1. EXTERNAL AND INTERNAL RESPIRATION
PHYSIOLOGY
EXTERNAL AND INTERNAL
RESPIRATION

3. Respiration
Movement of gases between the environment and the body’s cells
The exchange of air between the atmosphere and the lungs
Known as ventilation or breathing
Inspiration and Expiration
The exchanges of O2 and CO2 between the lungs and the blood
Transport of O2 and CO2 by the blood
The exchange of gases between blood and the cells

7. Anatomy of the Respiratory System
Nasal Concha
Air eddies
Air is cleaned
Warmed
Humidified
Tonsils and Adenoids
Lymph nodes that filter the air
Located in the nose, back of the throat, below the tongue

9. Larynx Contains Vocal Cords Thyroid Cartilage
Connective tissue bands that tighten to create sound when air moves past them
Thyroid Cartilage
Sensitive to Testosterone levels

14. Trachea
Conducts Air
Lined with pseudostratified ciliated columnar epithelium
Cilia can be paralyzed by cigarette smoke
Surrounded by C-shaped Cartilagenous rings and the trachealis muscle
Esophagus is dorsal to the trachea
Approximately 4 inches long

16. Conducting System or Respiratory Tree
Primary Bronchi
Surrounded by O-shaped cartilagenous rings
Bifurcates to Secondary Bronchi in the lungs
Respiratory Bronchioles
Surrounded by smooth muscles
Diameter of the airways becomes progressively smaller from the trachea to the bronchioles
The total cross-sectional area increases with each division of the airways

18. Pleural Membranes Visceral Pleura Parietal Pleura Serous Fluid
Attached directly to the lungs
Parietal Pleura
Attaches to the visceral pleura
Also attaches to the thoracic cavity
Serous Fluid
Separates the two pleura and lubricates in order to decrease friction
Consistency of egg whites
Pleurisy occurs when the fluid decreases
The Function of the Pleural Membranes is to hold the lungs open

20. Alveoli Clustered at the ends of the terminal bronchioles
Makes up the bulk of lung tissue
Primary function is the exchange of gases between themselves and the blood
Surrounded by elastic fibers
Creates Elastic Recoil

23. Capillaries
The alveoli are closely associated with an extensive network of capillaries
Blood vessels cover 80-90% of the alveolar surface forming a continuous “sheet” of blood in close contact with the air-filled alveoli

25. Respiratory Membrane Consists of The Wall of the Alveoli
The Respiratory Space
This is a fluid filled space
Pneumonia may cause the space to fill with more fluid than normal
This decreases the ability to exchange gases
The Wall of the Capillary

29. Gas Laws At sea level normal atmospheric pressure is 760mmHg
On top of Mt. Everest Patm = 153mmHg

30. Dalton’s Law
The total pressure exerted by a mixture of gases is the sum of the pressures exerted by the individual gases
78% N2
21% O2
1% CO2
Partial Pressure of gases
The pressure of a single gas in a mixture

31. Gas Law
The total pressure of a mixture of gases, is the sum of the pressures of the individual gases (Dalton’s Law)
Gases, singly or in a mixture, move from areas of higher pressure to areas of lower pressure
If the volume of a container of gas changes, the pressure of the gas will change in an inverse manner (Boyle’s Law)

32. Dalton’s Law
To find the partial pressure of any one gas in a sample of air, multiply the atmospheric Pressure (Patm) by the gas’s relative contribution (%) to Patm.
Partial pressure of an atmospheric gas =
Patm X % of gas in atmosphere
Partial pressure of oxygen = 760mmHg X 21%
PO2 = 760 X 0.21 = 160mmHg

33. Gases Move from High Pressure to Low Pressure
Air flow occurs whenever there is a pressure gradient

34. Alveoli Composed of a single layer of epithelium called Type I cells
Type II alveolar cells
Secretes surfactant
Surfactant decreases the surface tension of the water within the alveoli
Coats the inside of the alveoli
Cortisol causes the maturation of the type II cells in the fetal stage of development
Dust Cells
Phagocytes

38. Emphysema Loss of elastic fibers for elastic recoil during expiration
Elastin is destroyed by elastase
An enzyme released by immune cells
Have more difficulty exhaling than inhaling

39. Chronic Obstructive Pulmonary Disease (COPD)
Asthma, emphysema, chronic bronchitis

41. Pressure Gradients Arterial Pressures Alveolar Pressures
PO2 = 100mmHg
PCO2 = 40mmHg
Alveolar Pressures
Venous Pressures
PO2 = 40mmHg
PCO2 = 45mmHg
Tissue Pressures

42. Hemoglobin Oxygen is transported two ways in the blood
Dissolved in the plasma
Bound to hemoglobin
Mean Corpuscular Hemoglobin
Counting the RBC’s and quantifying the amount of hemoglobin per RBC
Hemoglobin Concentration or %

43. Hemoglobin One hemoglobin molecule binds up to four oxygen molecules
Percent oxygen saturation
Globin
Proteins in the hemoglobin
Alpha, beta, gamma and delta types
Adults have 2 alpha and 2 bets
Fetal Hb
Two gamma and two alpha