Core Organ Functions: A&P The Respiratory System Flashcards
What is the main muscle of ventilation?
The diaphragm
The most important expiratory accessory muscles
the abdominal muscles
The most important inspiratory accessory muscles
The cervical strap muscles
the scalenes help prevent inward motion of the ribs
the SCMs help to elevate the upper part of the rib cage
Lung anatomy: what is the point at which cartilate is totally absent from the airway wall?
The terminal bronchiole
The functional unit of the lung. it comprises of respiratory bronchioles, alveolar ducts, alveolar sacs, and grape-like clusters of alveoli.
The acinus
these types of cells form the majority of the epithelial surface of the alveolus
Type I cells
These types of cells produce surfactant and fuction as reserve precursor cells for type I cells
Type II cells
What are the two types of vascular supply for the pulmonary system?
- Bronchial: Arises from the aorta and the intercostal arteries, and is oxygenated systemic blood that provides nutrition to the tissues of the bronchi, visceral pleura, and pulmonary vasculature. NOT INVOLVED IN ALVEOLAR GAS EXCHANGE.
- Pulmonary: take deoxygenated sytemic blood and sends it to the pulmonary capillaries for interface with the alveoli
The movement of lung tissue depends on overcoming what 2 types of resistance?
- Elastic resistance of the lung parenchyma, chest wall, and gas-liquid interface in the alveoli
- Nonelastic resistance of the airways to gas flow.
What is the name of the work necessary to overcome elastic and non-eleastic resistance in the lungs?
The physiologic work of breathing
What is LaPlace’s law?
Pressure = (2 x surface tension) / Radius
-It helps to quantify the pressure within the alveolus with a given surface tension.
-The higher the surface tension, the greater the propensity of the alveolus to collapse.
This substance reduces surface tension, allowing the alveolus to more readily stay expanded
Surfactant
What is the formula for compliance?
Compliance = delta C/ delta P
The higher the pressure needed to produce a specific change in volume, the lower the compliance of the system and the higher is the elastic recoil of that same system.
What is Compliance affected by?
The presence of secretions, inflammation, fibrosis, fluid overload, etc
During laminar flow, what is the velocity of gas in the cylinder abutting the tube walls?
Zero
During laminar flow, where is the maximal flow velocity located?
in the innermos cylinder
What is the formula for resistance to laminar flow?
R = (8 x length x velocity) / (Pi x (radius)^4 flow) = Pb - Pa
Pb = barometric pressure
Pa = alveolar pressure
-Airway radius influences resistance by a power of 4.
-Gas density has no effect on resistance to laminar flow; only viscoscity influences resistance
-Less dense gases such as helium will not improve gas flow in the setting of laminar flow.
Random movements of gas through a tube created by flow through branched or disordered tubes resulting in a disruption of laminar flow
Turbulent flow
The resistance during turbulent flow is generally proportinal to?
The flow rate of the gas.
Turbulent flow is _____ sensitive to a change in radius
exquisitely more
A change in radius results in a change in resistance to a power of 5 of the change in radius
Resistance to turbulent flow is ______ proportional to gas density rater than viscosity
directly
As gas density decreases, resistance decreases as well
The ______ contains the most basic ventilation control centers, the dorsal respiratory group (DRG) and the ventral respiratory group (VRG).
medula oblongata
The _____ provides for a ventilation rate by rhythmically stimulating inspiration.
DRG
The ____ coordinates expiration
VRG
The ____________ communicate with respiratory centers in the medulla oblongata to alter the ventilation pattern and rate
Pontine respiratory centers (apneustic and pneumotaxic)
The ________ center sends siganls to the DRG to prolong respiration, whereas the _____ center functions to limit inspiration.
aneustic
pneumotaxic (will also increase the ventilatory rate and decrease inspiratory volume with increased stimulation)
The primary centers of ventilation control.
respiratory centers in the medulla and pons.
The midbrain and cerebral cortex may also affect the ventilatory pattern, in addition to relexes (swallowing, cough, and vomiting)
___________ in the airways of the lungs likely react to pressure changes from pulmonary edema or atelectasis, providing proprioception for the lungs and resulting in ventilatory alterations
Smooth muscle spindles
_____________________, tendon spindles primarily located in intercostal muscles, are stimulated when stretched, inhibiting further inspiration
Golgi tendon orgams
The __________________________ reflex, may also alter ventilation by inhibiting inspiration during lung distension.
Hering-Breuer
Central chemoreceptors are located in the _____ and relay information on ventilation needs based on ____
medulla
pH
Signaling to the respiratory centers is initiated at arterial partial pressure of oxygen < _____ mmHg
ventilation is not altered until oxyen partial pressure falls below ___ mmHg, at which point tidal volume and ventilation rate are increased
100
65
Deliver signals to the respiratory centers based on oxygen and carbon dioxide content from the periphery
carotid body chemoreceptors
Where are the carotid body chemoreceptors found?
at the bifurcation of the common carotid artery
How do the carotid body chemoreceptors communicate with respiratory centers?
via glossopharyngeal nerve
Peripheral carotid body chemoreceptors respond primarily to _____, while central chemoreceptors react to ________________.
lack of oxygen
elevations in carbon dioxide.
Delivers signals regarding partial pressure of oxygen via the vagus nerve, leading primarily to changes in circulation with minimal effect on ventilation
Aortic body chemoreceptors (found in the aortic arch)
Describe what happens to your carbon dioxide and oxygen levels during:
-significant altitude elevation
-breath holding
Explain how the ventilatory response changes for a given PaCO2 in the following settings:
-Normal
-Hypoxemic/metabolic acidosis
-Opioids/barbiturates
-anesthesia/prolonged anesthesia
Why is oxgen at supratherapeutic levels detrimental?
- Suppresses ventilation resulting in hypercarbia for PO2 levels 65mmHg in patients who depend on peripheral chemoreceptors for hypoxic ventilatory drive
- Free radical injury, resulting in acute lung injury
Relative concentrations of oxygen drive the movement of oxygen into the blood, allowing for oxygentation in the absence of ventilation, provided that a diffusion gradient is present.
Apneic oxygenation
The pulmonary diffusion capacity or the ability of carbon dioxide to pass between the alveoli to blood is __ times greater than oxygen, allowing for it to diffuse across the alveolar membrane with greater efficiency.
20
Explain the oxygen-hemoglobin dissociation curve
What is the Bohr effect vs. the Haldane effect?
The Bohr effect specifically describes hemoglobin’s decreased affinity for oxygen in environments with carbon dioxide elevation or acidosis
the haldane effect is the ability of deoxygenated hemoglobin to transport carbon dioxide by facilitating the formation of bicarbonate and acting as a buffer for formed hydrogen ions and a carboamino compound.
Ten percent of carbon dioxide in blood is ______, and the bulk of carbon dioxide is transported and stored as _______.
dissolved
bicarbonate
Ventilation distribution within the lungs depends on ___________ and ________________.
compliance of the alveoli
relative distending pressure.
In an upright patient, which part of the lungs are exposed to greater ventilation during inspiration?
The basal alveoli because they are relatively less inflated vs. the apical alveoli but are resting at a more compliant position with a greater distending pressure. The apical alveoli are resting at larger inflated volumes vs. the basal alveoli because of the greater complressing gravatational pressure outside the alveoli at the base.
During spontaneous ventilation, more gas is distributed to gravity-dependent areas.
Describe the West zone’s
Apex: Zone 1: PA>Pa>Pv
Zone 2: Pa>PA>Pv
Base: Zone 3: Pa>Pv>PA
Both ventilation and perfusion of alveoli increase at the ____ compared with the ___, but the rate of increase is greater for ______ than for _________.
Base
Apex
Perfusion
Ventilation
Ventilation in the excess of perfusion
What does it primarily alter?
Dead space
CO2 elimination
