These slides will help you know about the physiology of the respiratory system. These slides are the simplest version on how to know about the Physiology Of Respiratory System with its applied physiology.

1. Created by:
MeghaJayan
BSc Physician Assistant
VMCH-AHS

2. Parts Of Respiratory System
 Our respiratory Tract Consists of Nose, Mout,
pharynx, larynx or the voice box ,trachea or the
windpipe, bronchi which is also called as air way and
then the lungs.
The respiratory
tract is divided into
two. That is,Upper
Respiratory Tract
and the lower
respiratory tract

3. UPPER RESPIRATORY TRACT
 The Upper Respiratory Tract consist of nose, nasal
cavity and sinuses . The nasal sinuses are the air spaces
inside our skull bone and facial bone. This functions to
moisturise our nose (inside) and protects from dust
and dirt.

4. LOWER RESPIRATORY TRACT
 The lower respiratory tract consist of Larynx,
Trachea,Lungs , Bronchi ,Bronchioles and aslo tiny air
saccules called as Alveoli.

5. PHYSIOLOGY OF RESPIRATORY SYSTEM
 The ultimate function of the respiratory sytem is
gaseousexchange. That is Gaseousexchange consist of
obtaning oxygen from the atmosphere and removing
of carbondioxidefrom blood. So,oxygen is very
important for the normal metabolismand the
carbondioxide is the waste product of metabolism
 Carbondioxide playsa major role in acid-base
balance,it must be cleared from the body in
appropriate level though ventilation

6. LUNG VOLUME
 Lung volume are the static volumes of the air breathed
breathed byan individual. The lung volumes are of
four types.

7. TIDAL VOLUME (TV)
 Tidal volume is the volume of air breathed in and out
of lungs in a single normal quiet respiration.
 Tidal volumesignifies the normal depth of breathing.
 Normal Value = 500mL (0.5L)

8. INSPIRATORY RESERVE VOLUME
 Inspiratory reserve volume is an additionalvolume of
the air that can be inspired forcefullyafter the end of
normal inspiration.
 Normal Value = 3300mL (3.3L)

9. EXPIRATORY RESERVE VOLUME
 Expiratory resreve volume is the additonal volumeof
air that can be expired out forcefullyafter a nomal
expiration
 Normal Value= 1000mL (1L)

10. RESIDUAL VOLUME (RV)
 Residal volume is the volume of air remaining in the
lungs even after forced expiration. Normally, lungs
cannot be emptied completelyeven after by forcefull
expiration.
 Some quantity of air alwaysremains in the lungs even
after the forced expiration. Residual volume helps to
aerate the blood in between breathing and during
expiration. Normal Value = 1200mL (1.2L)

11. LUNG CAPACITIES
 Lung capacityare the combination of two or more
lung volumes. Lung capacitiesare of four types.

12. INSPIRATORY CAPACITY
 Inspiratory capacity is the maximum volumeof air that
is inspired after normal expiration(endexpiratory
position).
 It includes Tidal volume & Inspiratory reserve volume.
 IC= TV+IRV
 3800mL= 500+3300

13. VITAL CAPACITY
 It is the maximum volumeof air that can be expelled
out forcefullyafter a deep(maximal)inspiration.
 Vital capacity includes Inspiratory reserve volume,
tidal volumeand expiratory reserve volume.
 VC= IRV + TV + ERV
4800= 3300+500+1000

14. FUNCTIONAL RESIDUAL CAPACITY
 It is the volume of air remaining in the lungs after
normal expiration (after normal tidal respiration).
 Functional residual capacity includes respiratory
reserve volume and residual volume
 FRC = ERV + RV
2200mL=1000+ 1200

15. MECHANISM OF BREATHING
 Breathing occours when contraction and realxation of
muscle around the lungs changes the total volume of
air within the air passage inside the lungs. If the
pressure inside the lung is greater than tha of outside
the lungs, the air rushes out. If oppositeoccours, the
air rushes in.

16. INSPIRATORY MECHANISM
 Inspiration occours when the inspiratory muscles, ie,
the Diaphragm and External intercoastal muscles
contract and this causes increase in the sizeof the
thoracic cavity while contraction of the external
intercoastal muscles elevates the ribs and the sternum.
 In response to this, the air pressure inside the lumg
decreases below that of air outside the body. Beacause
gases move from a region f higher pressure to lower
pressure and air rushes to the lungs.

17. EXPIRATORY MECHANISM
 Expiration occours when the Diaphragm and the
external intercoastal muscles relax. Thus the elastic
fibers in the lungs tissues causes the lungs to recoil to
their original volume.
 The pressure of the air inside the lungs increases above
the air pressure outside the bodyand air rushes out.

18. REGULATION OF RESPIRATION
 The normal respiratory rate is 12-18 breathes per
minute. There are two types of regulation of
respiration. Ie, neural regulation and Chemical
Regulation of respiration
 Neural regulation has two responsibilities , on is for
the voluntarycontrol and other is for the automatic
control of breathing.

19. VOLUNTARY CONTROL
 This is located in the cerebral cortex and sends
impulses to the motor neurons innervating the
respiratory muscles.
 The motor neurons supplying the respiratory muscles
are inhibited when the expiratory muscles are being
suppliedand vice versa
 This system is active when more ventilation is required
like during exercise and defecation

20. AUTOMATIC CONTROL
 It involves the different groups of neurons located in
the brain system and their afferent and efferent
pathways. There are fourgroups of neurons located in
the reticular formation of the brain system
collectievelycalled as Respirtory Centers
 Inspiratory Center
 Expiratory Center
 Pneumotaxic Center
 Apneustic Center
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21. CHEMICAL MECHANISM
 Chemical mechanism of regulaion of respiration is
operated through the chemoreceptors whic give
response to chemical changes in blood such as ;
 Hypoxia
 Hypercapnea
 Increased Hydrogen Ion Concentration

22. TYPES OF CHEMORECEPTORS
Chemoreceptors are classified into tw groups
○Central Chemoreceptors
○Peripheral Chemoreceptors

23. CHEMICAL CHEMORECEPTORS
 The chemoreceptors present in the brain are called as
the central chemoreceptors. These chemoreceptors are
situated in Medulla Oblongata,close to dorsal
respiratory group of neurons.

24. PERIPHERAL CHEMORECEPTORS
 The chemoreceptos present in the Carotid and Aortic
region are called Peripheral Chemoreceptors.

25. ARTIFICIAL RESPIRATION
 Artificial Respiration is the breathing induced bysome
manipulativetechnique when natural respiration has
failed or caesed. There are two methods of Artificial
Respiration.
 Manual Methods
 Mechanical Method

26. MANUAL METHOD
 Manual method od resusitation can be done quickly
without waiting for any mechanical aids.
 There are two types of manual methos of resusitation,
they are;
 Mouth to Mouth Resusitation
 Holger-Nielsen Method

27. MECHANICAL METHOD
 Mechanical method of resusitation is done when
artificial respiration is needed for a long time.
 There are two types of artificial respiration;
 Drinker Method
 Ventilator Method

28. APPLIED PHYSIOLOGY OF TRACHEA
 Asthma is a long term lung disease that causes tracheal
inflammation and makes the airway narrow.
 This develop difficultyin breathing and talking.

29.  Acute bronchitis is very common and it developsdue
to cold or any other respiratory infections.
 Chronic bronchits is a very serious as compared to
acute bronchitis. It causes inflammationand
irritation in the bronchial tube . It can be caused
due to cigratte smoking

30.  Cystic fibrosis is caused do to severe damage to the
lungs and affects the cells that produce mucus and
sweat.

31. DISEASES OF ALVEOLI
 Pneumonia is an inflammatorycondition of
the lung primarilyaffecting the small air sacs known
as alveoli Symptoms typicallyinclude some dry
cough and difficulty in breathinng. Pneumonia is
usuallycaused by infection with viruses or bacteria.

32.  Lung cancer is caused due to smoking and second
handed cigratte smoking. Lung cancer is caused by
uncontrolled growth of cancer cells in the lungs. It
then affects the Liver, Brain, Adrenal Gland and also to
the Bones.

33. DISEASES IN PLEURA
 A pleural effusion is excess fluid that accumulates in
the pleural cavity, the fluid-filledspace that surrounds
the lungs. This excess fluid can impair breathingby
limiting the expansion of the lungs.

34.  Mesothelioma is a type of cancer that developsfrom
the thin layer of tissue that covers many of the internal
organs. The most common area affected is the lining of
the lung and chest wall