Respiratory System

1. Respiratory System Anatomy & Physiology II Tony Serino, Ph.D. Biology Department Misericordia University

2. Respiration • External Respiration • The exchange of gas between the blood and external environment (usually includes ventilation) • Internal Respiration • The exchange of gas between the blood and the tissues • Cellular Respiration • Burning of fuel to produce energy within cells • Ventilation (Breathing) • Movement of air in and out of the lungs

3. Respiratory Organs • Divided into: • Upper Respiratory Tract • Includes: nostrils (nares), nasal cavity, and nasopharynx • Lower Respiratory Tract • Includes: larynx, trachea, bronchi, and lungs • Conducting Air passages include: nares to terminal bronchioles • Move air to respiratory membrane • Condition the air • Moisten, Warm, Clean

4. Upper Respiratory Tract

5. Beginning of Lower Respiratory Tract

6. Larynx

7. Trachea

8. Mucous Membrane(pseudostratified columnar epithelium)

9. Bronchi • Primary bronchi lead to to each lung (left and right) • Secondary (lobar) bronchi lead to each lung lobe (3 on right and 2 on left)

10. Tertiary Bronchi Primary Bronchi Secondary Bronchi Bronchi Branches Tertiary (segmental) bronchi lead to each lung broncho-pulmonary segment Bronchi continue to divide at least 20 more times.

11. Broncho-pulmonary Segments

12. Left Lung Right Lung

13. Bronchioles • Air passages less than 1 mm in diameter are bronchioles. • The terminal bronchioles are the last of the purely conducting air passages.

14. Alveoli highly specialized for Gas Exchange • Lots of Surface Area • Highly vascular • Thin walls

15. Alveolus

16. P = pressure to collapse T = surface tension r = radius Role of surfactant is to decrease surface tension in alveoli.

17. Pressures affecting Breathing

19. Inspiration

20. Expiration

21. Pressure changes around lung

22. Only used during rapid breathing.

23. Lung Volumes

24. Normal Lung Volumes

25. Partial Pressure Favors Resp. Gas Movement

26. Time to Complete O2 Saturation in Pulmonary Capillaries

27. O2 PO2 = 100 mmHg PO2 = 100 mmHg Oxygen Content of Blood Whole Blood Plasma Oxygen Oxyhemoglobin Total Volume of Oxygen = 0.3ml Plasma + 20 ml whole blood

28. Hemoglobin

29. Oxyhemoglobin Dissociation Curve

30. Hemoglobin Affinity for Oxygen:Effect of Temperature Affinity decreases with increasing Temperature

31. Hemoglobin Affinity for Oxygen:Effect of pH Affinity decreases with increasing acidity (i pH)

32. Gas Exchange in Lungs

33. Gas Exchange in Tissues

34. Voluntary control located in cerebral cortex and acts through the corticospinal tract.Involuntary located in pons and medulla acting through the spinal cord in the roots of the phrenicnerve (C3-C5) and thoracic cord roots of theexternal (inspriation(I)) and internal (expiration(E)) intercostal nerves Neural Control of Breathing PRG –pontine resp. group (formerly the apneustic and pneumotaxic centers) –play role in smoothing between insp. and exp., especially during sleep, vocalization and exercise.VRG and DRG – ventral and dorsal resp. groupof the medulla. DRG primarily responsible forinspiration; VRG mixture of I and E neurons contains Pre-Botzinger complex which may bepacemaker cells for respiration

35. PRG DRG VRG Neural control of Breathing (smoothing) • Red is inhibitory • Black is excitatory (Insp. center) (Resp. pacemaker?) I neurons E neurons Hering-BreuerReflex Ext. Intercostals& diaphragm Int. Intercostals Lung Stretch Chemoreceptors

37. Medulla sensitive to H+ directly from CSF; indirectly to CO2

38. & ↑CO2 ↑H+

39. Factors Effecting Respiratory Centers

40. CO2 Drive

41. COPD