L05 Flashcards
Functions of the respiratory system
Consists of two tracts
* Upper respiratory tract
* Lower respiratory tract
* Supplies the body with oxygen
and eliminates carbon dioxide
(ventilation).
upper respiratory tract
- Consists of the nose, sinuses and nasal passages, pharynx,
tonsils and adenoids, larynx, and trachea.
● Warms and filters inspired air.
the nose
A passageway for air to pass to and from the lungs.
● Filters, humidifies, and warms the air as it is inhaled.
● Air entering the nostrils is deflected upward to the roof of the
nose before it reaches the nasopharynx.
● Ciliated mucous membranes (nasal mucosa) trap all the dust
and microorganisms in the inhaled air.
paranasal sinuses
ncludes 4 pairs of bony cavities.
● These airspaces are connected by ducts that drain into the nasal cavity.
● The sinuses are named by their location: frontal, ethmoidal, sphenoidal, and
maxillary.
● Prominent function: a resonating center for speech.
● Common site for infection.
pharynx, tonsils and adenoids
includes 4 pairs of bony cavities.
● These airspaces are connected by ducts that drain into the nasal cavity.
● The sinuses are named by their location: frontal, ethmoidal, sphenoidal, and
maxillary.
● Prominent function: a resonating center for speech.
● Common site for infection.
larynx
A cartilaginous epithelium-lined structure that connects the pharynx and
trachea.
● Also known as the “voice organ” or “voice box”.
● Protects the lower airway from foreign substances and facilitates coughing.
● Consists of the following:
○ Epiglottis: A valve flap of cartilage that covers the opening to the larynx
during swallowing
○ Glottis: The opening between the vocal cords in the larynx
○ Thyroid cartilage: The largest of the cartilage structures; part of it forms
the Adam’s apple
○ Cricoid cartilage: The only complete cartilaginous ring in the larynx
(located below the thyroid cartilage)
○ Arytenoid cartilages: Used in vocal cord movement with the thyroid
cartilage
○ Vocal cords: Ligaments controlled by muscular movements that produce
sounds; located in the lumen of the larynx
trachea
Windpipe
● Composed of smooth muscle with c-shaped rings of
cartilage.
● The cartilage rings give firmness to the wall of the trachea.
● The passageway between the larynx and the bronchi.
lower respiratory tract
Consists of the lungs which
include the bronchial and
alveolar structures.
● Responsible for gas
exchange.
the lungs
Paired elastic structures enclosed in the thoracic cage.
● Ventilation requires movement of the walls of the thoracic cage and floor – the
diaphragm.
● The inspiratory phase of respiration requires energy. The expiratory phase is
normally passive.
● Pleura: a serous membrane lining the lungs and walls of the thorax.
○ Visceral pleura: covers the lungs.
○ Parietal pleura: lines the thorax.
● Pleural fluid between the visceral and parietal pleura acts as a lubricant and
permits smooth motion of the lungs.
the lungs
Mediastinum: the middle of the thorax, between the pleural sacs that contain the
lungs.
○ Contains all thoracic tissue outside of the lungs.
● Lobes: each lung is divided into lobes.
○ Right lung: upper, middle, and lower lobes (3)
○ Left lung: upper and lower lobes (2)
● Bronchi & bronchioles: there are several divisions of the bronchi within each
lobe of the lung.
○ Bronchi: surrounded by connective tissue containing arteries, lymphatics,
and nerves.
○ Bronchioles: contain no cartilage in their walls. Patency depends on the
elastic recoil of the surrounding smooth muscle and alveolar pressure.
● Both bronchi & bronchioles are lined with cells covered with cilia. These cilia
propels mucus and foreign substances away from the lungs.
the lungs
Respiratory bronchioles: the transitional passageways between the conducting
airways and gas exchange airways.
○ Further leading into the alveolar ducts alveolar sacs alveoli
● Physiological dead space: the conducting airways (containing 150 mL of air)
that does not participate in gas exchange.
● Alveoli: where oxygen and carbon dioxide exchange takes place.
respiratory physiology
Most cells in the body obtain their energy from chemical reactions involving
oxygen and the elimination of carbon dioxide.
● There are three steps in the process of oxygenation:
○ Ventilation
○ Perfusion
○ Diffusion
ventilation
The process of moving gases into and out of the lungs.
● Requires coordination of the muscular and elastic properties of the lung and
thorax.
● The major inspiratory muscle of respiration is the diaphragm.
○ Controlled by the phrenic nerve
perfusion
The ability of the cardiovascular system to pump oxygenated blood to the
tissues and return deoxygenated blood to the lungs.
diffusion
Responsible for moving the molecules from one area to another.
○ From an area of higher concentration to an area of lower concentration.
● Diffusion of respiratory gases occurs at the alveolocapillary membrane.
○ Rate of diffusion can be affected by the thickness of the membrane.
● Patients with pulmonary edema, pulmonary infiltrates, or a pulmonary effusion
have an increased thickness of the alveolocapillary membrane, resulting in
slowed diffusion, slowed gas exchange, and impaired delivery of oxygen to
tissues.
● Surface area of the membrane can be altered as a result of chronic disease.