Respiratory System Flashcards
What lung structure is the site of exchange of oxygen and CO2?
alveoli
How many alveoli are in the lungs?
300 million
Is Intrapleural pressure less than or greater than atmospheric pressure?
less than
What is atelectasis?
collapsed lung
What seperates the lungs from the inner walls of the thorax?
serous fluid
What membrane secretes serous fluid?
parietal pleura
An increase in the volume of the intrathoracic cavity _____ intrapulmonic pressure. What does this cause?
decreases
air to rush into lungs (inspiration)
A decrease in the volume of the intrathoracic cavity _____ intrapulmonic pressure. What does this cause?
increases
air to rush out of the lungs (expiration)
What does contraction of the diaphragm cause the abdominal contents to do? What role does this play in obese people?
Causes them to move forward and downward.
In obese people this causes difficulties with inspiration because the diaphragm does not contract all of the way due to the inability of the abdominal contents to be moved forward and downward
What 4 muscles elevate the ribs?
- external intercostals
- scalenes
- sternocleidomastoid
- pectoralis minor
What 3 muscles pull the ribs down during forced expiration?
- Internal intercostals
- Rectus abdominis
- Internal oblique muscles of abdominal wall
How can airflow be calculated?
Airflow = P1 - P2 / Resistance
P1 - P2 is pressure difference between 2 areas
Resistance is resistance to airflow between 2 areas
Airflow increases in the difference between the 2 areas ____ and the resistance to airflow ____.
increases
decreases
What is the biggest factor affecting airflow at rest?
Diameter of the airway
What decreases the resistance to airflow during exercise?
bronchodilation
What is tidal volume?
the amount of air moved per breath
How do you calculate the volume of air moved per minute?
VE = TV × f
VE = volume of air expired per minute TV = tidal volume f = breathing frequency per minute
Pulmonary ventilation = ________ + ________
anatomical dead space + alveolar ventilation
Define tidal volume
the volume of inspired or expired air per breath
What is normal TV?
500-600 mL
What happens to tidal volume during exercise?
increases
Define inspiratory reserve volume
the maximal inspiration at the end of tidal inspiration
What is normal IRV?
1900-3000 mL
What happens to inspiratory reserve volume during exercise?
decreases
Define expiratory reserve volume
the maximal expiration at the end of tidal expiration
What is normal ERV?
800-1200
What happens to expiratory reserve volume during exercise?
decreases
Define total lung capacity
the volume in the lungs after maximal inspiration
What is normal TLC?
4200-6000 mL
What happens to total lung capacity during exercise?
decreases slightly
Define residual lung volume
the volume in the lungs after maximal expiration
What is normal RLV?
1000-1200 mL
What happens to residual lung volume during exercise?
decreases slightly
Define forced vital capacity
maximal volume expired after maximal inspiration
What is normal FVC?
3200-4000 mL
What happens to forced vital capacity during exercise?
decreases slightly
Define inspiratory capacity
maximal volume inspired following tidal expiration
What is normal IC?
2400-3600 mL
What happens to inspiratory capacity during exercise?
increases
Define functional residual capacity?
the volume in the lungs after tidal expiration
What is normal FRC?
1800-2400 mL
What happens to functional residual capacity during exercise?
decreases
Inspiratory reserve volume is _ times larger than tidal volume
5
Residual volume, inspiratory reserve, and expiratory reserve ____ with age. Explain why…
increase
Due to the decrease in the elastic components of the lung tissue with aging
What does FEV1 stand for?
The forced expiratory volume for 1 second
What is normal FEV1?
4800 mL
What is the normal FEV1 to FVC ratio?
80-85%
What happens to the FEV1 to FVC ratio in people with obstructive lung disease (asthma, emphysema, etc.)?
it decreases to around 70%
What happens to the FEV1 to FVC ratio in people with restrictive lung disease (due to kyphotic posturing)?
It increases to around 90%
Partial pressure of oxygen (PO2) must be _____ in the alveoli than in the blood and ____ in the blood than in the tissue in order for oxygen to diffuse
greater
greater
RBCs containing hemoglobin transport __% of oxygen
98%
What is normal O2 % saturation?
97-98%
What is the pressure of O2 in the lungs?
100 mm Hg
What is the pressure of O2 in the veins?
40 mm Hg
Percent O2 less than __% oxygen will not be delivered to the tissues
80
If percent O2 goes below __% supplemental oxygen should be prescribed
90
An increase in temperature, acidity, and/or 2,3 DPG shifts the oxyhemoglobin disassociation curve to the ____ which _____ the affinity of hemoglobin for oxygen
right
decreases
A decrease in temperature, acidity. and/or 2,3 DPG shifts the oxyhemoglobin disassociation curve to the ____ which _____ the affinity of hemoglobin for oxygen
left
increases
The effect that pH has on the oxyhemoglobin dissociation curve is called the ___ effect
Bohr
What are the 3 methods by which CO2 is transported?
- dissolved in plasma (7-10%)
- bound to hemoglobin (20%)
- as bicarbonate (70%)
In men, each 100 mL of blood contains approximately __ grams of Hb
16
In women, each 100 mL of blood contains approximately __ grams of Hb
14 (5-10% less than men)
Each gram of Hb can combine loosely with ___ mL of oxygen
1.34
How many mL of hemoglobin achieves full saturation?
20 mL (15 x 1.34)
How is oxygen capacity calculated?
= grams of hemoglobin x 1.34
The oxygen carrying capacity for men = __
The oxygen carrying capacity for women = __
What does the difference in these numbers signify?
- 4
- 8
Females cannot function as efficiently as men in terms of oxygen consumption, therefore they fatigue much quicker.
What happens to hemoglobin concentration during exercise?
It increases anywhere from 5-10%
What causes the increase in Hb during exercise?
Hemoconcentration or movement of fluid (water) from the blood into the surrounding cells and tissue
What increases hemoconcentration?
sweating
How do you calculate the percent saturation of hemoglobin?
= (O2 content of Hgb / O2 capacity of Hgb) x 100
What condition cause percent saturation to decrease?
emphysema
What is another cause of low blood oxygen?
obesity hyperventilation syndrome (OHS)
What are the 2 causes of obesity hyperventilation syndrome (OHS)?
- Defect in the brain’s control over breathing
- Excessive fatty-tissue weight against the chest wall
What 4 things can improve percent saturation?
- Quit cigarette smoking
- Avoid second hand smoke
- Exercise in order to increase CV endurance
- Weight loss
VO2 max ____ up to 25% with prolonged bed rest
decreases
Why does the oxidative capacity of skeletal muscles decrease with prolonged bed rest?
slow twitch fibers are converted to fast twitch
What molecule is responsible for gas exchange at the muscle?
myoglobin
Where is the respiratory control center found?
In a portion of the medulla oblongata and pons
What do central chemoreceptors in the medulla respond to?
Changes within the CSF, especially in H+ concentration or pH
What do peripheral chemoreceptors in the carotid arteries and aortic arch respond to?
Changes in blood PCO2 & H+ concentration
What is the technique called that uses ventilatory equivalents to estimate lactate threshold?
Ventilatory Threshold (VT)
The point at which the ventilatory equivalent of oxygen and the ventilatory equivalent of carbon dioxide is called what?
Respiratory compensation Point
High intensity exercises occur ____ the RCP
above
