Respiratory Physiology Flashcards
Immaturity of the respiratory tract is a major cause of ______
mobility and mortality in premature infants
____ production generally begins after week 20
surfactant
by the 25th to 28th week of gestation _____ are present to permit survival
sufficient alveoli
final adult alveolar number is about _____
700 million total
lack of stiff structural support for airways makes children more susceptible to ____ and _____
atelectasis (lung collapse) and obstruction
Upper airway consists of (3)
- nasopharynx
- oropharynx
- laryngopharynx
lower airway consists of (4)
- larynx
- trachea
- bronchi
- acinus
nasal cavity functions
- conducts gases to and from lungs
- filters, warms, humidifies air
- turbinates are convoluted and vascular
- rigid (bone/cartilage) to prevent collapse
- vibrissae trap foreign particles
- cilia sweeps mucous
What are the four paranasal sinuses
-maxillary, frontal, ethymoid, sphenoid
sinuses contribute to ____
speech resonance, heat and water vapor exchange , mucociliary action removes bacteria and debris
Eustachian tubes allow _______ of middle ear.
pressure equalizer
Eustachian tubes are open during swallowing, otherwise closed– horizontal position and shorter length in children predisposes to ________
ottis media in children
the conducting airways consists of :
nasal and oral pharynx, larynx, trachea, bronchi, and bronchioles
function of conducting airways
- direct air to respiratory exchange zones of the lung
- warm, filter, and humidify air
- no gas exchange across conducting airways
conducting airway epithelium is ________ epithelial cells
ciliated columnar epithelial cells
what is the primary defense mechanism of conducting airway epithelium?
mucociliary transport is a primary defense mechanism- moves inhaled particles and mucous to the esophagus for swallowing or coughing
Goblet cells produce ____
mucous
do children have more or less goblet cells than adults ?
more
function of the larynx
sound production, valve to control air movement out of lungs, prevent foreign substances from entering the trachea and lungs, expel foreign substances
larynx anatomy: hyoid bone –
a horseshoe shaped bone from the larynx is suspended
thyroid cartilage:
a v-shaped cartilage containing the vocal folds (attach anteriorly)
cricoid cartilage:
a ring shaped cartilage connected to the trachea, supports the arytenoid cartilages posteriorly
arythenoid cartilage
vocal folds connect on posterior side
Vocal folds:
vibrate when air passes over them, forming sound (longer folds create lower sounds, tighter folds, create, higher sounds)
Cough is initiated by _________ receptors in the ____
trachiobronchial receptors in carina (bifurcation of right and left mainstream bronchi)
cough is produced when ____ and ____ close tightly against air trapped in lungs
vocal folds and epiglottis
When a cough is initiated, expiratory muscles (intercostal and abdominal) contract and ________ against closed vocal folds and epiglottis; vocal fold and epiglottic suddenly open; _____ escapes, ejecting debris and mucus
increase pressure; high pressure air
cough is a defense against _____
excessive secretion or foreign/irritating substance
diminishing cough reflex increases risk of ____
aspiration
The trachea divides in the right and left main ____ at the carina
bronchi
Right lung has ___ lobular bronchi
3
Left lung has ___ lobular bronchi
2
lobular bronchi –> ____ –>_____
lobular bronchi–> segmental bronchi–> the terminal bronchioles
each lobe is separated into ______
independently-ventilated bronchiopulmonary segments
alveoli begin to form on the ________
respiratory bronchioles
adults have _____ alveoli per lung
350 milllion
alveoli is the surface for ___ and ___ exchange
O2 and CO2
Type 1 alveolar cells:
squamous epithelial cells (“pneumocytes”); majority of cells, form gas exchange surface
Type 2 alveolar cells:
produce surfactant; phospholipid-containing liquid that lowers surface tension (eases opening) and facilitates gas exchange
Type 3 alveolar cells
alveolar macrophages; phagocytize particles/ microbes that reach alveoli
Pleura is a thin continuous membrane covering ___ and ___
lungs (visceral pleura) and thoracic cavity (parietal pleura)
the visceral and parietal pleura are separated bye small amount of ______ to lubricate (around 15ml/ 1 tablespoon)
serous fluid
interpleural space is maintained at positive or negative pressure? which keeps lungs pressed against thorax wall
negative pressure
Parasympathetic nervous system, consists of the ___ nerve
vagus; stimulates constriction of bronchial smooth muscle (bronchioconstriction)
Sympathetic nervous system consists of _____ and _____ which causes ____ of bronchial smooth muscle
T1-T4 and epinephrine/norepinephrine (adernal gland medulla)
What is the sympathetic nervous system mediated by ?
b-2 adrenergic receptors
Bronchial artery system arises from ______ (oxygenated arterial blood); supplies blood to ____ and support lung structures (NOT to alveoli)
thoracic aorta; bronchi
Pulmonary artery system arises from ______ (delivers unoxygenated blood from ______), divides into right and left pulmonary artery
pulmonary artery; right ventricle
pulmonary artery system is a huge capillary network for ______ and is a high or low pressure arterial system?
gas exchange; low pressure
oxygenated blood exits through _______ into ____
pulmonary vein into left atrium
two mechanisms to increase capillary perfusion:
- recruiting (opening) previously closed capillary beds (normally only 25% of capillaries are perfused)
- increasing arterial blood flow
pulmonary arterioles constrict in response to____
alveolar hypoxia
Fluid balance across lung tissue regulated by 3 factors:
hydrostatic pressure, colloid osmotic pressure, capillary permeability
hydrostatic pressure:
blood pressure vs tissue pressure
colloid osmotic pressure
related to protein concentration on either side of a membrane
capillary permeability
leakiness between endothelial cells lining capillaries
Ventilation is the process of ______
moving air into and out of the lungs
purpose of ventilation is to allow ___ absorption from inspired air and removal of ___ to expired air
O2; CO2
Ventilation is influenced by ___, ____, ____
body position, age, body size and shape
Tidal Volume (TV)
the volume of air breathed in and out without conscious effort in a “normal” breath (500cc)
Inspiratory reserve Volume (IRV)
The volume of air above TV that can be inhaled with maximum effort after a normal inspiration (~3L)
Expiratory Reserve Volume (ERV)
The volume of air above TV that can be forcibly exhaled with maximal effort after normal exhalation (~1.2L)
Residual Volume (RV)
The volume of air left in the lungs after a maximum exhalation (~1.2L)
Vital Capacity (VC)
the total volume of air that can be exhaled after a maximum inhalation (VC= TV +IRV+ERV, ~4.7L)
Inspiratory Capacity (IC)
the total volume of air that can be inspired after a normal exhalation (IC=TV+IRV, ~2.4L)
Functional Residual Capacity (FRC)
The total volume of air in the lungs following a normal exhalation (FRC=ERV +RV, ~2.4L)
Total Lung Capacity (TLC)
The amount of air in the lungs at maximal inspiration (TLC= IRV + TV+ ERV +RV, ~6L)
Measure _____ as an indicator of “minute ventilation”(volume of air that is exchanged each minute)
respiratory rate
Hyperventilation indicates….
increase minute ventilation, indicates increased need for O2 for excess CO2 or increased respiratory drive (brainstem function)
Hypoventilation (decreased minute ventilation) indicates…
reduced need for O2 or low CO2, or reduced respiratory drive (brainstem function)
Primary objective of respiration is to
get O2 into the blood and CO2 out
What are the three primary contributors to gas exchange?
- neuromuscular function (maintaining mechanics of inspiration and expiration)
- Ventilation (gas movement in and out of lung)
- Diffusion/ perfusion of gases (across the gas exchange membrane)
____ and ____ affect gas movement into and out of lungs
airway resistance and lung compliance
lung ____ is the natural ability of lung tissue to collapse on itself (the magnitude of change in lung volume as a result of the change in pulmonary pressure)
lung compliance
____ decreases alveolar surface tension
surfactant
what is actelectasis?
complete or partial collapse of the lung
what are the mechanics of inspiration
- the diaphragm contracts and moves downward
- negative interpleural pressure and lung expansion occurs
- intercostal muscles contracts, elevating ribs and expanding thoracic volume
what are the mechanics of Expiration
- Diaphragm and intercostal muscles relax (na active expiration via diaphragm)
- Lungs passively recoil- increasing intrapulmonary pressure and pushing air out
___, ___ breathing results in increased alveolar ventilation vs rapid shallow breaths
slow, deep
the partial pressure of O2 in alveoli is generally slightly greater than the ____
arterial O2 tension (normally 95-100mmHg)
the presence of a large difference between alveolar and arterial O2 tension indicates poor diffusion of _____ into blood
alveolar O2
Anatomic dead space:
- pulmonary areas that do not participate in gas exchange (bronchi and bronchioles)
- increased with destruction or consolidation of alveoli
Alveolar dead space:
ventilated bu nonperfused
physiologic dead space:
anatomic dead space + alveolar dead space
The ease with which air resistance is moved into and out of the lungs depends on _______
airway resistance
Airway resistance depends on what 3 things?
- airway diameter (radius): airway resistance is inversely related to the 4th power of the radius
- Turbulence: more turbulent air flow created more resistance
- Space filling materials/ obstruction: decrease airway diameter and increase turbulence
Effects of gravity: compared to lower portions of the lung, the upper portions have: less_____; larger_____, lesser_____
less blood flow (less gas exchange); larger, partially inflated alveoli; lesser ventilation capacity
High lung compliance=
lung stretches and passively contracts easily
low lung compliance=
stiff lungs, difficulty expanding
O2 moves from alveoli to ____, and CO2 moves from _____ to alveoli
blood, blood
O2 and CO2 diffusion is impaired by decreased ______ and increase ______ of change surface
surface area; thickness
CO2 transport:
- small amount is dissolved in ____
- Some binds with ______
- Majority of CO2 diffuses into RBCs and converted to ______ by carbonic anhydrase
- plasma
- hemoglobin
- carbonic acid
Increased tissue metabolism increases ____ and __ production resulting in decreased Hb affinity for O2 and increased Hb affinity for CO2
pCO2 and H+
as blood reaches the alveolar capillaries, CO2 diffuses out of blood into the alveoli, increasing blood___, which increases ____ binding capacity
pH; O2
affinity of ____ binding to Hb is higher than either O2 or CO2
carbon monoxide (CO)
does the diaphragm have inherent pacemaker properties?
no
the diaphragm requires input form the respiratory center in the ___ and ___
pons and medulla
Central chemoreceptors affect the _____ center. They primarily respond to ____ extracellular pH (indicator of CO2 concentration by increasing ventilator)
- secondary response to reduced O2 concentration by ventilatory rate
respiratory center
peripheral chemoreceptors affect ___ and ____. They respond to ____ (reduced O2 concentration) by triggering increased respiratory center activity
carotid and aortic bodies; hypoxia
Lung receptors respond by ___, ____, ____ (junta capillary receptors sense decreased O2 result in increased ventilation)
stretch, irritant (cough), and hypoxia
