1. The Respiratory System

2. General Functions of the System Ventilation (breathing) – the entrance and exit of air into and out of the lungs Ventilation (breathing) – the entrance and exit of air into and out of the lungs External respiration – the exchange of gases (carbon dioxide and oxygen) between the air and blood External respiration – the exchange of gases (carbon dioxide and oxygen) between the air and blood Internal respiration – the exchange of gases between the blood and tissue fluid Internal respiration – the exchange of gases between the blood and tissue fluid Transport – of gases to and from the lungs and the tissues Transport – of gases to and from the lungs and the tissues

3. Anatomy and the flow of air: The Nose / Nasal passages begin to cleanse the air with course hairs inside the nostrils and continue to do so with cilia and mucus in the nasal cavities. The Nose / Nasal passages begin to cleanse the air with course hairs inside the nostrils and continue to do so with cilia and mucus in the nasal cavities. Air warmed by the blood vessels lying close to the surface of the lining of the airways. Air warmed by the blood vessels lying close to the surface of the lining of the airways. Air is moistened by the mucus epithelium that lines most of the air passages. Air is moistened by the mucus epithelium that lines most of the air passages. Conversely, as air leaves the body it deposits its moisture along the way. This can cause the nose to drip and is what is responsible for you being able to see your breathe on a cold day. Conversely, as air leaves the body it deposits its moisture along the way. This can cause the nose to drip and is what is responsible for you being able to see your breathe on a cold day.

4. Nose and Nasal Cavity 2 Nostrils 2 Nostrils 2 Nasal cavities separated by a septum composed of bone and cartilage. 2 Nasal cavities separated by a septum composed of bone and cartilage. Conchae are bony ridges that project out laterally trapping air and increasing surface area for moistening and warming. Conchae are bony ridges that project out laterally trapping air and increasing surface area for moistening and warming. Lacrimal glands (tear) drain into the nasal cavity which is why your nose runs when you cry. Lacrimal glands (tear) drain into the nasal cavity which is why your nose runs when you cry. Nasal cavity is separated from the oral cavity by the hard and soft palate. Nasal cavity is separated from the oral cavity by the hard and soft palate.

5. Pharynx Broken into three parts: nasopharynx, oropharynx, and laryngopharynx. Broken into three parts: nasopharynx, oropharynx, and laryngopharynx. The tonsils form a protective ring around the pharynx – this is lymphatic tissue that protects against the invasion of inhaled pathogens. The tonsils form a protective ring around the pharynx – this is lymphatic tissue that protects against the invasion of inhaled pathogens. It is the junction of air and food passage. The esophagus remains closed by the epiglottis unless a person is swallowing. It is the junction of air and food passage. The esophagus remains closed by the epiglottis unless a person is swallowing.

6. Larynx A cartilaginous structure A cartilaginous structure Contains the Adam’s Apple Contains the Adam’s Apple Called the voice box because it contains the vocal cords. Called the voice box because it contains the vocal cords. The vocal cords are mucosal folds supported by elastic ligaments, and the opening between them is the glottis. The vocal cords are mucosal folds supported by elastic ligaments, and the opening between them is the glottis. When air is expelled past the vocal cords through the glottis the cords vibrate producing sound. The greater the tension on the cords and the narrower the glottis, the higher the pitch. When air is expelled past the vocal cords through the glottis the cords vibrate producing sound. The greater the tension on the cords and the narrower the glottis, the higher the pitch.

7. Trachea Tube with c-rings of cartilage. The open part of the c is facing the esophagus – why do you think this is? Tube with c-rings of cartilage. The open part of the c is facing the esophagus – why do you think this is? Lined with pseudostratified ciliated columnar epithelium. Cilia beat upward moving the particles out of the system. Goblet cells produce mucus to trap debris. Lined with pseudostratified ciliated columnar epithelium. Cilia beat upward moving the particles out of the system. Goblet cells produce mucus to trap debris. Smoking destroys the cilia causing soot from smoking to get caught in the lungs. Smoking destroys the cilia causing soot from smoking to get caught in the lungs.

8. Bronchial Tree Contains the same histology as the trachea. Divides trachea into right and left primary bronchi. Contains the same histology as the trachea. Divides trachea into right and left primary bronchi. Branches into a large number of secondary bronchi that eventually lead to bronchioles – rings of cartilage are no longer present. Branches into a large number of secondary bronchi that eventually lead to bronchioles – rings of cartilage are no longer present. During an asthma attack, the smooth muscle of the bronchioles contracts, causing constriction and wheezing. During an asthma attack, the smooth muscle of the bronchioles contracts, causing constriction and wheezing. Each bronchiole leads to an elongated space enclosed by a bunch of air pockets called alveoli. Each bronchiole leads to an elongated space enclosed by a bunch of air pockets called alveoli.

9. Lungs Paired, cone-shaped structures. Paired, cone-shaped structures. The right lung has 3 lobes and the left, 2. The lobes are divided further into lobules which each have a bronchiole serving many alveolar sacs. The right lung has 3 lobes and the left, 2. The lobes are divided further into lobules which each have a bronchiole serving many alveolar sacs. Diaphragm sits inferiorly to the lungs. Diaphragm sits inferiorly to the lungs. Each lung is enclosed by a pleural sac (serous membrane). Each lung is enclosed by a pleural sac (serous membrane).

10. Alveoli Composed of simple squamous epithelium and is surrounded by capillaries which are also composed of simple squamous. What major function does the structure of simple squamous allow? Composed of simple squamous epithelium and is surrounded by capillaries which are also composed of simple squamous. What major function does the structure of simple squamous allow? Alveoli are covered in surfactant, a lipoprotein that allows them not to collapse under the pressure of water surface tension. Alveoli are covered in surfactant, a lipoprotein that allows them not to collapse under the pressure of water surface tension.

11. Breathing Mechanism Air into the lungs is called inspiration or inhalation. Air leaving the lungs is expiration or exhalation. Air into the lungs is called inspiration or inhalation. Air leaving the lungs is expiration or exhalation. When we are relaxed only a small amount of air moves into and out of the lungs with each breath = tidal volume (about 500ml). When we are relaxed only a small amount of air moves into and out of the lungs with each breath = tidal volume (about 500ml). Deep breathing = vital capacity (max in and max out). Deep breathing = vital capacity (max in and max out). About 70% never reaches the alveoli, it fills the rest of the air passages (dead air space). About 70% never reaches the alveoli, it fills the rest of the air passages (dead air space).

12. Ventilation Things to recall: location of intercostals, location of diaphragm, lungs adhere to thoracic wall because of the pleura, a continuous column of air extends from the pharynx to the alveoli. Things to recall: location of intercostals, location of diaphragm, lungs adhere to thoracic wall because of the pleura, a continuous column of air extends from the pharynx to the alveoli.

13. Inspiration Diaphragm contracts and lowers. Internal intercostals contract and lift the rib cage up and out – this increases the volume of the thoracic cavity. Diaphragm contracts and lowers. Internal intercostals contract and lift the rib cage up and out – this increases the volume of the thoracic cavity. Air pressure in the alveoli decreases due to the above and causes a partial vacuum. Air pressure in the alveoli decreases due to the above and causes a partial vacuum. Difference in alveolar compared to atmospheric pressure allows the lungs to fill. Difference in alveolar compared to atmospheric pressure allows the lungs to fill.

14. Expiration Passive phase – diaphragm and intercostals relax. Passive phase – diaphragm and intercostals relax. The volume of the thoracic cavity decreases to less than the atmospheric pressure allowing the air to leave the alveolar sacs. The volume of the thoracic cavity decreases to less than the atmospheric pressure allowing the air to leave the alveolar sacs.

15. Cough Reflex – dislodge foreign material from the lower respiratory passages. Initiated when the sensory receptors detect substances and initiate action potentials that pass along the vagus nerves to the medulla oblongata. Initiated when the sensory receptors detect substances and initiate action potentials that pass along the vagus nerves to the medulla oblongata. 2.5L of air is inspired  the epiglottis closes  the vestibular folds close tightly to trap the air in the lungs  the abdominal muscles contract to force the abdominal contents up against the diaphragm  the muscles of expiration contract forcefully. 2.5L of air is inspired  the epiglottis closes  the vestibular folds close tightly to trap the air in the lungs  the abdominal muscles contract to force the abdominal contents up against the diaphragm  the muscles of expiration contract forcefully. As a result the pressure in the lungs increases to 100 mm Hg then the vestibular folds and epiglottis open suddenly and air rushes at a high velocity carrying the particles with it. As a result the pressure in the lungs increases to 100 mm Hg then the vestibular folds and epiglottis open suddenly and air rushes at a high velocity carrying the particles with it.

16. Sneeze Reflex – dislodges foreign material from the upper respiratory passages. Similar to cough reflex. Similar to cough reflex. Source of irritation is in the trigeminal nerves in the nasal cavity. Source of irritation is in the trigeminal nerves in the nasal cavity. The uvula and the soft palate are depressed so that air is directed primarily through the nasal passages. The uvula and the soft palate are depressed so that air is directed primarily through the nasal passages.

17. Respiration and Health - URI Many times caused by Streptococcus pyogenes. Many times caused by Streptococcus pyogenes. Sinusitis – caused when nasal congestion blocks the openings between the nasal cavity and the cranial sinuses. Sinusitis – caused when nasal congestion blocks the openings between the nasal cavity and the cranial sinuses. Otitis Media – bacterial infection in the middle ear – spreads from nasal congestion through the eustachian tubes from the nasopharynx to the middle ear. Otitis Media – bacterial infection in the middle ear – spreads from nasal congestion through the eustachian tubes from the nasopharynx to the middle ear. Tonsillitis – occurs when the (lymphatic) tissues in the pharynx become inflammed. Tonsillitis – occurs when the (lymphatic) tissues in the pharynx become inflammed. Laryngitis – infection of the larynx – usually accompanies upper respiratory infection – if it doesn’t it could mean there is cancer in the throat. Laryngitis – infection of the larynx – usually accompanies upper respiratory infection – if it doesn’t it could mean there is cancer in the throat.

18. Respiration and Health - LRI Bronchitis – infection of the primary and secondary bronchi causes inflammation, mucus production, and usually results in coughing. Bronchitis – infection of the primary and secondary bronchi causes inflammation, mucus production, and usually results in coughing. Pneumonia – viral or bacterial infection of the lungs in which the bronchi and alveoli fill with a thick fluid. Pneumonia – viral or bacterial infection of the lungs in which the bronchi and alveoli fill with a thick fluid. Tuberculosis – caused by the bacteria Tubercle bacillus – the bacteria invade the lungs and cause the cells to isolate themselves by building a capsule. Tuberculosis – caused by the bacteria Tubercle bacillus – the bacteria invade the lungs and cause the cells to isolate themselves by building a capsule.

19. Respiration and Health – other respiratory disorders. Restrictive Pulmonary Disorders – vital capacity is reduced due to loss of elasticity (results from a build up in fibrous connective tissue) this is usually a result of inhaling asbestos or fiberglass. Restrictive Pulmonary Disorders – vital capacity is reduced due to loss of elasticity (results from a build up in fibrous connective tissue) this is usually a result of inhaling asbestos or fiberglass. Obstructive Pulmonary Disorders – air does not flow freely in the airways – includes things like chronic bronchitis (airways inflamed and full of mucus – cilia lost), emphysema (alveoli are distended and the area available for gas exchange is reduced), and asthma (disease of the bronchi and bronchioles – exposure to irritants causes spasms in the smooth muscle of the bronchi). Obstructive Pulmonary Disorders – air does not flow freely in the airways – includes things like chronic bronchitis (airways inflamed and full of mucus – cilia lost), emphysema (alveoli are distended and the area available for gas exchange is reduced), and asthma (disease of the bronchi and bronchioles – exposure to irritants causes spasms in the smooth muscle of the bronchi).

20. Lung Cancer Occurs in progressive steps: Occurs in progressive steps: 1 st – thickening and callusing of the cells lining the primary bronchi. 1 st – thickening and callusing of the cells lining the primary bronchi. 2 nd – cells with atypical nuclei appear in the callused lining. 2 nd – cells with atypical nuclei appear in the callused lining. 3 rd – a tumor made of these cells may occur in one area 3 rd – a tumor made of these cells may occur in one area 4 th – some of these cells break loose and penetrate other tissues a process called metastasis. 4 th – some of these cells break loose and penetrate other tissues a process called metastasis. Tumors may continue to grow eventually blocking off the bronchi completely and causing the lung to collapse. Tumors may continue to grow eventually blocking off the bronchi completely and causing the lung to collapse.

21. Aging and the Respiratory System Maximum breathing capacities decline and as a result fatigue increases. Maximum breathing capacities decline and as a result fatigue increases. Weakened intercostal muscles and increased inelasticity of the rib cage reduce the volume that the thoracic cavity can hold. Weakened intercostal muscles and increased inelasticity of the rib cage reduce the volume that the thoracic cavity can hold. Changes in the lungs and capillaries result in less efficient gas exchange. Changes in the lungs and capillaries result in less efficient gas exchange. Risk of contracting respiratory disease increases as the cells of the passages age and lose cilia. Risk of contracting respiratory disease increases as the cells of the passages age and lose cilia.