1. The Respiratory System
Chapter 17
The Respiratory System

2. Anatomy of the Respiratory System and Upper Respiratory Disorders
Lesson 17.1
Anatomy of the Respiratory System and Upper Respiratory Disorders
Discuss the generalized functions of the respiratory system, list the major organs of the respiratory system and describe the function of each, and describe the major disorders of the upper respiratory tract.

3. Structural Plan
Basic plan of respiratory system would be similar to an inverted tree if it were hollow; leaves of the tree would be comparable to alveoli, with the microscopic sacs enclosed by networks of capillaries
Diffusion is the mode for gas exchange that occurs in the respiratory mechanism

4. Structural Plan of the Respiratory Organs

5. The Gas-Exchange Structures of the Lung

6. Respiratory Tracts Upper respiratory tract—nose, pharynx, and larynx
Lower respiratory tract—trachea, bronchial tree, and lungs

7. Respiratory Mucosa
Mucous membrane that lines the air distribution tubes in the respiratory tree
More than 125 ml of mucus produced each day forms a “mucus blanket” over much of the respiratory mucosa
Mucus serves as an air purification mechanism by trapping inspired irritants such as dust and pollen
Cilia on mucosal cells beat in only one direction, moving mucus upward to pharynx for removal

8. Respiratory Mucosa Lining the Trachea

9. Nose
Structure
Nasal septum separates interior of nose into two cavities
Mucous membrane lines nose
Frontal, maxillary, sphenoidal, and ethmoidal sinuses drain into nose
Nasal polyps—noncancerous growths that project from nasal mucosa (associated with chronic hay fever)

10. The Paranasal Sinuses
The paranasal sinuses and the lacrimal sacs drain into the nasal cavity

11. Functions of the Nose Warms and moistens inhaled air
Contains sense organs of smell

12. Structure of the Pharynx
Pharynx (throat) about 12.5 cm (5 inches) long
Divided into nasopharynx, oropharynx, and laryngopharynx
Two nasal cavities, mouth, esophagus, larynx, and auditory tubes all have openings into pharynx

13. Structure of the Pharynx, Cont'd.
Pharyngeal tonsils and openings of auditory tubes open into nasopharynx; other tonsils found in oropharynx
Mucous membrane lines pharynx

14. Sagittal Section of the Head and Neck

15. Functions of the Pharynx
Passageway for food and liquids
Air distribution; passageway for air
Tonsils—masses of lymphoid tissue embedded in pharynx provide immune protection

16. Tonsillitis

17. Structure of the Larynx
Located just below pharynx; also referred to as the voice box
Several pieces of cartilage form framework
Thyroid cartilage (Adam’s apple) is largest
Epiglottis partially covers opening into larynx
Mucous lining
Vocal cords stretch across interior of larynx; space between cords is the glottis

18. The Larynx

19. Functions of the Larynx
Air distribution; passageway for air to move to and from lungs
Voice production

20. Laryngeal Cancer Incidence increases with age and alcohol abuse
Occurs most often in men over age 50
If larynx removed, “esophageal speech” or electric artificial larynx needed for speech

21. Upper Respiratory Infections (URIs)
Rhinitis—nasal inflammation, as in a cold, influenza, or allergy
Infectious rhinitis—common cold
Allergic rhinitis—hay fever
Pharyngitis (sore throat)—inflammation or infection of the pharynx

22. Laryngitis
Inflammation of the larynx resulting from infection or irritation
Epiglottitis—life-threatening condition caused by Haemophilus influenzae type B (Hib) infection
Croup—not life-threatening type of laryngitis caused by parainfluenza viruses producing a barking cough

23. Anatomical Disorders
Deviated septum—septum that is abnormally far from the midsagittal plane (congenital or acquired)
Epistaxis (bloody nose) can result from mechanical injuries to the nose, hypertension, or other factors

24. Trachea
Structure
Tube (windpipe) about 11 cm (4.5 inches) long that extends from larynx into the thoracic cavity
Mucous lining
C-shaped rings of cartilage hold trachea open
Function—passageway for air to move to and from lungs

25. Cross Section of the Trachea

26. Obstruction of the Trachea
Blockage of trachea occludes the airway, and if complete, causes death in minutes
Tracheal obstruction causes more than 4000 deaths annually in the United States
The Heimlich maneuver is a lifesaving technique used to free the trachea of obstructions; also called abdominal thrusts
Tracheostomy—surgical procedure in which a tube is inserted into an incision in the trachea so that a person with a blocked airway can breathe

27. A tracheostomy tube in place
What structure is posterior to the trachea? 27

28. Structure of the Bronchi, Bronchioles, and Alveoli
Trachea branches into right and left bronchi
Right primary bronchus more vertical than left
Aspirated objects most often lodge in right primary bronchus or right lung
Each bronchus branches into smaller and smaller tubes (secondary bronchi), eventually leading to bronchioles
Bronchioles end in clusters of microscopic alveolar sacs, the walls of which are made up of alveoli

29. Alveoli

30. Functions of Bronchi, Bronchioles, and Alveoli
Bronchi and bronchioles—air distribution; passageway for air to move to and from alveoli
Alveoli—exchange of gases between air and blood
Type II cells in the alveoli produce surfactant to help reduce surface tension or "stickiness"

31. Respiratory Distress Relative inability to inflate the alveoli
Infant respiratory distress syndrome (IRDS)—leading cause of death in premature infants resulting from lack of surfactant production in alveoli
Adult respiratory distress syndrome (ARDS)—impairment of surfactant by inhalation of foreign substances or other conditions

32. Structure of the Lungs
Size—large enough to fill the chest cavity, except for middle space occupied by heart and large blood vessels
Apex—narrow upper part of each lung, under collarbone
Base—broad lower part of each lung; rests on diaphragm

33. Lungs

34. Structure of the Pleura
Moist, smooth, slippery membrane that lines chest cavity and covers outer surface of lungs; reduces friction between the lungs and chest wall during breathing

35. Lungs and Pleura

36. Lungs and Pleura Function—breathing (pulmonary ventilation)
Pleurisy—inflammation of the pleura
Atelectasis—incomplete expansion or collapse of the lung (alveoli); can be caused by:
Pneumothorax—presence of air in the pleural space
Hemothorax—presence of blood in the pleural space

37. Pneumothorax

38. Respiration, Gas Exchange & Lower Respiratory Tract Disorders
Lesson 17.2
Respiration, Gas Exchange & Lower Respiratory Tract Disorders
Compare, contrast, and explain the mechanism responsible for the exchange of gases that occurs during internal and external respiration.
Describe the transport of gasses by blood, and list and discuss the volumes of air exchanged during pulmonary ventilation.
Identify and discuss the mechanisms that regulate respiration, and identify breathing patterns.
Identify and describe the major disorders of the lower respiratory tract.

39. Respiration Mechanics of breathing
Pulmonary ventilation includes two phases called inspiration (movement of air into lungs) and expiration (movement of air out of lungs)
Changes in size and shape of thorax cause changes in air pressure within that cavity and in the lungs because as volume changes, pressure changes in the opposite direction
Air moves into or out of lungs because of pressure differences (pressure gradient); air moves from high air pressure toward low air pressure

40. Mechanics of Breathing

41. Inspiration
Active process— muscles increase volume of thorax, decreasing lung pressure, which causes air to move from atmosphere into lungs (down the pressure gradient)
Inspiratory muscles include diaphragm and external intercostals
Diaphragm flattens during inspiration—increases top-to-bottom length of thorax
External intercostals—contraction elevates the ribs and increases the size of the thorax from front to back and from side to side

42. Expiration
Reduction in the size of the thoracic cavity decreases its volume and thus increases its pressure, so air moves down the pressure gradient and leaves the lungs
Quiet expiration ordinarily a passive process
During expiration, thorax returns to its resting size and shape
Elastic recoil of lung tissues aids in expiration

43. Expiration
Expiratory muscles used in forceful expiration are internal intercostals and abdominal muscles
Internal intercostals—contraction depresses the rib cage and decreases the size of the thorax from front to back
Abdominal muscles—contraction elevates the diaphragm, thus decreasing size of the thoracic cavity from top to bottom

44. Exchange of Gases in Lungs
Oxygen moves from alveoli into lung capillaries
Hemoglobin combines with oxygen, producing oxyhemoglobin
Carbaminohemoglobin breaks down into carbon dioxide and hemoglobin
Carbon dioxide moves out of lung capillary blood into alveolar air and out of body in expired air

45. Exchange of Gases in Lungs & Tissue Capillaries

46. Exchange of Gases in Tissues
Oxyhemoglobin breaks down into oxygen and hemoglobin
Oxygen moves out of tissue capillary blood into tissue cells
Carbon dioxide moves from tissue cells into tissue capillary blood
Hemoglobin combines with carbon dioxide, forming carbaminohemoglobin

47. Blood Transportation of Gases
Transport of oxygen
Only small amounts of oxygen (O2) can be dissolved in blood
Most oxygen combines with hemoglobin to form oxyhemoglobin (HbO2) to be carried in blood
Transport of carbon dioxide
Dissolved carbon dioxide (CO2) in plasma—10%
Carbaminohemoglobin (HbCO2)—20%
Dissolved in blood fluids and converted to Bicarbonate ions (HCO3−)—70%
H2O + CO2 <-> H2CO3 <-> H + HCO3-
Water carbon dioxide carbonic acid hydrogen bicarbonate

48. The Process of Respiration
Gas Exchange
Requires a pressure gradient
External respiration (exchange)—between lung alveoli and capillary blood
Oxygen leaves alveoli and enters capillaries.
Carbon dioxide leaves capillaries and enters alveoli.
Internal respiration (exchange)—between blood and tissues
Oxygen leaves capillaries and enters tissue.
Carbon dioxide leaves tissue and enters capillaries.

49. Volumes of Air Exchanged in Pulmonary Ventilation
Volumes of air exchanged in breathing can be measured with a spirometer
Tidal volume (TV)—amount normally breathed in or out with each breath
Vital capacity (VC)—largest amount of air that one can breathe out in one expiration

50. Volumes of Air Exchanged in Pulmonary Ventilation, Cont'd.
Expiratory reserve volume (ERV)—amount of air that can be forcibly exhaled after expiring the tidal volume
Inspiratory reserve volume (IRV)—amount of air that can be forcibly inhaled after a normal inspiration
Residual volume (RV)—air that remains in the lungs after the most forceful expiration

51. Pulmonary Ventilation Volumes

52. Regulation of Respiration
Regulation of respiration permits the body to adjust to varying demands for oxygen supply and carbon dioxide removal
Brainstem—central regulatory centers are called respiratory control centers (inspiratory and expiratory centers)
Medullary centers—under resting conditions the medullary rhythmicity area produces a normal rate and depth of respirations (12 to 18 per minute) The two most important control centers for regulating breathing rhythm in the medulla are
ventral respiratory group (VRG) for basic breathing patterns
dorsal respiratory group (DRG) adjusting breathing with an increase in RR with increase in PH

53. Central Regulatory Centers
Pontine centers—as conditions in the body vary, these centers in the pons can alter the activity of the medullary rhythmicity area, thus adjusting breathing rhythm
Brainstem centers are influenced by information from other parts of the brain and from sensory receptors located in other body areas

54. Regulation of Respiration

55. Regulation of Respiration, Cont'd.
Cerebral cortex—voluntary (but limited) control of respiratory activity
Receptors influencing respiration
Chemoreceptors—respond to changes in carbon dioxide, oxygen, and blood acid levels; located in carotid and aortic bodies
Pulmonary stretch receptors—respond to the stretch in lungs, thus protecting respiratory organs from over inflation

56. Regulation of Respiration (cont.)
Breathing Patterns
Measured in breaths per minute
Adults: 12 to 20
Children: 20 to 40
Infants: more than 40

57. Breathing Patterns Eupnea—normal breathing
Hyperventilation (Tachypnea)
—rapid and deep respirations
Hypoventilation—slow and shallow respirations
Dyspnea—labored or difficult respirations
Orthopnea—dyspnea relieved by moving into an upright or sitting position

58. Breathing Patterns, Cont'd.
Apnea—stopped respiration
Cheyne-Stokes respiration (CSR)—cycles of alternating apnea and hyperventilation associated with critical conditions
Kussmaul respiration— deep rapid respirations seen with acidosis (DKA)
Respiratory arrest—failure to resume breathing after a period of apnea

59. Regulation of Respiration (cont.)
Abnormal Ventilation
Hyperventilation
High oxygen level and low CO2 level (hypocapnia)
Increases blood pH (alkalosis)
Hypoventilation
Insufficient air in alveoli
Decreases blood pH (acidosis)
Results of hypoventilation:
Cyanosis
Hypoxia
Hypoxemia

60. Respiratory Disorders (cont.)
Infection
Common cold
Respiratory syncytial virus (RSV)
Croup
Influenza
Pneumonia
Lobar pneumonia
Bronchopneumonia
Pneumocystis pneumonia
Tuberculosis

61. Pneumonia 61

62. Respiratory Disorders (cont.)
Sudden Infant Death Syndrome (SIDS)
Also called crib death
Unexplained death
Seemingly healthy infant
Under 1-year-old
Usually occurs in sleep

63. Respiratory Disorders (cont.)
Allergic Rhinitis (Hay Fever)
Hypersensitivity to allergens
Watery discharge from eyes and nose
Seasonal or chronic
Asthma
Inflammation of airway tissues
Spasm in bronchial tubes
May be related to hypersensitivity to allergens

64. Respiratory Disorders (cont.)
Chronic Obstructive Pulmonary Disease (COPD)
Includes both chronic bronchitis and emphysema
Normal air flow obstructed
Reduced exchange of oxygen and carbon dioxide
Air trapping and overinflation of lungs
Dyspnea

66. Respiratory Disorders (cont.)
Cancer
Lung cancer
Most common cause of cancer-related deaths.
Most important cause is cigarette smoking.
Cancer of larynx
Linked to cigarette smoking and alcohol consumption
High cure rate

67. Bronchogenic carcinoma.67