compendium 4

• What are the 5 functions of the respiratory system?

  1. Respiration

  a. Ventilation - Movement of air in and out of lungs

  b. External respiration - Gas exchange between lungs and blood

  c. Transport of respiratory gases

  d. Internal respiration - Gas exchange between blood and tissues

  
  

  2. Regulation of blood pH

  
  

  3. Voice production

  
  

  4. Smell (olfaction)

  
  

  5. Protection
• What are the 2 divisions of the respiratory system?

  1. Structural classification

  o Upper respiratory tract - Has only CZ

  o Lower respiratory tract - Has CZ and RZ

  2. Functional classification

  o Conducting zone (anatomical dead space) = passages that conduct air (to the)

  o Respiratory zone = gas exchange regions of the distal airways
• Describe the Structure of the nasal cavity

  1. Vestibule - entry to nasal cavity

  (Stratified squamous epithelium, sweat and sebaceous glands and hair follicles)

  
  

  2. Hard Palate - Floor of nasal cavity (bone)

  
  

  3. Septum - Separates nasal cavity into left and right parts (carriage and bone)

  
  

  4. Concha - Bony ridges in nasal cavity (Pseudostratified ciliated columnar)
• What are the 5 functions of the Nasal Cavity

  · Passageway for air

  · Cleans the air

  · Humidifies and warms the air

  o via warm blood flowing through nasal cavity

  o via moisture from mucous epithelium and excess tears which drain into nasal cavity

  · Olfaction (or smell)

  · Sound of your voice
• What are the 3 regions of the pharynx and their epithelium and tonsil?

  1. Nasopharynx - Pseudostratified cililated columnar epithelium; pharyngeal tonsils

  2. Oropharynx - Stratified squamous epithelium; Palatine and Lingual tonsils

  3. Laryngopharynx - Stratified squamous epithelium
• What is the structure of the Larynx?

  Made up of 9 cartilage

  o 6 paired (Arytenoid, Corniculate, Cuneiform)

  o 3 unpaired (Thyroid (Adam's apple), Cricoid, Epiglottis)
• What are the 4 functions of the larynx?

  · Maintains an open passageway for air movement

  · Directs food into the oesophagus away from respiratory tract

  · Sound production via vocal folds

  · Trap debris from entering lungs
• What is the structure of the trachea?

  · Has 15-20 'C-shaped' hyaline cartilage rings for support

  · Dense connective tissue and smooth muscle in between cartilage rings

  · Tracheal lumen lined with pseudostratified ciliated columnar epithelium with goblet cells (mucous producing)
• What is the Tracheobronchial Tree?


  Branching structures of the respiratory system that resemble an upside-down tree trunk and its branches; includes trachea, bronchi, and bronchioles.
• Describe the structure of the Tracheobronchial Tree

  · Increase in smooth muscle and Decrease in cartilage

  · Carina

  · Primary bronchus sub divides into the secondary (lobar) bronchus

  · 3 secondary Lobar bronchi in right lung and 2 in the left

  · Secondary bronchi are divided into tertiary bronchi

  · Lobes can be divided into segments called the bronchopulmonary segments (9 in the RL and 8 in the LL) - in this unit remember 10 in each

  · Tertiary bronchi divide into bronchioles

  · Change in epithelium in lumen from pseudostratified ciliated columnar to simple ciliated columnar to simple ciliated cuboidal.
• What is the Carina?

  Where the trachea divides into 2 bronchi (largest ring of cartilage)
• Structure of the Alveoli on the respiratory membrane

  Simple squamous epithelium - allow for easy diffusion of gases. Contains:

  - Type 1 pneumocyte

  for Gas exchange = simple diffusion

  - Type 2 pneumocytes

  which is a Cuboidal cell and Secretes a surfactant to reduce surface tension

  - Macrophages

  
  

  Basement Membrane
• Structure of capillaries on the respiratory membrane.

  · Basement Membrane

  · Capillary endothelium (simple squamous)

  · Red Blood cells
• Describe Gas Exchange in the Alveoli in relation to the structure of the respiratory membrane

  Alveolus contains air (O2) that is inhaled. This is lined with alveoli epithelium (simple squamous) allowing easy diffusion of O2 and CO2. The epithelium sits on a BM beside an interstitial space. On the other side of the interstitial space is a blood capillary. All blood vessels are lined with epithelial cells (simple squamous).
• shape of lungs

  · Cone shaped with a base and apex

  · Left lung has 2 lobes + cardiac notch

  · Right lung has 3 lobes

  · Lobes separated by fissures

  · Hilum (hi-lum) on medial surface = Bronchopulmonary segments (10 in L and R Lungs)
• Hilum of the Lung

  Entry point for blood and nervous supply, lymphatic vessels and bronchi
• Describe the Respiratory Epithelium

  The inner lining of the trachea and bronchi contain cells that have small extensions called cilia that can move in a sweeping motion (as in the nasal cavity). Additionally, there are many goblet cells that secrete mucous, which traps unwanted particles before they reach the lungs. The cilia sweep the mucous back up the respiratory tract towards the oropharynx to be swallowed. Gas exchange is NOT happening here.
• What is the serous membrane in the thoracic cavity and its function?

  Pleura.

  
  

  - Acts as a lubricant, allowing the parietal and visceral pleura to slide past each other as the lungs and thoracic wall move during ventilation

  - Helps hold the parietal and visceral pleura together; which means the lungs are adhered to the thoracic wall. This means when the chest expands (e.g. when we breathe in) the lungs are pulled out and expand as well.
• What structures are part of the conducting zone?

  Nasal cavity, pharynx, larynx, trachea, primary bronchus, secondary bronchus, tertiary bronchus, bronchiole, terminal bronchiole
• What structures are part of the respiratory zone?

  Respiratory bronchiole, alveolar duct, alveolar sac, alveoli
• What is the correct epithelium to the following structures?

  1. Vestibule

  2. Nasal Cavity

  3. Nasopharynx

  4. Oropharynx

  5. Laryngopharynx

  6. Trachea

  7. Alveoli

  1. stratified squamous epithelium

  2. pseudostratified ciliated columnar epithelium

  3. pseudostratified ciliated columnar epithelium

  4. stratified squamous epithelium

  5. stratified squamous epithelium

  6. pseudostratified ciliated columnar epithelium (with goblet cells)

  7. simple squamous epithelium
• The 4 factors affecting gas exchange through the respiratory membrane

  1. Thickness of the RM

  2. Surface Area

  3. Diffusion Coefficient - how easily a gas can diffuse in and out of a liquid or tissue

  4. Partial Pressure - pressure exerted by each gas in a mixture of gases
• Describe partial pressure


  1. pressure exerted by each gas in a mixture of gases

  a. When the partial pressure (Pp) of a gas is greater on one side of the respiratory membrane compared to the other side, the gas moves from the side with the higher Pp to the side with the lower Pp
• How is Oxygen and Carbon Dioxide transported

  O2 - RBC (haemoglobin) or dissolved in plasma

  
  

  CO2 - HCO3- dissolved in plasma, CO2 dissolved in plasma or Bound to haemoglobin
• Explain partial pressure in gas transport.

  When air is inspired the partial pressure decreases from 160 millimetres of mercury to 104 mm of Hg. As the oxygen moves throughout the blood the partial pressure reduces to 95 mm Hg.

  As the oxygen crosses the interstitial space, the partial pressure decreases to 40mm Hg and once it reaches the tissues it becomes 20mm Hg.

  Once oxygen is used, unoxygenated blood travels back towards the alveoli crossing the interstitial fluid with a partial pressure of 45mm Hg and then crossing the respiratory membrane with a partial pressure of 40mm Hg. Then expired with a partial pressure of 27 mm Hg.
• Gas exchange occurs between....?

  1. The lung alveolus and a pulmonary capillary

  a. This is where the blood becomes oxygenated

  
  

  2. A general body cell and capillary

  a. Cells are supplied with oxygen and carbon dioxide is removed from the cellular environment
• What type of transport is used to exchange O2 and C02.

  Passive diffusion, which means they move from an area of higher concentration to an area of lower concentration (down the concentration gradient)
• What is Pulmonary Ventilation and the structures involved?

  Process of moving air into and out of the lungs

  
  

  · Lungs

  · Diaphragm

  · Rib cage

  · Sternum

  · Intercostal muscles
• What is Boyle's Law?

  Volume is inversely proportional to pressure (opposite)

  
  

  o Eg. If the volume of the container is larger the pressure is lower
• According to Boyles Law, what happens when you inspire and expire? (Volume Vs Pressure)

  · When you inspire, the volume in the alveoli increases and the pressure decreases.

  
  

  · When you expire, the volume in the alveoli decreases and the pressure increases.
• What is Barometric Air Pressure (PB) and Intra-alveolar pressure (Palv).

  1. Atmospheric air pressure outside the body

  
  

  2. Pressure inside the alveoli

  
  

  PB is normally 760 mm Hg so will be equal to 0 mm Hg
• Describe how surfactant and pleural pressure prevent lung collapsing.

  Surfactant reduces surface tension in the alveoli. If absent, alveoli would collapse.

  
  

  Intrapleural pressure < intraalveolar pressure = Visceral pleura adhering to parietal pleura (like 2 wet plastic films)
• Describe the path air takes as it moves into and out of the lungs?

  Nose - nasal cavity - pharynx - larynx - trachea - L/R primary bronchus - lobar bronchus - tertiary bronchus - bronchioles - terminal bronchiole - respiratory bronchiole - alveoli.
• How does the respiratory tract protect the lungs from dust and pathogens?

  Ciliated epithelium. Cilia moves dust and pathogens out of the respiratory tract. Mucus producing goblet cells also trap unwanted substances. Hairs trap and macrophages.
• How are oxygen and carbon dioxide exchanged in the alveoli?

  Oxygen is breathed into the lungs and makes its way to the alveoli and crosses the respiratory membrane. Oxygen binds to haemoglobin on RBC and is transported around the circulatory system to tissues and structures for energy production. Once energy production takes place carbon dioxide leaves the tissues (waste) and transported around the body in blood and the transferred back across the respiratory membrane, into alveoli and then exhaled out of the lungs.
• Why does expanding your thoracic cavity make you take a breath in?

  Pressure inside lungs decrease and becomes lower in pressure that the barometric pressure outside the body. Hence boyles law = inhale.
• Why would your lungs collapse if you were stabbed in the chest?


  Intrapleural pressure would be lost.
• How do oxygen and carbon dioxide pass between capillaries and tissue cells?

  Diffusion. Area of high concentration to low.
• Why do we breathe faster during and after exercise?

  Body is under stress and requires more oxygen that usual to produce energy. Increasing breathing rate helps provide oxygen to the tissues and muscles at a faster rate.
• What information do dynamic tests of lung function give you.

  Tell you lung function over a period of time.