1. Respiratory System

2. Respiration Ventilation: Movement of air into and out of lungs
External respiration: Gas exchange between air in lungs and blood
Transport of oxygen and carbon dioxide in the blood
Internal respiration: Gas exchange between the blood and tissues
Cellular Respiration: The use of O2 to produce ATP via Glycolysis, TCA cycle, & ETS

3. Respiratory System Functions
Gas exchange: Oxygen enters blood and carbon dioxide leaves
Regulation of blood pH: Altered by changing blood carbon dioxide levels Carbonic acid Buffer system
Sound production: Movement of air past vocal folds makes sound and speech
Olfaction: Smell occurs when airborne molecules drawn into nasal cavity
Thermoregulation: Heating and cooling of body
Protection: Against microorganisms by preventing entry and removing them

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

5. Nasal Cavity and Pharynx

6. Nasal Cavity and Pharynx

7. Nose and Pharynx Nose Pharynx External nose Nasal cavity
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
Skull-C6
Three regions
Nasopharynx
Oropharynx
Laryngopharynx

8. 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

9. Vocal Folds

10. Trachea Windpipe Divides to form Insert Fig 23.5 all but b
Rt , Lt Primary bronchi
Carina: Cough reflex
Insert Fig 23.5 all but b

11. Tracheobronchial Tree
Non-Acinus -Conducting zone
Trachea to terminal bronchioles which is ciliated for removal of debris, mucus lined
Passageway for air movement controlled by smooth muscle at end of terminal bronchioles
Cartilage holds tube system open and smooth muscle controls tube diameter
Acinus Portion - Respiratory zone
Respiratory bronchioles to alveoli
Site for gas exchange Area the size of a football field

12. Tracheobronchial Tree

13. Bronchioles and Alveoli

14. Alveolus and Respiratory Membrane

15. Lungs Two lungs: Principal organs of respiration Divisions
Right lung: Three lobes, shorter, broader, and has a greater volume.
Left lung: Two lobes, is longer and narrower than the right lung
Divisions
Lobes, bronchopulmonary segments, lobules

16. Lungs
The only point of attachment for each lung is at the hilum, or root, on the medial side. This is where the bronchi, blood vessels, lymphatics, and nerves enter the lungs.
Each lung is enclosed by a double-layered serous membrane, called the pleura. The visceral pleura is firmly attached to the surface of the lung. At the hilum, the visceral pleura is continuous with the parietal pleura that lines the wall of the thorax. The small space between the visceral and parietal pleurae is the pleural cavity. It contains a thin film of serous fluid that is produced by the pleura. The fluid acts as a lubricant to reduce friction as the two layers slide against each other, and it helps to hold the two layers together as the lungs inflate and deflate.

17. Thoracic Walls Muscles of Respiration

18. Thoracic Volume

19. Pleura Pleural fluid produced by pleural membranes Acts as lubricant
Helps hold parietal and visceral pleural membranes together

20. Pressure – Volume Relationships
As vol. , pressure 
As vol. , pressure 
This is given by Boyle’s Law which says:
P1V1 = P2V2
Why does this occur?
Remember, pressure equals force/area
P = Force/Area
So, in this equation as A gets larger P must get smaller.

22. Ventilation
Movement of air into and out of lungs via negative pressure pump mechanism
Air moves from area of higher pressure outside the lung to area of lower pressure created in the thorax and lungs by diaphram
Pressure is inversely related to volume in that as pressure goes down lung volume goes up

23. Inspiration
Begins with the contraction of the diaphragm and the external intercostals
This causes thoracic volume to 
Which causes lung volume to 
Which causes lung pressure to 
Now Palv is <Patm so air will flow down its pressure gradient and enter the lungs.
Inspiration ends when Palv=Patm

24. Inspiration Active process involving the
diaphragm and intercostal muscles

25. 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

26. Quiet expiration is a passive process that is due to the elasticity of the lungs.
Forced expiration is an active process due to contraction of oblique and transverse abdominus muscles, internal intercostals, and the latissimus dorsi.
Expiration

27. Expiration Usually passive Can become active Using internal
intercoastal and
abdominal
muscles

28. Alveolar Pressure Changes

29. Changing Alveolar Volume
Lung recoil
Causes alveoli to collapse resulting from
Elastic recoil and surface tension : Pneumothorax
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

30. Compliance Measure of the ease with which lungs and thorax expand
The greater the compliance, the easier it is for a change in pressure to cause expansion
A lower-than-normal compliance means the lungs and thorax are harder to expand
Conditions that decrease compliance
Pulmonary fibrosis
Pulmonary edema
Respiratory distress syndrome.

31. Alveolar Membrane Surfactant and water layer
Alveolar wall- Simple squamous epithelium
3) Basement membrane of alveolar wall
4) Interstitial space
5) Capillary wall- Simple squamous epithelium
6) Basement membrane of cap wall.

32. Alveolar Capillary Membrane

33. The factors that effect rate of gas exchange
Partial pressure gradients of O2 and CO2
Surface area of alveolar membrane
Thickness of capillary-alveolar membrane
Ventilation- perfusion mismatch

34. 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

35. 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

36. Pulmonary Capacities
Inspiratory capacity is the total amt of air that can be inspired after a tidal expiration:
IC = TV + IRV
Functional residual capacity is the amt of air in the lungs after a tidal expiration:
FRC = ERV + RV
Vital capacity is the total amt of exchangeable air:
VC = TV+IRV+ERV
Total lung capacity is the sum of all lung volumes and is normally around 6L in males:
TLC = VC + RV

37. Spirometer and Lung Volumes/Capacities

38. Lung Capacities Lung Volumes: TV IRV ERV RV Lung Capacities: VC FRC
TLC IC

39. 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

40. 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

41. 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

42. 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.

43. Gas Exchange

45. Changes in Partial Pressures

46. Hemoglobin and 02 Transport
280 million hemoglobin/ RBC.
Each hemoglobin has 4 polypeptide chains and 4 hemes.
Each heme has 1 atom iron that can combine with 1 molecule 02.

47. Hemoglobin Hemoglobin production controlled by erythropoietin.
Production stimulated by P02 delivery to kidneys.
Loading/unloading depends:
P02 of environment.
Affinity between hemoglobin and 02.

48. 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

49. 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

51. Shifting the Curve

52. C02 Transport C02 transported in the blood: HC03- (70%).
Dissolved C02 (10%).
Carbaminohemoglobin (20%).

55. 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

56. 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

57. Carbon Dioxide Transport and Chloride Movement

58. 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

59. Respiratory Structures in Brainstem

60. 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.

61. 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

62. Modifying Respiration

63. Regulation of Blood pH and Gases

64. 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

65. 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

66. 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.

67. Ventilation Patterns
Eupnea - Normal, quiet breathing
Dyspnea - Difficult breathing
Apnea - absence of breathing
Tachypnea - Rapid breathing rate
Bradypnea - Slow breathing
Hyperpnea - Deep breathing
Hypopnea - Shallow breathing
Hyperventilation - Rapid, deep breathing
Cheyne-Stokes breathing - periods of apnea interspersed with hyperpnea