-Pressure inside the alveoli
-Size of the pressure difference varies greatly with degree of physical activity and conditioning.
-Pressure between the parietal and visceral pleurae.
-Prevents lungs from collapsing too much by opposing the recoil of the elastic fibers in the lung tissue.
-4 mmHg (average) to -18 mmHg during powerful inhalation.
Tidal volume (TV)
-Amount of air moved into (inhale) or out of (exhale) lungs during a single respiratory cycle.
Resting tidal volume
-Amount of air inhaled or exhaled with each breath under resting conditions.
-500 ml in both males and females
Expiratory reserve volume (EVR)
-The amount of air that you can voluntarily expel AFTER you have completed a normal, quite respiratory cycle.
-Use your accessory expiratory muscles
-Amount of air remaining in the lungs even after a maximal exhalation.
--1200 ml in males; 1100 ml in females
-Amount of air that remains in the lungs even after complete collapse.
-30-120 ml (surfactant prevents collapse of alveolar surfaces).
-Cannot be measured in a healthy, living person.
Inspiratory reserve volume (IRV)
-Amount of air that can be taken in over and above the tidal volume
-IRV in males is about 3300 ml
-IRV in females is about 1900 ml
-The amount of air that can be drawn into the lungs after a quiet respiratory cycle has been completed.
-IC = TV + IRV
Functional Residual capacity (FRC)
-Amount of air remaining in the lungs after a quiet respiratory cycle has been completed.
-FRC = ERV + RV
-Maximum amount of air that can move into or out of the lungs in a single respiratory cycle.
-VC = ERV + TV + IRV
-VC = 4800 ml in males; 3400 ml in females
Total lung capacity
-The total volume of the lungs.
-TLC = VC + RV
-TLC = 6000 ml in males; 4500 ml in females
Breaths you take each minute
-Resting adult rate ranges from 12 to 18 breaths each minute.
-Approximately one breath for every four heartbeats
-Children take 18-20 breaths/minute
-Respiratory minute volume indicates how much air is moving into and out of the respiratory tract.
-Not all of the air actually contacts the respiratory membranes of alveoli.
-Alveolar ventilation rate is more important than the respiratory minute volume, because it determines the rate of delivery of oxygen to the alveoli
-Involves active inspiratory and expiratory movements.
-Requires use of accessory muscles of respiration
-Used to differentiate between obstructive and restrictive lung diseases.
-Determine the extent or progress of the disease
Increased Functional Residual Capacity (FRC) occurs in?
-Emphysema, Chronic Bronchitis
Forced vital capacity
-Measures the amount of gas expelled when the subject takes the deepest possible breath and then exhales forcefully and rapidly.
-FVC is reduced in patients with restrictive pulmonary disease.
Forced expiratory volume
-Same procedure, but examines the percentage of the vital capacity that is exhaled during specific time intervals of the FVC test (amount of air exhaled during the first second),
-Healthy people can exhale 75-85% of their FVC in the first second.
Each Hb molecule has?
-4 heme units and therefore can carry 4 oxygen molecules
-Therefore, each RBC can potentially carry over 1 billion oxygen molecules.
Lower pH changes?
-changes the shape of the Hb molecules and they release their oxygen more readily.
When PCO2 rises
-The rate of carbonic acid formation increases
-H+ diffuse out of the RBCs, and plasma pH drops.
- (slow, shallow breathing)
-Carbonic acid in blood increases significantly.
-Carbon dioxide builds up in the blood
-Decreases arterial blood pH (acidosis, pH lower than 7.35)
-(rapid, deep breathing)
-Carbonic acid in blood decreases.
-Carbon dioxide decreases
-Increases arterial blood pH (alkalosis, pH 7.45)
changes in pH and oxygen concentrations are monitored by ______ in the aortic and carotid bodies which stimulate the _______.
-(increase in arterial carbon dioxide typically caused by hypoventilation) sensed by chemorecerptors in carotid and aortic bodies. Stimulate neurons in medulla oblongata, respiratory centers increase rate and depth of respiration.
-(low arterial carbon dioxide typically from hyperventilation) results in decrease in chemoreceptor activity which slows respiratory rate.
Intrapleural pressure is the pressure between the _________ and __________ pleurae.
Disruption of intrapleural pressure by breaking the fluid bond between the pleurae is called a pneumothorax which can result in a collapsed lung or _____________.
The amount of air moved into or out of the lungs during a single respiratory cycle is the _______________.
The amount of air that you can voluntarily expel following a quiet respiratory cycle is the ___________.
-Expiratory reserve volume
The ___________ is the amount of air remaining in the lungs after maximal exhalation.
The __________________ is the amount of air that can be take in over and above the tidal volume.
-Inspiratory reserve volume
Quiet breathing is called __________ and is accomplished mainly by the _________,whereas forced breathing is called _________ and requires the use of accessory respiratory muscles.
____is the amount of air you move into or out of your lungs during a single respiratory cycle under resting conditions.
-Resting tidal volume