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170 Cards in this Set

  • Front
  • Back
Knowledge of respiratory physiology is important for what?
Proper diagnosis and treatment of pulmonary disease
What is the main function of the respiratory system?
To exchange gases in order to maintain pH, arterial oxygen, and CO2
Each lung is ____ shaped & covered with a ______
Cone shaped; with a visceral pleura
Which lung is larger and why?
The right lung because the left is smaller to make room for the heart
How many lobes does the right lung have?
3: upper, middle, lower
How many lobes does the left lung have?
2: upper, lower
All lobes of the lungs are subdivided into what segments?
Broncho-pulmonary segments
The lungs are innervated by which systems?
BOTH sympathetic & parasympathetic
Sympathetic stimulation to the lungs causes what?
Bronchodilation with vasoconstriction (so tubes in airway open up but blood supply is less)
Parasympathetic stimulation to the lungs causes what?
Bronchoconstriction with vasodilation (so tubes in airway close but blood supply increases)
As inspired air flows through the nose to the alveoli, the forward velocity is ______, which allows for diffusion through the alveoli into the pulmonary _________.
Slowed; Capillaries
What are the functions of the nose?
1. Filter air
2. Humidify air
3. Cool/warm the air to body temp
What is the function of the pharynx?
Serves as a conduit for air to travel by
What is the function of the larynx?
The epiglottis acts as a valve preventing food from entering the trachea
Voluntary control of breathing is important durning verbal communication where does it originate from?
the cortex
Where does the main control of respiratory centers arise from?
chemoreceptors
is Co2 regulated more tightly or o2
Co2
Where are central chemoreceptors located and what do they monitor?
medulla, measure co2 levels of arterial blood and the CSF
What equation shows the regulation of co2
CO2 + H20 ⇒ H2CO3 ⇒ H+ + HCO3 -
h+ ions stimulate the central chemoreceptors which stimulate what?
medullary centers
A rise in paco2 does what to alveolar ventilation?
increases it which restors paco2 to normal levels
where are peripheral chemoreceptors located
carotid and aortic bodies
peripheral chemoreceptors are stimulated by:
1. low arterial oxygen tension
2. high co2 tension (body is most sensitive to this)
3. acidocis
When the brainstem centers have been depressed by narcotics or anoxia what can maintain breathing?
carotid bodies
What is hering-bruer reflex (inflation reflex)?
It is the longest lung reflex. stimulated by lung inflation during inspiration. the reflex is inhibition of deep inspiration
Who does the hering-bruer reflex occur in?
newborns or patients under anesthesia
Where do the results if a sneeze stimulus occur
upper airways
what stimulates the sneeze or cough reflex?
stimulation of irritant receptors by particles, gases, or excessive amounts of sticky mucus
where do the results of a cough if stimulus occurs
lower airways
What does peripheral pain receptor stimulation result in?
hyperventilation, tachycardia, and rise in bp
What does visceral pain receptor stimulation result in?
inhibition of breathing, bradycardia. and fall in bp
during light sleep breathing is dominated by what control
chemical
During what stage of sleep does sleep apnea occur?
REM
When sleep apnea occurs what is stimulated by deranged blood gases because of obstruction of airways?
peripheral chemoreceptors
What is the normal range of ph
7.35-7.45
what is acidemia
ph below 7.35
what is alkalemia
ph above 7.45
Significant changes in ph can result in what?
coma or convulsions
What are 3 buffer systems for the blood?
1. hemoglobin and protiens bin with H+
2. Respiratory system: regulates paco2
3. Renal system: bicarbonate
What is normal paco2
35-45 mm Hg
how does hyperventilation control ph in blood?
decreases the paco2 levels which decreases h+ which moves ph higher
how does hypoventilation control ph in blood?
increase the paco2 levels which increases h+ which move ph lower
Where is bicarbonate produced?
kidneys
decreased pao2 results in what?
hypoxemia (decreased oxygenation of blood)
assesment of arterial blood gases provides information about what?
oxygenation, ventilation, and acid-base balance
when pa02 is adequate is oxygenation adequate?
yes
what is oxygenation?
binding of oxygen on hemoglobin
what are the signs of hypoxemia
1. pallor
2. cyanosis
3. skin coolness
4. unexplained behavioral change
What is the body's response to hypoxemia? and is it effective?
increased total ventilation. and may not be effective due to increased consumption of respiratory muslces
What is the structure lined with ciliated epithelium which carries debris toward the pharynx?
Trachea
How many horseshoe shaped cartilaginous rings form the trachea?
16 to 20
Which cartilaginous ring of the trachea is the most cephalic?
Cricoid ring
What do the cartilaginous rings protect the trachea from during forced inspiration and expiration?
compression/collapse
What does the trachea branch into?
left and right main bronchi
Which main bronchus branches at a more acute angle? (Left or Right)
Left
Which main bronchus is longer? (Left or right)
Left
Which main bronchus is more in line with the trachea? (Left or right)
Right
Which lung is predisposed to aspiration of material due to the alignment of the bronchus?
Right
What structure is defined as:
Small envaginations of the respiratory bronchioles, alveolar ducts, and alveolar sacs?
Alveoli
What are the thin walls of the alveoli suited for?
gas exchange
Which alveolar wall cells are large, flat, and comprise most of the internal alveolar surface?
Type 1 cells
Which alveolar wall cells are less numerous, ovoid in shape, and synthesize surfactant?
Type 2 cells
Ventilation is the process of ________ and ________
inspiration, expiration
Ventilation maintains optimal levels of _______ and _______
oxygen, carbon dioxide
Define Minute ventilation (Ve)
Volume of air expired each minute
A x B = Ve
What x What = Minute Ventilation?
Tidal Volume x Frequency
Vt x f
Tidal volume (Vt) is the sum of what two variables?
Volume of alveolar gas (Va)
Dead Air (Vd)
Does hyperventilation increase or decrease carbon dioxide levels?
decrease (hypocapnia)
Does hypoventilation increase or decrease carbon dioxide levels?
incresse (hypercapnia)
Is oxygen tension of alveolar air increased or decreased by hyperventilation?
increased
What lung volume is defined as:
The volume of gas inspired or expired during each respiratory cycle?
Tidal Volume (Vt)
What lung volume is defined as:
The maximum volume of gas that can be inspired from the peak of a tidal volume?
Inspiratory reserve volume
What lung volume is defined as:
The maximum volume of gas that can be expired from a normal tidal expiration
Expiratory reserve volume
What lung volume is defined as:
The volume of gas remaining after greatest expiration?
Residual volume
What lung capacity is defined as:
the amount of gas in the respiratory system after a maximal inspiration?
Total lung capacity (TLC)
What lung capacity is defined as:
The maximum volume of gas that can be expelled from the lungs after a maximal inspiration?
Vital capacity (VC)

VC = IRV + TV + ERV
What lung capacity is defined as:
The maximum volume of gas that can be inspired from the resting end expiration level?
Inspiratory Capacity (IC)

IC = TV + IRV
What lung capacity is defined as:
The volume of gas in the lungs when the respiratory system is at rest; volume in the lung at the end of a normal expiration?
Functional residual capacity (FRC)

FRC = ERV + RV
On what 2 factors does FRC depend?
Inward elastic recoil of the lung
Outward elastic recoil of the chest wall
What respiratory volume does Dead Space define?
Volume that does not participate in gas exchange
Which dead space is the volume of gas that is contained in the conducting airways?
Anatomic dead space
Which dead space is the volume of gas in wasted ventilation?
Alveolar dead space
What is physiologic dead space?
The total volume of air NOT involved in gas exchange
In normal individuals, are physiologic and anatomic dead space equal or unequal?
equal
In diseased individuals, what does physiological dead space equal?
anatomic dead space + alveolar dead space
True or False:
Inspired air is uniformly distributed throughout the lungs
FALSE
True or False:
Lungs are different in size which allows for unequal distribution
TRUE
In what position(s) does apical ventilation exceed basilar ventilation?
Sitting or Standing
In the supine position, which portion of the lung is better ventilated? (Anterior or Posterior)
Posterior
True or False:
During heavy breathing all areas of the lungs tend to be well ventilated
TRUE
During shallow breathing, what happens to some airways?
They become closed
What factors aside from position and depth of breath may cause limited ventilation? (4)
Respiratory muscle weakness
Regional airway obstruction
Abnormal lung/chest wall compliance
Disease
What is spirometry used to measure?
Lung volumes
Specific ventilatory capacities
Which specific lung volumes can spirometry measure?
tidal volume
inspiratory reserve volume
expiratory reserve volume
Which capacity can measure ventilatory capacity?
Forced Vital Capacity
To measure Maximum Voluntary Ventilation, how long must the patient breathe as rapidly and deeply as possible?
15 seconds
What does Maximum Voluntary Ventilation assess?
Respiratory muscle endurance
What is the FEV1?
(Forced Expiratory Volume at 1 second)
The volume of gas forcibly expired in 1 second after maximal inspiration
What information regarding the lungs does FEV1 give us?
Information about airway resistance and elastic recoil
By measuring what can we commonly determine alveolar ventilation?
CO2 elimination by the lungs
With restrictive diseases, what happens to total lung capacity and forced vital capacity? (Increase or decrease)
Decrease
With restrictive diseases, does the FEV1/FVC ratio increase or decrease?
Increases
With obstructive diseases, does the FEV1/FVC ratio increase or decrease?
Decreases
With obstructive diseases, does total lung capacity and functional residual capacity increase or decrease?
increase
In breathing, what must respiratory muscle forces overcome?
elastic recoil of the lungs and thorax
During breathing there is a frictional ________ to air flow
resistance
During inspiration, which tissues stretch?
lungs and thorax
During inspiration, is the pressure inside the chest negative or positive?
negative
During inspiration, do muscles contract to raise or lower the diaphragm?
lower
What is defined as:
The ratio of change in lung volume to change in distending pressure?
Lung compliance
With decreasing lung compliance, are lungs more or less stiff?
Stiffer
Does pulmonary fibrosis increase or decrease lung compliance?
decrease
What substance is increasingly present in lung tissue with pulmonary fibrosis?
collagen
What substance is decreased in the lung tissue with emphysema?
elastin
With emphysema, is lung compliance increased or decreased?
increased
What is the main purpose of surfactant?
lower surface tension inside the alveoli
What is atelactasis?
lung collapse
What two conditions may result from a delay in surfactant production?
low lung compliance
atelactasis
Is the chest wall elastic or inelastic?
elastic
Which tissues contribute to the elasticity of chest wall compliance?
Ribcage
Diaphragm
In which 3 disorders is chest wall compliance decreased?
Scoliosis
Skeletal muscle disorders
Abdominal disorders
From where does oxygen enter blood?
Alveolar air
From where does CO2 enter alveolar air?
The blood
How many alveoli do we have?
Several hundred million
What determines the amount of O2 and CO2 that is exchanged?
Metabolic activity of tissues
During strenuous exercise, how much greater may oxygen uptake be as compared to resting levels?
10 times
What is the respiratory quotient?
CO2 output/O2 uptake
The respiratory quotient is usually what at rest?
0.8
What is a synonym for partial pressure?
concentration
True or False:
The amount of pressure which a gas exerts is proportional to the amount of gas in the mixture
TRUE
What are the 4 factors determining the rate of diffusion of a gas? (Fick's Law)
Surface area available for gas exchange
Thickness of the tissue
Partial pressure gradient across the tissue
Diffusing constant for the gas
What happens to alveolar walls with Emphysema?
They may be destroyed or blocked by an emobolus
What happens to alveolar walls with pulmonary fibrosis?
They may be thickened
The partial pressure gradient of oxygen is ____ times greater than carbon dioxide
15
Carbon dioxide is _____ times more soluble than oxygen
20
Which gas diffuses more easily - CO2 or O2?
CO2
What are other factors influencing oxygen diffusion? (3)
Reduction in volume of blood flowing through capillaries
Reduction in red blood cell mass
Presence of abnormal hemoglobin molecules
By what pathway is oxygen transported to the tissue capillaries?
Blood
What is oxygen used for once it reaches target cells via the capillaries?
ATP production
What is the result of ATP production? (Aside from ATP)
CO2
How much of all O2 is transported as oxyhemoglobin?
99%
How many molecules of O2 can combine with 1 molecule of hemoglobin?
4
What determines the volume of oxygen that can combine with hemoglobin?
Partial pressure of dissolved O2
Is the oxyhemoglobin dissociation curve negatively or positively correlated?
positively
What is the usual level of O2 saturation in hemoglobin?
97%
At what range of O2 partial pressures is hemoglobin saturation 100%?
250 - 350 mmHg
How much of hemoglobin's O2 content is unloaded in the capillaries?
25%
During exercise, which way does the oxyhemoglobin dissociation curve shift?
Right
Pulmonary circulation carries the output of the _____ heart through the lungs to the _____ heart
right, left
Where is re-oxygenated blood deposited in the heart?
Left atrium
Sympathetic stimulation results in minor pulmonary vessel _________
constriction
Humoral substances such as histamine can cause significant ________
vasoconstriction
Ideal gas exchange involves:
equal volumes of air coming into the _______

coming in contact with equal volumes of _____ flowing through alveolar capillaries.
alveoli, blood
What is the relationship between Alveolar ventilation (Va) and Pulmonary blood flow (Q)?
Ventilation/Perfusion ratio
Va/Q
Ideally = 1
What is normal alveolar ventilation?
4 L/min
What is normal cardiac output?
5 L/min
What is normal ventilation/perfusion ratio?
0.8
On what two factors does lung ventilation depend?
Compliance
Openness
In COPD, the reduced ventilation to large areas of the lungs due to blockage by secretions results in what Va/Q ratios?
Low
On what does the blood flow to lungs depend?
Patency of blood vessels
In standing, gas exchange is ___ times greater and blood flow is ____ times greater at the base than at the apex of the lung
3, 10
In an upright person, is blood flow greater or lesser than ventilation at the apex?
less
By what systems is the rate and depth of respiration controlled?
Automatic & Voluntary
Where does the automatic system originate?
Brainstem
Where does the voluntary system originate?
Cerebral cortex
Do chemoreceptors more tightly control CO2 or O2?
CO2
In which areas do central chemoreceptors in the medulla monitor CO2 levels?
Arterial blood
CSF
What does a rise in Pa CO2 signal an increase in?
Alveolar ventilation
Where are peripheral chemoreceptors found?
carotid & aortic bodies
What 3 factors stimulate peripheral chemoreceptors?
Low arterial oxygen tensions
High arterial CO2 tension
Acidosis