice, not ciliated)
club cells
smooth muscle
what kind of cells are in the alveoli?
squamous (type I) cuboidal (type 2) macrophages capillaries (notice, no smooth muscle)
when do the goblet cells and mucous glands stop being in the respiratory tract?
after the bronchioles (you wont find them in the terminal bronchioles)
