anatomy and physiology of Respiratory System.pdf

RESPIRATORY
SYSTEM
MONICA LAISHRAM
FACULTY OF NURSING, ADTU

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TERMINOLOGY
RESPIRATION
•
LARYNX
•
DYSPNEA
•
CYANOSIS
•
MUCOCILARY ESCALATOR
•

ORGANS OF
RESPIRATION
NOSE
•
PHARYNX
•
LARYNX
•
TREACHEA
•
BRONCHI AND BRONHIOLES
•

NOSE
The right halves and left halves of
•
the nose is called dorsum.
The lower end of the dorsum is
•
round and is known as tip of nose.
The two nostrils are separated by
•
a soft median, columella. This is
continous with nasal septum.
Each nostril is bounded laterally
•
by ala.

Function of Nose
It is a respiratory passage
•
It is also the organ of smell.
•
The secretion of numerous serous
•
glands make the air moist, while
secretion of mucous glands trap
dust and other particles. Thus the
nose acts as an air conditioner
where the inspired air is warmed,
moistened and cleaned before it is
passed onto the delicate lungs.

Paranasal sinuses
Paranasal sinuses are air filled
•
spaces present within some
bones around the nasal cavities.
The sinuses are frontal, maxillary,
•
sphenoidal and ethmoidal
All of them opened to nasal cavity.
•

Function of paranasal
sinus
Make the skull lighter
•
Warm up and humidify the inhaled
•
air
These also add resonance to the
•
voice
Infection of the sinus is known as
•
sinusitis.

Types: Acute sinusitis and chronic
•
sinusitis
Acute: two or more symptoms
•
Chronic : Symptoms for 12 weeks
•
or more
Common cold, allergies, nasal
•
polyps, asthma, nasal septal
deviation.
Management: Decongestants and
•
saline nasal washes, antibiotic ,
steam inhalation

Rhinitis: Coryza is the
•
inflammation of the mucous
membrane inside the nose.
Common symptoms are stuffy
nose, runny nose, sneezing, post
nasal drip. Caused by viruses,
bacteria, irritants or allergens
Can be managed with intranasal
•
corticosteroids and intranasal
anti histamines.

PHARYNX
The pharynx is a wide muscular
•
tube, situated behind the nose, the
mouth and the larynx.
Clinically it is a part of the upper
•
respiratory passages are common.
Parts of pharynx:
•
The nasal part: Nasopharynx
•
The oral part: Oropharynx
•
The laryngeal part: Laryngopharynx
•
Inflammation of pharynx is known as
•
pharyngitis.

The upper part of the pharynx
•
transmits only air, the lower
part only foods but the middle
part is a common passage for
both air and food.
The nasopharynx part
•
pharynx is connected to the
middle ear via the
pharyngotympanic tube.

The eustachian tube (
•
pharyngotympanic tube) connects
the middle ear cavity with the
nasopharynx

The eustachian tube connects the
•
middle ear and clears mucus from
the middle ear into nasopharynx.
Opening and closing of the tube is
•
important.
Normal opening equalizes the
•
atmospheric pressure in the
middle ear: closing of the tube
protects the middle from
unwanted pressure fluctuations
and loud sounds

The tube opens when you yawn or
•
swallow due to contraction of
tensor veli palatini muscles.

Boundaries:
•
Superiorly: Base of the skull
•
Inferiorly: The pharynx is continuous
•
with esophagus at the level of the 6th
cervical vertebra.
Posteriorly: The pharynx glides
•
freely on the pre vertebral fascia
which separates it from the cervical
vertebral bodies
Anteriorly: It communicates with the
•
nasal cavity, the oral cavity and the
larynx.

Nasopharynx: It is the upper most
part of pharynx. The Eustachian
tube is at the lateral wall. This
tube equalizes the pressure on
the two sides of the tympanic
membrane.
Air passes from nasopharynx into
•
the larynx. Air and fluids/food
cross each other in to the
oropharynx
If one shouts or laugh while
•
eating or drinking , the fluids may
enter the larynx.

This produces a protective
•
bout of cough as food/fluid is
forbidden inside the larynx/
treachea

Oropharynx
Lies behind oral cavity C2, C3
•
vertebrae. It extends between
soft palate above to the upper
border of epiglottis below.
Oropharynx communicates
•
anteriorly with oral cavity; above
with nasopharynx and below with
larynopharynx.
It gives passage both to air and
•
food/fluid

LARYNGOPHARYNX
It lies behind larynx opposite
•
to the C5 and C6 vertebrae.
It extends between epiglottis
•
and cricoid cartilage and
anteriorly it is in the inlet of
larynx.
It gives passage only to
•
food/fluids.

WALDEYER’S LYMPHATIC
RING
It is a ringed arrangement of
•
lymphoid organs in the pharynx.
It surrounds the naso and
•
oropharynx with tonsilar tissue
located above and below the soft
palate.

STRUCTURE
1 pharyngeal tonsil
•
2 tubal tonsils on each side
•
2 palatine tonsils (tonsil)
•
Lingual tonsil
•

CLINICAL SIGNIFICANCE
Inflammation of tonsil is known as
•
tonsillitis.
Removal of tonsil is known as
•
tonsillectomy.

FUNCTIONS OF PHARYNX
Gives passage for air, foods and
•
fluids
Warms/ cools and humidified
•
inspired air
Helps in speech as it causes
•
resonance in voice
Helps in hearing
•
Protects the lymphoid tissue
•
forming waldeyer ring

LARYNX
The larynx lies in the anterior
•
midline of the neck, extending
from the root of the tongue to
the trachea.
The length of the larynx is 44
•
mm in male and 36 mm in
females.

At puberty, the male larynx
•
grows rapidly and becomes
larger ( adam’s apple) which
makes voice louder and low
pitched.
In adult male, it lies in front of
•
the third to sixth cervical
vertebrae.
In children and adult female, it
•
lies at a little higher level ( C1
to C4)

The larynx is made up of
•
skeletal framework of
cartilages. The cartilages are
connected by joints, ligaments
and membranes.

CARTILAGES OF LARYNX
The larynx
•
contains nine
cartilages, of
which three
are unpaired
and three are
paired.

Paired cartilages:
•
Arytenoid cartilage
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Corniculate
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Cuneiform
•
Unpaired cartilage:
•
Thyroid cartilage
•
Cricoid cartilage
•
Epiglotic
•

CAVITY OF LARYNX
Within the cavity of larynx, there
are two folds of mucous
membrane on each side.
The upper fold is the vestibular fold
and the lower fold is the vocal fold
The space between the right and
left vestibular folds is the rima
vestibuli
The space between the vocal folds
is the rima glottidis.

FUNCTION OF LARYNX
Acts as sphincter for lower
•
respiratory passage
Produces voice/ sound
•

The trachea is a non
•
collapsible , wide tube
forming the beginning of the
lower respiratory passage due
to C shaped cartilaginous ring
The posterior wall of trachea
•
is deficient of cartilage. This
is made of muscles and
fibrous tissue for expansion of
the esophagus during passage
of food.

The trachea is about 10-15 cm
•
long. Its upper half lies in the
neck and its lower half in the
superior mediastinum.
The diameter is about 2 cm in
•
male and 1.5 cm in female.

The trachea is supplied by
•
branches from the inferior
thryroid arteries. Its vein drain
into the left brachiocephalic
vein.
Lymphatic drain into the pre
•
tracheal and para tracheal
nodes.

HISTOLOGY OF TRACHEA
The trachea is lined by pseudo
•
stratified ciliated columnar
epithelium. The cells are of
varying height, giving a false
appearance of more than a layer
of cells.
Deep to the epithelium are mucus
•
and serous glands.
The main bulk is formed by the C
•
shaped hyaline cartilages to keep
it permanently patent.

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FUNCTION OF C SHAPED CARTILAGE:
C shaped cartilage keep the airway
patent.
The smooth muscles joining 2 ends
of c helps the esophagus to dilate
during the passage of bolus.
These provide flexibility to trachea
Ciliary escalator helps to remove
the mucus swallowed into
laryngopharynx or expectorated.

COUGH REFLEX
If irritated, the nerve endings in
•
larynx, trachea, bronchi pass
impulses by 10th
nerve to
respiratory center in brain stem.
There is deep inspiration, closure
•
of vocal cords, contraction of
abdominal and thoracic
respiratory muscles and the
increased pressure in lungs leads
to abduction of vocal cords to
expel the irritant through mouth.

LUNGS
Lungs are two voluminous
•
cone shaped organs
occupying most of the
thoracic cavity leaving a small
space for the heart.
Each lung cavity is enclosed
•
within pleural cavity which
contain serous fluid which
helps in expansion and
contraction of lungs.

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Pleura: It is a closed
•
serous sac which encloses
the lungs. It has two
layers, parietal pleura and
visceral pleura.
The pleural fluid prevent
•
friction during breathing.

Apex: It is rounded and rise
•
into the root of neck about 2.5
cm above the level of the
middle third of clavicle.
Base: It is the concave part
•
related with diahpragm.
Costal surface: It is the
•
surface related with ribs,
intercostal muscles.
Mediastinal surface: It is
•
related to the hilum.

Right lung vs left lung
It has 2
•
fissures and 3
lobes
Larger and
•
heavier,
weighs about
700 gms
Shorter and
•
broader
Anterior
•
border is
straight
It has 1 fisure
•
and 2 lobes
Smaller and
•
lighter ,
weighs about
600 gms
Longer and
•
narrower
Anterior
•
border is
interrupted by
cardiac notch

PORTION OF LUNGS
Lungs are made up of two
•
portions, a conducting portion
and respiratory portion
CONDUCTING PORTION: The
•
primary bronchus enters the
lung at the hilum.

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In the right lung it divides into
•
three secondary bronchi for each
three lobes i.e upper, middle and
lower separated by obligue and
horizontal fissures.
The three secondary bronchi are
•
divided into 10 segmental bronchi.
Left lung contains two lobes that
•
is upper lobe and lower lobe
separated by oblique fissures.
Therefore there are only two
secondary bronchi. There are 10
segmental bronchi in upper and
lower lobe

Each segmental bronchus divides
•
repeatedly till its diameter
becomes 1.0 mm.
At this level it is called terminal
•
bronchiole, with no cartilage.
RESPIRATORY PORTION: terminal
•
bronchiole divides further and
forms respiratory bronchiole,
alveolar sac and finally the
alveoli. Here the wall becomes
thinner.
Alveoli are lined by two types of
•

There are as many as 700 million
•
alveoli in each lungs, where they
facilitate gaseous of oxygen and
carbon dioxide exchange.
Type 1 pneumocytes
•
Types 2 pneumocytes which
•
secretes fluid called surfactant
which prevent the alveoli from
collapsing by decreasing surface
tension

PULMONARY
SURFACTANT
Because of the huge force of
•
surface tension in the lungs, the
airway may collapse after
expiration.
It can further can make re-
•
inflation during inspiration much
more difficult.
So the type II pneumocytes
•
secrete a substance called
SURFACTANT to reduce the force
of surface tension due to water

The fetus in the womb receives
•
oxygen from the mother. The
lungs of the fetus are not fully
functional, the lungs don’t
produce surfactant until 35 weeks
of fetal development.
This is the reason that premature
•
newborn infants are at an
increased risk of respiratory
distress syndrome due to airway
collapse

It could be fetal and result in
•
dead.
This can be treated through
•
pulmonary surfactant
replacement therapy and
mechanical ventilation.
Collapse of the lungs is known as
•
atelactasis.(complete or partial
collapse of a lung or section of
(lobe)
Anaesthesia, blockage of air
•
passage (bronchus or

MUSCLES OF
RESPIRATION
For quiet inspiration,
•
daiphragm, external
intercostal muscles.
Deep inspiration – erector
•
spinae, scalene muscles,
pectoral muscles.

PULMONARY
VENTILATION
It is the movement of air in
•
and out of alveoli
It is the process of flow of air
•
into the lungs during
inspiration and out of the
lungs during expiration
Air flows because of pressure
•
differences between the
atmosphere and the gases

The primary function of
•
pulmonary ventilation is to make
oxygen available to the blood,
which is transported by the
cardiovascular system throughout
the body to all the cells

Air like other gases, flows from a
•
region with higher pressure to a
region with lower pressure.
Involves 3 pressures
•
Atmospheric pressure: pressure
•
of air outside the body
Intraalveolar (intrapleural
•
)pressure: pressure within the
alveoli.
Intrapleural pressure: pressure
•
within the pleural cavity

During inspiration, the diaphragm
•
contracts and the thoracic cavity
increases its volume. This
decreases the intraalveolar
pressure so that air flows into the
lungs.
During expiration, the relaxation
•
of the diaphragm and elastic
recoils of the tissues decreases
the thoracic volume and increases
the intraalveolar pressure. This
pushes the air out of the lungs.

PHYSIOLOGY OF
RESPIRATION
The respiratory cycle consists of
•
inspiration, expiration and
diffusion of gases. In normal quite
breathing, there are about 15
complete respiratory cycles per
minutes, i.e respiratory rate of
normal adult is 12-16
breathes/minute.

Respiratory movements
The anteroposterior diameter is
•
increased
The transverse diameter is
•
increased
The vertical diameter is increased
•

Before inspiration, intrapulmonary
•
pressure equals atmospheric
pressure at about 760 mmHg

PULMONARY
CIRCULATION
Pulmonary circulation moves
•
the blood between the heart
and the lungs. It transport
deoxygenated blood to the
lungs to absorb oxygen and
release CO2. The oxygenated
blood the flows back to the
heart.

Pulmonary artery
•
divides into two,
each branch
carrying
deoxygenated
blood to the lungs.
Within the lung
tissues, the
pulmonary artery
divides and
redivides into
dense capillary
network around

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The pulmonary circulation
•
begins at the pulmonary valve,
making the vascular exit from
the right side of the heart and
extends to the orifices of the
pulmonary veins in the wall of
left atrium, which marks the
entrance into the left side of
the heart.

The pulmonary circulation is
•
supplied with both sympathetic
and para symphathetic
innervation
The exchange of gases between
•
air in the alveoli and the blood in
the capillaries takes place
Capillaries join up to form
•
pulmonary veins in each lung.
They leave the hilum and carry
oxygenated blood to heart.

REGULATION OF
RESPIRATION
Physiologically, the respiration is
•
controlled by respiratory center –
group of neurons present bilaterally
in medulla oblongata and pons.
Respiratory control is an involuntary
•
process.
The respiratory center: The
•
respiratory center is formed by
group of nerve cells( medulla
oblongata and pons) which controls
the rate and depth of respiration.

The active inspiratory center
•
nerves to the inspiratory
muscles, the phrenic nerve to
the diaphragm and intercostal
nerves to the external
intercostal muscles. These
muscles contract and lead to
expansion of the thorax and
the air is drawn into the lungs.

When the inspiratory center
•
neurons are not active, the
stimulus to the muscles stops and
the muscles relax. At this point
expiration occurs passively. This
rhythmic pattern continues till
any other stimulus affects the
neurons of inspiratory center.

Chemical control: Irritant receptors:
•
These are present between the
epithelial cells. These receptors get
stimulated by irritant gases or dust
particles. Activation of receptors
causes coughing and increased
mucus secretion
Chemoreceptors: In the body, few
•
receptors are present which respond
to changes in PH, pO2 and pCO2. The
sensitivity of chemoreceptors to
raised arterial CO2 concentration is
most important factor in maintaining
homeostasis of blood gases.

The chemoreceptors are located in
the medulla oblongata. They
monitor the level of CO2 and O2.
The types of chemoreceptors are
peripheral chemoreceptors and
central chemoreceptors:
The peripheral chemoreceptors are
present in the aortic bodies(
located in the arch of aorta) and
carotid bodies( located at
common carotid artery).

They are sensitive to change in
•
H+, PCO2 and PO2 in blood. Nerve
impulses from the peripheral
chemoreceptors are conveyed by
the glossopharyngeal and vagus
nerves to the medulla. It
stimulates the respiratory center.
The result is immediate increase
in the depth and rate of
respiration.

The central chemoreceptors:
•
They are present on the surface
of medulla oblongata. They
respond to changes in PCO2 and
H+ in CSF. These respond by
stimulating the respiratory center.
They increases the ventilation of
lungs and reduce arterial PCO2 .
This control normal blood gas
levels.

OTHER FACTORS THAT
INFLUENCE RESPIRATION
Limbic system: Emotional anxiety or
•
anticipation of activity, both may stimulate the
limbic system. This ends the input to the
inspiratory center. It increases the rate and
depth of ventilation.
Blood pressure: The carotid and aortic sinuses
•
contain baroreceptors. It detects the change in
blood pressure. It also affects respiration.

For example, increase in blood
•
pressure decreases the
respiration. Decrease in blood
pressure increases respiration.
Temperature: Increase in body
•
temperature will increase the rate
of respiration. A decrease in body
temperature decreases the
respiratory rate.
Pain: sudden, severe pain causes
•
apnea. Prolonged pain results in
increase of respiratory rate.

Irritation of airway:
•
Mechanical irritation of the
pharynx or larynx stoppage of
breathing for a while. It leads
to coughing or sneezing
Stretching of the anal
•
sphincter muscle: This
increases the respiratory rate.

LUNG VOLUMES AND
CAPACITIES
Lung volume is the static volume
•
of air breathed by an individual i.e
volume of air present in lung
under specific position of the
thorax. Lung volumes depends on
age, weight and gender and body
position. When two or more
volumes combine this is called
capacity.

Dead space: It is constituted
•
by air, which doesn’t
participate in diffusion,i.e air
present in nose, trachea and
bronchial tree. Normally it is
150 ml.
Tidal volume: Volume of gas
•
inspired or expired in each
breath during normal quiet
respiration. It is 400-500 ml.

Alveolar ventilation: It is the
•
volume of air that moves into and
out of alveoli per minutes.
Alveolar ventilation: Tidal volume-
anatomical dead
space)*respiratory rate
500-150*15=5.25L/min
Inspiratory reserve volume: It is the
maximum volume of gas, which a
person can inhale from end
inspiratory position. Its 2,400-
2,600ml.

Expiratory reserve volume:
•
Maximum volume of gas that can
be exhaled after normal
expiration. It is 1200-1500ml

Vital capacity: It is the
•
maximum amount of gas that
can be exhaled after
maximum inhalation, i.e it is
IRV+TV+ERV, 4,200- 4,500 ML.
Residual volume: It is the
volume of gas still present in
lungs after maximal
expiration. It is 1,200-1,500 ml

LUNG CAPACITIES
Inspiratory capacity: Amount of
•
gas inspired into the lungs after
normal tidal expiration.
IC=TV+IRV
Functional residual capacity
•
(FRC): Amount of gas remains in
the lungs after normal expiration.
FRC=ERV+RV (2500ml)
Vital capacity (VC): Amount of gas
•
expired from the lungs after a
maximum inspiration.

Total lung capacity (TLC max):
•
Amount of gas inspired to
expand the lungs to its
maximum extends. ( TLC=
TV+IRV+ERV+RV) 6000ML
Minute volume : It is the tidal
•
volume*respiratory rate. It is
500*12=6000 ml/min
Total lung volume:
•
IRV+TV+ERV+RV. It is 5,500-
6,000ml.

MECHANISM OF
RESPIRATION

PULMONARY FUNCTION
TEST
PFTs are a group of tests that
•
measures how well your lungs
work that is how well the lungs
take in and exhale air, and how
efficiently they transfer oxygen
into the blood.
They are useful in assessing the
•
functional and pathological
conditions. It is based on the
measurement of lung volumes of
air breathed in and out in normal
breathing and forced breathing. It

PURPOSES OF PFTs
Detect disease and serves as a
•
diagnostic tool, and has
investigation role
Evaluates severity, extent and
•
monitor the course of disease
Evaluates treatment
•
Measures effects and results of
•
treatment exposures.

Helps to diagnose asthma,
•
chronic bronchitis, respiratory
infections, lung fibrosis,
bronchiectasis, allergy,
emphysema, cystic fibrosis,
asbestosis which is the
inflammation of lungs, liver, lymph
nodes, eyes, skin
Used to evaluate physiological
•
aspect of breathing from
respiratory muscle function to the
diffusion of gas at the alveolar

Helps physiotherapy to distinguish
•
between obstructive and
restrictive lung problem and to
select appropriate treatment
Measures the effect of the given
•
treatment

PROCEDURE
Sit up straight
•
Get a good seal around the mouth
•
piece
Rapidly inhale maximally
•
Without any delay blow out as
•
hard as fast as possible
Continue the exhale until the
•
patient cannot blow no more

Expiration should continue at
•
least 6 sec in adult and 3 sec
children under 10 years
Repeat at least three technically
•
acceptable times ( without cough,
air leak and false start)

SPIROMETRY
In order to do spirometry, an
•
instrument that is spirometer is
used. Spirometer measures the air
capacity of the lungs during
controlled ventilatory maneuvers.
Spirometer is used to measure the
•
air flow, ventilatory regulation,
ventilatory mechanics and lung
volume during a forced expiratory
maneuver from full inspiration.

LUNG EXAMINATION AND
LUNG SOUNDS
Lung examination includes vital
•
signs and cardiac examination.
There are four elements-
observation, palpation,
percussion, ascultation.
Lung sounds:
•
Bronchial breath sounds: Normal
•
sounds when listemning over
large airways like trachea is
bronchial breath sounds

It can be present when a person is in the
•
setting of dense com

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