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Bio12 Respiratory System Presentation
- 2. v Major Functions v Gas exchange (external and internal exchange) v Cleanse/Moisten/Warm Air v Inspiration and expiration move air in and out of the lungs during breathing. v Cellular respiration is the final destination where ATP is produced in cells. Introduction
- 4. The Nose v The two nasal cavities are divided by a septum. v They contain olfactory cells, receive tear ducts from eyes, and communicate with sinuses. v The nasal cavities empty into the nasopharynx. v Auditory tubes lead from the middle ears to the nasopharynx.
- 5. The path of air
- 6. The Pharynx v The pharynx (throat) is a passageway from the nasal cavities to oral cavities and to the larynx. v The pharynx contains the tonsils; the respiratory tract assists the immune system in maintaining homeostasis. v The pharynx takes air from the nose to the larynx and takes food from the oral cavity to the esophagus.
- 7. The Larynx v The larynx is a cartilaginous structure lying between the pharynx and the trachea. v The larynx houses the vocal cords. v A flap of tissue called the epiglottis covers the glottis, an opening to the larynx. v In young men, rapid growth of the larynx and vocal cords changes the voice.
- 8. Placement of the vocal cords 15-8
- 9. The Trachea v The trachea, supported by C-shaped cartilaginous rings, is lined by ciliated cells, which sweep impurities up toward the pharynx. v Smoking destroys the cilia. v The trachea takes air to the bronchial tree. v Blockage of the trachea requires an operation called a tracheostomy to form an opening.
- 10. Cilia in the trachea 15-10
- 12. The Bronchial Tree v The trachea divides into right and left primary bronchi which lead into the right and left lungs. v The right and left primary bronchi divide into ever smaller bronchioles to conduct air to the alveoli. v An asthma attack occurs when smooth muscles in the bronchioles constrict and cause wheezing.
- 13. The Lungs v Lungs are paired, cone-shaped organs that lie on either side of the heart and within the thoracic cavity. v The right lung has three lobes, and the left lung has two lobes, allowing for the space occupied by the heart. v The lungs are bounded by the ribs and diaphragm.
- 14. The Alveoli v Alveoli are the tiny air sacs of the lungs made up of squamous epithelium and surrounded by blood capillaries. v Alveoli function in gas exchange, oxygen diffusing into the bloodstream and carbon dioxide diffusing out. v Infant respiratory distress syndrome occurs in premature infants where underdeveloped lungs lack surfactant (thin film of lipoprotein) and collapse.
- 15. Gas exchange in the lungs
- 16. v During breathing, air moves into the lungs during inspiration (inhalation) from the nose or mouth, then moves out again during expiration (exhalation). v A spirometer allows measurement of the components of air during breathing. Mechanism of Breathing
- 17. Respiratory Volumes v Tidal volume (VT) the normal amount of air moved in and out of the lungs when relaxed, is usually 500 ml. v Inspiratory reserve volume is the maximum amount of forcibly inspired air. v Expiratory reserve volume is the maximum amount of forcibly expired air. v Vital capacity is the maximum amount of air moved in and out on deep breathing, and is the sum of tidal, inspiratory reserve, and expiratory reserve volumes. v Air that remains in the lungs is residual volume.
- 18. Vital capacity
- 19. Inspiration and Expiration v There is a continuous column of air from the pharynx to the alveoli, and the lungs lie within the sealed-off thoracic cavity. v The thoracic cavity is bounded by the rib cage and diaphragm. v Pleural membranes line the thoracic cavity and lungs and the intrapleural pressure is lower than atmospheric pressure, keeping the lobules of the lungs from collapsing. v Minute Ventilation – The volume of inhaled and exhaled air in one minute.
- 20. Inspiration v When we inhale (inspiration) impulses from the respiratory center in the medulla oblongata cause the rib cage to rise and the diaphragm to lower, causing the thoracic cavity to expand. v The negative pressure or partial vacuum in the alveoli causes the air to come in. v Changing amounts of blood of H+ and CO2 detected by chemoreceptors in the carotid arteries and aorta increase breathing rate.
- 21. O2 UPTAKE DURING EXERCISE v VO2 - measured in ml/Kg/min v VO2max - maximal oxygen uptake v Metabolic Cart v Predicted VO2max testing v Astrand 6 min. test v Balke Test
- 23. Inspiration
- 24. Expiration v When we exhale (expiration), lack of impulses from the respiratory center allow the rib cage to lower and the diaphragm to resume a dome shape. v Expiration is passive, while inspiration is active. v The elastic recoil of the lungs causes expiration (gravity). v A deep breath causes alveoli to stretch; stretch receptors then inhibit the respiratory center via the vagus nerve.
- 25. Expiration
- 26. Expiration: active v Under extreme conditions, exhalation becomes dynamic. v Internal intercostal muscles contract forcing the ribs down and inward. v Tightening of the abdominal walls also pushes on the viscera which pushes the diaphragm and forces out even more air. v FEV1 – the amount of air forcibly expired in one second. Reduced in patients with COPD
- 27. Spirometry
- 28. v External Respiration v Individual gases exert pressure proportional to their portion of the total in a mixture of gases; this is called “partial pressure” (PO2). (Air - 21% O2, 0.04% CO2) v External respiration is the diffusion of CO2 from pulmonary capillaries into alveolar sacs and O2 from alveolar sacs into pulmonary capillaries. v Most CO2 is carried as bicarbonate ions. v The enzyme carbonic anhydrase, in red blood cells, speeds up the conversion of bicarbonate and H+ to H2O and CO2; CO2 enters alveoli and is exhaled. Gas Exchange
- 30. Hemoglobin Structure v Hemoglobin (Hb) takes up oxygen from alveoli and becomes oxyhemoglobin (HbO2). v 4 globular proteins (globin) & 4 heme units. v (64 000 daltons)
- 31. Internal Respiration v Internal respiration is the diffusion of O2 from systemic capillaries into tissues and CO2 from tissue fluid into systemic capillaries. v Oxyhemoglobin gives up O2, which diffuses out of the blood and into the tissues because the partial pressure of O2 of tissues fluid is lower than that of the blood. v After CO2 diffuses from tissue cells into the blood, it enters red blood cells where a small amount is taken up by hemoglobin, forming carbaminohemoglobin.
- 32. Internal Respiration Cont. v Most of the CO2 combines with water to form carbonic acid (H2CO3), which dissociates to release hydrogen ions (H+) and bicarbonate ions (HCO3 -); the enzyme carbonic anhydrase speeds this reaction. v The globin portion of hemoglobin combines with excess hydrogen ions to become reduced hemoglobin or HHb; this helps maintain a normal blood pH. v Blood leaving capillaries is a dark maroon color because red blood cells contain reduced hemoglobin.
- 33. External and Internal Respiration
- 34. External and Internal Respiration External v Hb + O2 à HbO2 v HbCO2 à Hb + CO2 v H+ + HCO3 - à H2CO3 à CO2 + H2O Internal v HbO2 à Hb + O2 v CO2 + H2O à H2CO3 à H+ + HCO3 - v Hb + CO2 à HbCO2 v H+ + Hb à HHb v HCO3 - dissolves in plasma Chemical Equation Summary
- 36. Respiratory Centre • located in the medulla oblongata • stimulated by the presence of CO2 and H+ ions. • neurons send automatic rhythmic discharge that triggers breathing • the signals travel to the diaphragm and the intercostal muscles via the phrenic nerve.
- 37. v Low O2 in blood registered by carotid and aortic bodies v Communication with respiratory centre v Increase in minute ventilation occurs v Hemoglobin has 200X affinity for CO than O2 Respiratory Centre Cont.
- 38. Hemoglobin Saturation (SO2) v Lungs: 98-100% saturated v Tissues: 60-70% saturated v Conditions affecting Saturation: v Partial Pressure of O2 – incr. é SO2 v pH – incr. pH é SO2 v Temperature – incr. temp ê SO2 v Exercise – increases temperature and decreases pH causing a decrease in arterial oxygen saturation (SaO2)
- 40. v Common Respiratory System Diseases: v Asthma v COPD v Chronic Bronchitis v Emphysema v Pleurisy v Cancer v Influenza v Sinusitis Respiration and Health
- 41. Sites of upper respiratory infections
- 42. Sinusitis v Sinusitis is infection of the cranial sinuses within the facial skeleton that drain into nasal cavities. v It occurs when nasal congestion blocks the sinus openings and is relieved when drainage is restored. v Pain and tenderness over the lower forehead and cheeks, and toothache, accompany this condition.
- 43. Lower respiratory tract disorders
- 44. COPD Chronic Bronchitis v Long-term cough with mucus Emphysema v A breakdown of the alveoli walls. Causes, Risk Factors, Symptoms v Smoking v Exposure to gases and fumes, cooking fire v Cough, Fatigue, many R.T.I, Wheezing
- 45. Asthma v Muscle lining small airways becomes irritated v Causes a narrowing of airway passages v Steroids or bronchodilators can be used to prevent constriction
- 46. Lung Cancer v Lung cancer follows this sequence of events: thickening of airway cells, loss of cilia on the lining, cells with atypical nuclei, tumor development, and finally metastasis. v Removal of a lobe or lung, called pneumonectomy, may remove the cancer. v Smoking, whether active or passive, is a major cause of lung cancer.
- 47. Normal lung versus cancerous lung 15-47
- 48. Chapter Summary v Air passes through a series of tubes before gas exchange takes place across an extensive moist surface in the alveoli of the lungs. v Respiration comprises breathing, external and internal respiration, and cellular respiration. v During inspiration, the pressure in the lungs decreases and air comes rushing in; during expiration, increased pressure in the thoracic cavity causes air to leave the lungs.
- 49. Chapter Summary Cont. v External respiration occurs in the lungs where oxygen diffuses into the blood and carbon dioxide diffuses out of the blood. v Internal respiration occurs in the tissues where oxygen diffuses out of the blood into tissue cells and carbon dioxide diffuses into the blood. v Spirometry is the measurement of lung capacities and can be used to diagnose certain respiratory conditions such as COPD.
- 50. Chapter Summary Cont. v The respiratory pigment hemoglobin transports oxygen from the lungs to the tissues and aids in the transport of carbon dioxide from the tissues to the lungs. v Hemoglobin’s oxygen affinity is affected by pH, temp and PO2 v The respiratory tract is especially subject to disease because it is exposed to infectious agents; also, cigarette smoking contributes to two major lung disorders—emphysema and cancer.