Respiratory System Flashcards
How does the respiratory system condition inspire air?
- humidify by serous and mucous secretions
- warm by underlying blood vessels
- filter by particles being trapped in mucous secretions
What is the respiratory system responsible for?
- respiration
- conditioning of inspired air
- phonation
- olfaction sense
- protecting the respiratory surfaces from environmental variations and pathogenic invasion
What is phonation?
production and utterance of speech sounds
Where is the nasal cavity?
above the bone that forms the roof of the mouth and curves down at the back to join the throat
What does the nasal septum do?
divide the nasal cavity into 2 fossa (nostrils)
What is each nasal fossa lined with?
pseudostratified ciliated columnar epithelial cells
What are the nasal conchae responsible for?
filtration, heating, and humidification of air inhaled through the nose
What is the largest space in the nasal cavity and where does it lie?
the inferior nasal meatus that lies beneath the inferior nasal concha and the lateral wall
Where is the superior nasal meatus?
between the superior and middle nasal conchae
What is the olfactory epithelium?
membranous tissue located inside the nasal cavity
What are the roles of the nasal fossa?
- decrease weight of the skull
- improve resonance of the voice
- temperature insulation
What are paranasal sinuses lined with?
respiratory mucosa (ciliated and secrete mucus)
What are paranasal sinuses innervated by?
the first and second branch of the trigeminal nerve (ophthalmic and maxillary)
What 5 cells line the respiratory tract?
- pseudostratified ciliated columnar cells
- mucous goblet cells
- brush cells
- basal cells
- small granule cells
What are basal cells?
cuboidal stem cells of the airway that line the basement membrane with a large nucleus (high sensitivity to cigarette smoke)
What is the mucociliary escalator responsible for?
movement of mucus up and out of the respiratory tract
What is the lamina propria?
a thin layer of areola connective tissue that supports the epithelium
What does the mucosa consist of?
epithelium and lamina propria
Why are nose bleeds common from the nasal cavity?
the region is highly vascularised (i.e. contains lots of blood vessels)
What is the pharynx?
passage between the oral and nasal cavities and the larynx and oesophagus
What does the pharynx do?
separate the air and food pathways
What is the nasopharynx?
the most superior part of the pharynx bounded superiorly by the skull base and inferiorly by the soft palate
What does the nasopharynx connect the pharynx to?
the oropharynx
What does the larynx link?
the pharynx to the trachea
What are the 3 types of cartilage support of the larynx?
- thyroid (largest)
- cricoid
- epiglottis
What is the epiglottis?
a flap made of elastic cartilage that covers the trachea during swallowing so that food does not enter the lungs
What is the glottis?
the region within the voice box that contains the vocal cords responsible for phonation and sound
What does the thyroid cartilage do?
protect the vocal cords together with the cricoid cartilage
What is the vestibular fold (false vocal cord)?
a fold of mucous membrane that encloses the vestibular ligament, not involved in sound production
What are true vocal cords (cricothyroid ligaments) responsible for?
sound production since they contain more elastic fibres
What is stridulating?
sound production by vibration or rubbing
Why do children have higher pitched voices?
their vocal cords are smaller and tighter
Where is the trachea and what does it link?
anterior to the oesophagus and links the larynx to the bronchus
What is the trachea wall strengthened by?
C-shape/tracheal cartilage
Why is tracheal cartilage C-shaped?
the oesophagus must expand to swallow
What is the trachealis muscle?
a sheet of smooth muscle that lines the back wall of the trachea
What does the trachea bifurcate into?
the left and right primary bronchi entering the lung at the hilum
How many lobar bronchi are in each lung?
3 in the right and 2 in the left
What do segmental bronchi supply?
bronchopulmonary segments, along which veins and lymphatic vessels drain
What happens further down the bronchial branches?
C-shape cartilage starts to form cartilage plates and smooth muscle increases
What is the order of the respiratory tract from nose to alveoli?
- nasal cavity
- pharynx
- larynx
- trachea
- primary bronchi
- lobar (secondary) bronchi
- segmental bronchi
- bronchioles
- terminal bronchioles
- alveoli
What does sympathetic and parasympathetic stimulation do to the bronchioles?
- sympathetic - bronchodilation
- parasympathetic - bronchoconstriction
What are alveoli?
tiny air sacs at the end of bronchioles where gaseous exchange takes place
What are alveoli surrounded by?
capillaries
What do type 1 and type 2 pneumocytes do respectively?
- type 1 - line alveolar surface
- type 2 - secrete surfactant proteins to reduce surface tension and prevent lung collapse
Why does the blood-air barrier exist in the gas exchange region of the lungs?
to prevent air bubbles from forming in the blood and blood from entering the alveoli
What are the 3 layers of the blood-air barrier?
- capillary endothelium
- alveolar epithelium
- ECM
What is the pleura?
a thin layer of tissue that covers the lungs and lines the interior wall of the chest cavity
How does the pleura protect the lungs?
by secreting a small amount of fluid that acts as a lubricant, allowing the lungs to move smoothly in the chest cavity while breathing (prevents friction)
What are the 2 layers of the pleura?
- parietal (outer) pleura - attaches to thoracic wall
- visceral (inner) pleura - covers the lungs, blood vessels, nerves and bronchi
What is the hilum?
the region where various structures forming the lung root pass to enter and exit the lung
Where is the apex of the lung?
above the 1st rib covered by the cervical pleura
What is the base of the lung?
the concave inferior surface resting on the diaphragm
What are the 3 lung surfaces?
costal, mediastinal, and diaphragmatic
What is the cardiac notch of the left lung?
where the apex of the heart rests (specifically the left cardiac ventricle)
What are the 2 fissures of the right lung?
oblique and horizontal
What do macrophages in the respiratory tract do?
clear away dust particles
What are the 3 steps of pulmonary circulation?
- deoxygenated blood shoots down from the right atrium to the right ventricle
- the heart pumps it out of the right ventricle and into the pulmonary arteries to begin pulmonary circulation
- the blood moves to the lungs, exchanges carbon dioxide for oxygen, and returns to the left atrium
Which main blood vessels supply the respiratory system?
bronchial arteries and veins
What is the aortic arch?
the curved part of the aorta that gives rise to major arteries that supply the head, neck, and upper limbs
What does lymphatic drainage do?
drain fluid from tissues and return it to the vascular circulatory system
Where do the lymphatics of the lung drain?
tracheobronchial nodes (lymph nodes) along the bronchi and pulmonary vessel through the hilum and into the posterior mediastinum
Where are parasternal nodes found?
in the thoracic wall, mammary glands and abdominal area to drain the inner breast quadrants
How many ribs are there and what do they do?
12 to protect the heart and lungs and prevent overexpansion during respiration
What does the thoracic bony cage consist of?
ribs, sternum, and thoracic spine
Where are costochondral junctions?
between the distal part of the ribs and the costal cartilages
What are costal cartilages?
bars of hyaline cartilage that connect the ribs to the sternum
What are the true ribs?
T1-7 that are attached directly to the sternum by costal cartilages
What are the false ribs?
T8-10 that do not directly connect to the sternum and instead are attached to the rib above them by cartilage
What are the floating ribs?
T11-12 whose costal cartilages do not attach them to any other bone or costal cartilage
What are the primary respiratory muscles?
diaphragm and external intercostal required for respiration at rest
What are the 4 accessory respiratory muscles?
- sternocleidomastoid
- pectoralis major and minor
- serratus anterior and posterior superior
- latissimus dorsi
What are the accessory respiratory muscles required for?
changing the depth and frequency of breathing
