Respiratory System Lecture Notes PDF

# Respiratory System **بسم الله الرحمن الرحيم** Dr. Badr Al-Amir Lecturer of physical therapy for cardiopulmonary disorders and geriatrics **لا إله إلا الله** ## ميثاق المحاضرة 1. Mobile phones are silent. 2. No recording without permission. 3. Mutual respect. 4. No side-talking. 5. Active part...

# Respiratory System **بسم الله الرحمن الرحيم** Dr. Badr Al-Amir Lecturer of physical therapy for cardiopulmonary disorders and geriatrics **لا إله إلا الله** ## ميثاق المحاضرة 1. Mobile phones are silent. 2. No recording without permission. 3. Mutual respect. 4. No side-talking. 5. Active participation. Dr. Badr Al-Amir (Fall 23-24) ## Objectives: By the end of this subject you will be able to: - Identify the surface and functional anatomy of the respiratory system. - Identify the muscles involved in respiration. - Identify the mechanics of respiration. - Recognize the control of respiratory mechanism. Dr. Badr Al-Amir (Fall 23-24) ## Respiration Processes - Breathing (ventilation): Oxygen in to and Carbon Dioxide out of the lungs - External respiration: gas exchange between air in the alveoli and blood in alveolar capillaries - Internal respiration: gas exchange between blood and tissues - Cellular respiration: oxygen used to produce ATP (energy), carbon dioxide is the waste product, **Q**: (Where does this process occur?) Inside the cell Dr. Badr Al-Amir (Fall 23-24) ## External and cellular respiration  Dr. Badr Al-Amir (Fall 23-24) ## External and cellular respiration  Dr. Badr Al-Amir (Fall 23-24) ## Thorax and Chest Wall ### Function: - Breathing - Protection of vital organs - Conduit  Dr. Badr Al-Amir (Fall 23-24) ## Thorax  Dr. Badr Al-Amir (Fall 23-24) ## Chest Wall ### Structure: #### Posteriorly: - Twelve thoracic vertebrae - The intervertebral discs #### Laterally: - Ribs (twelve on each side) - Three layers of flat muscles #### Anteriorly: the sternum which consists of: - The manubrium - Body - Xiphoid process Dr. Badr Al-Amir (Fall 23-24) ## Ribs ### Posteriorly: All ribs articulate with thoracic vertebrae posteriorly. Most ribs (from rib II to IX) have three articulations with the vertebral column. - The head of each rib articulates with the body of its own vertebra - With the body of the vertebra above - With the transverse process of its vertebra.  Dr. Badr Al-Amir (Fall 23-24) ## Ribs ### Anteriorly: - The costal cartilages of ribs 1 to 7 articulate with the sternum. - The costal cartilages of ribs 8 to 10 articulate with the inferior margins of the costal cartilages above them. - Ribs 11 and 12 are called floating ribs. Their costal cartilages are small, only covering their tips.  Dr. Badr Al-Amir (Fall 23-24) ## Pleura - Is the serous sac that surround the lungs - There are two layers of pleura: - Parietal pleura: Lining the inner surface of the cavity. - Visceral pleura: Is adherent to all surfaces of each lung and encloses them. - The pleural cavity: Contains a small amount of serous fluid. It lubricates the pleural surfaces and allows smooth, pain-free movement between them during breathing.  Dr. Badr Al-Amir (Fall 23-24) ## Respiratory tract  Dr. Badr Al-Amir (Fall 23-24) ## Respiratory tract | Conducting zone | Name of branches | Number of tubes in branch | |---|---|---| | Trachea | Trachea | 1 | | Bronchi | Bronchi | 2| | Bronchioles | Bronchioles | 4| | Terminal bronchioles | Terminal bronchioles | 8| | | | 16 | | | | 32 | | | | 6 x 10⁴ | | Respiratory zone | Respiratory bronchioles | 5 x 10⁵ | | | Alveolar ducts | | | | Alveolar sacs | 8 x 10⁶ | Dr. Badr Al-Amir (Fall 23-24) ## Respiratory tract  Dr. Badr Al-Amir (Fall 23-24) ## Respiratory tract | Conducting system | Name | Division | Diameter (mm) | How many? | Cross-sectional area (cm²) | |---|---|---|---|---|---| | | Trachea | 0 | 15-22 | 1 | 2.5 | | | Primary bronchi | 1 | 10-15 | 2 | | | | Smaller bronchi | 2 | | 4 | | | | | 3 | | | | | | | 4 | 1-10 | | | | | | 5 | | | | | | | 6-11 | | 1 x 10⁴ | | | | | | | 2 x 10⁴ | 100 | | | Bronchioles | 1-23 | 0.5-1 | 8 x 10⁷ | 5 x 10³ | | Exchange surface | Alveoli | 24 | 0.3 | 3-6 x 10⁸ | >1 x 10⁶ | Dr. Badr Al-Amir (Fall 23-24) ## Functions of Respiratory system | STRUCTURE | FUNCTION | |---|---| | Nose / nasal cavity | warms, moistens, & filters air as it is inhaled | | Pharynx (throat) | passageway for air, leads to trachea | | Larynx | the voice box, where vocal chords are located | | Trachea (windpipe) | keeps the windpipe "open"; trachea is lined with fine hairs called cilia which filter air before it reaches the lungs | | Bronchi | two branches at the end of the trachea, each lead to a lung | | Bronchioles | a network of smaller branches leading from the bronchi into the lung tissue & ultimately to air sacs | | Alveoli | the functional respiratory units in the lung where gases are exchanged | Dr. Badr Al-Amir (Fall 23-24) ## The respiratory system  Boardworks Ltd 2006 ## The respiratory system  Boardworks Ltd 2006 ## Non-respiratory Functions of Respiratory system 1. **Circulatory**: The breathing movements affect the rates of venous return and lymph flow. 2. **Circulatory**: The venous blood is filtered in the pulmonary capillaries so that no blood clots or other emboli would reach the arterial blood. 3. **Renal**: regulation of acid-base balance, by controlling the rate of CO2. 4. **Execratory function**: more than 250 volatile substances are excreted via respiratory system. 5. **Miscellaneous**: regulation of the body temperature. 6. **Metabolic and Endocrine functions**. Dr. Badr Al-Amir (Fall 23-24) ## The lungs  FIGURE 25.4 Structure of the right and left lungs. Dr. Badr Al-Amir (Fall 23-24) ## The lungs ### Broncho-pulmonary segments - Left and right upper lobes: (1) apical, (2) posterior, (3) anterior, (4) superior lingular, and (5) inferior lingular segments. - Right middle lobe (4) lateral and (5) medial segments. - Lower lobes (6) superior (apical), (7) medial-basal, (8) anterior-basal, (9) lateral-basal, and (10) posterior-basal segments. N.B.: The medial-basal segment (7) is absent in the left lung.  Dr. Badr Al-Amir (Fall 23-24) ## The lungs ### Broncho-pulmonary segments  Dr. Badr Al-Amir (Fall 23-24) ## The lungs | | Right Lung | Left Lung | |---|---|---| | Fissures | Two fissures | One fissure | | Lobes | 3 lobes | 2 lobes | | Segments | Ten segments | Nine-ten segments | | Main bronchus | Wider, shorter and more vertical | Narrower, longer and more angular | | Bronchi | 2 bronchi | 1 bronchus | | Weight | Heavier | Lighter | | Size | Larger, wider and shorter | Smaller and taller | | Cardiac notch | Absent | Present | | Lingula | Absent | Present | Dr. Badr Al-Amir (Fall 23-24) ## Respiratory Muscles  Dr. Badr Al-Amir (Fall 23-24) ## Accessory Muscles  Dr. Badr Al-Amir (Fall 23-24) ## Diaphragm ### Origin: - Costal origin: from the tips of the last six costal cartilages. - Xiphoid origin: two slips from the posterior surface. - Arcuate ligaments (three): Medial, Lateral and Median. - Crura: - Left: from the 1st & 2nd lumbar vertebral bodies. - Right: from the 1st, 2nd & 3rd lumbar vertebral bodies.  Dr. Badr Al-Amir (Fall 23-24) ## Respiratory Muscles ### Intercostal Muscles | Muscle | Superior attachment | Inferior attachment | Innervation | Function | |---|---|---|---|---| | External intercostal | Inferior margin of rib above | Superior margin of rib below | Intercostal nerves; T1-T11 | Most active during inspiration, supports intercostal space; moves ribs superiorly | | Internal intercostal | Lateral edge of costal groove of rib above | Superior margin of rib below, deep to the attachment of the related external intercostal | Intercostal nerves; T1-T11 | Most active during expiration; supports intercostal space; moves ribs inferiorly |  Dr. Badr Al-Amir (Fall 23-24) ## Respiratory muscles ### Inspiration **During forced inspiration**: - **The external intercostals**: raise the rib cage. - **Sternocleidomastoid muscles**: lift upward on the sternum. - **Anterior serrati**: lift many of the ribs. - **Scaleni**: lift the first two ribs.  Dr. Badr Al-Amir (Fall 23-24) ## Respiratory muscles ### Inspiration  FIGURE 3.34 Movement of thoracic wall during breathing. A. Pump handle movement of ribs and sternum. B. Bucket handle movement of ribs Dr. Badr Al-Amir (Fall 23-24) ## Respiratory muscles ### Inspiration  FIGURE 12.6 Alteration in alignment of fibers of the diaphragm due to hyperinflation. Note that the configuration of fibers is more horizontal than vertical and the normal dome shape is minimized. Dr. Badr Al-Amir (Fall 23-24) ## Respiratory muscles ### Expiration  Dr. Badr Al-Amir (Fall 23-24) ## Respiratory muscles ### Expiration **During forced expiration**: - **Abdominal recti**: pulling downward on the lower ribs and compress the abdominal contents upward against the diaphragm. - **Internal intercostals**: pull the rib cage downward. Diaphragm, during inspiration, has a negative pressure which means that the diaphragm needs to be activated for it to work, whereas during expiration, the diaphragm relaxes and has a positive pressure which means that the diaphragm is passively pulled down.  Dr. Badr Al-Amir (Fall 23-24) ## Respiratory Muscles ### Expiration / Inspiration  Dr. Badr Al-Amir (Fall 23-24) ## Respiration Mechanics ### Pleural pressure: - Is the pressure of the fluid in the thin space between the visceral, and parietal pleura. - At rest: there is normally a slight suction, which means a slightly negative pressure. Which is about (-5 cm H2O), to hold the lungs open to their resting level. - During normal inspiration: expansion of the chest cage pulls outward on the lungs with greater force and creates more negative pressure, to an average of about (-7.5 cm H2O). - During expiration: the events are essentially reversed.  Dr. Badr Al-Amir (Fall 23-24) ## Respiration Mechanics ### Alveolar Pressure: - Is the pressure of the air inside the lung alveoli. - When the glottis is open and no air is flowing into or out of the lungs: the pressures in all parts of the respiratory tree, all the way to the alveoli, are equal to atmospheric pressure, 0 cm H2O. - During inspiration: the pressure in the alveoli must fall to a value slightly below atmospheric pressure (below 0). To about -1 cm H2O. - During expiration: opposite pressures occur: The alveolar pressure rises to about +1 cm H2O, and this forces the air out of the lungs  Dr. Badr Al-Amir (Fall 23-24) ## Respiration Mechanics ### Transpulmonary Pressure - Is the difference between the alveolar pressure and the pleural pressure. - It is a measure of the elastic forces in the lungs that tend to collapse the lungs at each instant of respiration, called the recoil pressure  Dr. Badr Al-Amir (Fall 23-24) ## Pneumothorax  Dr. Badr Al-Amir (Fall 23-24) ## Respiration Mechanics ### Lung Compliance & Elastance - Compliance: Is the extent to which the lungs will expand for each unit increase in transpulmonary pressure - High compliance → Stretches easily. - Low compliance → Requires more force. - Elastance: Returning to its resting volume when stretching force is released.  Dr. Badr Al-Amir (Fall 23-24) ## Respiration Mechanics ### Surface Tension When water forms a surface with air, the water molecules on the surface of the water have an especially strong attraction for one another. As a result, the water surface is always attempting to contract. **Surfactant**: Is a mixture containing proteins and phospholipids. A surface active agent in water, it greatly reduces the surface tension of water. To keep the alveoli open. **Law of Laplace**: P = 2T/r - P = pressure - T = surface tension - r = radius According to the law of LaPlace, if two bubbles have the same surface tension, the smaller bubble will have higher pressure  Dr. Badr Al-Amir (Fall 23-24) ## Breathing Control **Simplified diagram of respiratory integration and control, showing the principal efferent (left) and afferent (right) pathways**. The respiratory areas, as well as the central nervous system links to them, are shown using a section through the brain, brain stem, and spinal cord. (From Figure 86-1 in Goldman L, Ausiello D. Cecil Textbook of Medicine. 23rd ed. Philadelphia: Saunders; 2008.)  Dr. Badr Al-Amir (Fall 23-24) ## Breathing Control  Dr. Badr Al-Amir (Fall 23-24) ## Breathing Control  Dr. Badr Al-Amir (Fall 23-24) ## Breathing Control ### Respiratory control center: medulla and pons. ### Respiratory sensors: **A- chemoreceptors**: - **Central (medulla):** respond to increased H+/increased PCO2. - **Peripheral (carotid body, aortic arch):** respond to decreased PO2. **B- Non-chemical regulation**: - **Higher centers**: cerebral cortex, limbic system and hypothalamus - **The respiratory system**: From the lung's stretch receptors, From the irritant receptors, from the (J) receptors and From the chest muscles and ligaments - **Cardiovascular system** - **Musculoskeletal system**  Dr. Badr Al-Amir (Fall 23-24) ## Lecature Activity  Boardworks Ltd 2006 ## References: - Guyton medical physiology 6th ed., 2006 - Gray’s Anatomy for students 3rd ed., 2015 - https://www.youtube.com/watch?v=0fVoz4V75_E - https://www.youtube.com/watch?v=wc2K1Olt4Q8 - https://www.youtube.com/watch?v=rzYFgT97tZw - https://www.youtube.com/watch?v=GD-HPx_ZG81 - https://www.youtube.com/watch?v=9j6BpanhpKY&t=63s - https://www.youtube.com/watch?v=BFDgTci0ck&feature=youtu.be - https://www.youtube.com/watch?v=lVacrVMmJX8 Dr. Badr Al-Amir (Fall 23-24)