respiratory system Flashcards
nasopharynx
continuation of nasal cavity to the soft palate
oropharynx
- soft palate to the upper border of epiglottis
- at 2nd cervical vertebrae
- passageway for food moving from mouth to esophagus and air from nasal cavity
laryngopharynx
extends from upper border of epiglottis to lower portion of the third, bodies of 4-5, upper portion of 6th vertebra
extends to esophagus
diaphragm origin
- xiphoid process
- costal margin
- laterally ribs 6-12
- posteriorly L1 and L2
diaphragm insertion
- central tendon
- thin but strong aponeurosis
- located near center of diaphragm but more anterior than posterior
- R and L hemidiaphragms
T/F: diaphragms separate different cavities w/different pressures
True
displacement of the diaphragm
- quiet breathing: 2/3 inch
- max excursion: 2.5-4 in
what might limit diaphragm displacement?
- obesity
- pregnancy
- size of various GI organs
- ascites
supine effects on diaphragm
- no effects of gravity
- level of diaphragm rises; greater excursion
- lung volumes low because of elevated position of abdominal organs
upright position effects on diaphragm
- diaphragm pulled down because effects of gravity
- reduced excursion but lung volumes increased
SL effects on diaphragm
- hemidiaphragms unequal
- uppermost side drops to lower position and has less excursion than in sitting
- higher but has less excursion
- lowermost (dependent) side rises higher in thorax and has greater excursion
T/F: You should position a patient with an injured lung with the injured side up so the “good lung” has greater excursion
True
which intercostal is used for inspiration?
external
which intercostal is used for expiration
internal
T/F: inspiration is a passive process at rest and during exercise
False: Active
contraction of diaphragm and external intercostals
relaxed breathing
- ribs drop
- diaphragm relaxes
elastic recoil
rebound of lungs after stretched by inhalation
why does elastic recoil occur?
- elastin in CT of lungs
- surface tension of the film of fluid lining alveoli
what are the muscles for inspiration
- external intercostals
- SCM
- scalenes
- pec minor/major
- upper trap
- SA
- rhomboids
- serratus posterior superior
- thoracic erector spinae
where is the apex of the lung located?
- in the root of the neck
- highest point approx 1 inch above middle 1/3 of each clavicle
lobar bronchi
pass into a lobe of the lungs from R or L bronchus
segmental bronchi
pass through a segment of each lobe
bronchioles
smallest segments of bronchi
respiratory zone
gas exchange airways made up of:
- respiratory bronchioles
- alveolar ducts
- alveoli
layers of the lungs?
- pleural space
- visceral pleura
- cervical parietal pleura
- costal parietal pleura
- mediastinal parietal pleura
- diaphragmatic parietal pleura
- costo-diaphragmatic recess
subatmospheric pressure is also called
negative intrapulmonary pressure
what causes air to flow into the lungs
difference in pressure between the atmosphere and alveoli. (high to low)
Intrapulmonary pressure change during
- inspiration
- expiration
- -3
2. +3
Intrapleural pressure change during
- inspiration
- expiration
- -6
2. -3
Transpulmonary pressure change during
- inspiration
- expiration
- +3
2. +6
how to measure static and dynamic lung volumes
spirometer
resting TV
350-500 mLs
minute ventilation
- assessment of effective ventilation
- L/min
- calculated by multiplying RR x TV
- rest: 5 L/min
- max ex: 70-125 L/min
Lung Compliance
- lungs have capacity to expand and stretch
- ease at which lungs can expand relative to pressure
- speaks to distensability of lung tissue
- stiffness of tissue
Elasticity
ability of lungs to return to their initial size after being stretched
T/F: emphysema has decreased compliance and are very difficult to inflate and have reduced capcity to recoil
False
- easy to inflate
- increased compliance
- decreased capacity to recoil
formula for lung compliance
ΔV/ΔP
surface tension
- created by fluid secreted onto lining of alveoli
- resists lung expansion/distension
- acts to collapse alveolus and raises pressure of alveolar air
surfactant
compound that reduces surface tension
what happens in the absence of surface tension
- recoil goes up
- compliance goes down
lungs of a pre term baby
Why don’t our lungs collapse when we aren’t actively breathing?
- because lungs are stuck to thoracic wall, always under elastic tension
- at functional residual capacity, elastic recoil of lung is balanced by elastic recoil of chest wall
V/Q ratio
0.8
distribution of pulmonary ventilation
2.5 x greater at base than apex
distribution of pulmonary perfusion
6x greater at base than apex
when does shunting occur
if perfusion occurs but very limited ventilation.
excess perfusion results in a R to L shunt
dead space
- if ventilation occurs w/limited perfusion
excess of ventilation results in
physiologic dead space
does a pulmonary embolism cause a shunt or dead space
shunt?
defects in ventilation perfusion matching can lead to
- hypoxia
- red oxygen delivery to peripheral tissue
Ventilation / perfusion scar
- test that measures air and blood flow in lungs
- most often dx or rule out PE
- involves radioactive albumin injected into blood and radionuclide into air breathed in
Dalton’s Law
- total pressure of gas mix is equal to sum of pressures of each gas in it
partial pressure
pressure of an individual gas
multiply % of gas by total pressure
CO2 transport in the blood
- CO2 dissolved in blood
- carried as bicarbonate ion
- carried combined w/hemoglobin
Increased CO2 in the blood
- shift to the R increases CO3 and H
- reduces blood pH
- CO2 retention (hypercapnic)
- hypoventillation
- reduced exhalation volumes
decreased CO2 in blood
- shift to L: decreased CO3 and H
- increases blood pH
- greater amounts of CO2 exhaled (hypocapnic)
- hyperventilation
- reduced exhalation volumes
How much O2 is delivered through a nasal canula in adults
1-6 L/min
what are some concerns using a nasal cannula
irritated and dried nasal mucosa
FIO2
fraction of inspired air that’s oxygen = 21%
for every L/min, increases by 4%
