1. The Respiratory System

2. What are the primary functions of the respiratory system?

3. Oxygen
Is obtained from the air by diffusion across delicate exchange surfaces of lungs
Is carried to cells by the cardiovascular system which also returns carbon dioxide to the lungs

4. 5 Functions of the Respiratory System
Provides extensive gas exchange surface area between air and circulating blood
Moves air to and from exchange surfaces of lungs

5. 5 Functions of the Respiratory System
Protects respiratory surfaces from outside environment
Produces sounds-speaking, singing
Participates in olfactory sense

6. Components of the Respiratory System
Figure 23–1

7. Organization of the Respiratory System
The respiratory system is divided into the upper respiratory system, above the larynx, and the lower respiratory system, from the larynx down

8. The Respiratory Tract Consists of a conducting portion:
from nasal cavity to terminal bronchioles
Consists of a respiratory portion:
the respiratory bronchioles and alveoli - Are air-filled pockets within the lungs
where all gas exchange takes place

9. The Respiratory Epithelium
Figure 23–2

10. Alveolar sac
Alveoli
Figure 23–2

11. The Respiratory Epithelium
For gases to exchange efficiently:
alveoli walls must be very thin (< 1 µm)
surface area must be very great (about 35 times the surface area of the body)

12. The Respiratory Mucosa
Consists of:
an epithelial layer
an areolar layer
Lines conducting portion of respiratory system

13. The Lamina Propria Underlies areolar tissue
In the upper respiratory system, trachea, and bronchi:
contains mucous glands that secrete onto epithelial surface
In the conducting portion of lower respiratory system:
contains smooth muscle cells that encircle lumen of bronchioles

14. How are delicate respiratory exchange surfaces protected from pathogens, debris, and other hazards?

15. The Respiratory Defense System
Consists of a series of filtration mechanisms
Removes particles and pathogens

16. Components of the Respiratory Defense System (1 of 2)
Goblet cells and mucous glands:
produce mucus that bathes exposed surfaces
Cilia:
sweep debris trapped in mucus toward the pharynx (mucus escalator)

17. Components of the Respiratory Defense System (2 of 2)
Filtration in nasal cavity removes large particles
Alveolar macrophages engulf small particles that reach lungs

18. What are the organs of the upper respiratory system and their functions?

19. The Upper Respiratory System
Figure 23–3

20. The Nose Air enters the respiratory system: Nasal hairs:
through nostrils or external nares
into nasal vestibule
Nasal hairs:
are in nasal vestibule
are the first particle filtration system

21. The Nasal Cavity The nasal septum:
divides nasal cavity into left and right
Mucous secretions from paranasal sinus and tears:
clean and moisten the nasal cavity
Superior portion of nasal cavity is the olfactory region:
provides sense of smell

22. Air Flow From vestibule to internal nares:
through superior, middle, and inferior meatuses

23. Meatuses Constricted passageways that produce air turbulence:
warm and humidify incoming air
trap particles

24. The Palates Hard palate: Soft palate: forms floor of nasal cavity
separates nasal and oral cavities
Soft palate:
extends posterior to hard palate
divides superior nasopharynx from lower pharynx

25. The Nasal Mucosa
Warm and humidify inhaled air for arrival at lower respiratory organs
Breathing through mouth bypasses this important step

26. The Pharynx A chamber shared by digestive and respiratory systems
Extends from internal nares to entrances to larynx and esophagus

27. Divisions of the Pharynx
Nasopharynx
Oropharynx
Laryngopharynx

28. The Nasopharynx Superior portion of the pharynx
Contains pharyngeal tonsils and openings to left and right auditory tubes

29. The Oropharynx Middle portion of the pharynx
Communicates with oral cavity

30. The Laryngopharynx Inferior portion of the pharynx
Extends from hyoid bone to entrance to larynx and esophagus

31. What is the structure of the larynx and its role in normal breathing and production of sound?

32. Anatomy of the Larynx
Figure 23–4

33. Cartilages of the Larynx
3 large, unpaired cartilages form the larynx:
the thyroid cartilage
the cricoid cartilage
the epiglottis

34. The Thyroid Cartilage Also called the Adam’s apple
Is a hyaline cartilage
Forms anterior and lateral walls of larynx
Ligaments attach to hyoid bone, epiglottis, and laryngeal cartilages

35. The Cricoid Cartilage Is a hyaline cartilage
Form posterior portion of larynx
Ligaments attach to first tracheal cartilage
Articulates with arytenoid cartilages

36. The Epiglottis Composed of elastic cartilage
Ligaments attach to thyroid cartilage and hyoid bone

37. Cartilage Functions
Prevents entry of food and liquids into respiratory tract
During swallowing:
the larynx is elevated
the epiglottis folds back over glottis
Thyroid and cricoid cartilages support and protect:
the glottis
the entrance to trachea

38. The Glottis
Figure 23–5

39. Sound Production Sound Variation Air passing through glottis:
vibrates vocal folds
produces sound waves
Sound Variation
Sound is varied by:
tension on vocal folds
voluntary muscles (position arytenoid cartilage relative to thyroid cartilage)

40. Speech Is produced by: phonation: articulation:
sound production at the larynx
articulation:
modification of sound by other structures

41. What is the structure of airways outside the lungs?

42. Anatomy of the Trachea
Figure 23–6

43. The Trachea Also called the windpipe
Extends from the cricoid cartilage into mediastinum
where it branches into right and left pulmonary bronchi

44. The Tracheal Cartilages
strengthen and protect airway
discontinuous where trachea contacts esophagus
Ends of each tracheal cartilage are connected by:
an elastic ligament and trachealis muscle

45. The Right Primary Bronchus
The Primary Bronchi
Right and left primary bronchi:
separated by an internal ridge (the carina)
The Right Primary Bronchus
Is larger in diameter than the left
Descends at a steeper angle

46. Structure of Primary Bronchi
Each primary bronchus:
travels to a groove (hilus) along medial surface of the lung
Hilus
Where pulmonary nerves, blood vessels, and lymphatics enter lung
Anchored in meshwork of connective tissue

47. What are the superficial anatomy of the lungs, the structure of a pulmonary lobule, and the functional anatomy of the alveoli?

48. Gross Anatomy of the Lungs
Figure 23–7

49. The Lungs Left and right lungs: The base:
are in left and right pleural cavities
The base:
inferior portion of each lung rests on superior surface of diaphragm

50. The Right Lung Has 3 lobes: superior, middle, and inferior
separated by horizontal and oblique fissures

51. The Left Lung Has 2 lobes: superior and inferior
are separated by an oblique fissure

52. Relationship between Lungs and Heart
Figure 23–8

53. Lung Shape Right lung: Left lung: is wider
is displaced upward by liver
Left lung:
is longer
is displaced leftward by the heart forming the cardiac notch

54. Extrapulmonary Bronchi
The Bronchial Tree
Is formed by the primary bronchi and their branches
Extrapulmonary Bronchi
The left and right bronchi branches outside the lungs
Intrapulmonary Bronchi
Branches within the lungs

55. A Primary Bronchus Branches to form secondary bronchi (lobar bronchi)
1 secondary bronchus goes to each lobe

56. Bronchi and Lobules
Figure 23–9

57. Secondary Bronchi
Branch to form tertiary bronchi, also called the segmental bronchi
Each segmental bronchus:
supplies air to a single bronchopulmonary segment

58. Bronchial Structure
The walls of primary, secondary, and tertiary bronchi:
contain progressively less cartilage and more smooth muscle
increasing muscular effects on airway constriction and resistance

59. Bronchitis Inflammation of bronchial walls:
causes constriction and breathing difficulty

60. The Bronchioles
Figure 23–10

61. Bronchiole Structure Autonomic Control Bronchioles:
have no cartilage
are dominated by smooth muscle
Autonomic Control
Regulates smooth muscle:
controls diameter of bronchioles
controls airflow and resistance in lungs

62. Bronchodilation Bronchoconstriction Asthma
Dilation of bronchial airways
Caused by sympathetic ANS activation
Reduces resistance
Bronchoconstriction
Constricts bronchi
Caused by:
parasympathetic ANS activation
histamine release (allergic reactions)
Asthma
Excessive stimulation and bronchoconstriction
Stimulation severely restricts airflow

63. Trabeculae Pulmonary Lobules
Fibrous connective tissue partitions from root of lung
Contain supportive tissues and lymphatic vessels
Branch repeatedly
Divide lobes into increasingly smaller compartments
Pulmonary Lobules
Are the smallest compartments of the lung
Are divided by the smallest trabecular partitions (interlobular septa)

64. Surfaces of the Lungs Exchange Surfaces
Each terminal bronchiole delivers air to a single pulmonary lobule
Each pulmonary lobule is supplied by pulmonary arteries and veins
Exchange Surfaces
Within the lobule:
each terminal bronchiole branches to form several respiratory bronchioles, where gas exchange takes place

65. The Bronchioles
Each tertiary bronchus branches into multiple bronchioles
Bronchioles branch into terminal bronchioles:
1 tertiary bronchus forms about 6500 terminal bronchioles

66. Alveolar Organization
Figure 23–11

67. Alveolar Organization
Respiratory bronchioles are connected to alveoli along alveolar ducts
Alveolar ducts end at alveolar sacs:
common chambers connected to many individual alveoli

68. An Alveolus Has an extensive network of capillaries
Is surrounded by elastic fibers

69. Alveolar Epithelium Consists of simple squamous epithelium
Consists of thin, delicate Type I cells
Patrolled by alveolar macrophages, also called dust cells
Contains septal cells (Type II cells) that produce surfactant

70. Surfactant Is an oily secretion Contains phospholipids and proteins
Coats alveolar surfaces and reduces surface tension

71. 3 Parts of the Respiratory Membrane
The thin membrane of alveoli where gas exchange takes place
3 Parts of the Respiratory Membrane
Squamous epithelial lining of alveolus
Endothelial cells lining an adjacent capillary
Fused basal laminae between alveolar and endothelial cells

72. Inflammation of Lobules
Also called pneumonia:
causes fluid to leak into alveoli
compromises function of respiratory membrane

73. Pleural Cavities and Pleural Membranes
Figure 23–8

74. Pleural Cavities and Pleural Membranes
are separated by the mediastinum
Each pleural cavity:
holds a lung
is lined with a serous membrane (the pleura)

75. The Pleura Consists of 2 layers: Pleural fluid: parietal pleura
visceral pleura
Pleural fluid:
lubricates space between 2 layers

76. Respiration External Respiration Internal Respiration
Refers to 2 integrated processes:
external respiration
internal respiration
External Respiration
Includes all processes involved in exchanging O2 and CO2 with the environment
Internal Respiration
Also called cellular respiration
Involves the uptake of O2 and production of CO2 within individual cells

77. 3 Processes of External Respiration
Pulmonary ventilation (breathing)
Gas diffusion:
across membranes and capillaries
Transport of O2 and CO2:
between alveolar capillaries
between capillary beds in other tissues

78. Pulmonary Ventilation
What physical principles govern the movement of air into the lungs?
Pulmonary Ventilation
Is the physical movement of air in and out of respiratory tract
Provides alveolar ventilation

79. Gas Pressure and Volume
Figure 23–13

80. Atmospheric Pressure Boyle’s Law The weight of air:
has several important physiological effects
Boyle’s Law
Defines the relationship between gas pressure and volume:
As volume decreases, pressure increases
In a contained gas:
external pressure forces molecules closer together
movement of gas molecules exerts pressure on container

81. Mechanisms of Pulmonary Ventilation
Figure 23–14

82. Respiration Causes volume changes that create changes in pressure
Volume of thoracic cavity changes:
with expansion or contraction of diaphragm or rib cage

83. The Respiratory Muscles
Figure 23–16a, b

84. The Respiratory Muscles
Figure 23–16c, d

85. 3 Muscle Groups of Inhalation
Diaphragm:
contraction draws air into lungs
75% of normal air movement
External intracostal muscles:
assist inhalation
25% of normal air movement
Accessory muscles assist in elevating ribs:
sternocleidomastoid
serratus anterior
pectoralis minor
scalene muscles

86. Changes in Respiratory System at Birth (1 of 5)
Before birth:
pulmonary vessels are collapsed
lungs contain no air
During delivery:
placental connection is lost
blood PO2 falls
PCO2 rises
At birth:
newborn overcomes force of surface tension to inflate bronchial tree and alveoli and take first breath

87. Changes in Respiratory System at Birth (4 of 5)
Large drop in pressure at first breath:
pulls blood into pulmonary circulation
closing foramen ovale and ductus arteriosus
redirecting fetal blood circulation patterns
Subsequent breaths:
fully inflate alveoli

88. Respiratory Performance and Age
Figure 23–28

89. 3 Effects of Aging on the Respiratory System
Elastic tissues deteriorate:
reducing lung compliance
lowering vital capacity
Arthritic changes:
restrict chest movements
limit respiratory minute volume
Emphysema:
affects individuals over age 50
depending on exposure to respiratory irritants (e.g., cigarette smoke)