RESPIRATORY SYSTEM
By : Dr. Santosh Sapkota
Instructor ,Faculty of zoology
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Respiration is a
catabolic process in
which respired O2 is
used in the oxidation of
food resulting in the
release of energy.
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Breathing involves
inspiration and
expiration.
Do you know Metabolism=…….+…...
Respiratory
system
originated from
embryonic:
NOSE
Nasal
septum
Nasal Cavity
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Nasal cavity is divide into left & right
chambers by nasal septum which is made up
of (……. , ……. & …….)
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Each nasal chamber composed of 3 different
regions;
1) Vestibular region=Anterior most wide region
of nasal chamber which contains mucous lining
and hairs.
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2) Olfactoy region.
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3) Respiratory region.
Olfactory region (mucosa)
✓ Sense of smell via ……………. nerve
✓Contains pseudostratified ciliated columnar
epithelium (MOE)
✓ 3 cell types : olfactory cells (= bipolar neurons )
sustentacular cells (supporting
cells)& basal cells
✓Bowmans gland present (mucus from this gland
keeps olfactory surface moist)
Respiratory epithelium :
• It conatins bony
projections known as
conchae or
turbinates.It remains
projected from lateral
wall of nose .
Bowmans gland is present in
a. Kidney
b. Brain
c. Nose
d. Eye
•Inflammation of nasal
mucosa :
•Bleeding from nose is :
•Coughing of blood is:
•Vomiting of blood is:
•Blood in urine :
• Most common site of
epistaxis is
Little’s area
Paranasal sinuses
air-filled extensions of
the
respiratory
part
of the
nasal cavity into the
following cranial bones
➢continuous with the nasal
cavities
➢ r esonat ion of speech
4 pairs
@FrEMS (Frontal,
Ethmoid, Maxillary,
Sphenoid)
•MAXImum size, MAXImum
chance of infection = MAXIlary
sinus
•Inflammation of sinus is
SINUSITIS
Common pathway for digestion
and respiration is
a. Larynx
c.Oesophagus
b. pharynx
d. trachea
➢ The pharynx is a
muscular tube that
connects the oral and
nasal cavity to the larynx
and oesophagus
➢ 3 parts
➢ Common pathway for the
respiratory and digestive
tract
Q. Eustachian tube connects middle ear
cavity to
a. Nasopharynx
b. oropharynx
c. Larynx
d. laryngopharynx
•Eustachian tube connects middle ear
cavity to nasopharynx
•Equalizes pressure across the two cavities
•Opens during activities such as
swallowing, yawning as well as during
changes in atmospheric pressure
LARYNX (VOICE BOX)
• Musculocartilagenous
• Composed of 9 cartilages
Q. Unpaired cartilage of
larynx is
a. Cricoid
c. Corniculate
b. arytenoid
d. cuneiform
3 single(unpaired)
@ETC
Epiglottis Thyroid
Cricoid
3 paired
@ACC
Arytenoid Corniculate
Cuneiform
Thyroid cartilage is the largest
• Thyroid cartilage is composed of two sheets (laminae), which join anteriorly
to form the laryngeal prominence (Adam’s apple).
• Cricoid is signet ring like only complete ring of cartilage to encircle any
part of the airway.
Q. Hyaline cartilage is
a. Thyroid
b. epiglottis
c. cuneiform
d. corniculate
Cricoid Arytenoid
Thyroid
Elastic : Epiglottis Corniculate
Cuneiform
Hyaline :
Vocal cords
•1 pair of true vocal cords( or vocal
folds) –
main role in sound production
•1 pair of false vocal cords ( or
vestibular folds) located just above
true cord
•Space between true vocal cord –
…………………………………
•The function of the epiglottis is to close the rima glottidis during
swallowing and so to prevent the passage of food and liquid
into the lungs (aspiration). This is why we can’t (and shouldn’t
try to) talk and breathe while swallowing.
Trachea (windpipe)
•10 – 12 cm length
•transports air to and from the
0
lungs
•supported by incomplete
cartilaginous tracheal cartilages
(rings) anteriorly 16-2 C-shaped
•C-shaped rings are …………..
cartilage
•The tracheal cartilages keep the
trachea patent; they are deficient
posteriorly
•The posterior gaps in the tracheal
rings are spanned by the involuntary
…………… muscle, smooth muscle
connecting the ends of the rings
•
trachea is lined by pseudostratified
ciliated columnar epithelium
Tracheal bifurcation (= divides into two)
•The point at which trachea
bifurcates is called ……………..
•Vertebral level is …………………
Bronchial Tree
• The trachea is divided into two main bronchi at the carina (right and left main
(primary) bronchus) entering each lung at hilum
• right main bronchus is Wider, runs Vertically and Shorter than the left main bronchus
• Each main (primary) bronchus divides into secondary ( lobar) bronchi, two on the
left and three on the right, each of which supplies a lobe of the lung.
• Each lobar bronchus divides into several (tertiary) segmental bronchi that
supply the bronchopulmonary segments
• Beyond this several divisions occur giving bronchiole and the smallest conducting
bronchiole is terminal bronchiole.
• Each terminal bronchiole gives rise to several generations of respiratory bronchioles,
characterized by scattered, thin-walled outpocketings (alveoli) that extend from their
lumens.
Alveoli
•Air filled sacs that helps in gases
exchange (diffusion of gas)
•…………………….epithelium
•Cells: alveolar cells (pneumocytes)
type I and type II
•Type II cells secrete ……………..
•Alveolar macrophages :………………
Outer covering of
lung
Outer ………. pleura and inner
………… pleura
Space in between these is
called
pleural space/ cavity that
contains pleural fluid
Space between lungs is called ?
Mediastinum ;heart, oesophagus, trachea
What separates the
thoracic cavity from
the abdominal
cavity?
•The diaphragm divides the thoracic and abdominal
cavities.
•……………….. muscle of respiration
•During inspiration, it ……….. and ………… , moves …………..
increasing the vertical diameter of the thoracic cavity
•During expiration, the diaphragm passively …………… and
returns to its original ……… shape moves …………. reducing
the volume of the thoracic cavity.
•vertebral levels of structures
piercing it:
•vena cava has eight letters (T8),
oesophagus has ten letters (T10),
and aortic hiatus has twelve
letters (T12).
•Supplied by ………… nerve, artery
•Normal breathing rate
•Increased breathing rate
•Decreased breathing rate
•Difficulty in breathing
Inspiration
•Always an …………..
process
•………………. is the main
muscle of inspiration
•External Intercostal
muscle
Expiration
• A …………….. process
• But forced expiration is
an
………….. process
• Expiratory muscles
are used during
exercise and
distress
• Internal intercostal
muscle
O2 transport
•Binded form with Hemoglobin (Hb)
……………………………….. 97%
• 3% ……………………………….
•Hb = Heme + globin
•4 Iron (Fe) containing heme part
that binds O2
•So 1 Hb molecule binds ……….
oxygen molecule
Iron in
hemoglobin is
present in
a.Ferrous form
(Fe+2)
b.Ferric form
(Fe+3)
•If iron is present in ferric form Hb is called
•1 g of Hb can carry ………ml O2
•Average Hb level is 15g/dl (15g in 100ml
blood)
•So 100ml blood can carry…………
O2- Hb dissociation curve
Curve is
sigmoid
shaped
BOHR EFFECT VS HALDANE EFFECT
•BOHR effect
•How Affinity of O2 with
Hb is affected by CO2
•The release/ unloading/
HALDANE effect
•How Affinity of CO2 with
Hb is affected by O2
•The release/ unloading/
dissociation
dissociation of O2 from Hb •of CO2 from Hb due to high
due to high CO2
O2
•In tissues
•In lungs
CO2 TRANSPORT
•Majority in the …………………….
form 70%
•Binded with Hb
………………………23%
•7% ………………………………
Chloride shift or hamburger
phenomena
maintains the electrical
neutrality of cells
Chloride moves into
erythrocytes, and
bicarbonate moves out
Maximum affinity
Q. maximum affinity towards Hb is of
a. O2
c. N2
b. CO2
d. CO
ANS D
Carbon monoxide has 200-300 times more affinity than O2
Combines with Hb to form CARBOXYHEMOGLOBIN
Volumes
•Tidal volume (TV)
the volume inspired or expired with each
normal breath 500ml
•Inspiratory reserve volume (IRV)
The
volume
that can
be inspired
forcefully after normal inspiration
3000ml
•Expiratory reserve volume (ERV)
The volume that can be expired forcefully after
normal expiration
1100ml
•Residual volume (RV)
•The volume that is always present in lungs and
cannot be expelled out 1200ml
Capacities
•Total lung capacity
The volume that lungs can occupy ( volume present in lungs
after maximum inspiration)
=TV+IRV+ERV+RV =5800ml (6L)
•Vital capacity
The volume that can be forcefully expired forceful inspiration
=TV+IRV+ERV =4600ml
Functional residual capacity
The that remains in lung after
normal tidal expiration
=ERV+RV = 2300ml
• Dead space
• Minute ventilation
• Alveolar ventilation
Control of Respiration
•Respiratory centres
Brainstem (pons and medulla)
Pons = pneumotaxic center and apneustic
center
Medulla = dorsal (inspiratory) group and
Ventral (Expiratory) group (@DIVE)
CHEMORECEPTORS
•Central chemoreceptors (in
medulla) Sensitive to
increased blood CO2 level
Our respiration is driven by blood CO2 level
(CO2 dependent)
Increased blood CO2 level causes rapid and
deep breathing.
•Peripheral chemoreceptors
Carotid and aortic bodies
Sensitive to decreased blood O2 level
Q. The cheeks of
people living in
Himalayan region
are red due to ??
Increased RBC
or
Polycythemia or
High
hemoglobin
Q. decreased level of O2 in blood is called
a. Hypoxia
c. Hypoxemia
b. hypercapnia
d. none
Hypoxia is decreased level of O2 in
tissues Hypoxemia is decreased level
of O2 in blood Hyercapnia is increased
level of CO2 in blood
Thank You!!!
Special thanks : Mr. Hemraj Aryal