The Respiratory System

1. 24 The Respiratory System

2. Learning Outcomes 24.1 Explain the functions of the respiratory system. 24.2 Explain the difference between internal respiration and external respiration. 24.3 Describe how the larynx produces voice sounds. 24.4 List the structures contained within the lungs. 24.5 Describe the coverings of the lungs and chest cavity.

3. Learning Outcomes (cont.) 24.6 Describe the events that lead to the inspiration and expiration of air. 24.7 Explain how the brain controls breathing and how normal breathing patterns can be disrupted. 24.8 Describe how oxygen is transported from the lungs to body cells.

4. Learning Outcomes (cont.) 24.9 Describe how carbon dioxide is transported from body cells to the lungs. 24.10 List and explain various respiratory volumes and tell how they are used to diagnose respiratory problems. 24.11 Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the respiratory system.

5. Introduction • Function • Move air in and out of lungs (ventilation) • Delivers oxygen (O2) • Removes carbon dioxide (CO2) • External respiration • Occurs in the lungs • Internal respiration • Occurs in the hemoglobin CO2 CO2 O2 Lungs O2 CO2 O2

6. Organs of the Respiratory System • Nose • Pharynx • Larynx • Trachea • Bronchial tree • Lungs

7. Nasal Cavity • Nasal septum divides the cavity into right and left portions • Nares – openings of the nose • Nasal conchae extend from walls of nasal cavity • Mucous membrane warms and moistens the air • Cilia help eliminate particles

8. Air-filled spaces within the skull bones Open into the nasal cavity Reduce the weight of the skull Equalize pressure Give the voice its certain tone Skull bones with sinuses include: Frontal Sphenoid Ethmoid Maxillae bones Paranasal Sinuses

9. Pharynx and Larynx • Pharynx • Serves both the respiratory and digestive systems • Larynx • Also called the “voice box” • Moves air in and out of the trachea and produces voice • Composed of three cartilages: • Thyroid cartilage • Epiglottic cartilage • Cricoid cartilage

10. Posterior Portion of Tongue False Vocal Cords True Vocal Cords Glottis Vocal Cords • Stretched between the thyroid cartilage and the cricoid cartilage • Upper – false cords • Lower – true vocal cords • Glottis – the opening between the vocal cords • Stretch = pitch of voice

11. Trachea • Referred to as the windpipe • Tubular organ made of rings of cartilage and smooth muscle • Extends from the larynx to the bronchi • Lined with cells possessingcilia(microscopic hair-like projections) Trachea Cilia move mucus up to the throat, where it is swallowed. Smoking destroys cilia.

12. Bronchi Bronchioles Bronchioles Bronchial Tree • Bronchi • Primary: First branches off trachea • Secondary • Tertiary • Bronchioles • Branch off tertiary bronchi

13. Bronchial Tree (cont.) • Alveoli • Thin sacs of cells surrounded by capillaries • Secrete surfactant • Fatty substance • Helps maintains the inflation of the alveoli between inspirations

14. Lungs • Cone-shaped organs • Right lung – three lobes • Left lung – two lobes • Pleura – membranes surrounding the lungs The lungs contain connective tissue, the bronchial tree, nerves, lymphatic vessels, and blood vessels.

15. Apply Your Knowledge ANSWER: • Which of the following sites would be the most lethal if obstructed by a foreign body? • Right bronchus • Left bronchus • Trachea SUPER!

16. The Mechanisms of Breathing Inspiration Expiration • Air rich in O2 enters the lungs from the atmosphere • The diaphragm contracts or flattens • The intercostal muscles raise the ribs • Air rich in C02 exits the lungs • The diaphragm relaxes • The intercostal muscles lower the ribs Breathing, or pulmonary ventilation, consists of inspiration (inhalation) and expiration (exhalation).

17. Respiratory center of the brain Medulla oblongata – controls rhythm and depth of breathing Pons – controls the rate of breathing Other factors CO2 levels in the blood pH of the blood Fear and pain Inflation reflex The Mechanisms of Breathing (cont.)

18. The Mechanisms of Breathing (cont.) • Causes of altered breathing patterns • Coughing • Sneezing • Laughing • Crying • Hiccups • Yawning • Speaking

19. Apply Your Knowledge Indicated whether each statement refers to (I) inhalation or (E) exhalation: __ The intercostal muscles lower the ribs __ The diaphragm contracts or flattens __ The intercostal muscles raise the ribs __ The diaphragm relaxes __ Air rich in O2 enters the lungs from the atmosphere __ Air rich in C02 exits the lungs ANSWER: E I BRAVO! I E I E

20. The Transport of Oxygen and Carbon Dioxide in the Blood • Most of the oxygen binds to hemoglobin • Oxyhemoglobin • Bright red in color • Some oxygen remains dissolved in plasma • If CO2 combines with hemoglobin at O2 sites, it forms carboxyhemoglobin

21. The Transport of Oxygen and Carbon Dioxide in the Blood (cont.) • Carbon dioxide gets into the bloodstream • Reacts with water in plasma and forms carbonic acid • Carbonic acid ionizes and releases hydrogen and bicarbonate ions • Bicarbonate ions attach to hemoglobin • Exhaled as waste product in the lungs

22. Apply Your Knowledge Describe what happens to carbon dioxide in the blood. ANSWER: Carbon dioxide can combine with hemoglobin and form carboxyhemoglobin. Most reacts with water in plasma to form carbonic acid. The carbonic acid ionizes and releases hydrogen and bicarbonate ions. The bicarbonate ions then attach to hemoglobin and are exhaled as a waste product from the lungs. Super!

23. Respiratory Volumes • Different volumes of air move in and out of lungs with different intensities of breathing • Measured to assess health of respiratory system

24. Tidal Volume Inspiratory Reserve Volume Expiratory Reserve Volume Respiratory Volumes (cont.) Amount of air that moves in or out of the lungs during a normal breath Amount of air that can be forcefully inhaled following a normal inhalation Amount of air that can be forcefully exhaled following a normal exhalation

25. Residual Volume Total Lung Capacity Vital Capacity Respiratory Volumes (cont.) Volume of air that always remains in the lungs even after a forceful exhalation Amount of air that can be forcefully exhaled after the deepest inhalation possible The total amount of air the lungs can hold

26. Apply Your Knowledge ___ Amount of air that moves during a normal breath ___ Amount of air that always remains in the lungs ___ Total amount of air the lungs can hold ___ Amount of air forcefully exhaled after deepest inhalation possible A. Total lung capacity B. Residual volume C. Tidal volume D. Vital capacity Match the following: ANSWER: C B A D Good Job!

27. Due to vibration of soft tissues when muscles of the palate, tongue, and throat relax Affects approximately 50% of men and 25% of women over the age of 40 Causes daytime sleepiness May be associated with obstructive sleep apnea Common Causes Enlargement of tonsils or adenoids Being overweight Alcohol consumption Nasal congestion Deviated nasal septum Snoring

28. Grade 1 Grade 2 Grade 3 Grade 4 Snoring (cont.) Mayo Clinic’s Sleep Disorders Center rating of snoring: Heard from close proximity Heard from anywhere in the bedroom Heard from just outside the bedroom door with door open Heard outside the bedroom door with the door closed

29. Snoring (cont.) • Lifestyle modifications to reduce snoring • Lose weight • Change sleeping position • Avoid using alcohol or medications that induce sleep • Use nasal strips to widen the nasal passages • Use dental devices to keep airways open • Treatments • CPAP • Surgery (uvulotomy) • Laser surgery

30. Common Diseases and Disorders

31. Common Diseases and Disorders (cont.)

32. Common Diseases and Disorders (cont.)

33. Common Diseases and Disorders (cont.)

34. Common Diseases and Disorders (cont.)

35. Common Diseases and Disorders (cont.)

36. Common Diseases and Disorders (cont.)

37. Apply Your Knowledge ANSWER: The medical assistant working for a general practitioner is taking the medical history of a new patient. The patient states, “Even after sleeping 8 to 9 hours, I still feel really tired.” The patient’s spouse states, “Well, you sure snore loud, as if the sleep is so good.” Which of the following is a possible cause for the excessive fatigue? Correct! • Sleep apnea • Depression • Tuberculosis

38. In Summary 24.1 The function of the respiratory system is to move air in and out of the lungs in a process known as ventilation, respiration, or breathing. 24.2 The exchange of oxygen and carbon dioxide in the lungs is called external respiration. The same exchange within the hemoglobin of red blood cells is internal respiration. 24.3 The larynx contains the vocal cords, which stretch between the thyroid and cricoid cartilages. The muscles of the lower (true) vocal cords stretch and relax them to produce different sounds.

39. In Summary (cont.) 24.4 The lungs contain connective tissue, the bronchial tree, nerves, lymphatic vessels, and blood vessels. The left lung consists of two lobes (upper and lower), and the right lung consists of three lobes (upper, middle, and lower). Within each lung are the primary, secondary, and tertiary branches of the bronchi, the bronchioles, and the alveoli. 24.5 The lungs are covered by, and the chest cavity is lined with, the pleura. The outer membrane is the parietal pleura and the inner membrane is the visceral pleura.

40. In Summary (cont.) 24.6 During inspiration, the diaphragm contracts and the intercostal muscles raise the ribs, increasing the space in the thoracic cavity. This decreases the pressure within the cavity so that the air outside the body passively flows into the thoracic cavity. During expiration, the diaphragm relaxes, pushing up into the thoracic cavity, and the intercostal muscles lower the ribs, forcing the air to flow out of the body.

41. In Summary (cont.) 24.7 Breathing is controlled by the respiratory center of the brain located in the pons and medulla oblongata. Carbon dioxide levels and pH levels of the blood also affect breathing. Everyday situations such as coughing, sneezing, laughing, crying, hiccups, yawning, and speaking also alter breathing patterns. 24.8 Most of the oxygen in the bloodstream binds to the hemoglobin within red blood cells, resulting in oxyhemoglobin, although a small amount does not bind to hemoglobin and remains dissolved in the plasma.

42. 24.9 Carbon dioxide binds to hemoglobin, resulting in carboxyhemoglobin. Most of the carbon dioxide that enters the body reacts with water in blood and cerebral spinal fluid to form carbonic acid. As carbonic acid ionizes, it releases hydrogen and bicarbonate ions, which attach to hemoglobin making its way back to the lungs to be exhaled. In Summary (cont.)

43. In Summary (cont.) 24.10 Respiratory volumes are measured to check the health of the respiratory system. The volumes are listed here and the normal capacities are found in the chapter: tidal volume, inspiratory and expiratory reserve volumes, residual volume, inspiratory capacity, functional residual capacity, vital capacity, and total lung capacity.

44. In Summary (cont.) 24.11 The diseases and disorders of the respiratory system are many and varied, as are the causes and treatments of these diseases. Many of the more common respiratory disorders, with their individual causes and treatments, are discussed in detail in the Pathophysiology section of this chapter.

45. End of Chapter 24 The air of ideas is the only air worth breathing. ~Edith Wharton