09 - Respiratory Anatomy Flashcards
Functions of the respiratory system
perform gas exchange
regulate blood pH
provide for olfaction
provide for phonation (sound)
Structures of the respiratory system
upper and lower airways
lungs and pleura
thoracic cage
muscles of respiration
Describe the upper airway
And the route of airflow
structures above the larynx (vocal cords)
Route of airflow
1. external nares (lined with nose hairs)
2. nose
3. nasal cavity (nasal conchae)
- increase SA for rapid warming and humidification of air and traps air
4. pharynx (3 zones)
- nasopharanyx
- oral pharanyx (also for food)
- laryngeal pharanyx (also for food)
5. larynx
What lines the nasal cavity
respiratory epithelium (cilia and goblet cells; a mucous membrane) and a smaller olfactory epithelium
What lines the oral cavity
pseudostratified cilliarly epithelium
Describe the purpose of the epiglottis
cartilaginous structure
covered by mucus membrane
stem attached to thyroid cartilage
leaf is free to move
protects the trachea from food stuff (aspiration) during deglutition (swallowing)
also aids in explosive maneuvers
- coughing/sneezing
- micturition
- defacation
- labour and delivery
structural support
What are the structures of the lower airways
below the larynx
- trachea
- bronchi
- alveoli
- lungs
Describe the trachea
~12cm long, ~3m diameter
C-shaped cartilage maintain patency
tracheal smooth muscle (posteriorly)
bifurcates (divides) into primary bronchi
lined by ciliated pseudostratified columnar epithelium –> forms a mucociliary apparatus
carina = internal ridge at bronchial junction (associated with cough reflex)
What are the four layers of walls of the trachea
1) epithelium
2) submucosa
3) hyaline cartilage
4) adventitia
Describe the bronchi and bronchioles
- primary (main) bronchi enter the hilum of the lungs to direct air to the right and left lung
- supported by rings of cartilage
- right primary (main) bronchus –> short, wide, vertical
- left primary (main) bronchus –> long, less vertical - secondary (lobar) bronchi dirext air to each lobe of the lung (3 right, 2 left)
- supported by plates of cartilage
lined by ciliated pseudostratified epithelium
Describe the lungs and lobes
lobes separated by fissures visible on the surface of the lungs
- right: superior, middle, inferior lobes
- left: superior and inferior lobes
lungs surrounded by pleural cavities that are lined by a serous membrane
- parietal pleura
- visceral pleura
Describe the tertiary (segmental) bronchi
direct air into discrete bronchopulmonary segments within the lobes of the lungs
- right = 10 segments
- left = ~8 segments
anatomically and functionally independent –> contain many small segments called lobules
forms a bronchial tree with extensive branching
at the ends, plates of cartilage get replaced by elastic fibres and smooth muscle
What does a terminal bronchiole mark
the beginning of a lung lobule (where gas exchange occurs)
Describe the lung lobules (acinus)
each lobule wrapped in elastic tissue and contains
- branch of a terminal bronchiole
- arteriole
- venule
- lymphatic vessel
terminal bronchioles –> respiratory bronchioles –> alveolar ducts –> alveolar sacs –> alveolus
What are the types of alveolar cells
Type 1: line the alveolar wall (pneumocyte)
- primary site of gas exchange
Type 2: secrete alveolar fluid and a substance called surfactant (reduces the surface tension of alveolar fluid to make it easier to breathe)
- elastic fibers also help to keep the alveoli open
Alveolar macrophages: provide immune surveillance
What makes up the gas exchange membrane
type 1 pneumocyte
basement membrane
pulmonary capilary endothelial cell
What are the two circulations of the lung
conducting regions of the lungs (trachea to terminal bronchiole) is supplied by the bronchial circulation
- receives oxygenated blood from the systemic circuit
respiratory regions of the lung (terminal bronchiole to alveolus)
- receives deoxygenated blood from the pulmonary circuit
Describe the thoracic cage
consists of 12 pairs of ribs and associated costal cartilage
- ribs articulate with 12 thoracic vertebrae
7 pairs of true ribs –> touches sternum
5 pairs of false ribs –> don’t touch sternum (free floating)
contains sternum (manubrium, body, xiphoid process)
Describe the features of the thoracic vertebrae and associated ribs
ribs possess facets for articulation with the vertebrae (synovial joint)
pedicle
lamina
body
head
rubercle
costal angle –> weakest part of the rib
costal groove –> houses an intercostal VAN) intercostal vein, artery and nerve)
What does the phrenic nerve innervate
skeletal muscle in the diaphragm
Describe the diaphragm
attaches to the inferior aspects of the rib cage and acts upon a central tendon
seperates the pleural cavity from the peritoneal cavity
many structures must pass through the diaphragm (one caval opening and two hiatuses)
