The Respiratory System Flashcards
nose, nasal cavity, pharynx, and associated
structures
Upper respiratory system
• Trachea, larynx, bronchi, bronchioles, and lungs
Lower respiratory system
• All airways that carry air to lungs:
— Nose, pharynx, trachea, larynx, bronchi, bronchioles, and terminal bronchioles
“Conducting zone”
• Sites within lungs where gas exchange occurs
— Respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli
“Respiratory zone”
• Structure
— External nares -> nasal cavity -> internal nares
— Nasal septum divides nose into two sides
— Nasal conchae covered by mucous
membrane
• Functions
— Warm, humidify, filter/trap dust and microbes
a. Mucus and cilia of epithelial cells lining nose
— Detect olfactory stimuli
— Modify vocal sounds
Nose
branch of medicine that deals with the
diagnosis and treatment of diseases of the ears, nose, and throat
(ENT)
Otorhinolaryngology
ENT means
ears, nose, and throat
divides nose into two sides.
Nasal septum
covered by mucous membrane.
Nasal conchae
- Warm, humidify, filter/trap dust and microbes.
a. Mucus and cilia of epithelial cells lining nose. - Detect olfactory stimuli.
- Modify vocal sounds.
Functions of nose
• Known as the “throat”
• Structure
- Funnel-shaped tube from internal nares to larynx.
• Three regions (with tonsils in the upper two).
- Upper: nasopharynx; posterior to nose.
a. Contains adenoids (pharyngeal tonsil) and
openings of auditory (Eustachian) tubes.
- Middle: oropharynx; posterior to mouth.
a. 2 pairs of tonsils; Palatine and lingual tonsils are
here.
- Lower: laryngopharynx (hypopharynx)
a. Connects with both esophagus and larynx: food
and air.
PHARYNX
Three regions of Pharynx (with tonsils in the upper two).
- Upper: nasopharynx
- Middle: oropharynx
- Lower: laryngopharynx (hypopharynx)
— posterior to nose.
a. Contains adenoids (pharyngeal tonsil) and openings of auditory (Eustachian) tubes.
Upper: nasopharynx
— posterior to mouth.
a. 2 pairs of tonsils; Palatine and lingual tonsils are here.
Middle: oropharynx
(hypopharynx)
a. Connects with both esophagus and larynx: food and air.
Lower: laryngopharynx
Known as the “throat”
PHARYNX
“Voice Box”
LARYNX
• “Voice Box”
• Made largely of cartilage (9 cartilages)
- Thyroid cartilage: V-shaped.
a. “Adam’s apple”: projects more anteriorly in
males.
b. Vocal cords “strung” here (and to arytenoids).
- Epiglottis: leaf-shaped piece; covers airway.
a. During swallowing, larynx moves up, so epiglottis
covers opening into trachea.
- Cricoid cartilage: inferior most portion.
- Arytenoids (paired, small) superior to cricoid.
a. True vocal cords for speech.
- Cuneiform and corniculate cartilages
a. Cuneiform cartilages (paired) – support vocal folds
and lateral aspects of the epiglottis.
b. Corniculate cartilages (paired) – horn-shaped pieces
of elastic cartilage, located at the apex of each
arytenoid cartilage.
LOWER RESPIRATORY SYSTEM: LARYNX
— V-shaped.
a. “Adam’s apple”: projects more anteriorly in
males.
b. Vocal cords “strung” here (and to arytenoids).
Thyroid cartilage
Larynx is Made largely of cartilage (9 cartilages)
1 in Thyroid cartilage
1 in Epiglottis
1 in Cricoid cartilage
2 in Arytenoids
2 in Cuneiform cartilages and
2 in corniculate cartilages
— leaf-shaped piece; covers airway.
a. During swallowing, larynx moves up, so epiglottis covers opening into trachea.
Epiglottis
inferior most portion.
Cricoid cartilage
— (paired, small) superior to cricoid.
a. True vocal cords for speech.
Arytenoids
— support vocal folds and lateral aspects of the epiglottis.
Cuneiform cartilages (paired)
– horn-shaped pieces of elastic cartilage, located at the apex of each arytenoid cartilage.
Corniculate cartilages
• Mucous membrane of larynx forms two pairs of folds.
- Upper/superior = vertical folds (vestibular folds) or false vocal cords.
- Vestibular folds – holding breath.
- Lower/inferior = vocal folds or true vocal cords.
a. Glottis is the opening of the vocal folds.
b. Contain elastic ligaments.
c. When muscles pull elastic ligaments tight, vocal cords vibrate → sounds in upper airways.
d. Pitch adjusted by tension of true vocal cords.
- Lower pitch of male voice.
a. Vocal cords longer and thicker; vibrate more
slowly.
VOICE PRODUCTION
Mucous membrane of larynx forms two pairs of folds:
• Upper/superior
• Lower/inferior
vertical folds (vestibular folds) or false vocal cords.
Upper/superior
holding breath.
Vestibular folds
vocal folds or true vocal cords.
Lower/inferior
opening of the vocal folds.
Glottis
Vocal cords longer and thicker; vibrate more slowly.
Lower pitch of male voice.
inflammation of the larynx that is most
often caused by a respiratory infection or irritants such as cigarette smoke.
Laryngitis
found almost exclusively in individuals who smoke.
Cancer of the larynx
Treatment of LARYNGITIS AND CANCER OF
THE LARYNX
radiation therapy and/or
surgery.
measurement of smoking. It is equivalent of smoking one pack of cigarettes a day for one year. There are 20 cigarettes in a pack, so if a person smokes 20 cigarettes a day for one year, it is called one pack-year.
Pack-year
Cigarette smoking causes
Lung cancer
“Windpipe”
TRACHEA
• “Windpipe”
• Location:
- Anterior to esophagus and thoracic vertebrae.
- Extends from end of larynx to primary bronchi.
• Structure:
- Lined with pseudostratified ciliated mucous
membrane: traps and moves dust upward.
- C-shaped rings of (hyaline) cartilage support trachea, keep lumen open during exhalation.
- Tracheostomy: opening in trachea for tube.
TRACHEA
- Anterior to esophagus and thoracic vertebrae.
- Extends from end of larynx to primary bronchi.
Location of TRACHEA
- Lined with pseudostratified ciliated mucous
membrane: traps and moves dust upward. - C-shaped rings of (hyaline) cartilage support trachea, keep lumen open during exhalation.
Structure of TRACHEA
opening in trachea for tube.
Tracheostomy
• Structure of bronchial tree.
- Bronchi contain cartilage rings.
- Primary bronchi enter the lungs.
- In lungs, branching → secondary bronchi
a. One for each lube of lung: 3 in right, 2 in left.
- Tertiary bronchi →→→ terminal bronchioles.
• These smaller airways.
- Have less cartilage, more smooth muscle.
- In asthma, these airways can close.
- Can be bronchodilated by sympathetic nerves,
epinephrine, or related medications (e.g., during exercise which relaxes smooth muscle, causing dilation in the airways, allowing for quicker lung ventilation because
air reaches the alveoli more quickly.
LOWER RESPIRATORY SYSTEM: BRONCHI, BRONCHIOLES
- Bronchi contain cartilage rings.
- Primary bronchi enter the lungs.
- In lungs, branching → secondary bronchi
a. One for each lube of lung: 3 in right, 2 in left. - Tertiary bronchi →→→ terminal bronchioles.
Structure of bronchial tree
- Have less cartilage, more smooth muscle.
- In asthma, these airways can close.
- Can be bronchodilated by sympathetic nerves,
epinephrine, or related medications (e.g., during exercise which relaxes smooth muscle, causing dilation in the airways, allowing for quicker lung ventilation because air reaches the alveoli more quickly.
These smaller airways of BRONCHI, BRONCHIOLES
• Two Lungs: left and right.
- Right lung has 3 lobes.
- Left lung has 2 lobes and cardiac notch (in which the apex of the heart lies).
• Lungs surrounded by pleural membrane.
- Parietal pleura attached to diaphragm and lining thoracic wall.
- Visceral pleura attached to lungs.
- Pleural cavity contains lubricating fluid.
- Broad bottom of lungs = base; pointy top = apex.
LOWER RESPIRATORY SYSTEM: LUNGS
Right lung has
3 lobes
Left lung has
2 lobes and cardiac notch
which the apex of the heart lies
cardiac notch
Lungs surrounded by
pleural membrane.
attached to diaphragm and lining
thoracic wall.
Parietal pleura
attached to lungs.
Visceral pleura
contains lubricating fluid.
Pleural cavity
Broad bottom of lungs
base
pointy top
apex
• Divided into lobules fed by tertiary bronchi.
• Further divisions → terminal bronchioles.
• → Respiratory bronchioles.
- Lined with nonciliated epithelium.
• → Alveolar ducts.
• → Alveolar sacs
• → Surrounded by alveoli.
LUNG LOBES
consist of two or more alveoli that share a common opening.
Alveolar sacs
MICROSCOPIC AIRWAYS
Terminal bronchioles →
Respiratory bronchioles →
Alveolar ducts →
Alveolar sacs →
Alveoli
• Cup-shaped outpouchings of alveolar sacs.
• Alveoli: two types of alveolar epithelial cells.
- Type I alveolar cells are the main sites of gas
exchange.
- Type II alveolar cells, containing microvilli, secrete alveolar fluid, which keeps the surface between the cells and the air moist.
- In the alveolar fluid are scattered surfactant-
secreting cells.
a. Lowers surface tension (keeps alveoli from
collapsing).
b. Humidifies (keeps alveoli from drying out).
LOWER RESPIRATORY SYSTEM: ALVEOLI
Cup-shaped outpouchings of alveolar sacs.
ALVEOLI
Alveoli: two types of alveolar epithelial cells.
— Type I
— Type II
alveolar cells are the main sites of gas
exchange.
Type I
alveolar cells, containing microvilli, secrete
alveolar fluid, which keeps the surface between the cells and the air moist.
Type II
In the alveolar fluid are scattered ____________
surfactant-secreting cells.
In the alveolar fluid are scattered surfactant-
secreting cells:
a. Lowers surface tension (keeps alveoli from
collapsing).
b. Humidifies (keeps alveoli from drying out).
keeps alveoli from collapsing
Lowers surface tension
keeps alveoli from drying out
Humidifies
• The exchange of O2 and CO2 between the air spaces
in the lungs and the blood takes place by diffusion
across the alveolar and capillary walls, which
together form the respiratory membrane.
• Respiratory membrane: alveoli + capillary.
- Gasses diffuse across these thin epithelial layers: air <—→ blood.
ALVEOLI
Respiratory membrane
alveoli + capillary.
ALVEOLI is The exchange of O2 and CO2 between the air spaces in the lungs and the blood takes place by diffusion across the alveolar and capillary walls, which together form the __________
respiratory membrane
• Several researchers have identified human
angiotensin converting enzyme 2 (ACE2) as an entry receptor for SARS-CoV-2.
• SARSCoV-2 is mostly transmissible through large respiratory droplets, directly infecting cells of the upper and lower respiratory tract, especially nasal ciliated and alveolar epithelial cells.
- ACE2 – regulates blood pressure.
PATHOPHYSIOLOGY OF COVID-19
ACE2 means
human angiotensin converting enzyme 2
is mostly transmissible through large
respiratory droplets, directly infecting cells of the upper and lower respiratory tract, especially nasal ciliated and alveolar epithelial cells.
SARSCoV-2
regulates blood pressure.
ACE2
RESPIRATORY: THREE MAJOR STEPS
- Pulmonary Ventilation (breathing)
- External Respiration (Pulmonary)
- Internal Respiration (Tissue)
- Moving air in and out of lungs.
Pulmonary Ventilation (breathing)
Gas exchange between alveoli and blood
External Respiration (pulmonary)
Gas exchange between blood and cells.
• Inhalation (or inspiration).
• Exhalation (or expiration).
Internal Respiration (tissue)
Inhalation or
inspiration
Exhalation or
expiration
• Air flows: atmosphere <—→ lungs due to difference in pressure related to lung volume.
- Lung volume changes due to respiratory muscles.
• Inhalation: diaphragm + external intercostals
- Diaphragm contracts (moves downward) →
increased lung volume.
• Cohesion between parietal-visceral pleura →
increased in lung volume as thorax volume increases.
RESPIRATION STEP 1: PULMONARY VENTILATION
diaphragm + external intercostals
Inhalation
• Exhalation is normally passive process due to muscle relaxation.
- Diaphragm relaxes and rises → decrease in lung volume.
- External intercostals relax → decrease in lung
volume.
• Active exhalation: exhale forcefully
- Example: playing wind instrument.
- Uses additional muscles: internal intercostals,
abdominal muscles.
EXHALATION
normally passive process due to muscle
relaxation.
Exhalation
Diaphragm relaxes and rises →
decrease in lung volume.
External intercostals relax →
decrease in lung volume.
— exhale forcefully
- Example: playing wind instrument.
- Uses additional muscles: internal intercostals,
abdominal muscles.
Active exhalation
• Volume and pressure are inversely related.
- As increase in lung volume → decrease in alveolar pressure.
- As decrease in lung volume → increase in alveolar pressure.
• Contraction of diaphragm → lowers diaphragm → increase in lung volume → decrease in alveolar pressure so it is < atmospheric pressure → air enters
lungs = inhalation.
• Relaxation of diaphragm → raises diaphragm →decrease in lung volume → increase in alveolar pressure so it is > atmospheric pressure → air leaves lungs = exhalation.
VOLUME-PRESSURE CHANGES IN LUNGS
Contraction of diaphragm → lowers diaphragm →increase in lung volume → decrease in alveolar pressure so it is < atmospheric pressure → air enters lungs =
inhalation
Relaxation of diaphragm → raises diaphragm → decrease in lung volume → increase in alveolar pressure so it is > atmospheric pressure → air leaves lungs =
exhalation
760mmHg
Atmospheric pressure
Alveolar pressure: 760mmHg
Intrapleural pressure: 756mmHg
At rest (diaphragm relaxed)
Alveolar pressure: 758mmHg
Intrapleural pressure: 754mmHg
During inhalation (diaphragm contracting)
Alveolar pressure: 762mmHg
Intrapleural pressure: 756mmHg
During exhalation (diaphragm relaxing)
breathing disorder of premature newborns in which the alveoli do not remain open due to a lack of surfactant.
RESPIRATORY DISTRESS
SYNDROME (RDS)
• breathing disorder of premature newborns in which the alveoli do not remain open due to a lack of surfactant.
• Symptoms include labored and irregular breathing, flaring of the nostrils during inhalation, grunting during exhalation, and perhaps a blue skin color.
• In mild RDS, may require only supplemental oxygen.
• In severe cases, oxygen may be delivered by nasal continuous positive airway pressure (NCPAP) through tubes in the nostrils or a mask on the face. In such cases, surfactant may be administered directly into the lungs.
- Betamethasone (steroid) – given to mothers to increase the development of surfactant in the lungs of the baby still inside the womb.
RESPIRATORY DISTRESS
SYNDROME (RDS)
labored and irregular breathing,
flaring of the nostrils during inhalation, grunting during exhalation, and
perhaps a blue skin color.
Symptoms of RESPIRATORY DISTRESS
SYNDROME (RDS)
may require only supplemental oxygen.
In mild RDS
oxygen may be delivered by nasal
continuous positive airway pressure (NCPAP)
through tubes in the nostrils or a mask on the face. In such cases, surfactant may be administered directly into the lungs.
In severe cases
given to mothers to increase
the development of surfactant in the lungs of the baby still inside the womb.
Betamethasone (steroid)
breaths/min; normal: 12/min
Frequency
— volume of one breath.
- Normal ~ 500 ml
a. About 70% of TV reaches alveoli (350 ml)
b. Only this amount is involved in gas exchange.
c. 30% in airways = anatomic dead space (prevents lung from collapsing)
Tidal volume (TV)
f (12/min) x TV = 6000 mL/min
Minute ventilation (MV)
anatomic dead space (prevents
lung from collapsing
30% in airways
• Measured by spirometer/respirometer
- Inspiratory reserve volume (IRV) = volume of air that can be inhaled beyond tidal volume (TV).
- Expiratory reserve volume (ERV) = volume of air that can be exhaled beyond TV
- Air remaining in lungs after a maximum expiration = residual volume (RV)
LUNG VOLUME
Measured by spirometer/respirometer
LUNG VOLUME
volume of air that can be inhaled beyond tidal volume (TV).
Inspiratory reserve volume (IRV)
volume of air that can be exhaled beyond TV
Expiratory reserve volume (ERV)
Air remaining in lungs after a maximum expiration
residual volume (RV)
TV + IRV
Inspiratory capacity
RV + ERV
Functional residual capacity (FRC)
IRV + TV + ERV
Vital capacity (VC)
VC + RV
Total lung capacity (TCL)
• Inspiratory capacity = TV + IRV
• Functional residual capacity (FRC) = RV + ERV
• Vital capacity (VC) = IRV + TV + ERV
• Total lung capacity (TCL) = VC + RV
LUNG CAPACITIES
• Eupnea = normal breathing
- Highly variable in pattern
- Costal breathing: shallow w/ rib movements
- Diaphragmatic breathing: deep breathing
• Hiccup – caused by spasmodic contraction of the diaphragm + spasmodic closure of the rima glottidis = sharp sound (hiccup)
BREATHING PATTERNS
normal breathing
Eupnea
shallow w/ rib movements
Costal breathing
deep breathing
Diaphragmatic breathing
caused by spasmodic contraction of the
diaphragm + spasmodic closure of the rima glottidis = sharp sound (hiccup)
Hiccup
• Mixture of gases (N2, O2, CO2, H2O, and others).
• Each gas has own partial pressure, such as PO2 or PN2.
• Sum of all partial pressures = atmospheric pressure (760 mmHg).
• Each gas diffuses down its partial pressure gradient.
NATURE OF AIR
Mixture of gases
N2, O2, CO2, H2O, and others
• Diffusion across alveolar to capillary membrane.
a. O2 diffuses from air (PO2 ~ 105 mm Hg) to
pulmonary artery (“blue”) blood (PO2 ~ 40 mm Hg). (Partial pressure gradient = 65 mm Hg).
b. Continues until equilibrium (PO2 ~100-105 mmHg).
- Meanwhile “blue” blood (PCO2 ~45) diffuses to
alveolar air (PCO2 ~40) (Partial pressure gradient = 5 mm Hg).
RESPIRATORY STEP 2: PULMONARY GAS
EXCHANGE: EXTERNAL RESPIRATION
• Occurs throughout body.
• O2 diffuses from blood to cells: down partial pressure gradient.
• PO2 lower in cells than in blood because O2 is used in cellular metabolism.
• Meanwhile CO2 diffuses in opposite direction: cells→ blood.
RESPIRATION STEP 3: SYSTEMIC GAS EXCHANGE: INTERNAL RESPIRATION
• 98.5% of O2 is transported bound to hemoglobin in RBCs.
- Binding depends on PO2.
- High PO2 in lung and lower in tissues.
- O2 dissolves poorly in plasma so only 1.5% is
transported in plasma.
• Tissue release of O2 to cells is increased by factors present during exercise.
- High CO2 (from active muscles).
- Acidity (lactic acid from active muscles).
- Higher temperature (during exercise).
TRANSPORT OF OXYGEN WITHIN BLOOD
__________ is transported bound to hemoglobin in RBCs.
98.5% of O2
O2 dissolves poorly in plasma so ________
only 1.5% is transported in plasma.
Tissue release of O2 to cells is increased by factors present during exercise.
- High CO2 (from active muscles).
- Acidity (lactic acid from active muscles).
- Higher temperature (during exercise).
High CO2
from active muscles
Acidity
lactic acid from active muscles
Higher temperature
(during exercise)
• CO2 diffuses from tissues into blood →
• CO2 carried in blood:
- Some dissolved in plasma (7%).
- Bound to proteins including hemoglobin (23%)
- Mostly as part of bicarbonate ions (70%).
a. CO2 + H2O <—→H+ + HCO3- (buffering capacity of
the blood, balances pH level).
• Process reverses in lungs as CO2 diffuses from blood
into alveolar air → exhaled.
TRANSPORT OF CARBON DIOXIDE
CO2 carried in blood:
- Some dissolved in plasma (7%).
- Bound to proteins including hemoglobin (23%)
- Mostly as part of bicarbonate ions (70%)
• Carbon monoxide (CO) is a colorless and odorless gas found in exhaust fumes from automobiles, gas furnaces, and space heaters and in tobacco smoke.
• CO binds to the heme group of hemoglobin, just as O2 does, except CO binds to hemoglobin is over 200x as strong as the binding of O2 hemoglobin.
• CO reduce the oxygen-carrying capacity of the blood by 50%
• Tx – administering pure oxygen, which speeds up the separation of carbon monoxide from hemoglobin.
CARBON MONOXIDE
POISONING
is a colorless and odorless gas
found in exhaust fumes from automobiles, gas
furnaces, and space heaters and in tobacco smoke.
Carbon monoxide (CO)
____________________of hemoglobin, just as O2 does, except CO binds to hemoglobin is over ________________
CO binds to the heme group,
200x as strong as the binding of O2 hemoglobin.
carrying capacity of the blood
by 50%
CO reduce the oxygen
administering pure oxygen, which speeds up the separation of carbon monoxide from hemoglobin.
Tx of CARBON MONOXIDE
POISONING
A group of tests that measure how well the lungs take in and release air.
PULMONARY FUNCTION TESTS
• A group of tests that measure how well the lungs take in and release air.
• How well they move gases such from the atmosphere into the body’s circulation.
• FVC (forced vital capacity – in liters), FEV1 &
FEV1/FVC ratio (forced expiratory volume in one
second.
• Normal result
• A value is usually considered abnormal if it is less than 80% of your predicted value.
PULMONARY FUNCTION TESTS
A value is usually considered abnormal if it is _________________ of your predicted value.
less than 80%
WHY IS THE PULMONARY FUNCTION TEST PERFORMED?
• Diagnose certain types of lung disease (e.g., asthma, bronchitis, and emphysema).
• Find the cause of SOB (shortness of breath)
• Measure whether exposure to chemicals at work affects lung function.
• Check lung function before someone has surgery.
• Assess the effect of medication.
• Measure progress in disease treatment.
CONTROL OF RESPIRATION (Three (3) Respiratory Center)
(1) Medullary rhythmicity area
(2) Pneumotaxic area
(3) apneustic area
(sends signal to the muscle involved in breathing – diaphragm, external and
internal intercostals) in medulla oblongata.
Medullary rhythmicity area
(responsible for limiting inspiration – on/off switch, prevents over distention of the lungs)
Pneumotaxic area
controls the intensity of breathing
apneustic area
• Cortical input: voluntary adjustment of patterns.
- For taking or cessation of breathing while swimming.
- Chemoreceptor input will override breath-holding.
REGULATION OF RESPIRATORY CENTER
voluntary adjustment of patterns.
Cortical input
will override breath-holding
Chemoreceptor
• Chemoreceptor input to → increase ventilation.
- Central receptors in medulla: sensitive to increased H+ or PCO2 in CSF.
- Peripheral receptors in arch of aorta + common carotids: respond to decrease PO2 as well as increase H+ or PCO2 in blood.
• Blood and brain pH can be maintained by this
negative feedback mechanism.
REGULATION OF RESPIRATORY CENTER (2)
sensitive to increased H+ or PCO2 in CSF.
Central receptors in medulla
respond to decrease PO2 as well as increase
H+ or PCO2 in blood.
Peripheral receptors in arch of aorta + common
carotids
• Respiration can be stimulated by:
- Limbic system: anticipation of activity, emotion.
- Proprioception as activity started.
- Increase of body temperature.
• Sudden pain can → apnea: stop breathing.
- Prolonged somatic pain can increase rate.
• Airway irritation → cough or sneeze.
• Inflation reflex.
- Bronchi wall stretch receptors inhibit inspiration.
- Prevents overinflation.
OTHER REGULATORY FACTORS OF RESPIRATION
anticipation of activity, emotion.
Limbic system
as activity started
Proprioception
Sudden pain can →
apnea: stop breathing.
Airway irritation →
cough or sneeze
• Obstructive pattern exists when air moves out of the lungs at a slower rate than that of a healthy person.
• Airway obstruction causes an increase in resistance.
• Restrictive lung disease – compliance of the lung is reduced, which increases the stiffness of the lung and limits expansion.
OBSTRUCTIVE AND RESTRICTIVE LUNG DISEASE
exists when air moves out of the lungs at a slower rate than that of a healthy person.
Obstructive pattern
compliance of the lung is reduced, which increases the stiffness of the lung and limits expansion.
Restrictive lung disease
VC
Vital Capacity
IRV
Inspiratory Reserve Volume
ERV
Expiratory Reserve Volume
RV
Residual Volume
FRC
Functional Residual Capacity
TLC
Total Lung Capacity
• Lungs lose elasticity/ability to recoil → more rigid; leads to
- Decrease in vital capacity.
- Decreased blood PO2 level.
- Decreased exercise capacity.
• Decreased macrophage activity and ciliary action →
- Increased susceptibility to pneumonia, bronchitis, and other disorders.
AGING AND THE RESPIRATORY SYSTEM
