Sample Exam Flashcards
If the rib cage is totally immobile, how is inspiration possible?
by diaphragmatic breathing
During expiration, which statement is true?
alveolar P > atmospheric P > pleural P
What is best associated with transpulmonary pressure?
measure of recoil tendency of the lung
What muscle is active during forced expiration?
rectus abdominis–> only extratory muscle, pulls rib cage down
If the visceral pleural erodes andallows a region of the alvelar space to communicate with the pleural space, what would hapeen to the functional residual capacity?
decreased
Which of the following statements best describes hysteresis at the onset of inspiration?
lung volume changes at aslower rate then the pleural P changes (filling up the lung with saline would diminish these forces)
Which is a function of surfactant?
helps stabilize alveolar size, reduces surface tension, offsets collapse pressure as radius decrease
What effect will histamine binding to H1 receptors have on the airway smooth muscle?
constrict
Using helium dilution method, the following data was obtained: [He]initial= 5ml/L [He]final= 4ml/L initial spirometer volume= 10L TV= 500mL IRV= 3.0 L ERV= 1.5L An adequate number of breaths were completed, and data was collected at the end of normal expiration. What is the total lung capacity?
FRC = (hei/ hef - 1 ) Vi
(4/5 - 1)10
(1.25-1)10
.25(10)= 2.5
- 5 + inspiratory capacity
- 5 + tital volume + IRV
- 5 + .5 + 3.0 = 6L
6.0L
Most of recoil tendency of the lung is due to what?
surface tension forces
What is a pathophysiologic consequence of hyperventilation?
decreased coronary blood flow
decreased stroke volume
repolarization of the heart impaired
skeletal muscle spasm
What is the major effect of sympathetic stimulation on airway smooth muscle?
dilate, most of the effect is indirect via blood borne
Why is the left ventricular output slightly higher than the right ventricular output?
some bronchial artery blood drains into the pulmonary veins
Which volumes or capacities cannot be determined with basic spirometry?
residual volume, functional residual volume
total lung capacity
What local effect will Prostaglandin E series have on airway smooth muscle?
dilation
Which of the following has the greatest effect on constriction of pre-capillary resistance vessels in the lung?
low alveolar oxygen
Without surfactant, as alveolar radius increases, what happens to the collapse tendency of the lung?
decreases
Rank the solubility of the different gases from greatest to least in aqueous fluid?
CO2 > O2 > N2
During exercise in an upright position, flow throughout the lung is equal. True or false?
False
Which of the following conditions would significantly increase total pulmonic blood volume?
mitral valve stenosis
Compared to atmospheric air, alveolar air has a higher concentration of which of the following?
CO2, water vapor
What effect does stimulation of the SNS have on sensitivity of peripheral chemoreceptors to hypoxia?
increases
Which of the following statements about carbon monoxide is true?
Pco of .6mmHg can be lethal
a partial pressure Pco=.4 can significantly decrease O2 transport
has a much greater affinity for hemoglobin compared to oxygen
the body produces very small quantities with physiologic effects
If the ventilation/perfusion ratio increases above normal, which of the following conditions is true?
increase the amount of physiologic dead space
If the ventilation/perfusion ratio decreases below normal, which of the following conditions is true?
increase in amount of physiologic shunt blood
What happens to virtually all circulating prostaglandins in the blood as they pass through the pulmonary capillaries?
they are inactivated/cleared
What percentage of CO2 in the blood is carried in the form of the bicarbonate ion?
70%
Stimulation of stretch receptors in the lungs will have what effect on the dorsal respiratory group?
inhibit
Which of the following responses would cause more oxygen to be released from hemoglobin?
decrease in local PO2
increase in PCO2
increase in 2,3 diphosphoglycerate
Most of the ventilatory response to a slight increase in CO2 levels is mediated by which of the following?
central chemoreceptors in the brain stem 70-80%
The basic ventilatory drive is set by neurons in which of the following areas?
dorsal respiratory group
Normal inspiration is usually terminated by which of the following?
pneuomotaxic center
What is the most prevalent cause of respiratory depression?
narcotics
Which of the following is associated with chronic mountain sickness?
increased hematocrit
increased pulmonary arterial BP
enlarged right ventricle
Stimulation of what receptors, would create a feeling of dyspnea?
J receptors in the parenchyma
In acute mountain sickness, the subject suffers deterioration of nervous system function primarily due to which of the following?
hypoxia
The negative pleural pressure generated to expand the lung and open the alveoli during the first breath is which of the following?
-40 to -60 cmH2O
During intermittent flow, which pressure is higher than the other during systole? Diastole?
systole: capillary P > alveolar P
diastole: alveolar P > capillary P
Where is capillary pressure the highest?
at the base of the lung because of gravity
What is zone 3?
continuous flow
What is zone 2?
intermittent flow
What is zone 1?
no flow
During continuous flow, which pressure is higher?
capillary P > alveolar P
When is pleural pressure equal to atmospheric pressure?
when the lung has collapsed
What is transpulmonary pressure?
the difference between alveolar and pleural pressure
you measure the recoil tendance of the lung
When does transpulmonary pressure peak?
at the end of inspiration
What is normal ventilation-perfusion ratio?
alveolar ventilation is matched to pulmonary capillary perfusion at a rate of 4L/min of air to 5L/min of blood
When would the ventilation-perfusion ratio decrease?
when there is decreased ventilation
When would the ventilation-perfusion ratio increase?
when there is a problem with decreased perfusion of the lungs
What does a decreased ventilation-perfusion ratio result in?
PO2 decreasing to 40mmHg
PCO2 increasing to 45mmHg
increase in physiologic shunt blood
What is physiologic shunt blood?
blood that is not oxygenated as it passes the lung
What does an increased ventilation-perfusion ratio result in?
PO2 increases to 45mmHg
PCO2 decreases to 0mmHg
increase of physiologic dead space
What is physiologic dead space?
area in lungs where oxygenation is not taking place (this includes non functional alveoli)
What keeps the lung from collapsing?
negative pleural pressure
What are the inspiratory muscles?
serratus anterior and posterior, scalenes, levator costarum
What are the expiratory muscles?
abdominals, internal intercostals, posterior and inferior serrratus, transverse thoracis, pyramidal
What does the diaphragm do?
drops floor of thoracic cage
What do all the inspiratory muscles do?
lift the rib cage
What are the muscles of expiration associated with?
recoil of the lungs
At the end of normal expiration, what does the volume of the lungs equal?
functional residual capacity
Why is it easier to fill a lung with saline rather than air?
because surface tension forces have been eliminated in the saline filled lung
What is the function of the pleural fluid?
acts as a lubricant between pleura
What effect will histamine binding to H2 receptors have on the airway smooth muscle?
dilation
Draw the picture for static lung capacities.
FRC= RV + ERV IC= TV + IRV VC = IRV + TV + ERV TLC = IRV + ERV + TV + RV
What is the total flow of the lungs?
pulmonic flow (RV output) + bronchial artery flow
Right ventricular output is equal to what?
100% cardiac output
What local effect will prostaglandin F series have on airway smooth muscle?
constriction
during inspiration, which of the following statements is true?
alveolar pressure pleural pressure
If pleural pressure is equal to atmostpheric pressure, what happened?
collapsed lung
When airflow stops, what happens to the pressures?
alveolar pressure = atmospheric pressure
Stabilizer of lumbar spine muscle?
transverse abdominis
Why does hyperventilation cause a decrease in oxy-hemoglobin affinity?
when you hyperventilate, you become more alkaline, promoting less released of oxy-hemoglobin
Non adrenergic, non cholinergic neurons that stimulate cause what?
constriction
Non adrenergic, non cholinergic neurons that inhibit cause what?
dilation
Right ventricular output is equal to what?
pulmonary output
Anytime cardiac output moves, what else moves?
pulmonary blood flow
decreased VC =?
restriction (inability to expand properly)
decrease flow rate (PEF FEV) =?
obstruction of airflow (asthma, etc.)
autonomic on vascular smooth muscle in the lung is..?
minimal
Which part of the autonomic system does the lung have?
both sympathetic and parasympathetic
With surfactant, as alveolar radius increases, what happens to the collapse tendency of the lung?
doesn’t change
What is the concentration of gases in the air from greatest to least?
N2 > O2 > CO2
What is the effect of gravity on flow?
there is more flow at the bottom of lung than the top of the lung
When bearing down, where would zone 1 be located?
near the apex of the lung
Which of the following conditions would significantly decrease total pulmonic blood volume?
tricuspid valve stenosis
What does the patent ductus arteriosis do?
moves blood from aorta to pulmonic trunk
Small amounts of CO that are produced in the body does what?
vasodilates
If you hyperventlate, what happens to the dead space?
decrease in amount of physiologic dead space
What is the normal ventilation/perfusion ratio?
.4
Compared to atmospheric air, alveolar air has a lower concentration of which of the following?
oxygen and nitrogen
What has a greater solubility in aqueous fluid, CO2 or CO?
CO2
How much of CO2 is dissolved in the blood?
7%
How much of CO2 is bound to hemoglobin?
23%
Inhibition of stretch receptors in the lungs will have what effect on the dorsal respiratory group?
stimulate
How do you increase body pH?
increased ventilation decreases CO2
Increased pH is inhibitory to what?
ventilation
Increased pH opposes the positive effects of what?
hypoxia on peripheral chemoreceptors
What is the vapor pressure of water at body temperature?
47mmHg
increase in pH is inhibitory to ventilation and opposes the positive effects of hypoxia on what chemoreceptors?
peripheral
Where are the ventral respiratory group of neurons located?
located bilaterally in ventral aspect of medulla
What can the respiratory group of neurons do?
can increase inspiratory and expiratory respiratory muscles during increased ventilatory drive
Where is the pneumotaxic center located?
dorsally in nucleus parabrachialis of upper pons
What does the pneumotaxic center do?
inhibits the duration of inspiration by turning of DRG ramp signal after start of inspiration
Where is the apneustic center located?
lower pons
What does the apneustic center do/
prevents inhibition of DRG under some circumstances
