respiratory system

• What is the primary function of the respiratory system?


  Regulation of blood pH
• What are the components of the upper respiratory tract?


  Nasal cavity, pharynx, paranasal sinus, and portion of the larynx above the vocal cords
• How does the nose contribute to the respiratory system?

  The nose opens at the nares leading to the nasal cavities, which are narrow canals separated by a septum
• What is the function of the pharynx in the respiratory system?


  The pharynx connects the nasal and oral cavities to the larynx
• What are the three parts of the pharynx?


  • Nasopharynx: Where the nasal cavities open above the soft palate
  • Oropharynx: Where the oral cavity opens
  • Laryngopharynx: Which opens into the larynx
• What role do paranasal sinuses play in the respiratory system?


  They act as resonance chambers amplifying vocal sounds
• What happens during an allergic response in the paranasal sinuses?


  Histamine is released, causing vasodilation and swelling of the sinuses
• What is the larynx commonly known as?

  The voice box
• What is the function of the epiglottis during swallowing?


  It prevents food from entering the larynx
• What structures are included in the lower respiratory tract?


  Larynx below the vocal cords, trachea, bronchi, bronchioles, and lungs
• What is the structure of the trachea?


  The trachea has walls made of connective tissue and smooth muscle reinforced by C-shaped cartilaginous rings
• How does the trachea relate to the esophagus?


  The trachea lies ventral to the esophagus, allowing it to expand during swallowing
• Describe the bronchial tree structure.


  • The trachea divides into right and left primary bronchi
  • Primary bronchi lead into the right and left lungs
  • Bronchi further divide into secondary bronchi
  • Secondary bronchi branch into smaller bronchioles

  
• What are alveoli responsible for?


  Gas exchange in the respiratory system
• How does gas exchange occur in the alveoli?


  Oxygen diffuses into the bloodstream while carbon dioxide diffuses into the alveoli
• What is the role of surfactant in the alveoli?


  It prevents the alveoli from collapsing during exhalation
• What is the primary role of the pleural membrane?


  • Holds lung tissue against the ribcage
  • Facilitates inspiration and expiration
  • Composed of visceral and parietal membranes
  • Contains pleural cavity filled with pleural fluid

  
• How many lobes does the right lung have?


  Three lobes
• What is the diaphragm's role in respiration?


  It is the primary muscle responsible for breathing
• What happens to the diaphragm during inhalation?


  The diaphragm contracts and flattens, creating a vacuum that pulls air into the lungs
• What is pulmonary ventilation?


  • The process of air flowing into the lungs during inspiration
  • Air flowing out of the lungs during expiration
  • Governed by pressure gradients produced by diaphragm and thoracic muscles

  
• What is the relationship between atmospheric pressure and pulmonary ventilation?


  Air flows from higher pressure to lower pressure during ventilation
• What are the three different pressures involved in pulmonary ventilation?


  • Atmospheric pressure
  • Intra alveolar (intrapulmonary) pressure
  • Intrapleural pressure
• Describe the process of inspiration.


  1. Inspiratory muscles contract (diaphragm descends; rib cage rises)
  2. Thoracic cavity volume increases
  3. Lungs are stretched; intrapulmonary volume increases
  4. Intrapulmonary pressure drops (to -1 mm Hg)
  5. Air flows into lungs until intrapulmonary pressure is 0

  
• Describe the process of expiration.


  1. Inspiratory muscles relax (diaphragm rises; rib cage descends)
  2. Thoracic cavity volume decreases
  3. Elastic lungs recoil passively; intrapulmonary volume decreases
  4. Intrapulmonary pressure rises (to +1 mm Hg)
  5. Air flows out of lungs until intrapulmonary pressure is 0

  
• What factors affect airflow in the respiratory system?


  • Surface tension of alveolar fluid
  • Lung compliance
  • Airway resistance
• How does surfactant affect surface tension in the alveoli?


  Surfactant reduces surface tension by breaking hydrogen bonds between water molecules
• What is lung compliance?


  It is the ease of lung and chest wall expansion
• What happens during bronchoconstriction?


  The bronchioles narrow, reducing airflow
• What triggers bronchodilation?


  The sympathetic nervous system and the release of adrenaline
• What is gas exchange?


  • The process by which oxygen and carbon dioxide move between the bloodstream and the lungs
  • Governed by passive diffusion
• What are Dalton’s and Henry’s laws in relation to gas exchange?


  • Dalton’s law: Total pressure of a gas mixture is the sum of the partial pressures of individual gases
  • Henry’s law: Amount of gas that dissolves in water is determined by its solubility and partial pressure in air

  
• What is the role of red blood cells in oxygen transport?


  They transport most oxygen molecules from the lungs to tissues
• How is carbon dioxide transported in the blood?


  7% is dissolved in plasma, 23% forms carbamino-haemoglobin, and 70% is transported as bicarbonate ions
• What factors affect the affinity of hemoglobin for oxygen?


  • Partial pressure of CO2
  • pH levels
  • Concentration of 2,3-DPG
  • Presence of unusual hemoglobin species
  • Temperature
• What is the role of chemoreceptors in respiration?


  • Stimulated by changes in chemical composition
  • Central chemoreceptors respond to pH changes in the CSF
  • Peripheral chemoreceptors monitor blood O2, CO2, and pH
• What is respiratory acidosis?


  • Increase in CO2 levels leading to decreased blood pH
  • Caused by conditions impairing CO2 elimination
  • Compensatory response involves kidneys excreting more H+ and reabsorbing bicarbonate

  
• What is respiratory alkalosis?


  • Decrease in CO2 levels leading to increased blood pH
  • Commonly caused by hyperventilation
  • Compensatory response involves kidneys reabsorbing fewer H+ and reducing bicarbonate reabsorption