Respiration I Flashcards
What is the most critical function of the respiratory system?
Provide oxygen to the cells
The elimination of ______ is a function of the respiratory system.
CO2
Regulating blood ____ is a function of the respiratory system and goes along with removal of _____ from the blood.
pH; CO2
If the respiratory system was not working well, how would the pH in the blood change?
Not removing CO2 from the blood -> drop in pH (more acidic blood)
In what three ways does the respiratory system provide microbial defense?
- Epithelial secretions
- Lymphoid tissue in tract
- Coughing and sneezing reflexes
T/F: The respiratory system can activate or inactivate chemical messengers in the blood.
True
Ex. Convert angiotensin I -> angiotensin II
What role does the respiratory system play in defense against blood clots?
Small blood clots get trapped in narrow vessels in lungs and are dissolved
What are the three different zones of the airways?
- Upper airways: mouth/nose -> pharynx -> larynx -> top of trachea
- Conducting zone: trachea -> 1’ bronchi -> 2’ bronchi -> 3’ bronchi -> bronchioles -> terminal bronchioles
- Respiratory zone: respiratory bronchioles -> alveolar ducts -> alveolar sacs
What is the major difference between bronchi and bronchioles?
Bronchi = cartilaginous rings and mucous glands
Bronchioles = no rings or glands; but add smooth muscle
What is different about the respiratory bronchioles?
Very thin-walled; have alveoli in walls
T/F: The conducting zone is where gas exchange occurs.
FALSE
Respiratory zone
___________ creates parallel airways to maintain airflow and minimize increasing resistance to airflow.
Branching
In the respiratory zone, microbial defense is provided by _____________.
Pulmonary macrophages
In the conducting zone, _____________ secrete mucus to trap airborne particles and pathogens.
Goblet cells
What structure on epithelial cells moves mucus to the pharynx?
Cilia
What happens to the air in the conducting zone?
Air is warmed and moistened
Cystic fibrosis impairs the normal function of the __________ zone.
Conducting
Impaired Cl- channel causes thick and dry mucous -> airways become obstructed
Airflow is regulated by ______________.
Bronchiolar smooth muscle
What characteristics of the alveoli make them well-suited for optimizing gas exchange?
- High surface area
- Highly vascularized
- Respiratory surface very thin
- Low rate of blood flow (time for exchange)
What are the three types of cells in the alveoli?
- Type I - epithelial; gas exchange
- Type II - secrete surfactant
- Macrophages - immune
The alveolar sacs are _____ in diameter.
0.5 micrometers
T/F: Respiratory gases diffuse easily through plasma membranes, but less easily through body fluids.
True
What is a respiratory gas?
Small non-polar molecule that diffuses down a concentration gradient
T/F: O2 has a higher solubility than CO2.
FALSE
CO2 = 77 mmol/L O2 = 2.2 mmol/L
What is the path of O2 once it gets to the alveolus?
Apical membrane, cytoplasm, and basal membrane of Type I cell -> basal lamina and connective tissue -> basal membrane, cytoplasm, apical membrane of endothelial cell -> plasma
What is the final destination of O2?
Mitochondria in various tissues
What are the two layers of the pleural sac?
Parietal (outer): adheres to thoracic wall and diaphragm
Visceral (inner): converts the outer surface of lung
The space between the parietal and visceral pleuras is the __________.
Pleural sac
What happens to the intracellular fluid as the thoracic cage expands and contracts?
Experiences pressure changes
________ is required to bring freshly oxygenated air into the lungs.
Ventilation
Ventilation relies on __________ differences between the air in the lungs and the air outside of the lungs.
pressure
What is the equation for air flow?
pressure gradient/resistance in airway
Define the pressure gradient that is a part of the flow function.
The difference between gas pressure in the lung and atmospheric pressure
T/F: During expiration alveolar pressure is greater than atmospheric pressure.
True
What is Boyle’s Law?
Describes how changing the volume of the lung will change the pressure
During inspiration, the diaphragm and external intercostals ________. What effect does this have?
contract; lowers floor of cavity and raises ribcage -> increased volume
During expiration, the diaphragm and external intercostals _______. What effect does this have?
relax; raises floor of cavity and lowers ribcage -> reduces volume
T/F: Intrapleural pressure is always subatmospheric.
True
T/F: As transplueral pressure increases so does lung volume.
True
Describe inhalation with pressure changes.
Intraplueral pressure decreases -> transpleural pressure increases -> air fills expanded lungs until it again matches atmospheric pressure
Describe exhalation with pressure changes.
Intraplueral pressure increases (approaches 0) -> transpleural pressure decreases -> air leaves lungs until it again matches atmospheric pressure
T/F: Forced inspiration and expiration are simply a result of muscles working harder.
False
Additional muscles are involved
A __________ occurs when the lung or pleural sac is punctured.
pneumothorax
What is the difference between an closed, open, and tension pneumothorax?
Closed = punctured lung; pleural pressure < 0 Open = punctured cavity; pleural pressure =0 Tension = punctured cavity but air can't escape so pressure > 0
What is lung compliance?
Defines the lungs “stretchiness” as its change in volume for a given change in pressure
If lung elasticity is ______ the lung volume will increase rapidly per unit change in pressure.
high
What are the two factors contributing to lung compliance?
- Elasticity
2. Surface tension
What is surface tension?
Static forces that pull water molecules together align the molecules so that there is a net negative charge facing the surface. This creates a net force pushing down into the water
T/F: The smallest alveoli are at the greatest risk for collapsing.
True
Most surface tension
T/F: The surface tension in the alveoli pulls the walls inward.
True
What is produced by Type II cells to reduce surface tension?
Surfactant
________ is an amphipathic phospholipid + protein molecule that forms a monolayer between ___________.
Surfactant; air and water
T/F: Surfactant is pushed to the bottom of water.
FALSE
Hydrophillic/hydrophobic interactions keep surfactant at the surface
Surfactant reduces surface tension by _________ density of H2O molecules.
decreasing
T/F: Surfactant will increase compliance by decreasing surface tension.
True
How is surfactant production regulated?
Stretch receptors in Type II cells; will increase during deep breathing
What is the most important factor in lung compliance?
Overcoming surface tension
What is the 2nd leading cause of death in premature infants?
Acute respiratory distress
What happens during acute respiratory distress?
Insufficient surfactant production -> lungs resist expansion
What is the major determinant of airway resistance?
Tube radius
What are some other factors that affect resistance?
- Transpulmonary pressure
- Elasticity of tissue
- Neural and chem control of smooth muscle
How does an increased resistance effect breathing?
Breath more deeply and more slowly
How does a decreased lung compliance affect breathing?
Breath more rapidly and shallowly
How does asthma effect breathing capabilities?
Increased resistance because of inappropriate muscle contraction
How is asthma treated?
Glucocorticoid and bronchodilators
How does COPD affect breathing?
Increases airway resistance
What is tidal volume?
V entering lungs per breath at rest
What is the inspiratory reserve volume?
Max V inspired. Often about 6x tidal volume
What is the expiratory reserve volume?
V exhaled beyond the tidal volume. About 3x tidal volume
What is residual volume?
V in lungs after maximum exhalation. Roughly 1 L.
What is vital capacity?
IRV + ERV + TV
Maximum amount of air that can be inspired after maximum expiration. About 5L
What is FEV1?
Forced expiratory volume in 1 second
During obstructive pulmonary disease, ________ is decreased while _________ remains normal.
FEV1; VC
During restrictive lung disease, ________ is decreased while _________ remains normal.
VC; FEV1
What is dead space?
Reduces the amount of fresh air reaching the alveoli
What is the best estimate of how much air reaches the alveoli?
Alveolar ventilation = (TV - dead space) x respiratory rate
How can you increase alveolar ventilation?
- Increase resp rate
2. Increase TV (most effective)
T/F: There is always some alveolar dead space.
True
What is the difference between anatomical, alveolar, and physiologic dead spaces?
Anatomical: in the airway
Alveolar: in the alveolus
Physiologic: sum of the other two
What is external respiration?
gas exchange between air and blood in pulmonary capillaries
What is internal respiration?
Gas exchange between blood in systemic capillaries and cells
What are the five steps of respiration?
- Ventilation
- External respiration
- Gas transport
- Internal respiration
- Cellular respiration
What is Dalton’s Law of gases?
Total pressure equals the some of individual pressures
T/F: Partial pressures will vary with altitude.
True
What is Henry’s Law?
Amount of gas dissolved in a liquid is proportional to the partial pressure of that gas in equilibrium with the liquid
How can you affect pressure inside an alveolus by changing surface tension or radius?
Increase pressure by increasing surface tension or decreasing radius
Why does resistance go down as air goes from medium sized bronchi towards the terminal bronchioles?
Branching
What is total lung capacity?
Vital capacity plus residual volume
Describe how anatomical dead space causes problems with ventilation?
Anatomical dead space air counts for air getting inspired into the alveolus. So, if you are inspiring a small amount of air, the dead space unoxygenated air will take up a higher percentage of space in the alveolus
Why is increasing tidal volume typically more effective than increasing respiratory rate?
Typically when increasing rr you lower the tv. This allows for the dead space air to take up a higher percentage of alveolar space per breath. Not as efficient as increasing TV
What can cause alveolar dead space?
Reduced or missing bloodflow to the alveoli
Why is there always some alveolar dead space?
Gravity plus vascular resistance
T/F: The top of the lung has the most efficient ventilation.
False
Bottom of lung due to more blood flow to alveoli
T/F: The partial pressure of gas in a liquid is equivalent to its concentration in the liquid.
FALSE
T/F: CO2 is much more soluble in liquid than oxygen.
True
What happens to the partial pressures of O2 and CO2 after internal respiration?
PP of O2 goes down
PP of CO2 goes up
Makes sense because O2 is consumed by cells and CO2 is put into the blood from cell waste
What are the three major determinants of O2 partial pressure in the alveolus?
- Atmospheric O2
- Rate of alveolar ventilation
- Rate of cellular O2 consumption
T/F: Only gas that is contributing to the partial pressure can diffuse.
True
How does the body regulate alveolar gas pressures?
Altered ventilation and metabolism together
What is hypoventilation?
Decreased ventilation relative to metabolism
What is hyperventilation?
Ventilation increased relative to metabolism
T/F: Hyperventilation occurs during exercise.
FALSE
Increased metabolism with the increased ventilation - not hyperventilation
Pulmonary edema, fibrosis of tissue between alveoli and capillaries, and strenuous exercise all alter gas exchange through which method?
Decreased diffusion from alveoli to blood
Fluid in lung (edema), thickening of wall (fibrosis), faster blood flow (exercise)
T/F: Diseases resulting in impaired diffusion will cause excess CO2.
False.
Will impair O2 not CO2 because CO2 is more soluble
What is the bodies response to limited air flow in certain alveoli?
Vasoconstriction of capillaries to those alveoli so blood can be shunted to fully functional alveoli
What is the bodies reaction to decreased blood flow to certain alveoli?
Drop in alveolar CO2 will cause bronchoconstriction so air is diverted to other alveoli
What are the partial pressures of O2 and CO2 leaving the lung?
O2 = 100 mmHg
CO2 = 40 mmHg
What are the partial pressures of O2 and CO2 in the systemic veins?
O2 = 40 mmHg
CO2 = 46 mmHg
