respiratory system

1. Respiratory System

2. What is Respiratory
System?
Your respiratory system is made up of the organs in
your body that help you to breathe. Remember, that
Respiration = Breathing. The goal of breathing is
to deliver oxygen to the body and to take away
carbon dioxide.

3. Organization and Functions of
the Respiratory System
Structural classifications:
 upper respiratory tract
 lower respiratory tract.
 Functional classifications:
 Conducting portion: transports air.
 Nose
 nasal cavity
 Pharynx
 Larynx
 Trachea
 progressively smaller airways, from the primary bronchi to the
bronchioles

4. Organization and Functions of
the Respiratory System
 Functional classifications: continued
 Conducting portion: transports air.
 Respiratory portion: carries out gas exchange.
 respiratory bronchioles
 alveolar ducts
 air sacs called alveoli
 Upper respiratory tract is all conducting
 Lower respiratory tract has both conducting and
respiratory portions

6. Respiratory System Functions
 Breathing (pulmonary ventilation)
 consists of two cyclic phases:
 inhalation, also called inspiration
 exhalation, also called expiration
 Inhalation draws gases into the lungs.
 Exhalation forces gases out of the lungs.
 Gas exchange: O2 and CO2
 External respiration
 External environment and blood
 Internal respiration
 Blood and cells

7. Respiratory System Functions
 Gas conditioning:
 Warmed
 Humidified
 Cleaned of particulates
 Sound production:
 Movement of air over true vocal cords
 Also involves nose, paranasal sinuses, teeth, lips
and tongue
 Olfaction:
 Olfactory epithelium over superior nasal conchae
 Defense:
 Coarse hairs, mucus, lymphoid tissue

8. Upper Respiratory Tract
 Composed of
 the nose
 the nasal cavity
 the paranasal sinuses
 the pharynx (throat)
 and associated structures.
 All part of the conducting portion of the
respiratory system.

9. Nose
 Provides an airway for respiration
 Moistens and warms air
 Filters inhaled air
 Resonating chamber for speech
 Houses olfactory receptors
 Size variation due to differences in nasal cartilages
 Skin is thin – contains many sebaceous glands

10. Nasal Cavity
 External nares – nostrils
 Divided by – nasal septum
 Continuous with nasopharynx
 Posterior nasal apertures – choanae

12. Nasal Cavity
 Two types of mucous membrane
 Olfactory mucosa
 Near roof of nasal cavity
 Houses olfactory (smell) receptors
 Respiratory mucosa
 Lines nasal cavity
 Epithelium is pseudostratified ciliated columnar
 And it is consists of
 Pseudostratified ciliated columnar epithelium
 Goblet cells within epithelium
 Underlying layer of lamina propria
 Cilia move contaminated mucus posteriorly

13. Nasal Conchae
 Superior and middle nasal conchae
 Part of the ethmoid bone
 Inferior nasal conchae
 Separate bone
 Project medially from the lateral wall of the
nasal cavity
 Particulate matter
 Deflected to mucus-coated surfaces

14. Paranasal Sinuses
 Paranasal sinuses:
 In four skull bones
 paired air spaces
 decrease skull bone weight
 Named for the bones in which they are housed.
 frontal
 ethmoidal
 sphenoidal
 maxillary
 Communicate with the nasal cavity by ducts.
 Covered with the same pseudostratified ciliated
columnar epithelium as the nasal cavity.

16. Pharynx
 Common to both the respiratory and digestive
systems.
 Commonly called the throat.
 Funnel-shaped
 slightly wider superiorly and narrower inferiorly.
 Originates posterior to the nasal and oral
cavities
 Extends inferiorly near the level of the
bifurcation of the larynx and esophagus.
 Common pathway for both air and food.

18. Pharynx
 Walls:
 lined by a mucosa
 contain skeletal muscles primarily used for swallowing.
 Flexible lateral walls
 distensible
 to force swallowed food into the esophagus.
 Partitioned into three adjoining regions:
 nasopharynx
 oropharynx
 laryngopharynx

19. Nasopharynx
 Superiormost region of the pharynx.
 Location:
 posterior to the nasal cavity
 superior to the soft palate
 separates it from the posterior part of the oral cavity.
 Normally, only air passes through.
 Soft palate
 Blocks material from the oral cavity and oropharynx
 elevates when we swallow.
 Auditory tubes
 paired
 In the lateral walls of the nasopharynx
 connect the nasopharynx to the middle ear.
 Pharyngeal tonsil
 posterior nasopharynx wall
 single
 commonly called the adenoids.

20. Oropharynx
 The middle pharyngeal region.
 Location:
 Immediately posterior to the oral cavity.
 Bounded by the soft palate superiorly,
 the hyoid bone inferiorly.
 Common respiratory and digestive pathway
 both air and swallowed food and drink pass through.
 2 pairs of muscular arches
 anterior palatoglossal arches
 posterior palatopharyngeal arches
 form the entrance from the oral cavity.
 Lymphatic organs
 provide the “first line of defense” against ingested or inhaled
foreign materials.
 Palatine tonsils
 on the lateral wall between the arches
 Lingual tonsils
 At the base of the tongue.

21. Laryngopharynx
 Inferior, narrowed region of the pharynx.
 Location:
 Extends inferiorly from the hyoid bone
 is continuous with the larynx and esophagus.
 Terminates at the superior border of the esophagus
 is equivalent to the inferior border of the cricoid cartilage in the
larynx.
 The larynx (voice box) forms the anterior wall
 Lined with a nonkeratinized stratified squamous
epithelium (mucus membrane)
 Permits passage of both food and air.

22. Lower Respiratory Tract
 Conducting portion
 Larynx
 Trachea
 Bronchi
 bronchioles and their associated structures
 Lungs
 Respiratory portion
 Lungs
 respiratory bronchioles
 alveolar ducts
 alveoli

23. Larynx (Voice Box)
 Short, somewhat cylindrical airway
 Location:
 bounded posteriorly by the
laryngopharynx,
 inferiorly by the trachea.
 Prevents swallowed materials from
entering the lower respiratory tract.
 Conducts air into the lower respiratory
tract.
 Produces sounds.

24. Larynx
 Nine pieces of cartilage
 three individual pieces
 Thyroid cartilage
 Cricoid cartilage
 Epiglottis
 three cartilage pairs
 Arytenoids: on cricoid
 Corniculates: attach to arytenoids
 Cuniforms:in aryepiglottic fold
 held in place by ligaments and muscles.
 Intrinsic muscles: regulate tension on true
vocal cords
 Extrinsic muscles: stabilize the larynx

26. Larynx
◊ Sound Production
 Two pairs of ligaments
 Inferior ligaments, called vocal ligaments
 covered by a mucous membrane
 vocal folds: ligament and mucosa.
 are “true vocal cords”
 they produce sound when air passes between them
 Superior ligaments, called vestibular ligaments
 Covered by mucosa
 vestibular folds: ligament and mucosa
 Are “false vocal cords”
 no function in sound production
 protect the vocal folds.
 The vestibular folds attach to the corniculate
cartilages.

27. Larynx
◊ Sound Production
 The tension, length, and position of the vocal folds
determine the quality of the sound.
 Longer vocal folds produce lower sounds
 More taunt, higher pitch
 Loudness based on force of air
 Rima glottidis: opening between the vocal folds
 Glottis: rima glottidis and the vocal folds

30. Trachea (Windpipe)
 A flexible, slightly rigid tubular organ
 often referred to as the “windpipe.”
 Extends through the mediastinum
 immediately anterior to the esophagus
 inferior to the larynx
 superior to the primary bronchi of the lungs.
 Anterior and lateral walls of the trachea are
supported by 15 to 20 C-shaped tracheal cartilages.
 cartilage rings reinforce and provide some rigidity to the
tracheal wall to ensure that the trachea remains open
(patent) at all times
 cartilage rings are connected by elastic sheets called anular
ligaments

32. Trachea (Windpipe)
 At the level of the sternal angle, the trachea
bifurcates into two smaller tubes, called the
right and left primary bronchi.
 Each primary bronchus projects laterally
toward each lung.
 The most inferior tracheal cartilage separates
the primary bronchi at their origin and forms
an internal ridge called the carina.

33. Bronchial Tree
 A highly branched system
 air-conducting passages
 originate from the left and right primary bronchi.
 Progressively branch into narrower tubes as they
diverge throughout the lungs before terminating in
terminal bronchioles.
 Primary bronchi
 Incomplete rings of hyaline cartilage ensure that they
remain open.
 Right primary bronchus
 shorter, wider, and more vertically oriented than the left
primary bronchus.
 Foreign particles are more likely to lodge in the right primary
bronchus.

34. Bronchial Tree
 Primary bronchi
 enter the hilum of each lung
 Also entering hilum:
 pulmonary vessels
 lymphatic vessels
 nerves.
 Secondary bronchi (or lobar bronchi)
 Branch of primary bronchus
 left lung:
 two lobes
 two secondary bronchi
 right lung
 three lobes
 three secondary bronchi.
 Tertiary bronchi (or segmental bronchi)
 Branch of secondary bronchi
 left lung is supplied by 8 to 10 tertiary bronchi.
 right lung is supplied by 10 tertiary bronchi
 supply a part of the lung called a bronchopulmonary segment.

36. Respiratory Bronchioles,
Alveolar Ducts, and Alveoli
True respiration begins in the smallest bronchioles
(respiratory bronchioles). They branch into alveolar ducts
and finally into the tiny alveoli. They look like tiny bunches of
grapes. This is where gas exchange happens. The capillaries
carrying oxygen lie right up against the alveoli and form
the respiratory membrane. Across this membrane the
oxygen is traded for carbon dioxide. Respiration has occurred.

38. Respiratory Bronchioles
The smallest bronchioles (0.5 mm in diameter) that connect the
terminal bronchioles to alveolar ducts; alveoli rise from
part of the wall, thus permitting the exchange of gases.

39. Alveolar Ducts
The terminal branch(es) of each respiratory
bronchiole in the lungs, lined by a simple
squamous epithelium, which deliver inspired
air to the alveolar sacs.

40. Alveoli
 Surrounded by fine elastic fibers
 Contain open pores that:
 Connect adjacent alveoli
 Allow air pressure throughout the lung to
be equalized
 House macrophages that keep alveolar
surfaces sterile

41. Lungs
 The lungs consist of the:
 smaller conductive zone
 larger respiratory zone.
 The respiratory zone (~3000 ml; 95% of the lung volume)
includes respiratory bronchioles, alveolar ducts and alveolar
sacs.

42. Gross Anatomy of the Lungs
 Each lung has a conical shape. Its 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, and 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.

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

44. Pleura and Pleural Cavities
 The outer surface of each lung and the
adjacent internal thoracic wall are lined by a
serous membrane called pleura.
 The outer surface of each lung is tightly
covered by the visceral pleura.
 while the internal thoracic walls, the lateral
surfaces of the mediastinum, and the
superior surface of the diaphragm are lined
by the parietal pleura.
 The parietal and visceral pleural layers are
continuous at the hilus of each lung.

45. 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

46. Blood supply of Lungs
 Lungs are perfused by two circulations:
pulmonary and bronchial
 Pulmonary arteries – supply systemic venous
blood to be oxygenated
 Branch profusely, along with bronchi
 Ultimately feed into the pulmonary capillary
network surrounding the alveoli
 Pulmonary veins – carry oxygenated blood
from respiratory zones to the heart

47. Blood Supply to Lungs
 Bronchial arteries – provide systemic
blood to the lung tissue
 Arise from aorta and enter the lungs at the
hilus
 Supply all lung tissue except the alveoli
 Bronchial veins anastomose with
pulmonary veins
 Pulmonary veins carry most venous
blood back to the heart

48. Respiratory events
 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

49. Pulmonary Ventilation
 Breathing or pulmonary ventilation,
consists of two phases:
 Inspiration – air flows into the lungs
 Expiration – gases exit the lungs

50. Inspiration
 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

52. Expiration
 Largely a passive process which
depends on natural lung elasticity
 As muscles relax, air is pushed out of
the lungs
 Forced expiration can occur mostly by
contracting internal intercostal muscles
to depress the rib cage

54. Nonrespiratory Air Movements
 Can be caused by reflexes or voluntary
actions
Examples
 Cough and sneeze – clears lungs of debris
 Laughing
 Crying
 Yawn
 Hiccup

55. Respiratory Volumes and
Capacities
 Normal breathing moves about 500 ml of air with
each breath (tidal volume [TV])
 Many factors that affect respiratory capacity
 A person’s size
 Sex
 Age
 Physical condition
 Residual volume of air – after exhalation, about 1200
ml of air remains in the lungs

56. Respiratory Volumes and
Capacities
 Inspiratory reserve volume (IRV)
 Amount of air that can be taken in forcibly
over the tidal volume
 Usually between 2100 and 3200 ml
 Expiratory reserve volume (ERV)
 Amount of air that can be forcibly exhaled
 Approximately 1200 ml

57. Respiratory Volumes and
Capacities
 Residual volume
 Air remaining in lung after expiration
 About 1200 ml

58. Respiratory Capacities

59. Respiratory Sounds
 Sounds are monitored with a
stethoscope
 Bronchial sounds – produced by air
rushing through trachea and bronchi
 Vesicular breathing sounds – soft
sounds of air filling alveoli

60. External Respiration
 Oxygen movement into the blood
 The alveoli always has more oxygen
than the blood
 Oxygen moves by diffusion towards the
area of lower concentration
 Pulmonary capillary blood gains oxygen

61. External Respiration
 Carbon dioxide movement out of the
blood
 Blood returning from tissues has higher
concentrations of carbon dioxide than air in
the alveoli
 Pulmonary capillary blood gives up carbon
dioxide
 Blood leaving the lungs is oxygen-rich
and carbon dioxide-poor

62. Gas Transport in the Blood
 Oxygen transport in the blood
 Inside red blood cells attached to
hemoglobin (oxyhemoglobin [HbO2])
 A small amount is carried dissolved in
the plasma

63. Internal Respiration

64. Factors Influencing
Respiratory Rate and Depth
 Physical factors
 Increased body temperature
 Exercise
 Talking
 Coughing
 Volition (conscious control)
 Emotional factors

65. Factors Influencing
Respiratory Rate and Depth
 Chemical factors
 Carbon dioxide levels
 Level of carbon dioxide in the blood is the
main regulatory chemical for respiration
 Increased carbon dioxide increases
respiration
 Changes in carbon dioxide act directly on
the medulla oblongata

66. Factors Influencing
Respiratory Rate and Depth
 Chemical factors (continued)
 Oxygen levels
 Changes in oxygen concentration in the
blood are detected by chemoreceptors in
the aorta and carotid artery
 Information is sent to the medulla
oblongata

67. Respiratory Disorders: Chronic
Obstructive Pulmonary Disease (COPD)
 Exemplified by chronic bronchitis and emphysema
 Major causes of death and disability in the United
States
 Features of these diseases (continued)
 Most victimes retain carbon dioxide, are hypoxic
and have respiratory acidosis
 Those infected will ultimately develop respiratory
failure

68. Emphysema
 Alveoli enlarge as adjacent chambers break
through
 Chronic inflammation promotes lung fibrosis
 Airways collapse during expiration
 Patients use a large amount of energy to
exhale
 Overinflation of the lungs leads to a
permanently expanded barrel chest
 Cyanosis appears late in the disease

69. Chronic Bronchitis
 Mucosa of the lower respiratory passages
becomes severely inflamed
 Mucus production increases
 Pooled mucus impairs ventilation and gas
exchange
 Risk of lung infection increases
 Pneumonia is common
 Hypoxia and cyanosis occur early

70. Chronic Obstructive
Pulmonary Disease (COPD)

71. Lung Cancer
 Accounts for 1/3 of all cancer deaths in
the United States
 Increased incidence associated with
smoking
 Three common types
 Squamous cell carcinoma
 Adenocarcinoma
 Small cell carcinoma

72. Sudden Infant Death
syndrome (SIDS)
 Apparently healthy infant stops
breathing and dies during sleep
 Some cases are thought to be a
problem of the neural respiratory control
center
 One third of cases appear to be due to
heart rhythm abnormalities

73. Asthma
 Chronic inflamed hypersensitive
bronchiole passages
 Response to irritants with dyspnea,
coughing, and wheezing

74. Developmental Aspects of the
Respiratory System
 Lungs are filled with fluid in the fetus
 Lungs are not fully inflated with air until
two weeks after birth
 Surfactant that lowers alveolar surface
tension is not present until late in fetal
development and may not be present in
premature babies

75. Developmental Aspects of the
Respiratory System
 Important birth defects
 Cystic fibrosis – oversecretion of thick
mucus clogs the respiratory system
 Cleft palate

76. Aging Effects
 Elasticity of lungs decreases
 Vital capacity decreases
 Blood oxygen levels decrease
 Stimulating effects of carbon dioxide
decreases
 More risks of respiratory tract infection

77. Respiratory Rate Changes
Throughout Life
 Newborns – 40 to 80 respirations per
minute
 Infants – 30 respirations per minute
 Age 5 – 25 respirations per minute
 Adults – 12 to 18 respirations per
minute
 Rate often increases somewhat with old
age