Viva Respiratory Flashcards
Normal respiratory rate
12-16 per minute
What are the types of respiration
• External respiration that involves exchange of respiratory gases, i.e. oxygen and carbon dioxide between the alveoli of the lungs and blood • Internal respiration that involves exchange of respiratory gases between blood and tissues.
Define respiratory unit
Name the structures of respiratory
unit.
Respiratory unit is the terminal portion of respiratory tract where the exchange of gases occurs • Respiratory bronchiole • Alveolar ducts • Antrum • Alveolar sacs • Alveoli
List the non-respiratory functions of
respiratory tract.
• Olfaction • Vocalization • Prevention of dust particles • Defense mechanism • Maintenance of water balance • Regulation of body temperature • Regulation of acid base balance • Anticoagulant function • Secretion of angiotensin converting enzyme (ACE) • Synthesis of hormonal substances.
What are the characteristic features
of pulmonary circulation?
• The wall of pulmonary blood vessels is thin
• These blood vessels are more elastic
• Smooth muscle coat is not well developed
in these blood vessels
• True arterioles have less smooth muscle
fibers
• Pulmonary capillaries are larger than
systemic capillaries.
What is the normal pulmonary blood
pressure?
Systolic pressure : 25 mm Hg
Diastolic pressure : 10 mm Hg
Mean arterial pressure : 15 mm Hg
Capillary pressure : 7 mm Hg
Enumerate the factors regulating
pulmonary circulation.
- Cardiac output
- Pulmonary vascular resistance
- Nervous factors
- Chemical factors.
Name the primary inspiratory and
primary expiratory muscles with the nerve
supply
Primary inspiratory muscles: • Diaphragm—innervated by phrenic nerve • External intercostal muscles—innervated by intercostal nerves. Primary expiratory muscles: Internal intercostal muscles—innervated by intercostal nerves.
Name the accessory respiratory
muscles
The accessory inspiratory muscles are sternomastoid, scalene, anterior serrati, elevators of scapulae and pectorals. The accessory expiratory muscles are abdominal muscles.
What is the role of lungs in defense
mechanism?
• Lung’s own defense: Secretion of immune
factors – defensins and cathelicidins
• Leukocytes: Neutrophils and lymphocytes
kill the bacteria and virus
• Macrophages: Engulf dust particles and
pathogens, act as antigen presenting cells;
secrete interleukins, tumor necrosis
factors and chemokines
• Mast cell: Produces hypersensitivity
reactions
• Natural killer cell: First line of defense
against virus
• Dendritic cells: Function as antigen
presenting cells.
What is pump handle movement?
What is its significance?
During inspiration the upper costal series
(second to sixth pair of ribs) are elevated
and the sternum moves upward and
forward. This type of movement of ribs and
sternum is called pump handle movement.
Significance: It increases the anteroposterior
diameter of thoracic cage during inspiration.
What are the movements of thoracic
cage during inspiration?
Thoracic cage enlarges during inspiration
and its size increases in all diameters.
Increase in anteroposterior diameter is due
to the elevation of upper costal series and
the upward and forward movement of
sternum. Increase in transverse diameter is
due to the elevation of lower costal series.
The increase in vertical diameter is due to
descent of diaphragm.
What is the bucket handle movement
During inspiration the central portions
(arches) of upper costal series (second to
sixth pair of ribs) and lower costal series
(seventh to tenth pair of ribs) swing outward
and upward. This is called bucket handle
movement.
Significance: It increases the transverse
diameter of thoracic cage during inspiration
What is pump handle movement?
What is its significance?
During inspiration the upper costal series
(second to sixth pair of ribs) are elevated
and the sternum moves upward and
forward. This type of movement of ribs and
sternum is called pump handle movement.
Significance: It increases the anteroposterior
diameter of thoracic cage during inspiration
What is the significance of contraction
of diaphragm during inspiration?
When the diaphragm contracts, it is
flattened. This increases the vertical diameter
of thoracic cage during inspiration.
Daltons law
It states that total pressure exerted by a
mixture of gases is equal to the sum of the
partial pressures of all the gases present
within it.
Henry’s law
It states that if temperature is kept constant,
amount of gas dissolved in any solution is
directly proportional to the partial pressure
of that gas.
Give the normal value of intrapulmonary or intra-alveolar pressure.
760
Why intra-alveolar pressure is equal
to that of atmospheric pressure? How
is it affected during inspiration and
expiration?
It is equal to the atmospheric pressure as during quiet breathing, at the end of expiration and at the end of inspiration, no air is going in and out of the lungs. During inspiration it decreases 3 mm Hg below its normal value, i.e. 757 mm Hg and during expiration it increases 3 mm Hg above its normal value, i.e. 763 mm Hg.
What is Valsalva maneuver and
Muller’s maneuver?
Forced expiration against a closed glottis
may produce positive intrapulmonary
pressure of > 100 mm Hg above the atmospheric value. This voluntary act is known as
Valsalva maneuver.
Forced inspiration against closed glottis
can reduce the intrapulmonary pressure
to < 80 mm Hg below the atmospheric
value. This voluntary act to reduce the intrapulmonary pressure is known as Muller’s
maneuver.
What is collapsing tendency of lungs?
What are the factors causing and preventing
collapsing tendency of lungs?
The constant threat of compression of the
lungs is called collapsing tendency of lungs.
Causing • Elastic property of lung tissues that induces the recoiling tendency of lungs • Surface tension exerted by the alveolar fluid. Preventing • Intrapleural pressure that overcomes elastic recoiling tendency of lungs • Surfactant that overcomes surface tension.
What is surfactant? Name the cells
secreting surfactant.
Surfactant is the lipoprotein substance that
reduces the surface tension induced by the
fluid lining in the alveoli.
It is secreted by type II alveolar epithelial
cells of lungs and Clara cells situated in
bronchioles
Surfactant prevents collapsing tendency of
lungs by reducing the surface tension in the
alveoli.
What is respiratory distress
syndrome or hyaline membrane disease?
It is the condition in infants with collapse of
lungs due to the absence of surfactant. In
adults it is called adult respiratory distress
syndrome (ARDS)
Define and give normal values of
intrapleural or intrathoracic pressure.
The intrapleural or intrathoracic pressure is
the pressure existing in the pleural cavity.
It is always negative. During inspiration it is
– 6 mmHg and during expiration it is –
2 mmHg.
What is the cause for negative intrapleural pressure?
The intrapleural pressure is negative
because of constant pumping of fluid
(secreted by visceral layer of pleura) from
the intrapleural space into lymphatic vessels
What is the significance of intrapleural pressure?
The intrapleural pressure prevents collapsing tendency of lungs. It is also responsible
for respiratory pump that increases venous
return.
How is intrapleural pressure
measured?
Intraesophageal balloon
Define and give normal values of
intraalveolar or intrapulmonary pressure
The intraalveolar or intrapulmonary pressure is the pressure existing in the alveoli of lungs. During inspiration it is – 4 mm Hg During expiration it is + 4 mm Hg
What is the significance of intraalveolar pressure?
alveolar pressure? • It causes flow of air into alveoli during inspiration and out of alveoli during expiration • It helps in exchange of gases between alveoli and blood.
What is transpulmonary pressure?
Transpulmonary pressure is the difference
between the intraalveolar pressure and
intrapleural pressure
What is compliance?
The expansibility of lungs and thorax is
known as compliance. It is defined as change
in volume per unit change in pressure
Define compliance in relation to
intraalveolar pressure and give normal
value.
In relation to intraalveolar pressure, compliance is defined as the volume increase in lungs per unit increase in intraalveolar pressure. Compliance of lungs and thorax = 130 ml/ cm H 2O. Compliance of lungs alone = 220 ml/cm H 2O.
Define compliance in relation to
intrapleural pressure and give normal
value.
In relation to intrapleural pressure, compliance is defined as the volume increase in
lungs per unit decrease in the intrapleural
pressure.
Compliance of lungs and thorax = 100 ml/
cm H2O. Compliance of lungs alone = 200
ml/cm H
2O.
Define work of breathing.
What are the types of resistance for
which energy is utilized during work of
breathing?
The work done by respiratory muscles
during breathing to overcome the resistance
in thorax and respiratory tract is known as
work of breathing.
• Airway resistance – that is overcome by
airway resistance work.
• Elastic resistance of lungs and thorax –
that is overcome by compliance work.
• Nonelastic viscous resistance – that is
overcome by tissue resistance work.
Define and give normal values of
lung volumes.
• Tidal volume: The volume of air breathed
in and out of lungs in a single normal quiet
breathing.
Normal value: 500 ml.
• Inspiratory reserve volume: The additional
amount of air that can be inspired
forcefully beyond normal tidal volume.
Normal value: 3,300 ml.
•
Expiratory reserve volume: The additional
amount of air that can be expired
forcefully after normal expiration.
Normal value: 1,000 ml.
• Residual volume: The amount of air
remaining in the lungs even after forced
expiration.
Normal value: 1,200 ml.
Figure 16.1 illustrates spirogram showing
lung volumes and capacities
What is lung capacity? Define and
give normal values of lung capacities.
Two or more lung volumes together are called lung capacity (Fig. 16.1). Lung capacities: • Inspiratory capacity: The maximum volume of air that can be inspired from the end expiratory position. It includes tidal volume and inspiratory reserve volume. Normal value: 3,800 ml. • Vital capacity: The maximum volume of air that can be expelled out forcefully after a maximal (deep) inspiration. It includes inspiratory volume, tidal volume and expiratory reserve volume. Normal value: 4,800 ml. • Functional residual capacity: The volume of air remaining in the lungs after normal expiration (after tidal expiration). It includes expiratory reserve volume and residual volume. Normal value: 2,200 ml. • Total lung capacity: The amount of air present in the lungs after a maximal (deep) inspiration. It includes all the four lung volumes i.e., inspiratory reserve volume, tidal volume, expiratory reserve volume and residual volume. Normal value: 6,000 ml.
Why the ‘Wheeze’ sound is heard
during expiration but not in inspiration of
an asthma patient?
During inspiration the intrapleural and
mediastinal negativity rises and as a result
the bronchial diameter increases. Reverse
occurs during expiration. Therefore
resistance to airflow is normally low in
inspiration and high in expiration. This is
why in bronchial asthma inspiration may
not be difficult but expiration becomes
difficult. This explains why the “Wheeze” in
bronchial asthma is heard during expiration
but not in inspiration.
What is the significance of residual
volume?
• It helps in the exchange of gases in
between breathing and during expiration
• It maintains the contour of the lungs.
What are the instruments used to
measure lung volumes and lung capacities?
- Spirometer
* Respirometer.
Name the lung volumes and capac
ities,
which can not be measured by spirometer
- Residual volume
- Functional residual capacity
- Total lung capacity.
