The document summarizes key aspects of the human respiratory system. It describes how respiration provides energy through the consumption of oxygen and production of carbon dioxide. It details the major parts of the human respiratory system including the nose, pharynx, larynx, trachea, bronchi, bronchioles and alveoli. It discusses gas exchange that occurs across respiratory surfaces and properties like permeability, thickness, surface area and blood supply. Finally, it outlines several respiratory disorders like sinusitis, pneumonia, tuberculosis and effects of smoking.

1. Respiration
• Energy is the capability to do work.
• All vital activities (e.g. movements, growth,
reproduction) depends energy.
• All organism obtained energy from food they
eat.
• Food is converted to water, carbon dioxide
and energy in the presence of oxygen by an
important process called aerobic respiration.

2. • Less complex animals absorb oxygen over the
entire body surface through diffusion.
• In higher animals there are special respiratory
organs such as gills and lungs.
• Excess carbon dioxide goes out through the
same system.

5. Properties of Respiratory surfaces
• That part of the body of an animal where
exchange of gases take place is called
respiratory surface e.g. lungs.
• Gaseous exchange occur through diffusion.
• For effective diffusion, respiratory surfaces
must possess the following properties.
1. It must be permeable, so that gases can pass
through it.
2. It must be thin.

6. 3. It should possess large surface area.
4. It should possess a good blood supply.
5. There should be steep diffusion gradient.

7. Human Respiratory System
• Human respiratory system consists of the
following parts.
1. Nose and Nasal cavities
2. Pharynx
3. Larynx
4. Trachea
5. Bronchi
6. Bronchioles
7. Alveoli

8. 1. Nose
• Externally visible part.
• Structure of human nose is composed of
bones (A bone is a rigid organ that constitutes part of the vertebrate
skeleton), cartilage (Cartilage is an important structural component of
the body. It is a firm tissue but is softer and much more flexible than bone.)and
fibro fatty tissues.
• External features depends upon the ethmoid
bone and the cartilages.

10. • Hairs in the nose help in filtration of air.
• Nostrils and nasal cavities are lined by mucous
membrane along with cilia.
• Mucous prevents the entry of microorganism
and dust inside the respiratory system.
• Mucous also help in moistening of the air.
• Underlying capillaries of mucous membrane
help in warming the air.

12. 2. Pharynx
• Pharynx is a cone shaped passage way leading
from the oral and nasal cavities to the
oesophagus and larynx.
• Pharynx is part of both the digestive and
respiratory systems.

15. 3. Larynx
• Larynx is an organ of complex structure that
serves as a dual function; as an air canal and
as the organ of voice.
• The larynx is composed of an external
skeleton of cartilage plates that prevent
collapse of the structure.
• The plates are fastened together by
membranes and muscles fibers.
• Two fibrous bands called vocal cords are
composed of mucous membrane stretched
horizontally across larynx.

20. 4. Trachea
• Below the larynx lies the trachea, a tube of 10
to 12 cm long and 2 cm wide.
• The wall of the trachea are composed of horse
shoe shaped incomplete cartilaginous rings.
• Trachea is lined with ciliated mucus
membrane.
• The trachea serves as passage for air,
moistening the air and warming it.

24. 5. Bronchi
• The trachea divides into two stem bronchi,
one each for the left and right lung.
• The right bronchus has a larger diameter and
is shorter than the left bronchus.
• Structure of the bronchi closely resembles
that of the trachea.

25. 6. Bronchioles
• The bronchioles are located at the end of the
bronchi and terminate in the alveoli.
• The bronchioles are approximately I mm or
less in diameter.
• The wall of bronchioles consist of ciliated
cuboidal epithelium and a layer of smooth
muscle.
• Bronchioles do not contain cartilage.

28. 7. Alveoli
• The alveoli form the gas exchange surface.
• The wall of each alveolus is only 0.1 micro
meter thick.
• On the outer side of alveolus is a dense
network of blood capillaries.
• Lining of each alveolus is composed of
squamous epithelium.
• Alveoli also contain collagen and elastic fibers.

31. 8. Lungs
• Human have two lungs, right and a left.
• Right lung is slightly larger than left lung.
• Right lung has 3 lobes.
• Left lung has two lobes.
• Each lung is enclosed in a thin membranous
sac called the pleura.

33. Lungs volumes and capacities
• The average adult human has a lung capacity
of approximately 5 liters.
• Tidal volume: is the volume of air exchanged
during one breath in and out in rest
conditions.
• Residual volume: is the volume (1.5 liter)of air
remaining in the lungs even after a forcible
expiration.

34. Control of breathing
• Involuntary control:
• Medulla Oblongata controls breathing
process.
• Ventral portion (inspiratory center) of medulla
oblongata increases inspiration.
• Dorsal and lateral portion (expiratory center)
inhibit inspiration and stimulate expiration.
• Breathing center communicate with
intercostal muscles by intercostal nerves and
with diaphragm by phrenic nerves.

39. • Voluntary control:
• With in limits, the rate and depth of breathing
are also under voluntary control.

40. Inspiration (inhalation) and Expiration
(exhalation)

41. Mechanism of transport of gases
• Transport of Oxygen in blood:
• 100 ml blood can carry 20 ml Oxygen.
• One gram of haemoglobin carry 1.34 ml oxygen.
• 100 ml blood contain 15 grams.
• 100 ml Arterial blood carry 19.4 ml oxygen
• 100 ml venous blood carry 14.4 ml
• Dissolved oxygen in plasma
• 100 ml blood carry 0.29 ml oxygen may increase
to 0.3 ml
• 100 ml venous blood has 0.12 ml of dissolved
oxygen may increase to 0.17 ml.

42. Transport of carbon dioxide
• i) As bicarbonate ions:
• Chloride shift or Hamburgur’s phenomenon
• ii) As carboxyhaemoglobin
• iii) As dissolved Carbon Dioxide in plasma

44. Respiratory pigments
1) Haemoglobin:
2) Myoglobin

48. Respiratory Disorders
• Sinusitis:
• Upper respiratory disorder.
• Sinusitis is an inflammation of the nasal sinuses
that may be acute or chronic.
• Sinuses are cavities in the skull.
• There 4 large sinuses
• Two inside the cheek bone (maxillary sinuses)
• Two below the mid of fore head (frontal sinuses)

49. • These cavities are covered by mucousal membranes.
• Causes:
• It may be caused
1. pathogens.
2. Allergens
3. dry air heating
4. Air conditioner
Symptoms:
1. Fever
2. Nasal obstruction
3. Pus like nasal discharge
4. Loss of sense of smell

50. 5. Facial pain or headache
6. Entering of nasal fluid into pharynx.
Treatment:
• Antibiotics
• Antiallergics and Decongestants

51. Otitis medius
• Inflammation of the middle ear
• Causes:
1. Allergy
2. Infection
3. Blockage of the eustachian tube
4. Nutritional deficiency
Symptoms
1. Sudden, severe earache

53. • Deafness and tinnittus (ringing in ear)
• Sense of fullness in air
• Irritability
• Fever, headache
• Fluid leaking from ear
• Nausea
• Difficulty in speaking and hearing.
• Treatment:
• Antibiotics
• Pain killers

54. Emphysema
• Lung disease
• Symptoms
1. Shortness of breath with exertion, eventually
breathlessness all the time.
2. Coughing
3. Fatigue
4. Cyanosis (Due to lack of oxygen)

55. • Causes:
• Chemical pollutants (smoking)

57. Lung cancer
• Symptoms:
1. Chronic cough
2. Constant chest pain
3. Coughing up blood
4. Shortness of breath
5. Recurrent pneumonia and bronchitis
6. Swelling of the neck and face
7. Loss of appetite and weight loss
8. fatigue

58. • Treatment:
1. Chemotherapy
2. Radiation
3. Surgery

60. Tuberculosis
• Bacterial infection of lungs
• Highly contagious
• Alveolar macrophage engulf the bacterium
but unable to digest it.
• Pathogen: Mycobacterium tuberculosis
[bacillus].

61. Causes:
1. Infectious air droplets
2. HIV infection
3. Low socioeconomics
4. Health worker
Symptoms:
1. Chronic cough
2. Chest pain
3. High fever
4. Rust colored sputum
5. Hard nodule called tubercle is formed in lungs.
6. Night sweats

62. Treatment
1. Isonicotinyl hydrazine, rifampin and small
amount of ethambutal and streptomycin.
2. Vaccines called Bacille Calmette Guerin [BCG]
are available.
3. Isolation of patients
4. Improving hygienic conditions

63. Pneumonia
• Infection of bronchial tubes and alveolar sacs of
lungs.
• The alveoli become filled with fluid and pus.
Pathogen: Streptococcus pneumoniae [Capsulated
gram positive bacteria].
• Hemophilus influenzae
• Legionella pneumophilia
• Staphylococcus aureus
• Mycoplasma
• Pathogen is transferred from person to person.

64. • If pneumonia is not treated at proper time,
following complication can occur.
• Pleural effusion (fluid around the lungs)
• Empyema (pus in pleural cavity)
• Hyponatremia (low blood Sodium level)
• Abscess in the lung
Symptoms:
Bacterial Pneumonia
1. High fever
2. Sharp chest pain
3. Difficulty in breathing
4. Shaking, chills, chattering teeth
5. Rapid pulse rate

65. • Viral Pneumonia
1. Fever
2. Dry cough
3. Headache
4. Muscles pain
5. Weakness
6. Bluish color to lips
• Mycoplasma Pneumonia
1. Violent cough attack
2. Chills

66. 3. Fever
4. Nausea
5. Vomitting
6. Slow heart beat
7. Breathlessness
8. Bluish color to lips and nail beds
9. Diarrhoea and muscle aches

67. • Treatment
• Antibiotics [tetracyclin and chloramphenicol].
• Vaccination. About eighty strains of
Streptococcus pneumoniae cause pneumonia.
• But vaccines are available for only twenty
three stains.

68. Effects of smoking on the respiratory
system
1. Damage of trachea and larynx.
2. Reduced lung function due to damage of
passage ways of lungs and unavailability of
air.
3. Damage of immune system
4. Coughing and wheezing
5. Physical damage of lungs