Respiratory System Flashcards
Name the main muscles involved in pulmonary ventilation
Diaphragm: inferior to the lungs.
External intercostal muscles: between the ribs.
List the order that air must move through in the respiratory system to reach the alveoli.
Nasal cavity -> pharynx -> trachea -> primary broncus -> secondary broncus -> tertiary bronchus -> terminal bronchus -> repiratory bronchioes -> alveolar ducts -> alveoli.
Name the conducting zone structures. What is the function of these structures?
Conduction zone consists of nose, nasal cavities, pharynx, larynx, bronchi and terminal bronchi.
Function: conducts gas to the respiratory zones.
Name the respiratory zone structures. What is the function of these structures?
Respiratory bronchioles and alveoli—site of gas exchange.
Alveoli are lined with a single layer of cells called alveolar type I and type II cells. Explain the functions of type I and type II alveolar cells.
Type 1—very flat shaped cells that are the major alveolar cell type where gas exchange occurs.
In between the type I cells are type II alveolar cells which secrete a substance known as surfactant which coats the gas-exposed alveolar surfaces.
What happens if insufficient surfactant is produced?
Surfactant reduces surface tension within the alveoli. Surface tension attracts liquid molecules to one another at gas-liquid interface. Surfactant is a detergent-like lipid and protein complex produced by type II alveolar cells. Reduces surface tension within alveoli due to alveolar fluid and discourages alveolar collapse. Insufficient quantity in premature infants causes infant respiratory distress syndrome, alveoli collapse after each breath.
During passive exhalation:
- The diaphragm contracts and the thoracic cavity pressure increases.
- The diaphragm contracts and the thoracic cavity pressure decreases.
- The diaphragm relaxes and the thoracic cavity pressure increases.
- The diaphragm relaxes and the thoracic cavity pressure decreases.
- The diaphragm relaxes and the thoracic cavity pressure increases.
During passive inhalation:
- the diaphragm contracts and the thoracic cavity pressure increases.
2.
the diaphragm contracts and the thoracic cavity pressure decreases. - the diaphragm relaxes and the thoracic cavity pressure increases.
- the diaphragm relaxes and the thoracic cavity pressure decreases.
2
The fuction of surfactant is:
to ensure alveoli doesn’t collapse.
How is most of carbon dioxide transported in blood?
as bicarbonate ions
Describe external respiration
- Oxygen and carbon dioxide gas exchange between pulmonary capillary blood and alveoli.
Differences in the partial pressure (PP) of these gases drives their movement across the respiratory membrane.
To simplify the idea of PP, might help to relate to concentration and amount of gas i.e. High PP of oxygen is similar to high concentration of oxygen.
Higher PP of oxygen in alveoli compared to in pulmonary capillaries results in oxygen diffusing from the alveoli into the blood. Blood becomes oxygen rich.
Gas will diffuse from high PP towards low PP (driven by pressure gradient).
Higher PP of CO2 in pulmonary capillaries compared to lower PP of CO2 in alveoli.
CO2 diffuses out of capillaries into the alveoli to be exhaled.
How is CO2 transported in blood?
7% Dissolved in plasma.
23% attached to Hb in RBCs as carbaminohemoglobin. Attaches to Hb at different sites to O2 as does not compete for attachment.
70% as bicarbonate (HCO3 -) in plasma.
Peripheral chemoreceptors are located within:
aorta
vital capacity is
the sum of the air forcefully inhaled plus exhaled.
Type I alveolar cells are primarily responsible for:
gas exchange
