Respiratory I Ventilation Flashcards
what are the functions of the respiratory system
-exchange of gases between the atmosphere and the blood
- regulation of pH
- protection from inhaled pathogens and irritants
-vocalization
-route for water and heat loss
what is ventilation
air moves in and out of lungs
what do gases diffuse between
alveoli and blood
-blood and tissues
what is the visceral pleura
attaches to the surface of the lung
what is the parietal pleura
covers the surface of the chest wall, diaphragm, and mediastinum
what does the pleural space contain
a thin layer of pleural fluid under negative pressure
what is the negative pressure in the pleural space referred to as
the intrapleural pressure
is intrapleural pressure higher or lower than atmospheric pressure
subatmospheric - lower
what is a pleural effusion
excess fluid in the pleural space which makes lung expansion difficult so the person will breathe shallow and fast
how many lobes are in the right and left lobe
right-3
left-2
what zone is the best site for gas exchange and why
zone 3 because it gets more air and blood due to gravity
what zone are the alveoli largest
zone 1
normally most of the lungs are zones _____
3 and 2
what two functional zones is the respiratory system divided into
conducting zone and the respiratory zone
what does the conducting zone consist of
trachea, bronchi, bronchioles, and terminal bronchioles
what does the respiratory zone consist of
respiratory bronchioles, alveolar ducts, and alveolar sacs
how much air is in the conducting zone and what is it called
150 mL called the anatomic dead space
what happens to the diameter and number of the airways as you move down
the diameter decreases and the number of each increases
what happens to the amount of cartilage and smooth muscle of the airways as you move down
decrease in cartilage and increase in smooth muscle
what happens to surface area of the airways as you move down
increases
what happens to air in the conducting zone
it is warmed, humidified and filtered
what is the function of cartilage and smooth muscle
cartilage: prevents airway collapse
smooth muscle: alters resistance to airflow
what is the formula for velocity of air
V = flow/cross sectional area
what are the cell types in alveoli
-type I cells (simple squamous epithelial cells)
- type II alveolar (produce surfactant)
-macrophages
what cells make up wall of alveoli
type I
what is the basement membrane fused of
the endothelium and the alveolar epithelium
what is the typical transit time at rest for an erythrocyte through an alveolar capillary
0.75 seconds
how long does gas exchange take
0.25 seconds
what are the numbers for diffusion equilibrium for O2 and CO2
PAO2 and PaO2 = 100
PACO2 and PaCO2 = 40
what are the partial pressure for O2 and CO2 in arteries
PaO2: 40 mmHg
PaCO2: 45 mmHg
what are the partial pressures for O2 and CO2 in alveoli
PAO2: 100mmHg
PACO2: 40 mmHg
what type of muscles are respiratory muscles
skeletal muscles
what controls the alpha motor neurons in the respiratory muscles
neurons in the medulla and pons
what are the inspiratory muscles and what does contraction do
-mainly diaphragm and external intercostals but also sternocleidomastoid and scalenes
- increases the size of the thorax and lungs and decreases Palv
what are the expiratory muscles and what does contraction do
-mostly internal intercostals, external oblique, internal oblique, transversus abdominus, and rectus abdominus
-contraction decreases the size of the thorax and the lungs causing increase in Palv
when do expiratory muscles contract
only with active expiration
what do the internal intercostals do in expiration
depress the ribs
what do the abdominal muscles do in expiration
push abdominal contents against the diaphragm compressing the lungs
what is the primary inspiratory muscle
the diaphragm
what is boyles law
P1V1=P2V2
what changes first: changes in volume or changes in pressure
changes in volume
for air to enter the lungs the pressure in the alveoli must be_____
lower than the atmospheric pressure
for air to leave the lungs the pressure in the alveoli must be ____
higher than atmospheric pressure
which way do the chest and lung recoil
chest recoils outward, lungs recoil inward
what does the elastic recoil of the lungs favor
a decrease in lung volume or compression
what does the elastic recoil of the chest wall favor
an increase in lung volume or expansion
how is the intrapleural fluid related to recoil
it overcomes recoil and keeps the chest wall and lungs attached together so when the chest moves the lungs move with it
what is the formula for transmural or transpulmonary pressure
Ptp = Palv - Pip
what must happen to the transmural pressure to produce inspiration vs expiration
-must increase to produce inspiration
-must decrease to produce expiration
what pressure value equals zero in a pneumothorax
Ptp is 0 because Pip = Patm
where is half of the energy expended for inspiration stored and when is it released
stored in elastic recoil and released during expiration to overcome airway resistance
at what pressure does inspiration begin
at rest when Patm = Palv
what happens to the pressures during inspiration
decrease in Pip from -5 to -7.5mmHg causes Ptp to increase to 7.5 mmHg which causes the lung volume to increase
what happens to Palv as air enters the lungs
it increases again
when does air flow stop in inspiration
when Palv = Patm again
what volume of air does normal inspiration move
500mL - tidal volume
why is expiration a passive process in relaxed breathing
relaxation of inspiratory muscles
what happens to the pressures during expiration
increase in Pip from -7.5 to -5 mmHg which causes Ptp to decrease from 7.5 to 5 mmHg
what 2 factors affect pulmonary ventilation
lung compliance and airway resistance
what is the formula for compliance
change in volume/ change in pressure
what does high compliance vs low compliance mean
high: lung stretches easily
low: difficult for lung to stretch
where are alveoli more compliant
in the base of the lungs
what is the opposite of compliance
elasticity
what is elasticity
lungs ability to return to its normal resting position
what does high elasticity mean
easy recoil
lungs with lower compliance require a ___ Ptp to increase volume
larger
what happens in obstructive lung disease and what happens to compliance
-elastic fibers destroyed
- increase in compliance: will breathe deep and slowly to reduce the work of breathing
what happens in restrictive lung disease to compliance
decreased compliance
-will breathe shallow and fast to reduce the work of breathing
what is an example of obstructive lung disease
emphysema
what is an example of restrictive lung disease
pulmonary fibrosis
how much of pulmonary elasticity does surface tension account for
two thirds
what is surface tension
force that occurs at any gas liquid interface due to the cohesive forces between liquid molecules
what force does the fluid covering alveoli exert
a constant force favoring contraction
what does the law of laplace describe
the relationship between surface tension and radius of an alveolus
what is the formula for the law of laplace
P = 2T/r
if two alveoli are connected and the surface tension is equal, in which of the alveoli is the pressure greater? because of this where will the air flow
pressure is greater in the small alveolus and air will flwo into the larger alveoli
what does surfactant do and what is it secreted by
reduces surface tension (and thus elasticity) and equalizes pressure between alveoli of different sizes
-secreted by type II alveolar cells
what is surfactant made of
phospholipids
some components of surfactant are components of ____ immunity
innate
surfactant is particularly important for reducing surface tension where and what does this do
in small alveoli which decreases the likelihood of alveolar collapse
surfactant decreases the work of ____
inspiration
when is surfactant production increased
with hyperinflation of the lungs, exercise and beta adrenergic agonists
what pathologies are associated with decreases in surfactant production
infant respiratory distress syndrome, acute respiratory distress syndrome, chronic smoking
what is the formula for air flow in the lungs
(Patm- Palv)/ resistance
what are the determinants of resistance
-radius of bronchi/bronchioles
-viscosity of substance
-length of tube
what determines the radius of bronchi/bronchioles
-bronchodilation
-bronchoconstriction
-mucus accumulation
what causes bronchodilation
EPI on B2, decreased O2and increased CO2
what causes bronchoconstriction
ACH on M3, increased O2, decreased CO2, and histamine
the airways with the smallest radius have the ____individual resistance and the ____ total resistance
highest individual and smallest total
what are the pathologies that increase airway resistance
obstructive diseases such as asthma, emphysema and bronchitis
what is the resting normal tidal volume
500mL
what is IRV
deepest breath possible
what is expiratory reserve volume
deepest breath out possible
what is the normal anatomic dead space
1 mL per pound of idea body weight which is the conducting zone of the respiratory system
what is the formula for the physiologic dead space
anatomic DS + alveolar DS
describe the alveolar dead space of a healthy young person
little or no alveolar dead space
describe the alveolar dead space of someone with low cardiac output and why
a lot of alveolar dead space due to low perfusion and thus a higher V/Q ratio
what is included in vital capacity
IRV + ERV + TV
what is included in total lung capacity
VC + RV
what is included in inspiratory capacity
TV + IRV
what is included in functional residual capacity
ERV + RV
what is the formula for minute, pulmonary or total ventilation
tidal volume x respiration rate
what is the formula for alveolar ventilation
(tidal volume - dead space volume) x respiration rate
which pulmonary function test is a better indicator of gas exchange: total ventilation or alveolar ventilation
alveolar ventilation
what is the normal respiratory rate
between 12-20 breaths/minute at rest
is it better to breath deeper or faster and why
deeper to get more air into the respiratory zone for gas exchange
what do measurements of expiratory flow reflect
air flow within large airways. used to test for increased airway resistance
what are the measurements of expiratory flow
-forced vital capacity
- forced expiration volume
what is the forced vital capacity
volume of air forcibly expired after maximal inhalation ~5L
what is the forced expiration volume
fraction of FVC expired during the first second
what is the normal forced expiration volume
.8 or 80%
what is FEV1 in obstructive lung diseases
less than 80%
what does FEV1 reflect
flow in large airways
what is eupnea
normal quiet breathing
what is hyperpnea and when does it occur
increased rate or volume due to higher metabolism
-during exercise
what is hyperventilation and when does it occur
increased rate or volume without increased metabolism
- during emotions,blowing up a ballon
what is hypoventilation and when does it occur
- decreased alveolar ventilation
- shallow breathing, asthma, restrictive lung disease
what is tachypnea and when does it occur
rapid breathing usually with decreased depth
-panting
what is dyspnea and when does it occur
-difficulty breathing, air hunger
- various pathologies or hard exercise
what percentage of total body energy does normal quiet breathing take
3-5%
what are obstructive diseases due to and examples
-due to increased airway resistance
- ex: asthma, emphysema, bronchitis, cystic fibrosis
what do obstructive diseases primarily impact and describe the breathing pattern
impacts expiration
- breathe slow and deep
what are restrictive diseases due to and example
decreased lung compliance
-ex: pulmonary fibrosis
what do restrictive diseases primarily impact and describe the breathing patttern
-impacts inspiration
-breathe fast and shallow
what is atopic asthma
-IgE mediated- type 1 hypersensitivity reaction
-an allergen leads to an inflammatory response that causes bronchospasms that obstruct airflow
what can chronic inflammation in atopic asthma lead to
imparied mucociliary response, edema and increased airway responsiveness
what are the quick relief and long term treatment options for atopic asthma
-quick: B2 agonists, anticholinergic agents
- long: inhaled corticosteroids, long acting bronchodilators
what can nonatopic asthma occur with
respiratory infections, exercise, hyperventilation, cold air, inhaled irritants, aspirin and other NSAIDS
what happens in the early phase response and late phase responses of atopic asthma
early: increased mucus production and mast cells release cytokines upon IgE binding
late: increased vascular permeability and edema
what type of lung disease is cystic fibrosis and what happens in it
- obstructive disease
-autosomal recessive disorder resulting in defective CTFR ion channel that results in abnormally thick mucus that obstructs airways
-defective Cl- secretion and excessive Na+ and H2O absorption
what are the treatments for cystic fibrosis
-antibiotics
-chest physical therapy (percussion and postural drainage)
- mucolytic agents
-pancreatic enzyme replacement
what chromosome is defective in cystic fibrosis
7
what is the pathway in cystic fibrosis
abnormal thick and viscid secretions
-development of a microenvironment that is protective of microbial agents and defective mucociliary clearance
- chronic airway obstruction and bacterial infection
- neutrophil influx and release of elastase and inflammatory mediators
- development of chronic bronchitis and respiratory failure
what happens in emphysema
destruction of elastic fibers and enlargement of airspaces due to destruction of airspace walls
what does emphysema lead to
- airway collapse which increases resistance and decreases flow
- damage to alveolar membrane so decreased gas exchange
- decreased elasticity and increased compliance
what happens in restrictive respiratory diseases
-chronic inflammation and the normal lung tissue is replaced with scar tissue/fibrosis (collagen fibers decrease lung compliance)
- low compliance - more difficult to inhale
- work of breathing increases (pt breathes shallow and fast decreases alveolar ventilation and decreases gas exchange
what are signs and symptoms of restrictive pulmonary diseases
-increased respiratory rate
-chronic cough - dry, non productive
-polycythemia due to hypoxia (decreased PaO2 and increased # RBCs)
