Pulmonary Flashcards
Conducting airways
– Provide for movement of air from the external environment to the point of gas exchange.
Contains just over 20 subdivisions
– Lined with pseudostratified columnar
epithelium
Bronchioles are
smallest conducting airway.
* No smooth muscle or cartilage
* Retention of ciliated cuboidal epithelium
Terminal respiratory units are
– Respiratory bronchioles and alveolar ducts
autonomic nervous system
parasympathetic
sympathetic
Afferents are primarily vagal.
- Bronchopulmonary stretch receptors
- Irritant receptors in proximal airway
- C-fibers– Respond to mechanical and chemical stimuli
Efferents
- Muscarinic bronchoconstriction-
- Pulmonary vasodilation
- Mucus gland secretion
Sympathetic fibers at rest
– Bronchial smooth muscle relaxation
– Pulmonary vasoconstriction
– Inhibition of secretory gland activity
NANC fibers
Functions primarily as reciprocal balance to excitatory cholinergic system
Two main components of flow:
pulmonary and bronchial
bronchial vessels
supply arterial blood to the bronchi to feed it and takes away deoxiginated blood
pulmonary lymphatics
- Run along airway and vascular system
– Found in connective tissue spaces of pleura and peribronchovascular sheaths, interlobular septa
– Terminate in bronchioles (do not enter alveoli)
compliance
ability of tissue to comply
- Intrinsic elastic property that relates a change in volume to a change in pressure
– Both compliance of chest wall and lungs contribute to pulmonary compliance.
– Chest wall does not change significantly with volume.
elastic recoil
ability to return back to its original shape
Determined by the shape/structure of the thorax
Two contributing factors to elastic recoil
- Tissue elasticity
- Force needed to change shape of air-liquid interface of alveoli
– Surface tension is directly proportionate to surface forces that the lung has to overcome to expand.
Inflation overcomes three opposing forces.
- Elastic recoil
– Inertia of the respiratory system
(insignificant)
– Resistance to airflow
Laminar flow–
Airway caliber is the principal determinant of airway resistance.
moving in 1 direction, no resistant
Turbulent flow
– Driving pressure is proportionate to the flow rate.
driving pressure to keep flow
Turbulent flow
– Driving pressure is proportionate to the flow rate.
driving pressure to keep flow
flow is turbulent at the
top
trachea
flow is laminar at
bottom
alveoli
bronchioles
most negative pressure is at the
apex of the heart
Distribution of perfusion
– Gravity influences distribution.
– In an upright patient there is a linear increase in flow from apex to base.
Hypoxic pulmonary vasoconstriction– Pulmonary arterioles are sensitive to alveolar.
pO2
When alveolar pO2 falls, resistance to flow
increases.
When alveolar pO2 falls, resistance to flow
increases.
Minute ventilation is
6 L/min.
Minute ventilation is
6 L/min.
Pulmonary artery blood flow is
5 L/min.
Overall V/Q ratio is.
0.8
is anatomical dead space.
2 L
Resting alveolar ventilation is
4 L/min.
If the area is too large, the A-a (atmospheric and arterial)gradient
increases.
Shunt–
Perfusion without ventilation
Atelectasis or consolidation
- Both pO2 and pCO2 fall because remaining respiratory units are over-ventilated relative to blood flow.
- Shunt cannot correct low pO2 by increasing minute ventilation.
sensory input
frequency, depth, timing of spontaneous breathing are modified by chemical and mechanical receptors.
carotid bodies
Chemoreceptors at bifurcation of common
carotid and aortic branch
– As pO2 falls, carotid body fires signals to medullary center.
Central chemoreceptors
– Mediate response to increased pCO2
– Dispersed throughout the brainstem
– Increased ventilation rate in response to increased pCO2 is a function of chemoreceptors.
Pulmonary stretch receptors
– Located in the airway smooth muscle and
mucosa
– Discharge in response to distention of the lung
– Increased lung volume decreases respiratory rate as a result of increased expiration time (Hering-Breuer reflex).
C-fibers near pulmonary capillary receptors are stimulated by irritants.Increases respiratory drive in
interstitial edema and pulmonary fibrosis
Proprioceptors
– Skeletal movement transmits to respiratory centers.
* Increased ventilation during exercise
Spindle receptors
- In diaphragm and intercostals provide feedback on muscle work
- When work is disproportionate to ventilation, dyspnea occurs
Chronic hypercapnia
– Brain pH is compensated.
– Central chemoreceptors less sensitive to arterial paCO2
– Carotid body drive is imperative.
Chronic hypoxia
.
– High altitudes, sleep apnea
– Lung disease and hypercapnia can remove endogenous stimuli to breathe
Which of the following is not true with respect to conducting airways?
Secretory glands increase as airway divides.
The section of the airway that offers the least resistance to airflow is the:
Terminal respiratory unit.
The section of the airway that offers the least resistance to airflow is the:
Terminal respiratory unit.
Autonomic innervation is the primary determinant of smooth muscle activity in the airway. Irritant receptors in the proximal airway are an example of:
Vagal afferents.
The NANC fibers serve primarily to:
Provide reciprocity to cholinergic excitation
The __________________ are very sensitive to alveolar partial pressure of oxygen (pO2).
Pulmonary arteries.
Elastic recoil is determined by:
Tissue elasticity and force needed to change alveolar air-liquid interface.
pulomanry obstructive disease
asthma and COPD
Asthma
an accelerated, inappropriate chronic inflammatory response occurring in response to any variety of triggers
Local inflammatory cells are activated:
Primarily mast cells and eosinophils.
Acute-acting mediators are released.
*cause bronchoconstriction
Leukotrienes
* Prostaglandins
* Histamine
Acute-acting mediators stimulate a variety of responses.
– Smooth muscle contraction
– Mucus hypersecretion
– Vasodilation
– Endothelial leakage
– Local edema formation
COPD
A disease characterized by persistent and progressive airflow limitation that is not fully reversible
normal response
Chronic bronchitis may or may not be present in
COPD
Chronic bronchitis
mucous hyper secretion
-wet cough constantly
A result of chronic airway injury and narrowing
– Inflammation of the small airways
– Hypertrophy of large airway mucus glands
– Increased mucus production
Chronic bronchitis, Normal ciliated pseudostratified squamous epithelium is replaced by
squamous metaplasia
COPD has to do with
airflow limitation
Emphysema
A disease of lung parenchyma – not airways
- alveola lose their attachment to lunch parenchyma
Loss of alveolar surface area and accompanying bed decrease gas exchange producing hypoxia and dyspnea.
Types of Emphysema
Centriacinar emphysema
Panacinar emphysema
Centriacinar emphysema
This is the type most often associated with smoking.
FEV1
how much a patient can put out in 1 sec
FVC
how much a patient can put out over how every much time
A patient with a FEV1/FVC of 70% and a normal FEV1 has
stage I COPD.
FEV1 gives you the
stage of COPD
restricted lung is usually
smaller than the normal lung
Restrictive lung disease
There is a variety or collection of pulmonary diseases that result in pulmonary fibrosis, scarring of lung parenchyma and increased recoil and decreased compliance.
- Restrictive lung diseases generally classified as intrinsic or extrinsic.
Intrinsic lung diseases (can’t keep volume in)
Asbestosis
* Pneumonitis
* Acute respiratory distress syndrome * Sarcoidosis
* Idiopathic pulmonary fibrosis
Idiopathic pulmonary fibrosis is one type of
restrictive lung disease with no identified cause.
Extrinsic restrictive lung eases
Neuromuscular
– Myasthenia gravis- weakness of diaphragm
- Anatomical (nonmuscular) – Kyphosis- lose compliance of chest wall
- Volume restricting
– Obesity
Hyperacute protective mechanisms that characterize an asthma attack include all of the following except:
Vasoconstriction
The primary inflammatory mediators that characterize an asthma attack include:
Eosinophils.
Which of the following obstructive pulmonary diseases is characterized by hypertrophy of the large airway mucus glands?
Chronic bronchitis.
Acute-acting mediators released during an asthma attack include all of the following except:
Procalcitonin.
The characteristics of chronic bronchitis include all of the following except:
Characterized by limited mucus production.
The characteristics of chronic bronchitis include all of the following except:
Which of the following is false in regards to the characteristics of emphysema?
Airway inflammation is a primary factor of disease.
The most sensitive spirometric parameter to detect early airflow limitation is:
FEV1/FVC.
The most sensitive spirometric parameter to detect early airflow limitation is:
Intrinsic restrictive lung diseases include all of the following except:
The pathology of restrictive lung diseases shares all of the following characteristics except:
Intrinsic restrictive lung diseases include all of the following except:
The pathology of restrictive lung diseases shares all of the following characteristics except:
Intrinsic restrictive lung diseases include all of the following except:
Myasthenia gravis.
Intrinsic restrictive lung diseases include all of the following except:
Myasthenia gravis.
Intrinsic restrictive lung diseases include all of the following except:
Myasthenia gravis.
Intrinsic restrictive lung diseases include all of the following except:
Myasthenia gravis.
