respiratory system

• The diaphragm contracts, causing it to flatten out and move downward into the abdominal cavity.
• Air flows from an area of high pressure (the atmosphere) into an area of low pressure (the lungs), resulting in exhalation.
• As the diaphragm moves downward, the volume of the thoracic cavity increases, decreasing pressure inside the chest.
• During exhalation, the intercostal muscles relax, allowing the rib cage to return to its original position.
• As the diaphragm moves downward, the volume of the thoracic cavity increases, decreasing pressure inside the chest cavity.
• at rest - 12 breaths a minute
• inspiration is active, while expiration is passive
• during exercise - up to 60 breaths per minute
• The external intercostals are responsible for inspiration by pulling up on the ribs during contraction.
• Expiration occurs when the diaphragm relaxes and returns to its dome shape, reducing the size of the thorax and raising airway pressures above atmospheric pressure.
• the lungs are divided into lobes by connective tissue septa (walls)
• The left lung has two lobes: superior and inferior
• The right lung has three lobes: superior, middle, inferior
• The internal intercostals are responsible for both inspiration and expiration by compressing the lungs during contraction.
• The abdominal muscles (external oblique) can be used for forced expiration when needed.
• alveolar macrophages remove debris from the lungs
• pneumocytes are involved in gas exchange between blood and air
• Increased activity of accessory muscles can increase tidal volume (TV) and vital capacity (VC).
• Bronchioles lead to smaller tubules called terminal bronchioles which end at clusters of alveoli
• function: regulating blood pH
• Upper respiratory zone:


  nose, pharynx
• lower respiratory zone: trachea, bronchi, bronchioles, alveoli
• conducting zone: brings air to the site of external respiration and consists of: trachea, bronchi, bronchioles, terminal bronchioles
• Tidal volume (TV) = the volume inspired or expired in a normal cycle of breathing
• Inspiratory Reserve Volume (IRV) = the maximal volume that can be inspired in addition to a tidal inspiration.
• Expiratory Reserve Volume (ERV) = the maximal volume that can be expired in addition to tidal expiration.
• Residual Volume (RV) = the volume remaining in the lungs at the end of a maximal expiration.
• Inspiratory Capacity (IC = TV + IRV) = the maximal volume that can be inspired following a normal expiration.
• Vital Capacity (VC = ERV + TV + IRV) = the maximal volume that can be expired following a maximal inspiration, i.e. the largest possible breath you can make. It is a useful single test of the ability to inflate and deflate the lungs
• Functional Residual Capacity (FRC = RV + ERV) = the volume in the lungs at the end of normal expiration when all the muscles of breathing are relaxed.
• Total Lung Capacity (TLC = RV + ERV + TV + IRV = FRC + IC) = the volume in the lungs at the end of a maximal inspiration.
• Because FRC and TLC include RV, they cannot be measured directly, and like RV, must be estimated i.e. 25% of Vital Capacity.
• Lung Capacity

  
• Peak Expiratory Flow Rate measurements


  peak expiratory flow rate (PEFR) using a standard Clement Clarke International Mini-Wright peak flow meter.
• Forced Expiratory Volume (FEV1) and Forced Vital Capacity (FVC) measurements using a Vitalograph
• Auscultation of breath sounds and heart sounds

  Posterior to the apices at C7 to the bases around T10 and laterally from the axillae down the seventh or eighth rib. Use the side-to-side sequence (left to right, down then right to left, down then left to right etc.)
• Breath sounds:

  Bronchial sounds: loud, high pitch/ around the trachea Bronchovesicular sounds: medium pitch sounds/ 1st and 2nd intercostal space besides the sternum vascular: soft, low pitch sounds/ entirety of lung field

  
• hear three types of normal breath sounds:-

  
• In which areas of the respiratory tract are mucus and ciliated epithelium absent?

  Mucus and ciliated epithelium are absent in the alveoli.
• What does internal respiration refer to?

  refers to the intracellular mechanisms that consume oxygen (O2) and produce carbon dioxide (CO2).

  It involves gas exchange between the vascular compartment and cellular compartment