Exam 3 Condensed Flashcards
Is the V/Q ratio higher at the top or bottom of the lungs and why?
high at top
due to GRAVITY, the apex is more ventilated by less perfused
What zone of the lungs are better ventilated and have experience the greatest volume change?
zone 3
What zone has the highest blood flow (most perfused)?
zone 3
What zone is the most ventilated?
zone 3
What zone has the higher PO2?
zone 1
What zone has the higher PCO2?
zone 3
What four mechanisms control breathing?
- control centers in brainstem
- chemoreceptors
- mechanoreceptors
- respiratory muscles
What are the 2 brainstem respiratory centers?
medulla
pons
What are the 2 respiratory groups of the medulla center?
dorsal
ventral
What does the dorsal respiratory group (DRG) do?
controls rhythm of inspiration
Where does the dorsal respiratory group (DRG) receive it signals from?
pre-Botzinger complex
Where does the dorsal respiratory group (DRG) send its signals?
diaphragm
What does the ventral respiratory group (VRG) do?
controls forceful expirations
Why is the ventral respiratory group (VRG) usually not active?
normal exhalation is passive
What respiratory group is responsible for the sign reflex with the help of the pre-Botzinger complex?
VRG
What are the 2 respiratory groups of the pons?
apneustic
pneumotaxic
What does the apneustic respiratory group do?
long inspiration with short expiration
What other respiratory group does the apenustic group talk with?
DRG (both deal with inspiration)
What does the pneumotaxic repiratory group do?
turns of DRG so it can control inspiration and rate of breathing
Where are the central chemoreceptors located?
under medulla in brainstem
What respiratory group do central chemoreceptors communicate with?
DRG
What molecule are central chemoreceptors most sensitive to?
[H+]
pH changes
Where are peripheral chemoreceptors located?
carotid body
aortic arch
What molecule are peripheral chemoreceptors most sensitive to?
changes in O2
What receptor receives more blood than organs?
peripheral chemoreceptors
Which peripheral chemoreceptor senses changes in pH while the other receptors does not?
carotid body receptors
What are the 2 mechanoreceptors?
irritant receptors
J receptors
What do irritant receptors do?
cause constriction of bronchial smooth muscles to increase breathing rate
- located in between epithelium
What do J receptors do?
sense enlargement of capillaries and will increase interstitial fluid (Starling force) to increase breathing
- located in alveolar walls near capillaries
What does the FEV1/FVC ratio represent?
percentage of a person’s vital capacity (FVC) that they can exhale in the first second of a forced exhalation (FEV1)
In asthma, is the FEV1 or FVC smaller and why?
FEV1
its harder to breath out
In fibrosis, is the FEV1 or FVC smaller and why?
FVC
harder to breath in
What is anatomic dead space?
volume of conducting airways
What is functional dead space?
hypoxic alveolar volume
What is physiological dead space?
functional + anatomical dead space
How do you calculate pulmonary minute ventilation?
tidal volume x breaths/min
How do you calculate alveolar ventilation?
(tidal volume - dead space) x breaths/min
What is tidal volume?
normal amount of air displace when breathing
What is expiratory reserve volume (ERV)?
max volume of air expired from lungs after a normal expiration
What is inspiratory reserve volume (IRV)?
max volume of air expired from lungs after a normal inspiration
What is residual volume?
amount of air left over after max expiration
How do you calculate inspiratory capacity
inspiratory reserve volume + tidal volume
IRV + VT
How do you calculate functional residual capacity?
expiratory reserve volume + residual volume
ERV + RV
How do you calculate vital capacity?
inspiratory reserve volume + expiratory reserve volume + tidal volume
IRV + ERV + VT
How do you calculate total lung capacity?
sum of all volumes
IRV + ERV + VT + RV
In zone 1 of the lungs what the relationship between, PA, Pa, Pv?
PA > Pa > Pv
In zone 2 of the lungs what the relationship between, PA, Pa, Pv?
Pa > PA > Pv
In zone 3 of the lungs what the relationship between, PA, Pa, Pv?
Pa > Pv > PA
Why is ventilation so poor in zone 1?
alveoli are not compliant
What is the Law of LaPlace?
attractive forces liquid molecules causes small alveoli to have high surface tension and are difficult to inflate
How do you calculate the alveolar pressure?
(2 x surface tension) / radius
In respiratory acidosis…
pH:
[HCO3-]:
PCO2:
direction of equation:
pH: decrease
[HCO3-]: increase
PCO2: increase
direction of equation: right
In respiratory alkalosis…
pH:
[HCO3-]:
PCO2:
direction of equation:
pH: increase
[HCO3-]: decrease
PCO2: decrease
direction of equation: left
In metabolic acidosis…
pH:
[HCO3-]:
PCO2:
direction of equation:
pH: decrease
[HCO3-]: decrease
PCO2: NO CHANGE
direction of equation: left
- too much acid in blood wipes out HCO3-
In metabolic alkalosis…
pH:
[HCO3-]:
PCO2:
direction of equation:
pH: increase
[HCO3-]: increase
PCO2: NO CHANGE
direction of equation: right
- excess HCO3-
In a closed pneumothorax, pressure of the pleural space ____ pressure of atm
pressure of pleural space < pressure of atm
In an open pneumothorax, pressure of the pleural space ____ pressure of atm
pressure of pleural space = pressure of atm
In a tension pneumothorax, pressure of the of pleural space ____ pressure of atm
pressure of pleural space > pressure of atm
What is the pressure of O2 in alveoli?
104
What is the pressure of CO2 in alveoli?
40
What is the pressure of O2 in mixed venous blood?
40
What is the pressure of CO2 in mixed venous blood?
46
What is the pressure of O2 in oxygenated blood?
100
What is the pressure CO2 in oxygenated blood?
40
What is the pressure of O2 in the air?
160
What are 3 reasons why PO2 in alveoli is lower than the atm PO2?
- water vapor
- left over air
- CO2 diluting O2
What is the most important regulator of pulmonary flow?
PO2 in alveoli
What is the enzyme that catalyzes CO2 + H2O –*-> H2CO3- —> HCO3- + H+
- carbonic anhydrase
What is the Haldane Effect?
CO2 transport via Hb is influenced by O2
ex: low O2 increases Hb binding to CO2
What is the Bohr Effect?
high CO2 and low pH can shift the O2 curve to the right
What 3 systems are used to regulate pH of body fluids?
- lung system
- kidney system
- buffering system
HCO3- concentration is regulated by what organs?
kidneys
CO2 concentration is regulated by what organs?
lungs
At higher P O2, more Hb molecules have transitioned from tensed to relaxed state there for a higher/lower affinity for O2
higher affinity
On a Hb-O2 disassociation curve, oxygen deprivation causes the curve the shift left or right?
right
What 3 things can affect the shape of the Hb-O2 curve?
temperature
pH
Co2
Does Hb have a higher or lower affinity for O2 at low temperatures?
higher
Does Hb have a higher or lower affinity for O2 at low pH?
lower
promotes O2 release
Does Hb have a higher or lower affinity for O2 at high CO2 levels?
lower
promotes O2 release
Is pH or CO2 the dominant controller of Hb affinity for O2?
pH
What is the purpose of 2,3-bisphosphoglycerate?
stabilizes the tense (deoxygenated) form of Hb, which reduces Hb’s affinity for oxygen.
* This increases the amount of free oxygen available for metabolically active tissues to use.
Does increasing dead space make is easier or harder to breath and why?
harder
more resistance
Does increasing diameter make is easier or harder to breath?
easier
How do you calculate resistance of a tube?
length / r^4
Starting at the nose last the passage of air.
nose → nasal cavity → pharynx → larynx → trachea → bronchi → bronchioles → terminal bronchioles → alveoli
What is advantageous about increasing the depth of breathing instead of breathing more?
better ventilates alveoli
How do central chemoreceptors regulate cerebral spinal fluid pH levels?
stimulate DRG to increase breathing which decreases CO2 levels and raises pH
What is the Hering-Breur reflex?
prevents overinflation of the lungs and limits the depth of inspiration
detected by mechanoreceptors
If vessel A has a increase in pressure of 58 and vessel B has an increase of 34 and both have the same flow volume, which one has the higher compliance?
vessel B
smaller presure = larger compliance
compliance = volume / pressure
In pulmonary circulation, if partial pressure of O2 in the alveolar gas increases, blood flow ____________
increases
pressure and flow are proportional
If you find high levels of H+ HCO3-, the _____________ chemoreceptors sense the high amount of H+ and send signals to ______
central chemoreceptors
DRG
______________ are stretch receptors in the lungs to prevent over inflation
mechanoreceptors
Pulmonary blood flow is unevenly distributed in lungs, arterial pressure at base of lungs is HIGHER/LOWER than alveolar pressure allowing blood flow to INCREASE/DECREASE
higher
increase
increase pressure = increased flow
If pressure is increased is flow increased or decreased?
increased
Zone 3 of the lungs has more or less intraplerual negative pressure
less negative pressure
(higher pressure)
