Pulmonary System Physiology 1 Flashcards
Quiet inspiration uses what muscle to inhale?
The diaphragm
Active inspiration uses what muscles to inhale?
Scalenes, external intercostals and scm
Active expiration uses what to exhale?
Rectus abdominis and internal intercostals
The elastic ability of the lungs to recoil on expiration is based on what 2 factors?
Elastin
Surface tension
What describes a tissues ability to distend i.e. the ability of the lungs to expand?
Compliance
What describes a tissues ability to recoil?
Elasticity
What do we have to overcome in order to inhale?
Surface tension. Dysfunctional surface tension leads to atelectasis (lung collapse).
What substance allows the body to overcome surface tension?
Surfactant. Epithelial type II cells produce surfactant (which contains proteins and lipids).
When is the lung most likely to collapse?
End expiratory volumes
In describing the work of breathing, is rate work elastic or non-elastic?
Non-elastic
In describing the work of breathing is depth work elastic or non-elastic?
Elastic
What describes the work required to overcome air friction in the respiratory passages?
Non-elastic work
The elastic work of the lungs has to overcome what 2 factors?
Elastic nature of tissue
Surface tension
What happens with decreased compliance?
It is harder to inflate the lungs. Compliance refers to the lung’s ability to stretch.
Histamine, leukotrienes and prostaglandins have what affect on lung airway passages?
Bronchoconstriction
Sympathetic stimulation with release of epi stimulates beta 2 receptors on bronchiole smooth muscle to do what?
Relax causing bronchodilation. Versus bronchoconstriction is caused by alpha receptor stimulation.
The rate at which new air reaches the respiratory areas is known as what?
Alveolar ventilation. Alveoli is the area of gas exchange.
The amount of air expired after quiet expiration is known as what?
Tidal volume. Quiet respiration refers to “normal” breathing.
Maximum inspiration followed by the measurement of the volume of air expired during maximum expiration is known as what?
Forced vital capacity
Volume of air that fills the conducting passageways is known as what?
Anatomical dead space
Volume of air in respiratory areas for which no gas exchange takes place is known as what?
Physiological dead space
The amount of air expired after 1 second is measured as what?
Forced expiratory volume at 1 second (FEV1). This is an important measurement for diagnosing and managing asthma.
In what conditions do we get vasoconstriction?
Stress
Inhaled irritants
The volume of air remaining in lungs after a forced expiration is known as what?
Residual volume
What nerve supplies the diaphragm?
Phrenic nerve
What respiratory center will spontaneously depolarize and allow for smooth breathing by sending signals to the phrenic nerve?
The dorsal respiratory group
What sends out inhibitory signals to the dorsal respiratory group, slowing down depolarization levels and helping set final respiratory rate and pattern?
The pneumotaxic centers
What sends signals to the accessory muscle groups leading to forced or active breathing?
Ventral respiratory groups
Where are the peripheral chemoreceptors located?
Aortic arch and carotids
What are peripheral chemoreceptors sensitive to?
Oxygen levels
With decreased oxygen levels where does the peripheral chemoreceptor send its signal to increase rate of breathing?
The dorsal respiratory group
Where are central chemoreceptors located?
In the brain
What are central chemoreceptors sensitive to?
Carbon dioxide levels
What will increased CO2 levels do?
They will cause the body to increase rate and depth of breathing
What is the major control factor of breathing?
CO2 levels. CO2 is toxic for us and thus our bodies want to expel it.
What factors affect diffusion across the respiratory membrane?
Membrane thickness –> decreased diffusion
Partial pressure differences
Surface area: decreased leads to decreased diffusion
A concept that allows us to understand respiratory exchange when there is an imbalance between alveolar ventilation and alveolar blood flow is known as what?
Ventilation/perfusion ratio which should be kept at 1 to match ventilation rate with blood flow
What is the physiological condition when the alveoli can’t ventilate the amount of blood coming into the lungs?
Physiological shunt. This is where the ventilation to perfusion ratio in the lung is decreased.
What disorders set up a physiological shunt?
Lung disease (e.g. emphysema)
A situation in which there is extra air but not enough blood to oxygenate it is known as what?
Physiological dead space. The ventilation to perfusion ratio is increased in this state.
What disorders will contribute to physiological dead space? Say which side of the ratio it will affect.
Hyperventilation: Increased alveolar ventilation, making it a physiological shunt.
Pulmonary embolism decreased blood flow, making it a dead space.
What three things affect the oxygen-hemoglobin dissociation curve?
(1) CO2 binding –> O2 dissociates from Hgb
(2) H+ ions –> O2 dissociates from Hgb
(3) Temperature –> O2 dissociates from Hgb
What are three ways CO2 is carried in the body?
(1) Dissolved in plasma (7%)
(2) Inside rbc, bound to Hgb (23%)
(3) In plasma as bicarbonate ion (HCO3-)(70%)
How is respiration involved in acid base balance?
Via creation of bicarbonate that acts as a buffer in the blood:
CO2+H2O–> H2CO3 –> H+ + HCO3-
