1. Respiratory System

2. Respiratory System Functions
Gas exchange: Oxygen enters blood and carbon dioxide leaves
Regulation of blood pH: Altered by changing blood carbon dioxide levels
Voice production: Movement of air past vocal folds makes sound and speech
Olfaction: Smell occurs when airborne molecules drawn into nasal cavity
Protection: Against microorganisms by preventing entry and removing them

3. Respiratory System Divisions
Upper tract
Nose, pharynx and associated structures
Lower tract
Larynx, trachea, bronchi, lungs

4. Nose and Pharynx Common opening for digestive and respiratory systems
Functions
Passageway for air
Cleans the air
Humidifies, warms air
Smell
Along with paranasal sinuses are resonating chambers for speech
Pharynx
Common opening for digestive and respiratory systems
Three regions
Nasopharynx
Oropharynx
Laryngopharynx

5. Larynx Functions Maintain an open passageway for air movement
Epiglottis and vestibular folds prevent swallowed material from moving into larynx
Vocal folds are primary source of sound production

6. Vocal Folds

7. Trachea Windpipe Divides to form Primary bronchi
Insert Fig 23.5 all but b

8. Tracheobronchial Tree

9. Bronchioles and Alveoli

10. Lungs Two lungs: Principal organs of respiration
Right lung: Three lobes
Left lung: Two lobes
Divisions
Lobes, bronchopulmonary segments, lobules

12. LUNG VOLUMES
The total volume contained in the lung at the end of a maximal inspiration is subdivided into volumes and subdivided into capacities
There are four volume subdivisions which:
do not overlap
can not be further divided
when added together equal total lung capacity

14. Capacities
Lung capacities are subdivisions of total volume that include two or more of the 4 basic lung volumes.

15. Basic lung volumes (memorize)
Tidal Volume (TV). The amount of gas inspired or expired with each breath.
Inspiratory Reserve Volume (IRV). Maximum amount of additional air that can be inspired from the end of a normal inspiration.

16. Basic lung volumes (memorize)
Expiratory Reserve Volume (ERV). The maximum volume of additional air that can be expired from the end of a normal expiration.
Residual Volume (RV). The volume of air remaining in the lung after a maximal expiration. This is the only lung volume which cannot be measured with a spirometer.

17. Basic lung capacities (memorize)
Total Lung Capacity (TLC). The volume of air contained in the lungs at the end of a maximal inspiration. Called a capacity because it is the sum of the 4 basic lung volumes. TLC=RV+IRV+TV+ERV

18. Basic lung capacities (memorize)
Vital Capacity (VC). The maximum volume of air that can be forcefully expelled from the lungs following a maximal inspiration. Called a capacity because it is the sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume. VC=IRV+TV+ERV=TLC-RV

19. Basic lung capacities (memorize)
Functional Residual Capacity (FRC). The volume of air remaining in the lung at the end of a normal expiration. Called a capacity because it equals residual volume plus expiratory reserve volume. FRC=RV+ERV

20. Basic lung capacities (memorize)
Inspiratory Capacity (IC). Maximum volume of air that can be inspired from end expiratory position. Called a capacity because it is the sum of tidal volume and inspiratory reserve volume. This capacity is of less clinical significance than the other three. IC=TV+IRV

21. Now you are ready Look at the diaphram: for tenting free air
abnormal elevation
Margins should be sharp
(the right hemidiaphram is usually slightly higher than
the left)

22. Check the Heart Size Shape Silhouette-margins should be sharp
Diameter (>1/2 thoracic diameter is enlarged heart)
Remember: AP views make heart appear larger than it actually is.

23. R Atrium R Ventricle 3. Apex of L Ventricle Superior Vena Cava
Cardiac Silhouette
R Atrium
R Ventricle
3. Apex of L Ventricle
Superior Vena Cava
Inferior Vena Cava
6. Tricuspid Valve
Pulmonary Valve
Pulmonary Trunk
9. R PA L PA

26. Check the costophrenic angles
Margins should
be sharp

27. Loss of Sharp Costophrenic Angles

28. Check the hilar region
The hilar – the large blood vessels going to and from the lung at the root of each lung where it meets the heart.
Check for size and shape of aorta, nodes,enlarged vessels

30. Finally, Check the Lung Fields
Infiltrates
Increased interstitial markings
Masses
Absence of normal margins
Air bronchograms
Increased vascularity

43. Hemothorax

47. Changing Alveolar Volume
Lung recoil
Causes alveoli to collapse resulting from
Elastic recoil and surface tension
Surfactant: Reduces tendency of lungs to collapse
Pleural pressure
Negative pressure can cause alveoli to expand
Pneumothorax is an opening between pleural cavity and air that causes a loss of pleural pressure

48. Pulmonary Volumes Tidal volume Inspiratory reserve volume
Volume of air inspired or expired during a normal inspiration or expiration
Inspiratory reserve volume
Amount of air inspired forcefully after inspiration of normal tidal volume
Expiratory reserve volume
Amount of air forcefully expired after expiration of normal tidal volume
Residual volume
Volume of air remaining in respiratory passages and lungs after the most forceful expiration

49. Pulmonary Capacities Inspiratory capacity Functional residual capacity
Tidal volume plus inspiratory reserve volume
Functional residual capacity
Expiratory reserve volume plus the residual volume
Vital capacity
Sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume
Total lung capacity
Sum of inspiratory and expiratory reserve volumes plus the tidal volume and residual volume

50. Spirometer and Lung Volumes/Capacities

51. Minute and Alveolar Ventilation
Minute ventilation: Total amount of air moved into and out of respiratory system per minute
Respiratory rate or frequency: Number of breaths taken per minute
Anatomic dead space: Part of respiratory system where gas exchange does not take place
Alveolar ventilation: How much air per minute enters the parts of the respiratory system in which gas exchange takes place

52. Physical Principles of Gas Exchange
Partial pressure
The pressure exerted by each type of gas in a mixture
Dalton’s law
Water vapor pressure
Diffusion of gases through liquids
Concentration of a gas in a liquid is determined by its partial pressure and its solubility coefficient
Henry’s law

53. Physical Principles of Gas Exchange
Diffusion of gases through the respiratory membrane
Depends on membrane’s thickness, the diffusion coefficient of gas, surface areas of membrane, partial pressure of gases in alveoli and blood
Relationship between ventilation and pulmonary capillary flow
Increased ventilation or increased pulmonary capillary blood flow increases gas exchange
Physiologic shunt is deoxygenated blood returning from lungs

54. Oxygen and Carbon Dioxide Diffusion Gradients
Moves from alveoli into blood. Blood is almost completely saturated with oxygen when it leaves the capillary
P02 in blood decreases because of mixing with deoxygenated blood
Oxygen moves from tissue capillaries into the tissues
Carbon dioxide
Moves from tissues into tissue capillaries
Moves from pulmonary capillaries into the alveoli

55. Changes in Partial Pressures

56. Hemoglobin and Oxygen Transport
Oxygen is transported by hemoglobin (98.5%) and is dissolved in plasma (1.5%)
Oxygen-hemoglobin dissociation curve shows that hemoglobin is almost completely saturated when P02 is 80 mm Hg or above. At lower partial pressures, the hemoglobin releases oxygen.
A shift of the curve to the left because of an increase in pH, a decrease in carbon dioxide, or a decrease in temperature results in an increase in the ability of hemoglobin to hold oxygen

57. Hemoglobin and Oxygen Transport
A shift of the curve to the right because of a decrease in pH, an increase in carbon dioxide, or an increase in temperature results in a decrease in the ability of hemoglobin to hold oxygen
The substance 2.3-bisphosphoglycerate increases the ability of hemoglobin to release oxygen
Fetal hemoglobin has a higher affinity for oxygen than does maternal

58. Oxygen-Hemoglobin Dissociation Curve at Rest

59. Oxygen-Hemoglobin Dissociation Curve during Exercise

60. Shifting the Curve

61. Transport of Carbon Dioxide
Carbon dioxide is transported as bicarbonate ions (70%) in combination with blood proteins (23%) and in solution with plasma (7%)
Hemoglobin that has released oxygen binds more readily to carbon dioxide than hemoglobin that has oxygen bound to it (Haldane effect)
In tissue capillaries, carbon dioxide combines with water inside RBCs to form carbonic acid which dissociates to form bicarbonate ions and hydrogen ions

62. Transport of Carbon Dioxide
In lung capillaries, bicarbonate ions and hydrogen ions move into RBCs and chloride ions move out. Bicarbonate ions combine with hydrogen ions to form carbonic acid. The carbonic acid is converted to carbon dioxide and water. The carbon dioxide diffuses out of the RBCs.
Increased plasma carbon dioxide lowers blood pH. The respiratory system regulates blood pH by regulating plasma carbon dioxide levels

63. Carbon Dioxide Transport and Chloride Movement

64. Respiratory Areas in Brainstem
Medullary respiratory center
Dorsal groups stimulate the diaphragm
Ventral groups stimulate the intercostal and abdominal muscles
Pontine (pneumotaxic) respiratory group
Involved with switching between inspiration and expiration

65. Respiratory Structures in Brainstem

66. Rhythmic Ventilation Starting inspiration Increasing inspiration
Medullary respiratory center neurons are continuously active
Center receives stimulation from receptors and simulation from parts of brain concerned with voluntary respiratory movements and emotion
Combined input from all sources causes action potentials to stimulate respiratory muscles
Increasing inspiration
More and more neurons are activated
Stopping inspiration
Neurons stimulating also responsible for stopping inspiration and receive input from pontine group and stretch receptors in lungs. Inhibitory neurons activated and relaxation of respiratory muscles results in expiration.

67. Modification of Ventilation
Chemical control
Carbon dioxide is major regulator
Increase or decrease in pH can stimulate chemo- sensitive area, causing a greater rate and depth of respiration
Oxygen levels in blood affect respiration when a 50% or greater decrease from normal levels exists
Cerebral and limbic system
Respiration can be voluntarily controlled and modified by emotions

68. Modifying Respiration

69. Regulation of Blood pH and Gases

70. Herring-Breuer Reflex
Limits the degree of inspiration and prevents overinflation of the lungs
Infants
Reflex plays a role in regulating basic rhythm of breathing and preventing overinflation of lungs
Adults
Reflex important only when tidal volume large as in exercise

71. Ventilation in Exercise
Ventilation increases abruptly
At onset of exercise
Movement of limbs has strong influence
Learned component
Ventilation increases gradually
After immediate increase, gradual increase occurs (4-6 minutes)
Anaerobic threshold is highest level of exercise without causing significant change in blood pH
If exceeded, lactic acid produced by skeletal muscles

72. Effects of Aging
Vital capacity and maximum minute ventilation decrease
Residual volume and dead space increase
Ability to remove mucus from respiratory passageways decreases
Gas exchange across respiratory membrane is reduced