Exam I: Pulmonary Flashcards
what are the key parts of respiration
ventilation-moving air into lungs
diffusion- exchange with blood at alveoli
transport- moving gases to tissues
transfusion/perfusion- gas exchange with tissues
what is the mucucilliary system (clearance)
cells with hairs lines upper and lower respiratory tract,
secrete a sticky mucus layer
spin the incoming air and trap viruses/bacteria in sticky layer
wash layer back to larynx to be killed by HCl in stomach
what saves us from constant PNA
coughing/sneezing
mucocilliary system
macrophages in alveolus
what happens in the conducting zone of the airway
transports and distributes air
warms and humidifies air
traps and clears harmful particles in mucus
what resp structures make up the conducting zone
trachea
bronchi
bronchioles
terminal bronchioles
what happens in the respiratory zone of the airway
exchange gas across alveolar capillary membrane
what structures make up the respiratory zone
respiratory bronchioles,
alveolar ducts,
alveolar sacs
what cells makes up the alveoli tissue
simple squamous epithelium
what tissues are present between gas in alveoli and gas in blood
epithelial cells of alveolus
endothelial cells of capillary
thin layer of fluid between
where is surfactant produced
type II alveolar cells
what structures are within the alveoli
type 2 alveolar cells- produce surfactant
basement membrane- structure of alveoli(type I alveolar cells)
elastin- recoil of alveoli
alveolar epithelium- where it makes contact with capillaries
what is role of surfactant
reduces surface tension
every alveolus has a __________ to prevent infection
macrophage
how many true ribs are there
7 pairs
how many false ribs are there
5 pairs (2 are floating)
how many floating ribs are there
2 pairs
inner intercostal and external intercostal muscles run in ___________ directions
opposite
what are the steps of inspiration
-diaphragm contracts
-sternocleidomastoid pulls sternum and 1st rib
-ribs elevated by scalenes, pec minor, and external intercostals
-rib cage turns out like bucket handle
causes an increase in volume and negative pressure
what are the steps of expiration
passive exp
elasticity of alveoulus
active exp
internal intercostals and abd muscle
causes a decrease in volume and positive pressure
Where is the visceral pleura?
on external lung surface
where is the parietal pleura
lines the thoracic cavity
what is between the visceral and parietal pleura
pleural cavity with thin layer of fluid
what is purpose of constant negative pressure in pleural cavity
suck lungs to rib cage
what law tells us about the relationship between pressure and volume
boyles law
inverse relationship
what law tells us about the relationship between volume and temp
charles law
direct relationship
what does pressure have to be for inspiration
at least 758 (ATM is 760)
what does pressure have to be for expiration
at least 761
what is the law of partial pressures
Daltons law
what is PO2 of venous blood
40mmhg
What is the PO2 of alveolar air?
105 mmhg
What is the PCO2 in the alveoli?
40 mmhg
what is PCO2 in the venous blood
46 mmhg
what is PO2 of atomoshpheric air
159
what causes diffusion process to occur between alveoli and capillaries
partial pressure difference
What is the PO2 of arterial blood?
100 mmhg
what is PCO2 of arterial blood
40
what is Paw
partial airway pressure
what is P A
alveolar pressure
what is Ppl
pleural pressure (pleural space)
what is Pta
Transairway pressure (tracheal wall)
what is PL
transpulmonary pressure
(pressure between alveoli sac and pleural cavity) (pressure within lung tissue)
what is Pl at rest
-5 cm H2O
Pta = ________ - __________
Paw (airway) - Ppl (pleural pressure)
Pl = _________ - ___________
P A (alveolar) - Ppl (pleural)
this is a negative pressure compared to ATM
what creates Ppl
elasticity of lungs
why do your lungs collapse in pneumothorax
no longer - pressure, becomes + so lungs collapse
Ppl ________ during inspiration and _________ during expiration
decreases
increases
P A _________ and returns to zero during inspiration and __________ then returns to zero during expiration
decreases
increases
when do we read peak tidal volume
end of inspiration
what are the 4 volumes we measure in lungs
inspiratory reserve volume
tidal volume
expiratory reserve volume
residual volume
what is total lung capacity formula?
inspiratory reserve volume
tidal volume
expiratory reserve volume
residual volume
or
vital capacity + residual volume
What is vital capacity formula?
inspiratory reserve volume + tidal volume + expiratory reserve volume
What is inspiratory capacity formula?
tidal volume + inspiratory reserve volume
what is functional residual capacity formula?
expiratory reserve volume + residual volume
what is normal tidal volume
500 ml
what is normal IRV (inspiratory reserve volume)
3100 ml
what is normal ERV (expiratory reserve volume)
1100 ml
what is normal RV (residual volume)
1200 ml
what is the definition of inspiratory capacity
The maximum amount of air that can be inspired after the expiration of a normal breath at rest
what is normal inspiratory capacity (IC)
3500 (TV + IRV)
What is FRC (functional residual capacity)?
Amount of air that Remains in lungs at the end of normal expiration
what is normal FRC
2400 (ERV + RV)
what is VC (vital capacity)
Maximum amount of air expelled from lungs after first filling the lungs to a max then expiring to a max
everything - residual volume
what is normal VC
4800 TV + IRV + ERV
What is TLC (total lung capacity)?
Maximum volume of air the lungs can hold
what is normal TLC
6000 (IC + FRC) (or all volumes)
what is FEV1
maximum forced expiratory volume in 1 second
what is FVC%
percentage of FVC forcibly exhaled in one second
what condition do we use FEV1 and FVC% tests for
COPD
bronchitis
emphysema
what factors influence VC
size (height)
environment
what factors change lung functions throughout life
lung damaging activities (smoking)
exercise
age
what is Minute ventilation (MV)
TV x RR
volume of air moved in a minute
what is anatomic dead space in lungs
volume of conducting zone that takes up space but does not exchange gas
where does stale air come from
anatomic dead space, air that is not exchanged
what causes alveolar dead space
inadequate perfusion of ventilated alveoli
what is antomical + alveolar dead space
physiologic dead space volume
what is normal amount of lung being used
1/3
T/F with alveolar dead space shallow/fast breathing is more effective than deep slow breathing
false, deep slow breathing allows for movement in dead spaces
how does hyperventilation affect PCO2
Decreased arterial PCO2 (increases pH)
how does hypoventilation affect PCO2
increased arterial PCO2, decreases pH
What is compliance of the lungs?
how much effort is required to stretch the lungs and chest wall
lung A has set pressure with low volume
lung B has same pressure with higher volume
which lung is more compliant
B
what condition has increased compliance but decreased recoil
emphysema
how does surfactant affect compliance
increases compliance
how do we measure lung compliance
spirometer
how does COPD affect lung compliance
increased compliance with decreased elasticity
How does ARDS affect lung compliance?
decreased compliance (less surfactant)
how does scarring affect lung compliance
decreases
how does pneumonia affect lung compliance
decreases
how do restrictive diseases affect lung compliance (asthma)
decreases
what is recoil direction of rib cage
inward
what is recoil direction of lungs
outward
where do opposing recoil of lungs and rib cage meet
FRC functional residual capacity
how does standing affect lung compliance
-top of lung stretched by gravity
-lower lung more compliant
-upper lung less compliant
what is purpose of surfactant
- Reduces surface tension
- Stops alveoli collapsing and sticking together
without surfactant compliance would ___________
decreases
what determines resistance in airway
radius
what leads to increased resistance in lungs
bronchoconstriction:
parasympathetic stimulation
environmental insults (smoke, cold)
what leads to decreased resistance in lungs
sympathetic stimulation
high CO2
where is turbulent airflow found
highest in smaller bronchi
increases in velocity
how does turbulence affect resistance
increases
how does lung volume affect resistance
increased lung volume decreased resistance
how does forced expiration affect airway pressures/resistance
compresses airway with positive pressure, increasing resistance
when does the lung have the most resistance
high and low volumes
what is the equal pressure point
point in the lung where pleural pressure is same as terminal bronchiole
during peak expiration, pressure is same inside and outside lung
lower pressure of conducting airway is protected by cartilage
what part of airway are we in after reaching EPP
conducting airway, protected by cartilage
how does emphysema affect EPP
EPP moves to smaller branches without cartilage, so air cannot be moved out
how does asthma (restrictive lung disorder) affect lung “work”
increases inspiratory work
how does emphysema (obstructive lung disease) affect lung “work”
increased expiratory work
why do pulmonary vessels need to be compliant
to accommodate stroke volume variations from R vent
what percent of CO goes through pulmonary circulation
100%
what is the purpose of pulmonary circulation
bring blood into contact with alveoli for gas exchange
what is inspired air
PO2
PCO2
159 mmhg (160?)
0.3 mmhg
what is alveolar air
PO2
PCO2
104 mmhg (102?)
40 mmhg
what is arterial blood
PO2
PCO2
95-105 (100) mmhg
40mmhg
what is tissue fluid
PO2
PCO2
40 mmhg
46 mmhg
what is venous blood
PO2
PCO2
40 mmhg
46 mmhg
what causes diffusion in lungs
concentration gradient/ partial pressure
what does the lung filtrate
emboli
thrombi
-small blockages in lungs are better than in heart, brain, kidneys
what is the fucntion of the lung for metabolism
formation of angiotensin 2 by ACE
inactivation of bradykinin, prostaglandins
what are the lungs a reservoir for
hemorrhagic shock
what are the three secondary functions of the lungs
filtration of embli/thrombi
metabolism
blood reservoir
what kind of blood is in pulmonary arteries
deoxygenated
what kind of blood is in pulmonary veins
oxygenated
where does bronchiole circulation come from
R lung -third post intercostal
L lung- aorta
what is function of pulmonary circulation
pick up O2 in lungs
what is function of bronchiole circulation
oxygenate lung tissue
how is pressure in pulmonary circulation when compared to systemic
low resistance, low pressure
pulmonary vessels have _______ smooth muscle
less
what is pressure of systolic and diastolic in pulmonary circulation
15/5
how does an increase in CO affect pulmonary resistance
decreases
what is lung recruitment
opening of more capillary beds to contact alveolar sacs
capillaries also dilate
what are the three ways lungs increase capacity
recruitment
distension
dilation
what is the purpose of recruitment
increased flow at low velocity allows for greater gas exchange
increased areas of capillaries available for gas exchange
lowers pressure and prevents pulmonary edema
how does a high lung volume (increased alveolar size) affect resistance
INSPIRATION
pleural pressures more negative, extra-alveolar vessels expand
expansion of alveolus compresses alveolar vessels, increasing resistance
how does a low lung volume affect resistance
exhalation
more positive pleural pressures compress extra-alveolar vessels
increases resistance
what is the time of lowest resistance in lungs
-FRC (functional residual capacity)
volume at rest after passive expiration
-least compression of blood vesses
how does hypoxia (low O2 tension) in alveoli affect pulmonary vessel resistance
causes pulmonary vasoconstriction
why does hypoxia of alveoli cause pulmonary vasoconstriction
maintain ventilation/perfusion balance
shunt blood to areas of higher oxygenation
how does generalized hypoxemia affect pulmonary vasculature
pulm vasoconstriction
what has a lower hydrostatic pressure, capillaries or alveoli
capillary
what creates pressures within the alveoli
air pressure (pushing out)
surface tension (pullin in)
what creates pressure within the pulmonary capillary
hydrostatic pressure (pushing out)
colloidal osmotic pressure (pulling in)
what fluids are around alveoli/capillary
interstitial fluid
lymph drainage
what is the normal net filtration pressure of capillary to interstitial space
+1 mmhg
a negative hydrostatic pressure of the interstitial fluid leads to a ____________ affect from the capillary
suction
what direction does fluid go between capillary, interstitial space, and alveoli
in normal conditions goes from capillary to interstitial fluid
where does excess fluid from interstitial space go
lymphatic system (has a pressure of -5 mmHg)
where does excess fluid from alveoli go
interstitial fluid
What is physiology of pulmonary edema?
pressure in pulmonary capillaries increases from L sided HF
pressure in interstitial space is greater than +5 mmHg,
fluid cant drain completely into lymphatics
fluid goes into alveoli
pulmonary edema
what condition causes pulmonary edema
L sided HF
damage to pulmonary membrane
what safety factors protect us from death r/t pulmonary edema
negative interstitial pressure
lymphatic pumping
decreased interstitial osmotic pressure
when standing up, the lung has more - pressure, the top of the lung is stretched, and compliance of lung is ____________ so more air goes to __________ part of lung because it is _________ compliant
decreased
lower
more
when standing which part of the lung has more perfusion and ventilation
base of the lung (gravity and compliance effects)
what is Zone 1 of lung
not normal
PA (alveoli) is greater than Pa (arteries)
alveoli compresses arteries
what is zone 2 of lung
Pa (arteries) > PA (alveoli) > Pv (venous)
flow limited by alveolar pressure, dialating venules will not increase flow
what is zone 3 of the lung
Pa >Pv>PA
blood flow is not determined by alveolar pressure
how does gravity affect V/Q
V/Q mismatch
perfusion higher in base of lung
V/Q low at base (excess blood in base)
V/Q high at apex (excess air at apex)
what is normal V/Q
1/1
how does airway obstruction affect V/Q ratio
low V/Q ratio
low V/Q is a ________ issue
ventilation
in a low V/Q ratio
PAO2 ______ normal
PACO2 ______ normal
less than
greater
in a high V/Q ratio
PAO2 ______ normal
PACO2 ______ normal
greater
less than
an arterial obstruction causes a _________ V/Q ratio which causes ___________
high
dead space
what diseases cause low V/Q ratio
COPD
bronchitis
asthma
emphesymea
what causes a high V/Q ratio
pulm embolism
Does FiO2 change with altitude?
no, PaO2 changes
PAO2 is
alveolar O2
paO2 is
arterial O2
what causes drop of atmospheric O2 to alveolar O2
converted to water with CO2 to humidify air (turbinates)
what are factors that affect diffusion
Ficks
thickness of membrane
surface area of membrane
diffusion coefficient
partial pressure difference
how does PNA affect diffusion
thicker walls 2/2 edema = decreased diffusion
CO2 diffuses _______ than O2
faster
How much O2 is dissolved in plasma?
2%
How much CO2 is dissolved in plasma?
10%
what limits the diffusion of O2 and CO2 between capillaries and alveoli?
perfusion, not diffusion rate
what medication can increase diffusion between capillaries and alveoli
N2O
what percent of lungs do we usually use
30%
what increases the diffusion capacity of respiratory membrane
exercise
what happens inside lung to increase lung capacity to exchange O2 CO2
opening of dormant capillaries and increasing of diffusion capacities
(recruitment)
amount of O2 and CO2 in tissues is equal to the amount of O2 and CO2 in ________________
venous blood
how much O2 is carried on Hgb
98% (2% in plasma)
what is the affinity of RBC for carbon monoxide
250x O2 affinity
how does an increased metabolic rate affect PO2
decreases PO2
how does a decreased metabolic rate affect PO2
increases PO2
how does an increased metabolic rate affect CO2
increased
how does a decreased metabolic rate affect CO2
decreased
what factors affect Hgb affinity for O2
acidosis (H or CO2) = decreased affinity
pCO2 increased CO2 = decreased affinity
temp, increased temp = decreased affinity
DPG, increased DPG = decreased affinity
what is DPG
2,3-diphosphoglycerate
released by hypoxic cells
what does hgb decreased affinity for O2 mean
Hgb has a weaker hold, tissues receive O2 more easily, happens in response to increase metabolism or acidotic/hypoxic states
what does SaO2 tell us
% of binding sites occupied by O2
if a tissues has an unusually low PO2 Hgb gives up O2 __________ easily
more (decreased affinity for O2)
how does anemia affect SaO2
SaO2 can read 100% but still hypoxia
how does carbon monoxide affect SaO2
SaO2 can read 100% even in hypoxia
what is it called when oxygen combines with Hbg
oxyhemoglobin
what is a right shift in the oxyhemoglobin dissociation curve
decreased affinity for O2
what is a left shift in the oxyhemoglobin dissociation curve
increased affinity for O2
what processes cause a left shift in the oxyhemoglobin curve
alkalosis
decreased PCO2
decreased temp
low DPG
carboxyhemoglobin
Methemoglobin
abnormal hemoglobin
what causes a right shift in oxyhemoglobin curve
acidosis
high PCO2
increased temp
high DPG
abnormal hemoglobin
What is the Bohr effect?
shift in the oxyhemoglobin dissociation curve caused by changes in CO2 and H+ concentration in blood
How is CO2 transported in the blood?
70% Bicarbonate
20% on Hgb
10% Plasma
what catalyzes the process of CO2 and H2O forming H2CO3 (carbonic acid)
carbonic anhydrase
What is the chloride shift?
HCO3- ions move out of red blood cells into the plasma down a concentration gradient.
To maintain the electrical balance, Cl- ions take their place.
AKA hamburger shift
when Hgb is deoxygenated CO2 can bind to it, this creates
carbaminohemoglobin
What is the Haldane effect?
increased O2 = decreased Hgb affinity for CO2 (arterial blood)
decreased O2 = increased Hgb affinity for CO2 (venous blood)
blood can carry _______ CO2 than O2
more
when oxygen is attached to Hgb what is given off?
what does this then attach to?
what does this become
what breaks it down
what is then diffused out of RBC
H+
HCO3 from Cl- exchange
carbonic acid
carbonic anhydrase breaks it into CO2 and H20
CO2 diffuses out
What is pulmonary circulation?
circulation of deoxygenated blood between heart and lungs
what is bronchiole circulation
oxygenated blood to provide lung tissues
L lung from aorta
R lung from 3rd posterior intercostal arteries
where does deoxygenated blood from bronchiole circulation empty
pulmonary vein, so LA doesnt receive 100% saturated blood
a decreased V/Q ratio is a __________ issue
ventilation
an increased V/Q ratio is a _________ issue
perfusion
what are causes of VQ mismatch
PE (decreased perfusion)
COPD (decreased ventilation)
diffusion block (fluid in lungs)
asthma (decreased ventilation)
what has a greater impact on O2: ventilation or perfusion
ventilation
what two ways is O2 transported
2% in plasma
98% in RBC (hgb)
what are the 4 ways CO2 is transported
10% plasma
20% plasma bicarb
50% RBC bicarb
20% carbaminohemoglobin
why is plasma conversion of CO2 to bicarb slow
no carbonic anhydrase
why is plasma conversion of CO2 to bicarb fast
has carbonic anhydrase
what happens to bicarb in RBC when it reaches the lungs
breathed off as CO2
Where are peripheral chemoreceptors located?
carotid and aortic bodies
Where are central chemoreceptors located?
medulla oblongata
what are mechanoreceptors in the lungs sensitive to
stretch
J receptors
irritant (cough)
where is an area of high concentration of irritant mechanoreceptors
carina
what muscle are involved in inspiration
sternocleidomastoid- raises sternum
external intercostals- flips ribs out
diaphragm- pulls down
what is end result of inspiratory muscle movement
increased (-) pressure
-5 (baseline) to -10 - -30
What are chemoreceptors sensitive to?
CO2
H
O2
inspiration has to be triggered by
muscles
expiration is mostly
passive recoil
what breathing control centers are in the Medulla
DRG (dorsal respiratory group)
VRG (ventral respiratory group)
what breathing centers are in the PONs
pneumotactic center
what does the DRG do
PURE inspiration
basic rhythm of quiet breathing
what does the VRG do
increased ventilation over quiet/resting
increases Expiration and inspiration
using muscle for expiration
what is the pneumotactic center responsible for
depth and rate of breathing
T/F the pneumotactic center is dormant during quiet breathing
false
always active
what triggers pneumotactic center
CO2
T/F we dont need a trigger for inspiration
false
must trigger inspiratory muscle
T/F we need a trigger for expiration
false
normally passive recoil
what part of respiratory cycle does emphysema screw up
expiratory, loss of recoil of lungs
when is electrical activity high in the diaphgram
inspiration (makes sense since this is contraction and expiration is relaxation)
in inspiration pleural pressure is __________ and electrical activity is ________
decreased
increased
in expiration pleural pressure is __________ and electrical activity is ________
increased (to baseline)
decreased (to baseline)
Where does the DRG receive input from?
chemo and mechanoreceptors
pneumotactic center
what is the inspiratory ramp signal
-signal transmitted to inspiratory muscle increases steadily for 2-3 second during quiet respiration
-ramp allows for a steady increase in volume rather than short gasps
inspiratory phase is (shorter/longer) than expiratory phase
Shorter
what makes the ramp effect
transmission of impulse
length of time of muscle activation
what is the role of the pneumotactic center
regulates DRG
controls rate and duration of inspiration
depth and speed or breathing
when is VRG activated
during times of increased respiratory need (exercise)
when forced expiration needed
when is VRG inactive
quiet respiration
what respiratory control center stimulates forced expiration
VRG
why is CO2 the trigger for respiration
has a smaller range of intravascular levels (40 arterial, 46 tissues)
increased CO2 (increases/decreases) respiratory depth and rate
increases
what is feedforward control
proprioceptors in joints/muscles can trigger increased respiration in response to increased movement
is feedforward control CO2 controlled
no
what fine-tunes the feed forward control
negative feedback
what nerve primarily carries mechanoreceptor impulses
vagus nerve
Where are pulmonary stretch receptors located?
airway smooth muscle in bronchi and bronchioles
what stimulates the pulmonary stretch receptors to fire
increased pressure in lungs (stretch)
What is the Hering-Breuer reflex?
reflex triggered to prevent over-inflation of the lungs.
Pulmonary stretch receptors present in the smooth muscle of the airways respond to excessive stretching of the lung during large inspirations.
what prevents overstretch of lungs during inspiration
Hering Breuer reflex of pulmonary stretch receptors
When is the Hering-Breuer reflex activated?
3x tidal volume (1500 ccs)
where are irritant mechanoreceptors found
epithelium of larger conducing airway
what triggers irritant receptors
particulate matter causing inflammation mediators (histamine, serotonin, prostaglandins)
what are the conducting airways
trachea, bronchi, bronchioles, terminal bronchioles
do conducting airways have air exchange
NO
what is response of irritant receptor activation
cough/sneeze
bronchoconstriction
what illnesses can irritant receptor activation cause issues in
asthma, emphysema
what cells does asthma cause issues with
goblet cells
where are the J receptors located
in/near alveoli- juxtapulmonary receptors
What do J receptors respond to?
acute congestion/edema
damage
what is response of J receptors
stimulates increased ventilation
what do the peripheral chemosensors respond to
CO2, H+, O2 (in that order)
What do the central chemoreceptors respond to?
primarily
CO2
secondarily
H
what is goal of all mechanoreceptors
increase ventilation
get O2 to body
when do chemo receptors respond to PO2
<60mmHg
T/F the blood brain barrier is highly permeable to H and HCO3
False
its poorly permeable
T/F metabolic acidosis significantly lower CSF pH
False
T/F respiratory acidosis significantly lower CSF pH
true
T/F the blood brain barrier is permeable to CO2
True
its a gas passes freely
what happens after CO2 crosses BBB
combines with water and becomes H and HCO3 in CSF
how long does it take the kidney respond to acid/base imbalances
2-3 days
how long does it take the lungs to respond to acid/base imbalances
immediate
what triggers the respiratory centers in the medulla
H+ in CSF
where does H+ in CSF come from
CO2 crossing BBB
where do peripheral chemoreceptors send their signals
DRG
what kind of oxygen do peripheral chemoreceptors read
PaO2,
not total oxygen content
what else are peripheral chemoreceptors sensitive to
cyanide
arterial pressure <60
what chemo receptors sense hypoxia
only peripheral
hyperventilation leads to (hypo/hyper) capnia
hypo
resp alk
T/F hyperpnea during exercise causes abnormal blood CO2
False
increased metabolism creates CO2, no no hypocapnia
hypoventilation leads to (hypo/hyper) capnia
hyper
resp acidosis
what can trigger hyperventilatoin
hypoxia
when is hyperventilation triggered by hypoxia
PaO2 < 60 mmHg,
causes decreased PaCO2 and high pH in short term
how does body respond to high altitude
hypocapnia initially increases CSF pH
overtime bicarb is excreted by the kidneys, allowing an increase in ventilation
do arterial O2, CO2 and pH change during exercise
NO
what are bodies fluid chemical buffers for hydrogen ions
Rapid but temporary
Bicarbonate
proteins
ammonia
phosphate
how do the lungs regulate hydrogen ions
rapid
respond to acidosis by increasing ventilation, thus eliminating CO2 and decreasing pH
how do the kidneys regulate hydrogen ions
slow, powerful
eliminate non-volitile acids
secretes H+
reabsorbs HCO3-
generates new HCO3
what is the most important ECF buffer?
formula?
bicarb
H2O+ + CO2 <-> H2CO3 <-> H+ + HCO3
what is the phosphate renal buffer
formula
phosphate
HPO4- + H+ <-> H2PO4- (phosphoric acid)
what is the ammonia renal buffer formula
ammonia
NH3 + H+ <-> NH4+ (ammonium)
what is an important intracellular buffer
proteins
H+ + Hb <-> HHb (hemoglobin)
where does 60-70% of buffering occur
cells
what determines the effectiveness of a buffer system
-concentration of reactants
-pK of system and pH of body fluids
what is pK
concentration of H+ per pH reading. balanced is pK=6.1
know the bicarb buffer equation
H2O+ + CO2 <-> H2CO3 <-> H+ + HCO3
what enzyme has to be present to convert H2O and CO2 to carbonic acid and vise versa
carbonic anhydrase
what is the most important buffer in ECF
bicarbonate buffer system
what organs closely regulate the bicarb formula
lungs- CO2
kidney- HCO3-
How do the lungs regulate pH?
increased H+ -> increased alveolar ventilation -> decreased pCO2
How do kidney regulate pH?
eliminate non-volatile acids (sulfuric acid, phosphoric acid)
filter bicarb (HCO3)
secretion of H+
reabsorption of bicarb
production of new bicarb
excretion of bicarb
for every HCO3 reabsorbed, the must be a __________ secreted
H+
where is most bicarb reabsorbed in the kidney
proximal tubule- 85%
thick ascending loop of henle- 10%
late distal tubule - 4.9%
collecting duct- .1%
how is sodium bicarb reabsorbed/excreted in proximal tubule and thick loop of henle
1) Na+ H+ pump exchange takes Na from tubule, puts H into tubule
2) carbonic acid formed
3) carbonic acid broken into CO2 and H2O
4)H2O excreted
5) CO2 reabsorbed into cell
6) CO2 combines with H2O in cell with carbonic anhydrase to form H2CO3 (carbonic acid)
7) H+ breaks off from carbonic acid
8) HCO3 (bicarb) reabsorbed into blood
9) H+ is available to exchange for another Na (step one)
how does aldosterone affect renal pH control
causes sodium uptake and H+ secretion (Na/H pump)
how is bicarb reabsorbed and H secreted in intercalated cells of late distal and collecting tubules
1) CO2 absorbed from blood
2) CO2 combines with water in intercalated cell to form carbonic acid
3) carbonic acid dissociates into HCO3 and H+
4) HCO3 is reabsorbed
5) H is secreted (into urine) by use of ATP or with a K exchange
increase CO2 = ___________ H+ secretion
increased
what is increased CO2 in body leading to acidotic state
resp acidosis
increased extracellular H = _____________ H+ secretion
increased
what causes an increase in tubular fluid buffers to increase H+ secretion
respiratory or metabolic acidosis
what conditions cause you to increase H+ secretion and HCO3 reabsorption
increased PCO2 (resp acidosis)
increased H+ and decreased HCO3 (metabolic acidosis)
increase in aldosterone
increased angiotensin 2 (increases aldosterone)
decreased ECF volume
hypokalemia
what conditions cause a decrease in H secretion and HCO3 reabsorption
decreased PCO2
decreased H+ and decreased HCO3 (metabolic alkalosis)
decrease in aldosterone
decreased angiotensin 2 (decreases aldosterone)
increased ECF volume
hyperkalemia
what is renal compensation for acidosis
increased H secretion
increased HCO3 reabsorb
produce new HCO3
what is kidneys response to alkalosis
decreased H secretion
decreased HCO3 reabsorb
loss of HCO3 in urine
in acidosis when H+ is being in secreted what must be present in urine
buffers, limited to the amount of free H kidneys can excrete
what is the minimum pH of urine before damage occur
4.5, this is why we need buffers for H excretion
what occurs when NaHPO4- acts as a buffer in urine
one Na used to exchange for H for excretion, forms with NaHPO4- as a buffer
Turns NaHPO4 to H2PO4, phosphoric acid
new HCO3 formed in cell to be reabsorbed into blood
what is NH3
ammonia
what is NH4
ammonium
where is NH4 secreted in nephron
proximal,
thick loop of henle,
distal tubules
where does glutamine come from
amino acid metabolism from liver
what does glutamine break down into
2 bicarbs
2 ammonium
how does ammonium get removed from tubular cell
Na+ /NH4+ exchange pump (NH4 excreted)
how is H+ and NH3 buffered in collecting tubules
NH3 is permeable, freely passes through tubular cell wall into tubular lumen
CO2 froms with H2O to form bicarb in cell, with H+ as byproduct
H+ excreted with ATP from tubular cell
NH3 and H form NH4, excreted with Cl- to form ammonium chloride
what causes acidosis (pH <7.4)
metabolic: decreased HCO3
respiratory: increased pCO2
what causes alkalosis (pH>7.4)
metabolic: increased HCO3
respiratory: decreased pCO2
what is normal body pH
7.35-7.45
what is normal ratio of HCO3 to CO2
20:1
what is the pH range that is compatible with life
6.8-7.8
acid base imbalance chart
what is Respiratory acidosis:
pH:
Primary disturbance:
Compensation:
pH: low
PD: increased CO2
Comp: renal acid excretion, bicarb reabsorption
what is metabolic acidosis:
pH:
Primary disturbance:
Compensation:
pH: low
PD: decreased HCO3
Comp: hyperventilation to cause low CO2
what is Respiratory alkalosis:
pH:
Primary disturbance:
Compensation:
pH: high
PD: decreased CO2
Comp: decreased renal acid excretion (retain more H) increased bicarb excretion (B intercalated cells)
what is metabolic alkalosis:
pH:
Primary disturbance:
Compensation:
pH: high
PD: increased HCO3
Comp: hypoventilation with increased CO2
what is normal ABG HCO3
22-26 mEq/L
what is BG interpretation for
pH: 7.12
PCO2: 50
HCO3: 18
mixed acidosis
what is BG interpretation for
pH: 7.6
PCO2: 30
HCO3: 29
mixed alkalosis
what is measured in anion gap
Cation
Na +
Anion
Cl-
HCO3-
in body fluids anions should be ___________ cations
equal to
what is a normal anion gap
8-16
how do you calculate anion gap
Na-(Cl+HCO3)
when do we use anion Gap
metabolic acidosis
what are the unmeasured anions
proteins
sulfates,
ketones,
phosphates,
lactate,
what does an increased anion gap tell us
an increase in the unmeasured anions
what is a metabolic acidosis with a normal anion gap
hyperchloremic metabolic acidosis
(increased Cl, decreased HCO3)
what is metabolic acidosis with an increased anion gap
(so Cl normal, HCO3 low)
normochloremic metabolic acidosis
-diabetic ketoacidosis
-lactic acidosis
-salicylic acid
what is BG interpretation for
pH: 7.2
PCO2: 55
HCO3: 26
resp acidosis
what are causes of respiratory acidosis
brain damage
pneumonia
emphysema
lung disorders
what is BG interpretation for
pH: 7.5
PCO2: 40
HCO3: 30
metabolic alkalosis
What are the causes of metabolic alkalosis?
increased base intake (NaHCO3)
vomiting gastric acid
mineralcorticoid excess (aldosterone)
overuse of diuretics (except carbonic anhydrase inhibitors)
what is BG interpretation for
pH: 7.34
PCO2: 29
HCO3: 15
metabolic acidosis (resp compensation)
what is BG interpretation for
pH: 7.49
PCO2: 48
HCO3: 35
metabolic alkalosis (resp compensation)
what is BG interpretation for
pH: 7.34
PCO2: 60
HCO3: 31
respiratory acidosis (metabolic compensation)
what is BG interpretation for
pH: 7.62
PCO2: 20
HCO3: 20
respiratory alkalosis (metabolic comp)
what is BG interpretation for
pH: 7.09
PCO2: 50
HCO3: 15
mixed acidosis
how does the kidney regulate the body fluid acidity
bicarbonate
what is carbonic acid
H2CO3
what actually drives respiration
H+ ions around pons in CSF
where do loop diuretics work
thick ascending loop of henle
what are the loop diuretic examples
furosemide
bumetanide
ethacrynic acid
which transporter does the loop diuretic work on
1 na, 2 cl and 1 K transporter
“triple transporter”
what do loop diuretics bind up to have effect
2 chloride on triple transporter
what does loop diuretic cause excretion of from triple transporter
Na
K
Cl
where do thiazide diuretics work
early distal tubule- on sodium chloride transporter
what does thiazide diuretic inhibit
sodium chloride transporter- so sodium stays in lumen and draws water into lumen for excretion
what are some aldosterone antagonists
spironolactone, eplerenone
what are some sodium channel blockers
amiloride, triamterene
how do osmotic diuretics work and where?
proximal convoluted tubule
pull water in to dilute the extra concentrates in the lumen
where do loop diuretics work
thick ascending loop of henle
block Cl on triple symporter, so K and Na stay in the lumen to be excreted along with Mg and Ca
where do thiazide diuretics work
distal convoluted tubule
blocks the Na Cl sympoter
where do K sparing diuretics work
collecting duct
block aldosterone and Na channels on Na K antiporter
what are types of K sparing diuretics
Na channel blockers ( amiloride)
Aldosterone antagonist (spironolactone)
define pulmonary ventilation
inflow and outflow of air between the atmosphere and lung alveoli
how can lungs be contracted
- downward and upward movement of the diaphragm to lengthen or shorter the chest cavity
-elevation and depression of the ribs to increase or decrease AP diameter
what is considered quiet breathing
the movement of diaphragm to expand lungs
What is minute respiratory volume
Total amount of new air moved into the respiratory passages each minute
Min resp vol= tidal vol + resp rate per min
What is a normal min resp vol
6L/min
What are the lung volumes
Tidal volume
Inspiratory residual volume
Expiratory reserve volume
residual volume
What are the four lung capacities
Vital lung capacity (tv+ irv+ erv)
Inspiratory capacity (tv+irv)
Functional residual capacity
Total lung capacity
When bicarb is being brought into the RBC through a transporter what is being pushed out
Chloride molecule
How much non-volatile acid produced a day
~60-80 mmol/day
What are the important renal tubular buffers
Phosphate
Ammonia
Renal regulation of acid base
Eliminate non volatile acids
Filter bicarb
Reabsorb bicarb
Produce new bicarb
Excrete bicarb
Secrete H ions
How is glutamine formed
From metabolism of amino acids
What is the systolic and diastolic for systemic circ
93/2
What’s the average MAP for pulmonary capillaries
10
What happens to pulmonary resistance as CO increases? Why?
Decreases
Recruitment and distention
Reduced airflow to a particular region of the lung leads to:
Reduced blood flow to that area
Blood shunts to alveoli that has airflow
Generalized hypoxemia=
Generalized vasoconstriction
Leads to high pressures backing up in the heart
What’s the interstitial osmotic pressure
14 mmHg
Colloid osmotic pressure ____ and hydrostatic pressure _____
Pulls
Pushes
How does smooth muscle tone affect flow
PNS causes constriction and increased mucous production
SNS causes dilation and increased fluid secretion
Environmental insults can cause vasoconstriction
High CO2 causes dilation of resp tract
How does turbulence influence resistance
Increases resistance
Branching airways decreases resistance
Define Bohr effect
CO2 and H are affecting the affinity of Hb for oxygen
Define Haldane effect
Oxygen is affecting the affinity of Hb for CO2 and H
What airway generations are the conducting zone
0 trachea
1-2/3 bronchi
4-7 bronchioles
8-16 terminal bronchioles
What airway generations are the respiratory zones
17-18 respiratory bronchi
19-21 alveoli duct
22-23 alveoli sac
Physiological dead space is about ____ of ____ _____ in healthy people
1/3
Tidal volume
How can you determine alveolar ventilation
Measure CO2 output
Equal pressure point
The pressure inside the alveolar duct/respiratory bronchi is = the pressure in the pleural cavity
What factors affect the rate of diffusion in a fluid
Solubility of gas in the fluid
Cross sectional area of the fluid
Distance through which the gas must diffuse
Molecular weight of the gas
Temp of the fluid
The O2 conc/ partial pressure is controlled by
Rate of absorption of O2 into the blood
Rate of entry of new O2 into the lungs
What does the pneumotaxic center do
Controls the “switch off” point in the inspiratory ramp
Controls the filling phase of the lung cycle
When does dead space occur
When there is ventilation but no perfusion
When does a shunt occur
When there is perfusion but no ventilation
What is a normal FEV1/FVC%
80%
Airway obstruction is 47%
What causes chronic pulmonary emphysema
Infection
Obstruction
Loss of parenchyma
What are consequences of COPD
High airway resistance
Decrease diffusing capacity
Pulm hypertension
Consequences of pna
Significant decrease in arterial hgb saturation
Hypoxia is sensed by
Peripheral chemoreceptors
Define hypoxia
Low O2 supply at lungs and tissue
Define hypoxemia
Low PaO2
Low blood O2
Control of ramp signal
Rate of increase
Control of limiting point (drop off point)
