3. Basic structure of the respiratory system Flashcards
Describe the role of the nasal cavities.
They warm and humidify the air passing through the nasal cavities.
Describe nasal cavities
Lined by olfactory mucosa
Very sensitive
Innervated by ethmoidal nerve
Describe the resistance of the nasal cavities and the implications for exercise.
High resistance - when exercising, breathing is mainly done through the mouth because that is a path of lower resistance and more water is lost
3 Functions of paranasal sinuses
Help to lighten the skull Effect resonant quality of voice Protective of brain: Form crumple zone Air in them acts as “double glazing”
What are the bony structures underlying the epithelial layer on the lateral side of the nasal cavities called?
Conchae
What are the paranasal sinuses?
4 sets of blind-ended out-pocketings of the lateral walls of the nasal cavities
Paranasal Sinuses: Frontal, Maxillary, Ethmoid, Sphenoid
What are the 3 parts of the pharynx and where are they found?
Nasopharynx: behind the nasal cavities
Oropharynx: posterior to the tongue, consists of lymphoid tissue
Laryngopharynx: below the epiglottis
What is the larynx?
Cartilaginous structure that is supported from the roof of the mouth from the hyoid bone
What structure is attached to the vocal ligaments which open and close entry to the larynx?
Arytenoid cartilage
What causes phonation?
Vibration of vocal ligaments
Form sphincter to stop anything other than air entering airway
Why is cartilage horseshoe shaped deficient posteriorly?
Trachea always kept open without muscular effort
When does the trachea divide?
Sternal angle
angle of Louis
Where do the primary, secondary and tertiary bronchi lead?
Primary: Into the lungs (L or R)
Secondary: To individual lobes
Tertiary: Specific segment
Which bronchus is shorter and more vertical?
Right primary bronchus
What reduces bronchiolar and alveolar surface tension?
Surfactant
At which level is no cartilage found?
Bronchiole
Why is surfactant produced in the bronchioles?
There is higher resistance as they have a smaller diameter, surfactant makes them smoother
Describe the faces of the pleural cavity
Visceral: Faces lung
Parietal: Faces thoracic wall
What drives oxygen across the blood air barrier?
PO2 Air = 100 mmHg
PO2 Blood = 40 mmHg
Where are many lymph nodes found within the lungs?
At the hilum
Position of diaphragm
Margin attached to costal margin (lower edge of rib cage)
Why does the centre of the dome of the diaphragm bulge up?
Because of pressure difference between pleural and abdominal cavities
Describe the abdominal surface of the diaphragm
Holes for: IVC, Oesophagus, Aorta and Thoracic duct
Considerable innervation
Phrenic nerves goes through it and innervates underneath
What is the phrenic nerve (C3,4,5) motor to?
Diaphragm
3 groups of ribs
Directly attached to sternum (1-7)
Attached to costal cartilage above (8-10)
Floating
Describe the water pump motion seen in the ribs directly attached to the sternum
External intercostal muscle contraction pulls ribs upwards and because of angle of ribs they move outwards. (Anterior part of ribs is lower)
Describe the bucket handle motion of the ribs attached to the costal cartilage
Middle part of rib is lower than posterior and anterior
Contraction causes lateral movement
How many cartilage rings are around the trachea?
~ 20
