Repiratory Systems Flashcards
(23 cards)
Primary function of the lung
Maintain tension of oxygen and carbon dioxide of the arterial blood in normal range,
The fundamental mechanisms achieved in attaining respiration
Ventilation , diffusion , perfusion
Pulmonary function tests are classified into
Tests that assess ventilation , tests that asssess gas exchange in lungs and tests that assess pulmonary circulation
Process of ventilation is concerned with
movement of air in and out of the alveoli
The most sensitive and non invasive test of lung function to differentiate obstructive from restrictive disease
FEV1
Airflow of lungs can be broken down into three interconnected regions
Upper airway. , conducting airway and alveolar airway
Alveolar airway is also known as
Lung parenchyma or acinar tissue
Two crucial functions provided by nose and upper airway
(1) filtering out large particulates to prevent them from reaching the conducting and alveolar pathways
(2) serving to warm and humidify air as it enters body
In addition to olfaction
Most of the 5-10 micrometer impact on the nasopharynx and race the rest of their path
Impact on the nasopharynx and do not enter conducting airway ,
Settle on mucous membranes in the nose and pharynx .
Because of momentum , do not follow airstream , curves downwards into lungs ,
Impact on or near tonsils and adenoids
What are the collections of immunologically active lymphoid tissue in the back of the pharynx
Tonsils , adenoids
What is the respiratory center composed of
Several groups of neurons located bilaterally in the medulla oblongata and pons of the brain stem
Respiratory center is divided into three major collections of neurons
1.a dorsal respiratory group , mainly causes inspiration (dorsal medulla )
2. Ventral respiratory group , mainly causes expiration (ventral medulla )
3.The pneumotaxic center
Controls rate and depth of breathing (dorsally pons )
Describe the Chemical control of respiration (long answer )
The respiratory activity is highly responsive to changes in
O2 , CO2 , H+in tissues .
Goal of respiration is to maintain proper concentration of them
The effect of oxygen in the chemical control of respiration
Acts almost entirely on peripheral chemo receptors located in carotid and aortic bodies . These receptors in turn transmit appropriate signals to reps center for real control
The area sensitive to blood CO2 and H+ conc.
Chemosensitive area
H+ concentration and respiratory stimulation
*likely the primary stimulus
*H+ ions do not easily cross the BBB, Hence changes in it have less effect than CO2 in blood
*tho CO2 is said to stimulate these neurons secondarily by changing H+ conc
Timed vital capacity (FEV1)
Aka forced expiratory volume in 1 second (FEV1)
*Defined as the percentage of FVC expired in the specified time (in 1 sec =FEV1, in 2 sec =FEV2)
*measures FVC in relation to time ,
an index of air flow rate
*Normal conditions - 72 to 85% of FVC is expired in the first second ,
95% in 2 seconds
97% in 3 seconds
* generalised test to detect airway obstruction
*ratio of FEV1:FVC important than clinical measurements .
Normally 0.8
Clinical importance of FEV1
*detect generalised airway obstruction
1. FEV1<72% , difficulty exhaling air due to ob,
Hallmark of obstructive lung disease like bronchial asthma
2. FEV1 FVC ratio normal in restrictive lung disease
What is periodic breathing ?
Cyclical repetition of apnea and shallow breathing (like hyperpnea) in normal individuals.
* can occur in normal conditions and in CHEYNE-STOKES RESPIRATION (occurs in diseases and abnormal condition )
Cheyne-Stokes Respiration seen in
- occurs in deep sleep of normal individuals
- more common in congestive cardiac failure , *uremia or Renal failure
and brain diseases - premature infants
*unacclimatized persons at high altitude
Patients have increased sensitivity to CO2 due to disruptions of neural pathways .
Accumulation of CO2causes hyperventilation that lowers PCO2
Decreased co2 removes the co2 drive on ventilation and produces apnea which consequently increases pco2 again
What is valsalva ratio
Measure of parasympathetic and sympathetic function .
Ratio of minimal heart rate in phase IV to max heart rate in phase II as depicted in terms of RR interval
= longest R-R interval during phase 4 / shortest R-R interval, during phase II
Valsalva Maneuver
procedure is performed closing both nostrils and then blowing into a tube connected to sphyg- momanometer. By putting strain, blowing pressure is maintained at 40 mm Hg for 15 seconds.
Has 4 phases
1. Onset of strain , transient increase in blood pressure e
