The document defines and describes the respiratory system. It outlines the organs involved like the nose, pharynx, larynx, trachea, lungs and their functions. The document also explains the process of respiration from breathing to gas exchange in the lungs and tissues, and defines various lung volumes like tidal volume, inspiratory reserve volume, vital capacity and more.

1. RESPIRATORY SYSTEM
Prepare by : Yannawar P.D.
(M. Pharmacy) DCOP Latur.

2. CONTENT
 Definition
 Types and phases
 Respiratory organs
 physiology of respiration
 Lung volume capacity

3. Definition:
 It is the set of organs that allow a person to breath, exchange oxygen
and carbon dioxide through out the body
Or
 It is biological system consist of specific organs which involve in
exchange of gases in human.
 Main organ: lungs

4. .
Respiration:
• It is process by which oxygen is taken in and carbon dioxide is given out i.e.
Exchange of gases between atmosphere, blood, cells.
• Respiratory rate of normal adult: 12 to 18 respiration per minute
Types of respiration: ( lungs external blood internal tissue)
1. external respiration: Exchange of gases between lungs and blood
2.internal respiration: Exchange of gases between blood and tissue.

5. Phases of respiration
1. Inspiration:
Air enters lungs from atmosphere
It is active process
2. Expiration
Air leaves lungs into atmosphere
It is passive process

6. Function of Respiratory system
 Gas exchange i.e. O2 & CO2
 Warming and humidifying air
 Olfaction( sensation of smell)
 Vocalization( larynx or voice box)
 Prevention from dust particles
 Defense mechanism
 Regulation of acid base balance.

7. .
Respiratory organs (respiratory track)
1. Nose
2. Pharynx upper respiratory system
3. Larynx (voice box)
4. Trachea (wind pipe)
5. {2 Bronchi} (1-bronchus)
6. Bronchioles
7. Lungs(right and left lungs
8. Muscles of breathing (intercostal and diaphragm)
9. Alveoli (air sacs)
conducting part
Exchange part
Lower respiratory system

8. Nostril
Nasal cavity
Pharynx
Larynx
alveoli
bronchiole
Figure: Respiratory system

9. NOSE
 Main route for air entry in which air is filtered by hairs in nostrils
 It has 2 portion:
External nares( open outside)
Internal nares (opens in pharynx)
 Nasal cavity:
It is anterior area of nose lined with sticky membrane and contains tiny, surface hairs, cilia and
hyaline cartilage.
Nasal septum divide nasal cavity into right and left side.
olfactory lobe is a pair of lobe at the anterior end of the cerebrum which is involved in
olfaction or sense of smell.
 Function:
Filtering, cleaning, warming and humidification of air.

10. PHARYNX (throat)
 It lies superior to larynx and posterior to nasal and oral cavity and is called as
Nasopharynx
Oropharynx
Laryngopharynx
Function : It is common passage for food and air
 LARYNX (VOICE BOX or sound box)
It is short passage which connect laryngopharynx with trachea
It have different type of cartilage like Adams apple, epiglottis.
Function: It involve in breathing, creating vocal sound
Epiglottis
Epiglottis (cartilaginous, leaf-shaped flap) is small movable "lid" just above the larynx
that prevents food and drink from entering your windpipe

11. TRACHEA
 It is tubular passage way for air.
 It start from larynx and divide into right and left bronchus.
 12 cm long and 2.5 cm diameter trachea is composed of 16 to 20 incomplete C
shaped rings of hyaline cartilage.
 base of the trachea (windpipe) that separates the openings of the right and left
main bronchus
 Function: main function is to carry air( passage of O2) in and out of your lungs

12. Continue…
 Bronchi
Right and left primary bronchus goes to right and left lungs and divide into primary, secondary
and tertiary bronchi.
Tertiary Bronchi divided into smaller and smaller branches called terminal bronchioles
Bronchial tree: it is branching system of trachea, bronchi, bronchioles, alveolar duct, and alveolar
sac and alveoli which conduct air from windpipe into lungs.
 Alveoli :
Terminal bronchiole divides to form respiratory bronchiole which expands and form alveolar duct
which form sac like structure called alveoli, Where exchange of gases occur.

13. Lungs :
Structure of lungs:
There are 2 lungs
It is Cone shaped, upper narrow part is apex and lower broad part is base.
Right lung: 3 lobe( superior, middle, inferior )
Left lung : 2 lobe (superior, inferior )
This lobe divide by fissure called horizontal and oblique fissure.
Pleura :
Pleura is protective membrane which is visceral( inner ) and partial (outer)
pleura.
It have pleural cavity which contains pleural fluid help to prevent friction.
Function: main function of the lungs is the process of gas exchange called
respiration (or breathing)
Base

14. Diffusion of gases through respiratory membrane
 Wall of alveoli are extremely thin and are covered with network of blood vessels,
due to this gases in alveoli are in close contact blood
 Hence, gas exchange occur between blood and membrane of alveolar duct, sac and
alveoli this membrane are together called as pulmonary membrane or respiratory
membrane.
 Role of hemoglobin in transport of O2 and CO2.
 Hemoglobin 4 heme + globin
oxygen Carbon dioxide
oxyhemoglobin(98%) carbaminohemoglobin (25 %)
Remaining CO2 react with water in presence carbonic anhydrase to form bicarbonate
ion which is transported in plasma

15. .
 Mechanism of respiration
 Entire physiology of respiration involves following steps:
1.Breathing or pulmonary ventilation ( inhalation and exhalation)
2.External respiration
3.Transport of O2 to tissue
4.Internal respiration
5.Transport of CO2 from tissue

16. Continue…
Breathing or Pulmonary ventilation:
This is movement of air into and out of the lungs. Breathing supplies
oxygen to the alveoli, and eliminates carbon dioxide.
The main muscles involved in breathing are the intercostal muscles and
the diaphragm.
There are 11 pairs of intercostal muscles occupying the spaces between
the 12 pairs of ribs.
They are arranged in two layers, the external and internal intercostal
muscles.
The diaphragm is a dome-shaped muscular structure separating the
thoracic and abdominal cavities.

17. Dalton law
Every gas is mixture of gases and have there own pressure.
Pressure excreted by specific gas in mixture is called as partial pressure (p)
Atmospheric air is mixture of O2, CO2 ,N2 , water vapors and other gases
 Atm. Pressure of O2 (pO2) = 160 mmHg
 Atm. Pressure of CO2 (pCO2) = 0.3 mmHg
Partial pressure is important to find out movement of O2, CO2 between atmosphere, lungs, blood and tissue cells.
Partial pressure of O2, CO2 between atmosphere, lungs, blood and tissue cells are as follows
Po2 Pco2
Alveoli 105 40
Oxygenated blood 100 40
Deoxygenated blood 40 45

18. Pulmonary air volume and capacities:
• In normal quiet breathing there are about 12-16 complete respiratory cycles per minute. The amount of
air exchanged during breathing is measured by an instrument called Spirometer or Respirometer
• The amount of air present in lung under different condition is known as pulmonary air volume
Volume Definition Capacity
Tidal volume TV This is the amount of air passing into and out of the lungs during each cycle of
breathing.
500 ml
Inspiratory
reserve volume
IRV during forced inspiration, amount of air which can be taken into lungs 1900 -
3300ml
Expiratory
reserve volume
ERV during forced expiration, amount of air which can be expelled out of lungs 1100ml
Residual
volume
RV This is the volume of air remaining in the lungs after forceful expiration.
Vital capacity VC This is the largest volume of air which can be expired after deepest possible
inspiration.
VC= TV+IRV+ERV
(3 to 5
litres)

20. Questions
1. Define respiration. What do you mean by external and internal respiration
2. Draw and label figure showing respiratory system
3. Enlist respiratory organ
4. Describe : pharynx, larynx, trachea, bronchial tree
5. Explain muscles of involve in mechanism of respiration
6. Give structure and function of lungs
7. Define and give normal value :
a. Tidal volume
b. Inspiratory reserve volume
c. Expiratory reserve volume
d. Residual volume
e. Vital capacity