Flashcards in PSL301: Respiratory 2 Deck (72)
rapid heart rate
Person turns blue, especially under the nails
Trachypnea, tachycardia, grunting when expiring, and cyanosis are symptoms of...
Respiratory distress syndrome of the newborn
Treatment for respiratory distress syndrome of the newborn
P1V1 = P2V2
relationship between pressure and volume
How does air get into lungs?
Diaphragm contracts, increasing thoracic volume = decreasing thoracic pressure.
Atm pressure > alveolar pressure
Air flow down pressure gradient
How does air get out of the lungs?
Diaphragm relaxes, decreasing thoracic volume = increasing thoracic pressure.
Atm pressure < alveolar pressure
Air flow down pressure gradient
Diaphragm is controlled by __ nerve
Where is the phrenic nerve located?
spinal segments C3, C4, C5
Scalenes are attached to the...
first 2 ribs
sternocleidomastoids are attached to the...
Inspiratory muscles consist of...
The rib cage can increase in dimension in 2 ways
1. anterior-posterior (pump handle)
2. lateral (bucket handle)
When are expiratory muscles used?
- voluntary expiration
- fast breathing frequency
Internal intercostals effect on rib cage during expiration
contract -> force rib cage inwards
Abdominal muscles effect on rib cage during expiration
contract -> force rib cage inward & force abdomen into thoracic cavity to decrease lung volume
How does the movement of diaphragm and rib cage affect the lungs when they are not attached to the thoracic wall?
Fluid in pleural cavity has enough surface tension, and act as glue
Pressure in pleural cavity
Intrapleural pressure is always POSITIVE / NEGATIVE with respect to atm pressure and alveolar pressure
Volume of pleural cavity
The inner membrane of the pleura is called...
The outer membrane of the pleura is called...
Are expiratory muscles normally used?
No, expiration is usually a passive process
What creates the intrapleural pressure?
The opposing forces between the chest wanting to expand and the lungs wanting to collapse
___ of the chest wall tries to pull chest outwards
____ of the lungs creates an inward pull
Puncture in the intrapleural cavity makes it atm = no more glue
chest and lungs do whatever they want:
chest expand out
lungs collapse in
Treatment for penumothroax
- wet dressing to wound (air in pleural cavity can only flow outwards)
- CPR to re-inflate lungs
How does the alveolar pressure change during inspiration & expiration?
min = middle of inspiration (-1 mmHg)
max = middle of expiration (+1 mmHg)
How does the intrapleural pressure change during inspiration & expiration?
-3 at the beginning of inspiration
-6 at the beginning of expiration
Remember that it is always negative!
Which takes longer, inhale or exhale?
Exhale takes about 3x longer
2 factors that influence breathing
1. lung compliance
2. airway resistance
Degree the lungs will comply by changing their volume when subjected to change in intrapleural pressure
Lung compliance is influenced by...
1. elastin fibre
2. surface tension in alveoli
Force that opposes the movement of air
Airway resistance is influenced by...
1. type of flow
2. airway diameter
Elastin fibres are found...
between alveolar cells
Elastin fibers are composed of...
single elastin molecules cross-linked with each other
What happens to elasticity of lungs as we get older?
What happens to elasticity in people with empysema?
Relationship between elasticity and compliance?
Formula: lung compliance
CL = change in volume / change in distending pressure
pressure difference between alveoli and intrapleural cavity
Pulmonary fibrosis causes lung compliance to...
get worse (harder to expand)
Emphysema causes lung compliance to...
get better (expand easily)
surfactants ___ the surface tension
Increased surface tension will cause alveoli to...
(more pressure pushing on the bubble)
Law of LaPlace
P = 2T/r
According to LaPlace, what size alveoli experience greater pressure?
Purpose of surfactants at the aveoli
To equalize the pressures experience by the big and small bubbles
Why don't we want smaller alveoli collapsing into bigger ones?
Smaller ones have more SA, which is better for gas exchange
Respiratory distress syndrome of the newborn is due to...
Type II alveolar cells don't produce enough surfactant, so less SA at alveoli -> less gas exchange
3 types of flow
What type of flow is in the respiratory system?
mainly laminar, but turbulent at branch points
Formula for resistance
L = length of tube
n = viscosity of air
r = radius of tube
90% of the resistance in the airway comes from...
trachea & bronchi
How does the bronchioles contribute to resistance?
Not much (large x-section area)
By changing diameter (smooth muscles)
Histamine causes the bronchioles to...
CO2 / E on B2-adrenergic receptors cause bronchioles to...
When resistance in airway is increased, what happens to the pressure?
More negative alveolar pressure during inspiration
More positive alveolar pressure during expiration
Needed to maintain constant volume of air
Total pulmonary ventilation tells us...
how much air moves into and out of the lungs per minute
Formula: total pulmonary ventilation
minute ventilation = VT * respiration rate
Normal respiration rate
Normal minute ventilation
Formula: alveolar ventilation
(VT - DSV) * RR
How much air is usually in the dead space?
Alveolar ventilation is...
volume of air reaching the gas exchange areas per minute
Difference between total ventilation and alveolar ventilation
Alveolar ventilation takes into account DSV, which does not reach the alveoli
Typical alveolar ventilation is...