respiratory system

1. Chapter 13 respiratorysystem

2. Organs of the Respiratory System • Nose • Pharynx • Larynx • Trachea • Bronchi • Lungs—alveoli

3. Functions of the Respiratory System • Gas exchanges between the blood and external environment • Occurs in the alveoli of the lungs • Passageways to the lungs purify, humidify, and warm the incoming air • Helps control the body’s pH

4. The Nose • Only externally visible part of the respiratory system • Air enters the nose through the external nostrils (nares) • Interior of the nose consists of a nasal cavity divided by a nasal septum • Vomer, ethmoid and cartilage

5. Anatomy of the Nasal Cavity • Olfactory receptors are located on the superior surface • Lined with respiratory mucosa • Moistens air • Traps incoming foreign particles

6. Anatomy of the Nasal Cavity • Lateral walls have projections called conchae • Increase surface area • Increase air turbulence within the nasal cavity • The nasal cavity is separated from the oral cavity by the palate • Anterior hard palate (bone) • Posterior soft palate (muscle)

7. Anatomy of the Nasal Cavity Figure 13.2

9. Paranasal Sinuses • Air filled cavities within bones surrounding the nasal cavity • Sinuses are located in the frontal, sphenoid, ethmoid and maxillary bones • Function of the sinuses • Lighten the skull • Act as resonance chambers for speech • Produce mucus that drains into the nasal cavity

10. Paranasal Sinuses Figure 13.2

11. Pharynx (Throat) • Muscular passage from nasal cavity to larynx • Three regions of the pharynx • Nasopharynx—superior region behind nasal cavity • Oropharynx—middle region behind oral cavity • Laryngopharynx—inferior region attached to larynx • The oropharynx and laryngopharynx are common passageways for air and food

12. Pharynx Figure 13.2

13. Larynx • Formed by 8 rigid hyaline cartilages and a flap of elastic cartilage (epiglottis)

14. Larynx • Epiglottis • Protects the superior opening of the larynx • Routes food to the esophagus and air toward the trachea • When swallowing, the epiglottis rises and forms a lid over the opening of the larynx

15. Larynx • Plays a role in speech – voice box • True vocal cords • Vocal folds • Lower folds • Vibrate with expelled air to create sound • Vocalization • False vocal cords • Vestibular folds • Upper cords

16. Trachea (Windpipe) • 4” tube that connects larynx with bronchi • Walls are reinforced with C-shaped hyaline cartilage

17. Hyaline Cartilage

18. Trachea (Windpipe) • Lined with pseudostratified ciliated columnar epithelium • Cilia beat continuously toward pharynx • Removes dust and other debris from lungs

19. Pseudostratified Ciliated Columnar Epithelium

20. Bronchial Tree • Primary bronchi - directs air into lungs • Secondary bronchi - directs air into lobes • Tertiary bronchi – directs air into segments or lobules

21. Bronchial Tree

22. Bronchial Tree • Bronchioles - small muscular tubes • Terminal bronchioles • Respiratory bronchioles

23. Bronchial Tree Divisions • Alveolar ducts • Alveolar sacs

24. Bronchial Tree Divisions • Alveoi • Microscopic air sacs • Simple squamous epithelium • Permits rapid gas exchange

25. Simple Squamous Epithelium

26. Lungs • Soft, spongy, cone-shaped organs • Apex is near the clavicle (superior portion) • Base rests on the diaphragm (inferior portion) • Each lung is divided into lobes by fissures • Left lung—two lobes • Right lung—three lobes

27. Lungs

28. Respiratory Membrane • Pulmonary capillaries cover external surfaces of alveoli • O2 and CO2 must cross respiratory membrane when moving between alveoli and pulmonary capillaries

29. Respiratory Membrane • Three layers • Simple squamous epithelium (alveolar wall) • Fused basement membrane • Capillary epithelium • Air on one side, blood on other side of membrane

30. Respiratory Membrane

31. Gas Exchange • Gas diffuses across respiratory membrane • Oxygen enters the blood • Carbon dioxide enters the alveoli

32. Four Events of Respiration • Pulmonary ventilation—moving air in and out of the lungs (breathing) • External respiration—gas exchange between pulmonary blood and alveoli • Oxygen moves into the blood • Carbon dioxide move from the blood into alveoli

33. Four Events of Respiration • Respiratory gas transport—transport of oxygen and carbon dioxide via the bloodstream • Internal respiration—gas exchange between blood in systemic capillaries and tissue cells

34. Mechanics of Breathing (Pulmonary Ventilation) • Completely mechanical process that depends on volume changes in the thoracic cavity • Volume changes lead to pressure changes • Air flow because of a pressure gradient • Air flow stops when pressures equalized • Again - air flows into or out of lungs due to air pressure gradients

35. Mechanics of Breathing (Pulmonary Ventilation) • Two phases • Inspiration = inhalation • Lung volume increases • Pressure lower in lungs than in atmosphere • Air flows into lungs • Expiration = exhalation • Lung volume decreases • Pressure higher in lungs than in atmosphere • Air flow out of lungs

36. Inspiration • Inspiratory muscles contract • Lung volume increases • Pressure in lungs drops below atmospheric pressure (< 760mmhg) • Air flows into lungs

37. Expiration • Inspiratory muscles relax • Lung volume decreases • Pressure in lungs rises above atmospheric pressure (> 760mmhg) • Air flows out of lungs

38. External Respiration – Alveolar Gas Exchange • O2 diffuses from alveoli into blood of pulmonary capillaries • CO2 diffuses from blood in pulmonary capillaries into alveoli • Blood leaves the lungs high in O2 and low in CO2

39. Gas Transport in the Blood • O2 transport in the blood • Almost all (>98%) O2 transported in blood by hemoglobin (oxyhemoglobin - HbO2) • Small amount is dissolved in plasma

40. Gas Transport in the Blood • CO2 transport in blood • Most is transported in plasma as bicarbonate ion (HCO3–) – 70% • Carbaminohemoglobin (Hb-CO2) – 20% • 10% dissolved in plasma

41. Internal Respiration • Exchange of gases between blood and body cells • CO2 diffuses out of tissue into blood • Hemoglobin releases O2 • O2 diffuses from blood into tissue

42. External Respiration, Gas Transport, and Internal Respiration Figure 13.10

43. Neural Regulation of Respiration • Neural centers that control rate and depth are located in the medulla and pons • Medulla — sets basic rhythm of breathing • Pons — controls respiratory rate

44. Factors Influencing Respiratory Rate and Depth • CO2 levels • Increased levels of CO2 in the blood increases the rate and depth of breathing • O2 levels • Very, very low level of O2 in the blood will stimulate breathing

45. The organ that is directly superior to the trachea is the __________________. • pharynx • larynx • nasal cavity • epiglottis

46. In the lungs ____________________________. • O2 diffuses from blood into alveoli • CO2 can not cross the respiratory membrane • both O2 and CO2 diffuse across the respiratory membrane • the respiratory membrane is composed of alveolar cell, fused basement membrane and a somatic body cell

47. Most oxygen is carried in the blood ______. • dissolved in plasma • as HCO3- • as carbaminohemoglobin • bound to hemoglobin

48. Air flows out of the lungs due to ___________. • increased air pressure in the lungs • increased volume of the lungs • stimulation by CO2 • stimulation of respiratory muscles • decreased lung volume

49. The End!