Chapter 6: The Respiratory System Flashcards
Where are the lungs located?
in the thoracic cavity
Label the anatomy of the respiratory system.
Where does gas exchange occur within the respiratory system?
in the lungs
How does air enter the respiratory tract?
through the nares of the nose
it then passes through the nasal cavity where it is filtered by mucous membranes and nasal hairs
Where does the air go after it passes through the nasal cavity? Differentiate these 2 structures.
air then passes into the pharynx and the larynx
pharynx: behind the nasal cavity; a food and air pathway
larynx: below the pharynx; an air pathway only, no food
How is food kept out of the respiratory tract?
the glottis (opening of the larynx) is covered by the epiglottis during swallowing
The larynx contains 2 __________.
vocal cords
Where does the air flow after it passes through the larynx?
air passes into the cartilaginous trachea and then into one of the 2 mainstream bronchi
What type of cells do the bronchi and trachea contain? What function does this serve?
ciliated epithelial cells to catch material that has made it past the mucous membranes in the nose and mouth
The bronchi are divided into smaller structures called:
bronchioles
The bronchioles end in which structures? What occurs at these structures?
alveoli: tiny balloon-like structures
the site of gas exchange
What are alveoli coated with and what purpose does this serve?
coated with surfactant
lowers surface tension at he alveolar surface and prevents the alveolus from collapsing on itself during exhalation
What are 2 key differences between the left and right lungs.
left lung: 2 lobes, slightly smaller
right lung: 3 lobes, slightly larger
What are the membranes that surround each lung called and what is their function?
pleurae
form a closed sac against which the lungs expand
(note: the pleurae can be divided into the visceral pleura and the parietal pleura)
Describe the structure of the pleura.
the visceral pleura: adjacent to the lung
intrapleural space: between the 2 membranes, contains a thin layer of fluid to lubricate the 2 surfaces
the parietal pleura: adjacent to the chest wall
Where is the diaphragm located and what is it’s purpose?
a thin, muscular structure the divides the thoracic cavity and the abdominal cavity
a skeletal muscle involved in generating the negative pressure for lung expansion
Explain the mechanism of negative-pressure breathing (inhalation). (4)
- at rest, the intrapulmonary pressure equals the atmospheric pressure
- inhalation involves the contraction of the diaphragm and external intercostal muscles to increase the the intrathoracic volume
- increase in intrathoracic volume causes decrease in relative pulmonary air pressure
- the decrease in pressure within the lungs causes external air to flow in
note: inhalation is an active process
What is the function of the intrapleural space?
at rest, the intrapleural space maintains a lower air pressure than the lungs to keep the lungs inflated
if the intrapleural pressure reaches zero (due to puncture) the lungs would collapse
Explain the process of exhalation.
- the diaphragm and external intercostal muscles relax the decrease the intrathoracic volume
- the decrease in intrapulmonary volume results in an increase in intrapulmonary pressure
- air exists the lungs to equalize the pressure between the lungs and the outside world
note: exhalation is not necessarily an active process
this process can be sped up using internal intercostal muscles and abdominal muscles to actively decrease the thoracic cavity volume