Exam III Flashcards
If the rib cage is totally immobile, how is inspiration possible?
By diapragmatic breathing
During expiration, what is the relationship between alveolar, atmospheric and pleural pressures?
Alveolar P > atmospheric P > pleural P
At which point is the only time that alveolar pressure is equal to pleural pressure?
End of inspiration and end of expiration
Which muscles are active during inspiration?
Diaphragm, external intercostalis, SCM, anterior serratus, scaleni, serratus posterior superior, levator costarum
Which muscles are active during expiration?
Rectus abdominus, int/ext obliques, transverse abdominus, internal intercostalis, serratus posterior inferior, transversus thoracis and pyramidal
Which muscle drops the floor of the thoracic cage on inspiration?
Diaphragm
Which muscle, in expiration, has a role in lower back pain?
Transverse abdominus
True/False: Under resting conditions, expiration is passive.
True
If the visceral pleura erodes and allows a region of the alveolar space to communicate with the pleural space, what would happen to the functional residual capacity?
It would be decreased
What describes hysteresis at the onset of inspiration?
The pleural pressure changes at a faster rate than lung volume
What is the function of a surfactant?
Reduce surface tension forces
Surfactants are produced by which cells?
Type II alveolar epithelial cells
What effect will histamine binding to H1 receptors have on the airway smooth muscle?
Constriction
What effect will histamine binding to H2 receptors have on airway smooth muscle?
Dilation
What effect will histamine binding to PG-E receptors have on airway smooth muscle?
Dilation
What effect will histamine binding to PG-F receptors have on airway smooth muscle?
Constriction
Most of the recoil tendency of the lung is due to:
Surface tension forces (2/3)
[1/3 comes from elastic CT]
What are the pathophysiologic consequences of hyperventilation?
SV and CO, coronary blood flow, cerebral blood flow and serum potassium all decreased, Repolarization of heart impaired, oxyhemoglobin affinity increased and skeletal muscle spasm/tetani
What is the common thread in most of the pathophysiologic consequences of hyperventilation?
Hypocapnic alkalosis
What is the major effect of sympathetic stimulation on airway smooth muscle?
Dilate, most of the effect is direct via blood borne (dilate B receptors)
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 can’t be determined with basic spirometry?
Residual volume, function residual capacity and total lung capacity
Function residual capacity is equal to:
The sum of residual volume + ERV
Total lung capacity is equal to:
Residual volume + ERV + IRV + TV
What has the greatest effect on constriction of the pre-capillary resistance vessels in the lung?
Low alveolar oxygen
Without surfactants, as alveolar radius increases, what happens to the collapse tendency of the lung?
Decreases
What is the function of low alveolar oxygen?
Causes release of a local vasoconstrictor that shunts blood to better ventilated areas
Rank the solubility of N2, O2 and CO2 from greatest to least aqueous fluid.
CO2 > O2 > N2
True/False: During exercise in an upright position, flow throughout the lung is equal.
False: In an upright position, more flow will occur toward the base
Which condition would significantly increase total pulmonic blood volume?
Mitral valve stenosis (also possibly blood moving from the aorta to pulmonic trunk)
Compared to atmospheric air, alveolar air has a higher concentration of:
CO2 and water vapor
Compared to atmospheric air, alveolar air has a lower concentration of:
Nitrogen and oxygen
What effect does stimulation of the SNS have on sensitivity of peripheral chemoreceptors to hypoxia?
Increases
If ventilation/perfusion ratio increases above normal, which condition would occur?
Increase in the amount of physiologic dead space
If ventilation/perfusion ratio decreases below normal, which condition would occur?
Increase in the 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 happens to angiotensin I as it passes through the lung?
Converted to angiotensin II
What percentage of CO2 in the blood is carried in the form of bicarbonate?
70%
What percentage of CO2 in the blood is dissolved?
7%
What percentage of CO2 in the blood binds to hemoglobin?
23%
Stimulation of stretch receptors in the lungs will have what effect on the dorsal respiratory group?
Inhibition
Which conditions would cause more oxygen to be released from hemoglobin?
Decreases in local PO2 and pH, and increases in PCO2 and 2,3 diphosphoglycerate
The ventilatory response to a slight increase in CO2 levels is mediated by:
Central chemoreceptors in the brain stem (70-80%) and peripheral chemoreceptors in the aortic and carotid bodies (20-30%)
The basic ventilatory drive is set by neurons located where?
Dorsal respiratory group
Normal inspiration is usually terminated by:
Pneumotaxic center
If the pneumotaxic center can’t terminate normal inspiration, what does?
Stretch receptors in the lung
What is the most prevalent cause of respiratory depression?
Narcotics
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:
Hypoxia
The negative pleural pressure generated to expand the lung and open the alveoli during the first breath is:
-40 to -60 cm H20
Respiratory centers are located in the:
Brain stem
Respiratory centers are influenced by:
Higher brain centers, peripheral mechanoreceptors and peripheral/central chemoreceptors
The negative pleural pressure generated from inspiration to expiration varies between:
-5 and -7.5 cm H20
Subatmospheric pressure occurs during _____, while supra-atmospheric pressure occurs during _____.
Inspiration; expiration
What is the term that describes pleural pressure changing at a faster rate than lung volume?
Hysteresis
What normally accounts for most of the work of breathing?
Compliance work
What percentage of total body energy is required for ventilation?
3-5%
Normal breathing is also termed:
Eupnea
What is the term describing an increase in pulmonary ventilation matching an increase in metabolic demand?
Hyperpnea
What is the term describing an increase in pulmonary ventilation that is greater than metabolic demand?
Hyperventilation
A decrease in CO2 concentration to less than 40 mmHg would be described as:
Hyperventilation or respiratory alkalosis
What is the term describing a decrease in pulmonary ventilation less than metabolic demand?
Hypoventilation
An increase in CO2 concentration to greater than 40 mmHg would be described as:
Hypoventilation or respiratory acidosis
An increased frequency of respiratory rate would be called:
Tachypnea
Dyspnea when recumbent and relief when standing upright would be called:
Orthopnea
Absence of breathing is termed:
Apnea
Difficulty breathing is called:
Dyspnea
What causes lung collapse?
Puncture of the parietal pleura, erosion of visceral pleura and a major airway being blocked by air
What is the function of pleural fluid?
Provide lubrication
True/False: Surface tension forces are eliminated in air-filled lungs.
False: They are eliminated in saline-filled lungs
Inspiratory capacity is equal to:
TV + IRV
Vital capacity is equal to:
IRV + TV + ERV
The first 11 generations of branching in the lung are the:
Bronchi
The next 5 generations of branching after the first 11 are the:
Bronchioles
The last 4 generations of branching in the lung are the:
Respiratory bronchioles
Which receptors in afferent nerves are associated with smooth muscle and stretch receptors involved in reflex control of breathing and cough reflexes?
Slow-adapting receptors
Which receptors in afferent nerves are sensitive to mechanical stimulation?
Rapidly-adapting receptors
C-fibers are selectively stimulated by:
Capsaicin
Which fibers contain neuropeptides such as substance P, neurokinin A and calcitonin gene-related peptide?
C-fibers
Elicit constriction of airways is mediated by:
Parasympathetic reflex and local constrictor responses
The normal level of HCO3 is:
24 mEq/L
What regulates HCO3 levels?
Kidneys
What regulates CO2 levels?
Lungs
Total pulmonic blood volume accounts for what percentage of total blood volume?
9%
What percentage of cardiac output comes from right ventricular output?
100%
What effects will the ANS have on pulmonary vascular smooth muscle?
SNS; mild vasoconstriction
PSNS; mild vasodilation
During systole, what is the relationship between capillary and alveolar pressures?
Capillary P > Alveolar P
During diastole, what is the relationship between capillary and alveolar pressures?
Alveolar P > Capillary P
What is the third most abundant gas in air behind nitrogen and oxygen?
Argon
The respiratory membrane consists of what 2 cell layers?
Alveolar epithelium and capillary endothelium
What percentage of oxygen is bound to hemoglobin? Dissolved?
97% bound; 3% dissolved
What happens to oxygen in the cells?
80% converted to CO2; 20% converted to H20
The most common symptom of decompression sickness is:
Pain in joints, muscles of arms/legs (85-90%)
The cough reflex utilizes which cranial nerve?
CNX
The sneeze reflex utilizes which cranial nerve?
CNV
Which antibodies dominate the upper respiratory tract?
IgA
Which antibody type is predominantly a mucosal antibody?
IgE
Which antibody type dominates the lower respiratory tract?
IgG
In the upper respiratory tract, what is the highly vascularized radiator that warms inspired air?
Nasal turbinates
What condition is associated with an increased incidence of bacterial infections?
Chronic alcoholism
