This presentation is useful to understand anatomy and physiology of human respiratory system

1. RESPIRATORY SYSTEM
Dr. Rupali A. Patil
Associate Professor, Pharmacology Department
GES’s Sir Dr. M. S. Gosavi College of Pharm. Edu. & Res., Nashik

2. RESPIRATION
The exchange of gases between the
atmosphere, lungs, blood, and tissues.

3. Functions
• Supplies the body with O2 and disposes of CO2
• Filters inspired air
• Produces sound
• Contains receptors for smell
• Rids the body of some excess water and heat
• Helps regulate blood pH

4. Lung
Bronchial tubes
Nose
Mouth
Trachea
Diaphragm
Respiratory
system

5. FUNCTIONAL ANATOMY
• Upper respiratory tract (URT)
– Nose & nasal cavity
– Pharynx
– Larynx
– Upper Trachea
• Lower respiratory tract (LRT)
– Lower trachea
– Bronchial tree
– Lungs

6. Nose
▪ Also called external nares.
▪ Divided into two halves by the nasal septum.
▪ Contains the paranasal sinuses where air is warmed.
▪ Contains cilia which is responsible for filtering out foreign
bodies.
Nose and Nasal Cavities
Nasal concha Sphenoid sinus
Internal naris
Nasopharynx
External naris
Frontal sinus
Middle nasal concha
Inferior nasal
concha

7. ▪ External nares - opening to exterior
▪ Internal nares - opening to pharynx
▪ Nasal conchae - folds in the mucous membrane that
increase air turbulence and ensures that most air contacts
the mucous membranes
Functions of Nose
▪ Provides an airway for respiration
▪ Moistens and warms entering air
▪ Filters and cleans inspired air
▪ Resonating chamber for speech
▪ Detects odors in the air stream (olfactory receptors)

8. Pharynx
▪ Common space used by both the respiratory & digestive
systems. Common pathway for both air & food.
▪ Commonly called the throat.
▪ Originates posterior to the nasal and oral cavities and extends
inferiorly near the level of the bifurcation of the larynx &
esophagus.
▪ Walls are lined by a mucosa and contain skeletal muscles that
are primarily used for swallowing.
▪ Flexible lateral walls are distensible in order to force swallowed
food into the esophagus.

9. Three Sections of the Pharynx
▪ Nasopharynx
▪ contains pharyngeal tonsils (adenoids): aid in the body’s immune
defense.
▪ Oropharynx
▪ back portion of the mouth that contains the palatine tonsils : aid in the
body’s immune defense.
▪ Laryngopharynx
▪ bottom section of the pharynx where the respiratory tract divides into the
esophagus and the larynx.

10. • Functions of pharynx:
– Way for both air & food
– Warming, moistening & humidifying air
– Protection
– Speech
– Taste
– Hearing

11. Larynx (Voice box)
▪ A short, somewhat cylindrical
airway ends in the trachea.
▪ Prevents swallowed materials
from entering the lower
respiratory tract.
▪ Conducts air into the lower
respiratory tract.
▪ Produces sounds.
▪ Supported by a framework of
nine pieces of cartilage (three
individual pieces and three
cartilage pairs) that are held
in place by ligaments and
muscles.
Hyoid Bone Epiglottis
Thyrohyoid
Membrane
Cricothyroid
Ligament
Cricothyroid
Muscles
Cricothyroid
Cartilage
Trachea
Thyroid
Cartilage

12. • Functions of larynx:
– Way for both air
– Warming, filtering & humidifying air
– Protection of lower respiratory tract
– Speech
– Production of sound

13. Trachea (windpipe)
▪ A flexible tube.
▪ Extends through the mediastinum
and lies anterior to the esophagus
and inferior to the larynx.
▪ Cartilage rings reinforce and provide
rigidity to the tracheal wall to ensure
that the trachea remains open at all times.
▪ At the level of the sternal angle, the
trachea bifurcates into two smaller
tubes, called the right & left primary
bronchi.
▪ Each primary bronchus projects
laterally toward each lung.
Trachea
Bronchi
Larynx

14. • Functions of trachea:
– Warming, moistening & humidifying air
– Cough reflex
– Support
– Mucociliary escalator
– Prevention of kinking & obstruction of the airway

15. Lungs
▪ Conical shape.
▪ Wide, concave base rests upon the muscular diaphragm.
▪ Its superior region called the apex projects superiorly to a
point that is slightly superior and posterior to the clavicle.
▪ Both lungs are bordered by the thoracic wall anteriorly,
laterally, and posteriorly, & supported by the rib cage.
▪ Toward the midline, the lungs are separated from each other
by the mediastinum.
▪ The relatively broad, rounded surface in contact with the
thoracic wall is called the costal surface of the lung.

16. Left lung
– divided into 2 lobes by oblique fissure
– smaller than the right lung
– cardiac notch accommodates the heart
Right lung
– divided into 3 lobes by oblique and horizontal fissure
– located more superiorly in the body due to liver on
right side

17. Covering of the lungs: Pleura
▪ The outer surface of each lung and the adjacent internal
thoracic wall are lined by a serous membrane called pleura.
▪ Each lung is tightly covered by deep layer, visceral
(pulmonary) pleura.
▪ Superfacial layer, Parietal pleura lines thoracic cavity (Internal
thoracic walls, lateral surfaces of the mediastinum, and the
superior surface of the diaphragm).
▪ The parietal and visceral pleural layers are continuous at the
hilus of each lung.

18. The Lungs and Pleural Coverings

19. • Pleural Cavities
• The potential space between the serous membrane layers is a
pleural cavity.
• The pleural membranes produce a thin, serous pleural fluid
that circulates in the pleural cavity and acts as a lubricant,
ensuring minimal friction during breathing.
▪ Pleural effusion – pleuritis with too much fluid

20. Trachea and Bronchial Tree

21. Tracheal Anatomy

22. Tracheal Anatomy

23. Respiratory Tree Divisions
• Primary bronchi
• Secondary bronchi
• Tertiary bronchi
• Bronchioles
• Terminal bronchioles
• Alveolar ducts & alveoli

24. Bronchial Tree

25. Respiratory Tree Divisions

26. ?
Trachea divides into???

27. Conducting Zones

28. • Formed by division of the
trachea
• Enters the lung at the hilus
(medial depression)
• Right bronchus is wider,
shorter, and straighter than
left
• Bronchi subdivide into
smaller & smaller branches
Primary Bronchi

29. Lower Bronchial Tree

30. Alveoli and Respiratory Membrane

31. Vocal Folds and Ligaments

32. RESPIRATORY PHYSIOLOGY

33. • Pulmonary ventilation – moving air in and out of the lungs
• External respiration – gas exchange between pulmonary
blood and alveoli
• Respiratory gas transport – transport of oxygen and carbon
dioxide via the bloodstream
• Internal respiration – gas exchange between blood and
tissue cells in systemic capillaries
Events of Respiration

34. Respiration
• Pulmonary ventilation = “breathing”
• External respiration = occurs within the lungs
• Transport of respiratory gases = via the blood
• Internal respiration = occurs within the tissues

35. • Completely mechanical process
• Depends on volume changes in the thoracic cavity
• Volume changes lead to pressure changes, which lead to
the flow of gases to equalize pressure
1. Mechanics of Breathing (Pulmonary Ventilation)
• Two phases
a. Inhalation (inspiration): draws gases into the lungs.
b. Exhalation (expiration): forces gases out of the lungs.

36. • Diaphragm and intercostal muscles contract
• The size of the thoracic cavity increases
• External air is pulled into the lungs due to an increase in
intrapulmonary volume
a. Inhalation

37. a. Inhalation
▪ During inhalation, the
diaphragm contracts and the rib
cage rises up.
▪ This expands the volume of the
chest cavity.
▪ The chest cavity is sealed, so
this creates a partial vacuum
inside the cavity.
▪ Atmospheric pressure fills the
lungs as air rushes into the
breathing passages.

38. b. Exhalation
▪ Often exhaling is a passive
event.
▪ When the rib cage lowers
and the diaphragm relaxes,
pressure in the chest cavity
is greater than atmospheric
pressure.
▪ Air is pushed out of the
lungs.
Exhalation
Rib cage
lowers
Air Exhaled

39. • Carbon dioxide movement out of the blood
•Blood returning from tissues has higher concentrations of
CO2 than air in the alveoli
•Pulmonary capillary blood gives up CO2
• Blood leaving the lungs is O2 -rich and CO2-poor
2. External Respiration

40. • Oxygen transport in the blood
•Inside RBCs attached to Hb (oxyhemoglobin [HbO2])
•A small amount is carried dissolved in the plasma
3. Gas Transport in the Blood
3.1 Oxygen

41. • CO2 transport in the blood
•Most is transported in the plasma as bicarbonate ion (HCO3
–)
•A small amount is carried inside RBCs on Hb, but at different
binding sites than those of O2
3.2 Carbon dioxide

42. • Exchange of gases between blood and body cells
• An opposite reaction to what occurs in the lungs
•Carbon dioxide diffuses out of tissue to blood
•Oxygen diffuses from blood into tissue
4. Internal Respiration

43. Internal Respiration

44. A Summary of
External Respiration,
Gas Transport, &
Internal Respiration

45. Pressures
• Atmospheric pressure
• Alveolar pressure
(intrapulmonary pressure)
• Intrapleural pressure
• Boyle’s Law
– More volume=less pressure
– Less volume=more pressure

46. Thoracic Volume and Inspiration

47. Thoracic Volume and Expiration

48. Changes in Thoracic Volumes

49. Factors Influencing Pulmonary Ventilation
• Airway Resistance
• Surface Tension
• Lung Compliance

50. Respiratory Volumes and Capacities

51. Volumes and Capacities

52. Volumes and Capacities

53. Non-Respiratory Air Movements

54. Regulation of Respiration
• Medullary respiratory center
– Dorsal respiratory center
(DRC)
– Ventral respiratory center
(VRC)
• Pontine center
formerly called the Pneumotaxic
center
• Hypothalamus

55. • Activity of respiratory muscles is transmitted to the brain by
the phrenic and intercostal nerves
• Neural centers that control rate and depth are located in the
medulla
• The pons appears to smooth out respiratory rate
• Normal respiratory rate (eupnea) is 12–15 respirations per
minute
• Hypernia is increased respiratory rate often due to extra
oxygen needs
Neural Regulation of Respiration

56. Neural
Regulation of
Respiration

57. Gas Transport

58. Basic Properties of Gases
Dalton’s Law of Partial Pressures

59. Partial Pressure and Gas Exchange

60. At the Lungs

61. At the Tissues

62. Factors Influencing Gas Transport and
Hemoglobin Saturation

63. Factors Influencing Gas Transport and
Hemoglobin Saturation

64. Factors Affecting Breathing
Rate and Depth

65. Homeostatic Imbalances of the
Respiratory System
• Sinusitis
• Laryngitis
• Pleurisy
• Dyspnea
• Pneumonia
• Infant respiratory distress
syndrome (IRDS)
• Emphysema
• Chronic bronchitis
• Asthma
• Tuberculosis
• Cystic fibrosis
• Pulmonary embolism
• Sleep apnea
• Hypoxia

66. ?

67. Thank You