Anatomy and Physiology of Respiratory System

1. By: Tengse Kiran A.
(Assistant Professor)
DJPS College of Pharmacy (B. Pharm) Pathri
Academic Year : 2019-2020

2. Respiration
 Respiration is the process by which oxygen is taken in
and carbon dioxide is given out.
 Normal Respiratory Rate at Different Age
Newborn : 30 to 60/minute
Early childhood : 20 to 40/minute
Late childhood : 15 to 25/minute
Adult : 12 to 16/minute.

3. TYPES OF RESPIRATION
Respiration is classified into two types:
1. External respiration that involves exchange of respiratory
gases, i.e. oxygen and carbon dioxide between lungs and
blood
2. Internal respiration, which involves exchange of gases
between blood and tissues.

4. PHASES OF RESPIRATION
Respiration occurs in two phases:
1. Inspiration :during which air enters the lungs from
atmosphere
2. Expiration: during which air leaves the lungs

5. The organs of the respiratory
system are
 nose
 pharynx
 larynx
 trachea
 two bronchi (one bronchus to each lung)
 bronchioles and smaller air passages
 two lungs and their coverings, the pleura
 muscles of respiration -- The diaphragm and intercostals
Muscles

6. Organs Of Respiration

7. NOSE AND NASAL CAVITY

8. The pathway of air from the nose
to the larynx.

9.  The roof is formed by the cribriform plate of the ethmoid
bone, and the sphenoid bone, frontal bone and nasal
bones.
 The floor is formed by the roof of the mouth and consists
of the hard palate in front and the soft palate behind .
 The medial wall is formed by the septum.
 The lateral walls are formed by the maxilla, the ethmoid
bone
 The posterior wall is formed by the posterior wall of the
pharynx.

10.  Nose is first entry part of the respiratory passages
 Warm, Moisten, Filter and clean the air.
 Olfactory Function

11. PHARYNX
 pharynx is divided into three parts: nasopharynx,
oropharynx and laryngopharynx
 Structure
1.Mucous membrane lining
2. Fibrous tissue
3. Muscle tissue. This consists of several involuntary
constrictor muscles that play an important part in the
mechanism of swallowing (deglutition)
 vagus and glossopharyngeal nerves supplied to the
Pharynx

12. Functions
 Passageway for air and food.
 Warming and humidifying.
 Hearing. The auditory tube, extending from the nasal
part to each middle ear, allows air to enter the middle
ear. Satisfactory hearing depends on the presence of
air at atmospheric pressure on each side of the
tympanic membrane
 Protection. The lymphatic tissue of the pharyngeal
and laryngeal tonsils produces antibodies in response
to antigens,e.g. microbes
 Speech. The pharynx functions in speech; by acting as
a resonating chamber for the sound ascending from
the larynx, it helps (together with the sinuses) to give
the voice its individual characteristics

13. LARYNX
 The larynx or 'voice box' extends from the root of the
tongue and the hyoid bone to the trachea. It lies in
front of the laryngopharynx at the level of the 3rd, 4th,
5th and 6th cervical vertebrae.
 Until puberty there is little difference in the size of the
larynx between the sexes. Thereafter it grows larger in
the male

14. Figure Larynx – 1.viewed from behind. 2. viewed from the front.

17. Structures associated with the
larynx
 Superiorly — the hyoid bone and the root of the tongue
 Inferiorily — it is continuous with the trachea
 Anteriorly — the muscles attached to the hyoid bone
and the muscles of the neck
 Posteriorly — the laryngopharynx and 3rd to 6th
cervical vertebrae
 Laterally — the lobes of the thyroid gland

18. Structure
Cartilages
• 1 thyroid cartilage
• 1 cricoid cartilage hyaline cartilage
• 2 arytenoid cartilages
• 1 epiglottis elastic fibrocartilage

19. Functions
 Production of sound. Sound has the properties of
pitch, volume and resonance
 Speech. This occurs during expiration when the
sounds produced by the vocal cords are manipulated
by the tongue, cheeks and lips.
 Protection of the lower respiratory tract: Epiglotiss
close the Larynx during Swallowing
 Passageway for air
 Humidifying, filtering and warming air

20. Trachea
 The trachea or windpipe, is a tubular passageway
for air that is about 12 cm (5 in.) long and 2.5 cm (1 in.)
in diameter.
 It is located anterior to the esophagus
 16 to 20 incomplete (C-shaped) rings of hyaline
cartilages.
 Connective tissue and involuntary muscle join the
cartilages and form the posterior wall where they are
incomplete.
 The soft tissue posterior wall is in contact with the
oesophagus

21. Fig.: The relationship of the trachea to the oesophagus.

23.  There are three layers of tissue which 'clothe' the
cartilages of the trachea.
 The outer layer: consists of fibrous and elastic tissue
and encloses the cartilages
 The middle layer: consists of cartilages and bands of
smooth muscle that wind round the trachea in a
helical arrangement. There are some areolar tissue,
containing blood and lymph vessels and autonomic
nerves
 The inner lining: This consists of ciliated columnar
epithelium, containing mucus-secreting goblet cells

24. Fig: Microscopic view of ciliated mucous membrane.

25. Functions
 Support: prevents kinking and obstruction of the
airway as the head and neck move. The absence of
cartilage posteriorly allows the trachea to dilate and
constrict.
 Cough reflex
 Warming, humidifying and filtering of air

26. Bronchi
 At the superior border of the fifth thoracic vertebra,
the trachea divides into a right primary bronchus
and a left primary bronchus.
 Carina
 secondary bronchi
 tertiary (segmental) bronchi
 Bronchioles
 terminal bronchioles
 bronchial tree

28.  Mucus produced by goblet cells traps the particles, and
the cilia move the mucus and trapped particles toward
the pharynx for removal.
 Plates of cartilage gradually replace the incomplete
rings of cartilage in primary bronchi and finally
disappear in the distal bronchioles.
 As the amount of cartilage decreases, the amount of
smooth muscle increases.

29. Functions
 warming and humidifying
 support
 removal of particulate matter
 cough reflex.
 Control of air entry:
Sympathetic nerve : Dialatation
and parasympathetic nerve : Constriction

30. Lungs
Surface Anatomy:
The lungs are paired cone shaped organs in the
thoracic cavity.
 They are separated from each other by the heart and
other structures.
 Each lung is enclosed and protected by a double-
layered serous membrane called the pleural
membrane.
 parietal pleura,
 visceral pleura,
 Pleural cavity
 Pleural fluid
 Pleuritis: Inflamation of pleural membrane .

32.  The lungs extend from the diaphragm to just slightly
superior to the clavicles and lie against the ribs
anteriorly and posteriorly.
 Base: inferior concave portion
 Apex: Superior
 The surface of the lung lying against the ribs, the
costal surface.
 The mediastinal (medial) surface of each lung
contains a region, the hilum (or hilus)
 cardiac notch: Due to the space occupied by the
heart, the left lung is about 10% smaller than the right
lung

34. Lobes, Fissures, and Lobules

36. MICROSCOPIC AIRWAYS
Terminal bronchioles
Respiratory bronchioles
Alveolar ducts
Alveolar sacs
Alveoli

38. Alveoli

39. Structure of alveoli
 The walls of alveoli consist of two types of alveolar
epithelial cells
Type I alveolar cells--simple squamous epithelial cells
forms inner lining
Type II alveolar cells(septal cells)—cuboidal epithelial
cells secretes the alveolar fluid
Alveolar macrophages (dust cells)– phagocytosis

40.  The exchange of O2 and CO2 between the air spaces in
the lungs and the blood takes place by diffusion across
the alveolar and capillary walls, which together
form the respiratory membrane.
 Blood Supply to the Lungs

41. Mechanism of Respiration
 Respiration occurs in two phases namely inspiration and
expiration.
 The main muscles of respiration in normal quiet
breathing are the intercostal muscles and the
diaphragm
A} Intercostal muscles:
 There are 11 pairs of intercostal muscles that occupy the
spaces between the 12 pairs of ribs
 They are arranged in two layers,
1. the external and
2. internal intercostal muscles
 The diaphragm is supplied by the phrenic nerves

43.  The first rib is fixed. Therefore, when the intercostal
muscles contract they pull all the other ribs towards
the first rib. Because of the shape of the ribs they move
outwards when pulled upwards. In this way the
thoracic cavity is enlarged anteroposteriorly and
laterally.
 The intercostals muscles are stimulated to contract by
the intercostals nerves.

44. Diaphragm
 dome-shaped structure separating the thoracic and
abdominal cavities.
 It forms the floor of the thoracic cavity and the roof
of the abdominal cavity and consists of a central
tendon.
 When central tendon relaxed diaphragm is at 8th
thoracic vertebra and if contracted get position at 9th
thoracic vertebra.
 he diaphragm is supplied by the phrenic nerves

45. The intercostal muscles and the diaphragm contract
simultaneously ensuring the enlargement of the thoracic
cavity in all directions, that is from back to front, side to
side and top to bottom.

46. Cycle of respiration
12 to 15 times per minute
1. Inspiration :
simultaneous contraction of the intercostal muscles and
the diaphragm
Increase in thoracic cavity
parietal pleura moves with the walls of the thorax and
the diaphragm.
This reduces the pressure in the pleural cavity

47. The visceral pleura follows the parietal pleura pulling the
lung with it.
Stretches the lungs
Fall down the pressure inside alveoli and airway
passage
drawing air into the lungs
The process of inspiration is active, as it requires
expenditure of energy for muscle contraction

48.  2. Expiration
Relaxation of the intercostal muscles and the diaphragm
results in downward and inward movement of the rib cage
elastic recoil of the lungs
pressure inside the lungs exceeds
air is expelled from the respiratory tract
This process is passive as it does not require the expenditure of
energy
After expiration, there is a pause before the next cycle begins

49. Physiological variables affecting
respiration
 Elasticity: Regain original position
 Compliance : This is a measure of the distensibility of
the lungs. i.e. the effort required to inflate the alveoli
compliance and elasticity are opposing forces
 Airflow resistance: When this is increased, e.g. in
bronchoconstriction, more respiratory effort is required
to inflate the lungs.

50. Control of respiration

51. 1. Respiratory Centre
This widely dispersed group of neurons, collectively
called the respiratory center, can be divided into three
areas on the basis of their functions:
(1) the medullary rhythmicity area in the medulla
oblongata;
(2) the pneumotaxic area in the pons; and
(3) the apneustic area, also in the pons
2. Cortical Region
3. Chemoreceptors
4. Proprioceptors

53. Lung volumes and Capacities
1.Tidal volume (TV): This is the amount of air which
passes into and out of the lungs during each cycle of
quiet breathing (about 500 ml).
2.Inspiratory reserve volume (IRV). This is the extra
volume of air that can be inhaled into the lungs during
maximal inspiration.
3.Inspiratory capacity (1C). This is the amount of air
that can be inspired with maximum effort. It consists of
the tidal volume (500 ml) plus the inspiratory reserve
volume
4.Functional residual capacity (FRC). This is the
amount of air remaining in the air passages and alveoli
at the end of quiet expiration

54. 5.Expiratory reserve volume (ERV). This is the largest
volume of air which can be expelled from the lungs
during maximal expiration.
6.Residual volume (RV). This cannot be directly
measured but is the volume of air remaining in the
lungs after forced expiration.
7.Vital capacity (VC). This is the maximum volume of
air which can be moved into and out of the lungs:
VC = Tidal volume + IRV + ERV
8. Total Lung Capacity:
VC+RV

55. Transport of Respiratory Gases
Composition of Air

56. External respiration: exchange of gases between alveolar air
and capillary blood.

57. Internal respiration: exchange of gases
between capillary blood and tissue cells

58. Transport of gases in the bloodstream
 Transport of blood oxygen and carbon dioxide is essential
for internal respiration to occur.
Oxygen:
1.5 % O2 dissolve in plasma
98.5 % bound to hemoglobin.
Heme- 4 iron atoms
O2+ Heme Oxyhemoglobin (Reversible binding)
Higher the PO2 , higher will be the binding of O2.

59.  Carbon Dioxide
Deoxygenated Blood contain about 53% of gaseous CO2
1) 7% dissolve in blood and exhaled from lungs through
alveoli
2) 23% combines with amino acids in protein part of
globin . Forms Carbaminohemoglobin
Hb + CO2 Hb-CO2
3) 70% forms Bicarbonate ions in the RBC and in other
cells .
CO2 + H2O C. A. H+ + HCO3 -

60. HCO3- shift with the Cl-
HCO3- comes in blood plasma and in alveoli it
reversibly forms the CO2 and get exhaled.

61. Artificial Respiration
Artificial respiration is required whenever there is an
arrest of breathing, without cardiac failure. Arrest
of breathing occurs
1. Accidents
2. Drowning
3. Gas poisoning
4. Electric shock
5. Anesthesia.
Stoppage of oxygen supply for 5 minutes causes
irreversible changes in tissues of brain, particularly
tissues of cerebral cortex. So, artificial respiration
(resuscitation) must be started quickly without any
delay, before the development of cardiac failure.
Purpose of artificial respiration is to ventilate the
alveoli and to stimulate the respiratory centers

62. METHODS OF ARTIFICIAL RESPIRATION
(Resuscitation Method)
 Manual Methods:
 Instrumental Respiration:

63. 1. Manual Methods:
 a. Schafer’s Method
The subject is laid in prone position and a small pillow
is placed underneath the chest and epigastrium.

64.  b. Sylvester’s Method:
The subject is placed in supine position
 The operator stands or at the head end and holds
the two arms of the subject.
 The operator then raises the subject’s hands above his
head and then folds the hands back upon the chest,
compressing the chest wall at the same time. Such
movements alternately increase and decrease the
thoracic cavity, thus drawing in and pushing out air
from the lungs.

65. c. Holger-Nielson Method
 The subject is placed in the prone position with the
arms abducted at the shoulders and elbows remaining
flexed.
 The face is turned to one side and rests on the hands.
 The mouth is cleaned after wiping out mucus, fluid,
etc., from it.
 The operator kneels down in front of the subject facing
towards the head.
 Two hands are placed on the two sides of the back of
the chest with the thumbs and fingers spread
apart.Then the operator puts his body weight leaning
forwards upon the subject’s back. This compresses the
chest and helps in expiration.

66.  The subject’s arms forwards by holding them above the
elbows. This helps in natural inspiration. This process
is repeated about 10-12 times a minute.

67. d) Mouth-to-mouth method
 The subject is laid in the supine position with extended
head.
 operator sits by the side of the subject’s head.
 hold the lower jaw of the subject by one thumb and
index-finger and clamps the nostrils with the other thumb
and index-finer.
 keeps the mouth over the subject’s mouth and exhales
forcibly which causes inflation of the lungs and thorax
 The operator then takes off his mouth and the process is
repeated 10-20 times per minute

69. e. EVE’s Rocking Method
 The patient is tied on a stretcher.
 The head and feet are alternately tilted through an
angle of 45°.
 Eight or nine movements are carried out per minute, 7
seconds for each movement—4 seconds head down
and 3 seconds feet down.
 When the head is down, the weight of the abdominal
viscera presses against the diaphragm, so that air is
pushed out of the lungs (expiration).
 When the feet are down, diaphragm descends and air
is drawn into the lungs (inspiration).

70. 2. Instrumental Method
 Drinker’s Method
In this method the patient is placed in an airtight
chamber, the head remaining outside. By
mechanically driven pumps, the pressure in the
chamber is alternately lowered and raised.
Used in morphine poisoning, in paralysis of the
respiratory muscles, as in poliomyelitis, pneumothorax
etc

72. b. Bragg Paul’s Method:
 A rubber bag is wrapped round the chest wall of the
subject.
 By suitable pumps, pressure in the bag is alternately
raised and lowered thus compressing and relaxing the
chest wall alternately. In this way respiration is carried
out.

73. Continuous Insufflation Method:
 This method is used in subjects who are to undergo
operation requiring opening of the thorax.
 A thin flexible tube is inserted in the trachea and
constant stream of oxygen (with or without 5% CO2) is
allowed to pass into the lungs .
 In this way it is possible to maintain respiration
without any movement of the subject.

74. Intermittent Inflation Method:
 This method is adopted to maintain the respiration
of animals during experiments. Various types of
apparatus have been designed for this purpose. In the
simplest method, a cannula is introduced and tied
to the trachea.

75. c. Tank respirator:
 In tank respirator the patient’s body is placed inside
the tank and his head is protruded through a flexible
but airtight collar.
 By means of some pumps, the pressure inside the
chamber is made positive and negative alternately.

77. Thank You!!!!