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![Central Chemoreceptors
• Located in the ventro-lateral surface of the medulla
• sensitive to a increase of [CO2] and H+ ion concentration
in arterial blood and CSF
• Increased CO2 = increased concentration of H+ ions (↓
pH)
• ↓ arterial pH causes the respiratory system to attempt to
restore normal blood pH by…
– ↑ ventilation to decrease CO2 levels
– This results in an increase in pH to normal levels](https://image.slidesharecdn.com/therespiratorysystem250410111254-250603041938-31bcfd7c/75/The-Respiratory-system-_250410_111254-pdf-43-2048.jpg)
The Respiratory system _250410_111254.pdf
- 1. The respiratory system Dr.Rana AWADA
- 2. Nasal cavity Pharynx Esophagus Clavicle UPPER RESPIRATORY SYSTEM LOWER RESPIRATORY SYSTEM RIGH T LUNG Bronchioles Bronchus Trachea Larynx Tongue Nose Ribs Diaphragm LEFT LUNG RIGHT LUNG Structurally,the respiratory system consists of two parts: Structures of the Respiratory System
- 3. Nose External nose –portion visible on face The interior structures of the external nose have three functions: • warming, moistening, and filtering incoming air; • detecting olfactory stimuli; • modifying speech vibrations as they pass through the large, hollow resonating chambers. Internal nose – large cavity beyond nasal vestibule • Internal nares or choanae • Ducts from paranasal sinuses and nasolacrimal ducts open into internal nose • Nasal cavity divided by nasal septum and subdivide cavity into meatuses: Increase surface are and prevents dehydration • Olfactory receptors in olfactory epithelium
- 4. Cilia and mucus Theepithelial surfaces of the airways, from nose to the lungs: Ø contain cilia that transport the mucus to the pharynx Ø Mucus are secreted by the goblet cells Functions: • Mucus is important to keep the lungs clear of particle matter and many bacteria that enter the body on dust particles. • warmed the air moving into body by the heat providing by the presence of the capillaries
- 5. Each lung isenclosed and protected by a double-layered membrane known as the pleural membrane: The visceral pleura: covers the external surface of lung The parietal pleura: covers the wall of the thoracic cavity The pleural cavity: a space between the two layers, contains a lubricating fluid (intrapleural fluid). This pleural fluid reduces friction between the membranes, allowing them to slide easily over one another during breathing. Lungs
- 6. Functionally, the respiratorysystem consists of two parts: 1. Conducting zone – Filter, warm and conducts air to lungs Nose, pharynx, larynx, trachea, bronchi, bronchioles and terminal bronchioles Functions of the Respiratory System
- 7. 2. Respiratory zone– main site of gas exchange between air and blood Respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli Functions of the Respiratory System Alveoli highly important for Gas Exchange
- 8. Dr. Lina SABRA-MAKKE Componentsof Alveolus Lungs receive blood from Pulmonary artery- deoxygenated blood Bronchial arteries – oxygenated blood to perfuse the muscular walls of bronchi and bronchioles
- 9. a) Type Ialveolar cells: • thin epithelial cells •Make up most of the alveolar walls b) Type II alveolar cells: • thick epithelial cells that produce a detergent; Surfactant c) Alveolar macrophages: • phagocytosis and defense The main types of alveolar cells
- 10. Surfactant • Complex mixtureof phospholipids and lipoproteins substance secreted by the type II alveolar cells • Formed at the last week of pregnancy • covers and coats alveolar surface • reduces the tendency of alveoli to collapse
- 11. • In thelungs we have two major cholinergic and adrenergic receptors subtypes: M3 cholinergic and β2 adrenergic receptors • Stimulation of M3 receptors causes bronchoconstriction while the stimulation of β2 receptors causes a bronchodilation. ü Its is useful to note that an asthma is a chronic inflammation of smooth airways and is characterized by an intense broncho- constriction. ü We used an adrenaline to calm this problem. ü Thus, β2- adrenergic drugs (Ventolin: Salbutamol) are used in the treatment of asthma
- 12. Pneumothorax • Pneumo meansair and thorax is the chest cavity. Its is an abnormal collection of air in the pleural cavity. • It occurs when air leaks into the space between your lungs and the chest wall. • This air pushes on the outside of your lungs and makes it collapse. A pneumothorax can be a complete lung collapse or a collapse of only a portion of the lung. • Symptoms usually include sudden chest pain and shortness of breath.
- 13. Pulmonary ventilation The processof gas exchange in the body, called respiration, has three basic steps: 1. Pulmonary ventilation ( pulmon- lung), or breathing, is the inhalation (inflow) and exhalation (outflow) of air and involves the exchange of air between the atmosphere and the alveoli of the lungs. 2. External (pulmonary) respiration is the exchange of gases between the alveoli of the lungs and the blood in pulmonary capillaries across the respiratory membrane. In this process, pulmonary capillary blood gains O2 and loses CO2. 3. Internal (tissue) respiration is the exchange of gases between blood in systemic capillaries and tissue cells. In this step the blood loses O2 and gains CO2. Within cells, the metabolic reactions that consume O2 and give off CO2 during the production of ATP are termed cellular respiration
- 14. Factors Affecting PulmonaryVentilation Lung compliance • Ability of the lungs to be expanded, stretched, or inflated. • Depends on Elasticity of the lung tissue refers to the ability of the lung to inflate easily. Surface Tension • The force of attraction between liquid molecules. • Surfactant reduces the surface tension in the alveoli allowing them to easily expand to twice their size with each breath and it interferes with the attraction between fluid molecules.
- 15. 1. Pulmonary ventilation •2 mechanisms: inspiration (breathing in) and expiration (breathing out) • Boyle’s Law: Volume and pressure are inversely related ↑ volume = ↓ pressure • Air always flows from an area of higher pressure to an area of lower pressure
- 16. Pulmonary Pressures Pressure gradient:The difference between intrapulmonary and atmospheric pressures • Atmospheric pressure: The pressure exerted by the weight of the air in atmosphere (~ 760 mmHg at sea level) • Intra-alveolar (Intrapulmonary) pressure: The pressure inside the lungs • Intrapleural pressure: The pressure inside the pleural space. • Transpulmonary pressure The difference betweenthe intra- alveolar and intrapleural pressures.
- 17. Exhalation Exhalation results fromelastic recoil of the chest wall and lungs, both of which have a natural tendency to spring back after they have been stretched. Exhalation starts when the inspiratory muscles relax. As the diaphragm relaxes, its dome moves superiorly owing to its elasticity. As the external intercostals relax, the ribs are depressed. These movements decrease the vertical, lateral, and anteroposterior diameters of the thoracic cavity, which decreases lung volume. In turn, the alveolar pressure increases to about 762 mmHg. Air then flows from the area of higher pressure in the alveoli to the area of lower pressure in the atmosphere
- 20. Airway resistance • Theflow of air through the airways depends on both the pressure difference and the resistance • Airway resistance is most affected by changes in the diameter of the bronchioles – ↓ diameter of the bronchioles = ↑ airway resistance • During inspiration, the resistance to airflow decreases • During expiration, the resistance to airflow increases
- 21. At rest When lungsare at rest, the pressure on the inside of the lungs is equal to the pressure on the outside of the thorax
- 22. During inspiration The diagramand external intercostals contract Thoracic cavity increases in size and volume of lungs expand Alveolar pressure decreases to 758 mmHG Intrapleural pressure decreases to 754 mmHg Subclavius muscle Forced inhalation
- 23. During exhalation The diaphragmand external intercostals relax Thoracic cavity decreases in size and lungs recoil Alveor pressure increases to 762 mmHg Intrapleural pressure increases to 756 mmHg Forced exhalation
- 24. Spirometry The apparatus usedto measure the volume of air exchanged during breathing is a spirometer or respirometer; the record is called spirogram
- 25. Spirogram of LungVolumes and Capacities
- 26. Lung volumes andcapacities
- 27. Lung Volumes • TidalVolume (VT) – amount of air entering/leaving lungs in a single, “normal” breath – 500 ml at rest • Inspiratory Reserve Volume (IRV) – additional volume of air that can be maximally inspired beyond VT by forced inspiration – 3100 ml. at rest • Expiratory Reserve Volume (ERV) – additional volume of air that can be maximally expired beyond VT by forced expiration – 1200 ml. at rest
- 28. • Residual Volume(RV) – volume of air that remain in the lungs after a forced maximum expiration, keeping the lungs partially inflated – 1200 ml. at rest Lung Volumes
- 29. Lung Capacities Minute ventilation(MV) = total volume of air inhaled and exhaled each minute Normal healthy adult averages 12 breaths per minute moving about 500 ml of air in and out of lungs (tidal volume) MV = 12 breaths/min x 500 ml/ breath = 6 liters/ min Lung capacities are combinations of specific lung volumes. Total Lung Capacity = Inspiratory Reserve Volume (IRV) + Tidal Volume (TV) + Expiratory Reserve Volume (ERV) + Residual Volume (RV)= 4800 mL +1200 mL = 6000 mL in males and 3100 mL+ 1100 mL = 4200 mL in females . Vital Capacity = Inspiratory Reserve Volume (IRV) + Tidal Volume (TV) + Expiratory Reserve Volume (ERV)= 4800 mL in males and 3100 mL in females. Inspiratory Capacity = Inspiratory Reserve Volume (IRV) + Tidal Volume (TV)= 500 mL + 3100 mL = 3600 mL in males and 500 mL +1900 mL =2400 mL in females Functional Residual Capacity = Expiratory Reserve Volume (ERV) + Residual Volume (RV)= 1200 mL + 1200 mL = 2400 mL in males and 1100 mL + 700 mL = 1800 mL in females
- 30. Normal Lung Volumesand capacities
- 31. Minute ventilation The totalvolume of air inspired and expired each minute minute ventilation (ml/min) = tidal volume (L/breath) 0.5 L/ breath x x respiratory rate (breaths/min) 15 cycles/min 7.5 L/min
- 32. Anatomic dead space •In any average adult, about 70 % of the tidal volume actually reaches the respiratory portion of the respiratory system, while 30% remains in air spaces of the conducting portion of the respiratory system. These areas are known as the anatomic dead space (VD) that does not undergo respiratory exchange • Role: Warms and filtered the air
- 33. Alveolar ventilation rate Todetermine how much fresh air enters the alveoli per minute; Alveolar ventilation rate (ml/min) = (tidal volume – anatomic dead space) x respiratory rate 5250 ml/min Tidal volume and anatomic dead space: (ml/breath) Respiratory rate: (breaths/min)
- 34. Neural Control ofBreathing by Motor Neurons • The brainstem generates breathing rhythm • Phrenic nerve – Innervates the diaphragm • Intercostal nerves – Innervate the external and internal intercostal muscles
- 35. Generation of theBreathing Rhythm by the Brainstem • Central control of respiration is not completely understood • Research indicates that respiratory control centers are located in the brainstem • Respiratory control centers include… – Medullary Rhythmicity Area of the medulla oblongata – Pneumotaxic Area of the pons – Apneustic Center of the pons
- 36. Medullary Rhythmicity Area •Includes two groups of neurons: – Dorsal Respiratory Group – Ventral Respiratory Group
- 37. Medullary Rhythmicity Area TheDorsal Respiratory Group • The medullary inspiratory center • Functions in quiet breathing – The respiratory cycle is repeated 12 - 15 times/minute • Quiet breathing - Inhalation – The dorsal inspiratory neurons transmit nerve impulses via the phrenic and intercostal nerves to the diaphragm and external intercostal muscles – When these muscles contract, the lungs fill with air
- 38. Medullary Rhythmicity Area TheVentral Respiratory Group • Inspiration and expiration center • Functions only in forced breathing • The ventral expiratory neurons transmit nerve impulses to the muscles of breathing – Accessory inspiratory muscles – The internal intercostals – The abdominal muscles
- 39.
- 40. Pneumotaxic Area The PontineRespiratory Group • Facilitates the transition between inspiration and expiration •Regulates the frequency of respiration
- 41. External carotid body internal carotid body aortic body Carotid body Medulla oblongata ØPeripheral chemoreceptors Ø Central chemoreceptors
- 42. Peripheral Chemoreceptors • Location: –Carotid and aortic bodies – Connected to medulla by afferent neurons in the glossopharyngeal (N IX) nerve and vagus ( N X) nerve • Chemical concentration of the blood is most important – Changing levels of O2,CO2 and pH of the blood – Sensitive to low arterial O2 concentrations (below 60 mmHg)
- 43. Central Chemoreceptors • Locatedin the ventro-lateral surface of the medulla • sensitive to a increase of [CO2] and H+ ion concentration in arterial blood and CSF • Increased CO2 = increased concentration of H+ ions (↓ pH) • ↓ arterial pH causes the respiratory system to attempt to restore normal blood pH by… – ↑ ventilation to decrease CO2 levels – This results in an increase in pH to normal levels
- 44. Disturbances in Respiration Hypercapnea •An ↑ in the arterial CO2 concentration with a resultant ↓ in pH • This condition stimulates the… – Central chemoreceptors and peripheral chemoreceptors – Medullary respiratory centers • Stimulates an increase in ventilation
- 45.
- 46. Transport of oxygenand carbon dioxide • Blood transports gases between the lungs and body tissue 1) Oxygen transport 2) Carbon dioxide transport
- 47. Oxygen transport • Dissolvedin watery blood plasma (2%) • In chemical combination with hemoglobin inside red blood cells (98%) to form the oxyhemoglobin (HbO2) in a reversible reaction
- 48.
- 49. B) Acidity (pH) ↑H+ ions (↓ pH) = ↓ Hb affinity for O2
- 50. C) Carbon dioxidepressure ↑ arterial PCO2 = ↓ Hb affinity for O2
- 51. D) Temperature ↑ bodytemperature = ↓ Hb affinity for O2
- 52. Carbon dioxide transport ØDissolved in the blood plasma (7%) Ø In chemical combination with carbaminohemoglobin (23%) hemoglobin as Ø Transported in plasma as bicarbonate ions (HCO3-) (70%)
- 53.
- 54. Oxygen in tissuecell Oxygen in lungs
- 55. Carbon Dioxide intissue cell 82
- 56. 83 Chloride Shift • bicarbonateions diffuse out RBCs • chloride ions from plasma diffuse into RBCs • electrical balance is maintained
- 57. Carbon Dioxide inLungs 84