Pulmonary Flashcards
goblet cells
secrete mucous
prostaglandins
heparin (anticoagulant)
histamine
cilia
pushes mucous towards pharynx
cystic fibrosis
water layer gets too thick
bronchiectasis
remodeling and thickening of the walls of the large airways
caused by recurrent infxn
what are some causes of bronchiectasis
cystic fibrosis AIDS tuberculosis chronic bronchitis primary ciliary dyskinesia
type I cells alveoli
for gas exchange
type II cells alveloi
sufactant cells
what are the two main factors contributing to inward force of the alveoli
elastic recoil
surface tension of water
what usually causes respiratory distress syndrome in neonates
lack of surfactant
what are a few things that can cause atelectasis
pressure on outside of lungs (fluid build up)
mucus plug blocking airway
lack of surfactant
anesthesia
what is the distance between alveoli and capillary (healthy pt)
0.1-1.5 micrometers
how does air move in and out
pressure gradient
why does the lung move with the thoracic wall?
fluid is the cohesive force and keeps the two pleural membranes together
is the pressure positive or negative in the intrapleural space? why?
negative
lungs pull in, chest pulls out, lymphatic system draining fluid
what happens to alveolar pressure during inspiration and expiration
inspiration decreases then back to base
expiration increases then back to base
what happens to intrapleural pressure during inspiration and expiration
inspiration gets more negative
expiration goes back to base (still negative)
what are the two types of work during breathing
compliance work
airway resistance work
what is flow proportional to?
change in pressure/ resistance
emphysema causes
smoking
alpha 1 antitrypsin (protease inhibitor) deficiency
emphysema DLCO increased or reduced
DLCO reduced
pulmonary fibrosis
thickened alveolar membrane
stiff lung
caused by increased production of fibroblasts and collagen
pulm fibrosis DLCO increased or reduced
reduced
airway resistance
determined by length of tubing, viscosity, and radius
Poiseuille’s Law
determining factors for the radius of the respiratory tubes (4)
mechanical connections (connective tissue, alveoli) physical (mucous) neural control (ANS) paracrine and endocrine (CO2, histamine, prostaglandins, WBC)
pulmonary function test
help determine obstructive vs restrictive disorder
measures FEV1/FVC
bronchitis
inflammation, mucus, infxn, air trapping
asthma mechanism
foreign substance
release of IgE
mast cell degrannulation
muscle contraction, mucus
if the FEV1/FVC > 75% but FVC <75% obstructive or restrictive
restrictive
FEV1/FVC <75%
obstructive
FEV1/FVC > 75% and Normal FVC
normal healthy pt
why in a spirometer chart is the exhale peak fast then slow down slope?
bc as lung volume decreases the airflow out decreases bc bronchioles collapsed easily by chest pressure
closing volume
volume of gas in the lungs in excess of the RV at the time when small airways close
closing capacity
closing volume + RV
what increases closing capacity
age
smoking
FRC decreases
laying down
anesthesia
obesity
FRC < Closing Capacity
closing of some airways occurs during TV breathing
V/Q mismatch
alveoli not being V
pulmonary “minute” ventilation
RR x TV
physiological deadspace
anatomical deadspace + alveolar deadspace
alveolar ventilation
RR x (TV - deadspace volume) ~4.2 L/min
equation for ventilation of alveoli
VA(L/min)= VCO2 (ml/min)/PACO2
metabolic acidosis
VA decrease
PACO2 increase
metabolic alkalosis
VA increase
PACO2 decrease
hypernea (exercise breathing)
?
normal blood volume of the lungs
450mL (9% of total blood)
mean BP in RV
25/ 2 mmHg
mean BP in pulm arteries
15mmHg
mean BP in pulm capillaries
7-8mmHg
mean BP in pulm veins
5mmHg
starlings hypothesis
fluid movement due to filtration across the wall of capillary is a balance of hydrostatic P and osmotic P
Capillary fluid movement equation
(Pc-Pi) - (Oc- Oi)
Pc
capillary pressure
variable depending on pulmonary or systemic
Pi
variable pulmonary or systemic
net positive
fluid will move from capillary to interstitial space
net negative
fluid will move from interstitial space into capillary
3 problems leading to pulmonary edema (changes in starling forces)
nephrotic syndrome (oc decrease)
pulm capillary membrane damage (oc decrease oi increase)
left heart failure (pc increase)
what happens during normal LA pressure increase
recruit more capillaries to open to keep pressure low
V/Q= 1
normal
V/Q> 1
perfusion low
dead space
V/Q< 1
ventilation low
pulmonary shunt
how does the body compensate for high V/Q
bronchoconstriction
how does the body compensate for low V/Q
vasoconstriction
hydrostatic pressure
caused by weight of the blood above it in the vessels due to gravity (pressure increases as you go closer to the ground)
what is the V/Q ratio for the zone 1 of the lung
V/Q>1
how can you clinically measure the V/Q of the lungs
use xenon and capture with a gamma camera
partial pressure
pressure of a single gas
daltons law
total pressure of a mixture of gases is the sum of the pressures of the individual gases
henrys law
at constant temp the amount of a given gas dissolved in a given type and volume of liquid is directly proportional to the partial pressure of that gas in the equilibrium
do equal partial pressures mean equal concentrations of different gases?
NO
what is atomospheric PO2
160mmHg
why is the partial pressure of oxygen in the alveoli not equal to the atmospheric partial pressure of oxygen?
it is humidified and that reduces the partial pressure
oxygen leaves alveoli constantly
water vapor pressure
47mmHg
tracheal PO2 equation
FiO2 * (Patm- PH2O)
PAO2 correcting for humidity and oxygen leaving equation
[FiO2 * (Patm- PH2O) - (PACO2/RQ)]
RQ
ratio of total CO2 production to O2 consumption (CO2/O2)
sugars (carb diet) RQ
1
lipids RQ
0.7
proteins RQ
0.8
mixed RQ
0.8
how do the nonalveolar lung tissues get blood flow
bronchial artery supplies
azygos vein take some to RV
pulmonary vein take some to LV (shunt)
thebesian veins are involved in what
anatomical shunt in heart
what are the factors that affect oxygenation of tissues (5)?
decrease alveolar PO2 diffusion of oxygen through membrane gas transport calc total oxygen carrying capacity CaO2 CO poisoning
how do you decrease PO2?
go higher in altitude
asthma or other obstructive disease (air trapping)
ficks law of diffusion
diffusion rate is proportional to:
(change in pressure * SA * diff. coefficient)/membrane thickness
examples of problems with diffusion
emphysema (loss of SA) pulmonary fibrosis (thickening of membrane) pulm edema (fluid in interstitial space)
DLO2
diffusing capacity of the lung for O2
what is the change in DLO2 when you increase cardiac output (Q)?
it decreases because of decreased pulmonary capillary transit time
pick which one is diffusion limited: nitrous oxide oxygen carbon dioxide carbon monoxide
CO
what is the purpose of the A-a gradient
diagnose the reason for hypoxemia
what is the equation for the A-a gradient?
[FiO2 *(Patm - PH2O)-(PACO2/0.8)] - PaO2
what is a normal A-a gradient
10mmHg
what are the two ways oxygen can be transported?
dissolved in plasma
bound to Hb
what happens to the affinity of Hb to oxygen when the CO2 increases?
the affinity for oxygen decreases
equation for amount of O2 bound to Hb
total Hb * 1.34 * SO2
anemia
decreases Hb and thus decreases CaO2
hematocrit
ratio of red blood cells to plasma (normal range 40-50)
polycythemia
increase in RBC and hematocrit/Hb due to blood doping
blood doping (2)
injection of RBC
use of EPO
polycythemia vera
bone marrow defect
increase in RBC
slows BF and increases clots
red coloring or blueish tint to areas
what does PO2 determine
amount of O2 dissolved in plasma
oxygen saturation of Hb
PO2 = 60 what is SaO2?
90%
PO2= 40 what is SaO2
75%
do ionic interactions that form salt bridges in heme increase or decrease the affinity for O2?
decrease
bohr effect
decrease in O2 affinity of Hb in response to decrease pH due to increased CO2
what causes a right shift in the oxyHb curve?
acidosis
hypercarbia
hyperthermia
increase DPG
how does DPG decrease the affinity of oxygen to Hb
by binding the Hb and causing a conformational change
carrying capacity equation
(total Hb * 1.34 * SO2) + (PaO2 * 0.003)
carry capacity units
mLO2/dL
does CO poisoning shift the curve to the left or the right
left
what are the three ways that CO2 is carried in the blood?
dissolved in plasma (7%)
bound to Hb (23%)
bicarbonate (70%)
what is the role of carbonic anhydrase
H20+CO2=H2CO2
haldane effect
as Hb is oxygenated that promotes carbon dioxide dissociation
what in the brain stem controls breathing (neuronal control)
medulla generates signal
dorsal respiratory group DRG
normal breathing inspiration
ventral respiratory group VRG
inspiration and EXPIRATION (mostly ex)
what two neuronal signaling centers are in the pons to regulate breathing
pneumotaxic center (slower action pot) apneustic center (faster action pot)
what do both the pneumotaxic and apneustic centers relay their signal to?
DRG
where do the vagus and glossopharyngeal nerves send afferent info to?
DRG
what do the central chemoreceptors detect changes in?
CO2
and Hydrogen
what do the peripheral chemoreceptors detect changes in?
O2
(hydrogen and CO2)
aortic and carotid bodies
activation of peripheral chemoreceptors
low PO2 binds to protein on glomus cell inhibits K release increases Calcium entry releases Ach causes action potential on vagus or glosso nerve
T/F the body is more sensitive to changes in CO2 and pH than O2
true
if you are hypercapnic and hypoxic how does that effect the sensitivity of our respiratory changes?
additive and more sensitive
nociceptors
stimulated by particles/gases
elicits bronchoconstriction, cough, tachypnea
hering breuer reflex
overinflation of the lungs
inhibit inspiration at the DRG (inhibits phrenic nerve)
are the peripheral chemoreceptors located on arterial or venous blood supplies? why does this matter?
arterial blood
-b/c when exercising the PaO2 will stay high but you are using more O2, how does your body signal to increase RR?? stretch receptors in your muscles
can the higher brain control breathing?
yes you can change how your breathing by thinking about it
what are the two things in the limbic system that help control breathing?
hypothalamus
amygdala
