Worksheet 15: Respiratory system
What are the 2 divisions of the Respiratory system? What are the components of each?
Upper respiratory system : nasal cavity, pharynx, larynx
Lower respiratory system: trachea, bronchi, bronchioles, alveoli, lungs
Describe the following regions:
Nasal cavity: area divided by nasoseptal cartilage. Made up of the vomer and perpendicular
plate. Has nasal conchae extending from the walls. Lined with olfactory mucosa and
olfactory epithelium
Pharynx: muscular tube connecting the nasal cavity to the larynx
Nasopharynx: part of pharynx located posterior to nasal cavity. Pharyngeal tonsil
(adenoids) can be found here.
Oropharynx:part of pharynx located posterior to mouth and uvula, epiglottis is its
inferior boundary. Lingual and palatine tonsils found here.
Laryngopharynx: area surrounding larynx. The continuation of the laryngopharynx
becomes the esophagus
What is the larynx?
A valve that serves for protection and vocalization. It contains the vestibular ligaments and
the vocal ligaments. The vestibular ligaments are for protection and the vocal ligaments are
for vocalization.
What are the types of cartilage that support the larynx?
Epiglottis: closes the larynx when swallowing to prevent food from entering the windpipe
Cricoid cartilage: inferior boundary of the larynx, makes one complete circle around the
larynx
Arytenoid cartilages: anchor the vocal ligaments
Thyroid cartilage: protective cartilage known as “adam’s apple”…medial to thyroid gland
What is the functions of the laryngeal muscles?
To close the glottis for protection and open it for air flow and also to control the tension of
vocal ligaments to allow different pitch in voice
**The continuation of the larynx is the trachea and this will be lined with Pseudostratified
ciliated columnar epithelium.**
Provide a brief description of the structure(s) of the trachea (include 3 types of tissues one may
find in the trachea).
Trachea contains c-shaped cartilage rings for support from collapse and a band of smooth
muscle on its posterior surface called trachealis muscle. The trachea has a luminal surface
made up of pseudostratified ciliated columnar epithelium. The cartilage around the
trachea is called hyaline cartilage
After the trachea splits at the carina, it becomes the bronchi and then the bronchioles. Compare
or contrast the structure of bronchi and bronchioles
Bronchi are large, have cartilage, and goblet cells
Bronchioles are smaller, have no cartilage nor goblet cells ** important because you don’t
want mucus to be produced deep in the lungs
What are the different types of bronchioles? What type of tissue can you find in each?
Muscular bronchioles: have smooth muscle, ciliated simple columnar tissue in lumen and
are continuous with terminal bronchioles
Respiratory bronchioles: no smooth muscle. This allows for some gas exchange to happen
here. Lined with simple cuboidal tissue
Alveolar ducts are continuous with respiratory bronchioles, describe the structure and function of
alveoli.
Alveolar lobules are clusters of alveoli which are sacs formed by simple squamous tissue.
This is where most if not all gas exchange occurs. Walls of the alveoli are fused to the walls
of blood vessels. This allows for a smoother transition and exchange of gases.
Alveoli also have lots of wandering macrophages
Type 1 alveolar cell helps with gas exchange and type II alveolar cell is also called clara or
club cell and it is important in the release of surfactant which helps reduce surface tension.
Without this, alveolar sacs will collapse
Provide a “flow” of air from trachea to an alveoli sac/lobule
Trachea primary bronchisecondary bronchitertiary bronchimuscular
bronchioleterminal bronchiolerespiratory bronchiolealveolar ductalveolar lobule
**Alveoli are composed of one layer of squamous cells therefore red blood cells can only
squeeze through the walls of the alveoli ONE BY ONE.**
What are the membranes that surround the lungs and the thoracic cavity?
Epithelial membranes called pleura. The visceral pleura surrounds the lungs and the
parietal pleura surrounds the thoracic cavity. In between these there may be a potential
space that can be created by the accumulation of air or fluid. This however would cause a
collapsed lung (pneumothorax) because the presence of air or fluid in between the pleura
would not allow the lung to fully expand.
What are some differences between the right and left lungs?
R lung has 3 lobes, slightly larger
L lung has 2 lobes, slightly smaller because it has to compensate for the heart’s slight left
deviation
Describe how the blood becomes saturated with oxygen and how CO2 leaves the body
As blood arrives to the alveoli, oxygen that came from the outside will diffuse into the red
blood cell and the waste or CO2 that the cell carried will diffuse out of the cell into the
alveoli and travel back up through the bronchioles, bronchi, trachea, and eventually out of
the body.
What muscle of the body is responsible for the greatest increase in volume of the thoracic cavity?
Diaphragm. It is innervated by the phrenic nerve
What muscles are used during forced inspiration?
SUPERFICIAL MUSCLES
Pectoralis minor, scalenes, intercostal muscles
What muscles are used during forced expiration?
DEEP muscles
Transverse thoracis, internal intercostal muscles, transverse abdominus, internal oblique