1: Respiratory System Flashcards
functions
gas exchange between air and blood
move air between exchange surfaces of lungs
protect respiratory surface from outside environment
produce sound
helps smell
respiratory tract
passageway for air to travel to and from lungs
conducting portion = from nasal cavity to terminal bronchioles
respiratory portion = respiratory bronchioles and alveoli
upper respiratory system = nose, nasal cavity, sinuses, pharynx
lower respiratory system = larynx, trachea, bronchi and lungs
conducting and respiratory zones
airways branch total of 23 times
irregular dichotomous patter - each airway divides into two daughter airways
alveoli appear as buds in the bronchiole wall from branch 17 onwards
from branch 20 onwards, whole airway is alveoli
left lung smaller for heart
left lung = 2 lobes
right lung = 3 lobes
respiratory mucosa
lining of conducting portion of respiratory tract
made of epithelial layer and an areolar layer
epithelial layer = ciliated columnar epithelium containing many mucous cells
areolar layer = called lamina propria, contains many mucous glands that secrete onto epithelial surface
conducting portion of lower respiratory system contains smooth muscle
nasal cavity
air enters through nostril (external nares) then into nasal vestibule (at front of nasal cavity)
nasal hairs for filtration
air flows through three nasal meatuses (channels created by bony structures called nasal conchae)
palates in oral cavity
hard palate = form bottom of nasal cavity above oral cavity
soft palate = extends posterior to hard palate, divides superior nasopharynx from lower pharynx
pharynx
chamber for respiratory and digestive uses
3 division - nasopharynx, oropharynx, laryngopharynx
air then enters the larynx which is a cartilaginous structure that surrounds the glottis (voice box)
glottis = opening between vocal folds, production of sound by changing air flow past vocal folds
sound and speech
sound produced by air passing through glottis, vibrating the vocal folds and producing sound waves
sound variation caused by tension on vocal folds (voluntary muscle)
during speech, phonation = sound production at the larynx
articulation = modification of sound by other structures
trachea
2.5cm diameter, 11cm length
15-20 cartilaginous rings
C shaped so posterior wall can easily distort for large amounts of food
end of trachea connected by elastic ligament and trachealis muscle which can contract to change diameter - autonomic control
sympathetic stimulation also increases diameter
bronchi
right and left primary bronchi separated by an internal ridge called the carina
right bronchus is larger in diameter and descends at steeper angle
each primary bronchi travel to hilum along medial surface of lung
bronchial tree
formed by primary bronchi and their branches
primary bronchus branch to form secondary bronchi
1 secondary bronchus goes to each lobe
extrapulmonary bronchi = the left and right bronchi branches outside the lungs
intrapulmonary bronchi = branches within the lungs
secondary bronchi
branch to the tertiary bronchi
each tertiary (segmental) bronchi supplies air to single bronchopulmonary segment
right lung = 10 segments
left lung = 8 or 9 segments
bronchi structure
walls contain progressively less cartilage as go down bronchial tree
this increase muscle effects on airway constriction and resistance
each tertiary bronchus branches into multiple bronchioles
bronchioles have no cartilage so are dominated by smooth muscle
autonomic control regulates smooth muscle, controlling diameter and airflow
control bronchodilation and bronchoconstriction
alveoli
air filled pockets within lungs
gas exchange takes place
surrounded by dense network of capillaries
oily secretion called surfactant onto alveolar surfaces where it forms a superficial coating over a thin layer of water - plays key role in keeping alveoli open by reducing surface tension
pleural cavities
thoracic cavity walls are the ribcage and diaphragm
each lung surrounded by single pleural cavity which is lined by serous membrane called the pleura
pneumothorax = air in pleural cavity, breaking fluid bond between pleurae and allowing lung’s elastic fibres to recoil
haemothorax = blood accumulates in pleural cavity