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)
how many lobes:
R lung
L lung
3 lobes- right lung
2 lobes- left lung + lingula (+ space for heart)
whats the pulmonary A’s relative position to the broncioles?
RALS
- R pulm A is Anterior
- L pulm A is Superior
where is an inhaled foreign body likely to end up?
- if upright– RLL
- if suping- RUL
what passes the diaphragm at T8
IVC and phrenic N
“ I8 10eggs at12”
what passes the diaphragm at T10
esopahgus, and vagus N (CNX)
“ I8 10eggs at12”
what passes through the diaphragm at T12?
aorta, thoracic duct, azygous vein,
“red, white, and blue”
“ I8 10eggs at12”
what bifurcates at
C4
T4
L4
C4- common carotid
T4: trachea
L4: abdominal aorta
after a normal breath, how much more can you breathe in?
after a normal breath how much can you breathe out
IRV
ERV
how much is breathed in while silently/quietly breathing?
and what is the amount?
TV (= 500 mL)
what is the amount thats left in your lungs after a silent breath out?
FRC = ERV+ RV
what is the total amount you can breathe out after a big breath in?
vital capacity
TV+ IRV+ ERV
whats the total amount thats left in your lung after a big breath in
Total lung capacity
TV+ IRV+ ERV +RV
what lung volumes cannot be measured? why?
FRC and TLC and RV
FRC and TLC both have RV in them which is not measurable
how do you measure the physiologic dead space?
taco paco peco paco
Vd= VT * ((PaCO2- PECO2)/ (PaCO2) )
how do you calculate minute ventilation?
VE= VT* RR
how do you calculate alveolar ventilation?
Va= (VT- VD)*RR
or
Va= VE- VD
a normal VD?
150 mL/breath
a normal RR
12-20 breath/min
what is methemoglobin
hemoglobin who has an Fe3+
what can methemoglobin be caused by?
nitrites and benzocaine
in what situation would you give someone nitrites and thiosulfate?
to MAKE methemoglobin. Why? because methemoglobin has high affinity for cyanide. in cases of cyanide poisoning it can sequested the cyanide
what does methemoglobin poisoning look like? whats the cure?
cyanotic. chocolate colored blood.
give the patient Methylene Blue + vitamin C
what is carboxyhemoglobin
hemoglobin thats bound to carbon monoxide
what does carboxyhemoglobin poisoning look like? whats the cure?
it causes cherry red skin, headaches and dizziness
the cure is: 100% hyperbaric O2
(hint: fires, car exhaust, gas heater)
how do you calculate O2 content of blood?
(1.34* Hb* SaO2) + (0.003PaO2)
what gases are perfusion limited?
O2( good health, not emphysema or fibrosis), CO2, N2O
what gases are diffusion limited?
CO
O2 (in emphysema and fibrosis)
how do you calculate the diffusion capacity?
Velocity of gas= ADk ((P1-P2)/ T)
so increasing surface area, diffusion coefficient of the gas and pressure differences in the 2 chambers will cause more rapid diffusion
meanwhile increasing the thickness of the barrier will cause lower diffusion
