Lecture 21 & 22: Respiratory System Flashcards
Respiratory System
Provides gas exchange of O2 and CO2
Nose, para-nasal sinus, pharynx, larynx, trachea, bronchi, lungs
Upper respiratory system (structurally)
Nose (external and nasal cavity)
Para-nasal sinus
Pharynx
Lower respiratory system (structurally)
Larynx
Trachea
Bronchi
Lungs
Conducting zone (functionally)
Function: filter, regulates temperature, moistens air and conducts it to lungs
Structures: nose, paranasal sinus, pharynx, larynx, trachea, bronchi, bronchioles, terminal bronchioles
Respiratory zone (functionally)
Function: gas exchange between air and blood in the lungs
Structures: respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli
Nose
External nose
Nasal cavities
External nose
Anterior extension formed by cartilage (septal and alar) and bone (nasal bone, maxillary bone, frontal bone)
Nostrils formed by alar cartilage, opening of external nose, diameter is dependent on contraction of muscles
Nasal cavity
2 osseo-cartilaginous spaces separated by nasal septum
Above nostril is nasal vestibule with short thick hairs
Vestibule joins to nasopharynx via choanae or posterior nasal aperature
Boundaries of nasal cavity
Roof: mainly ethmoid bone, some contribution of frontal and sphenoid bone
Floor: mainly maxillary bone, some contribution of palatine bone; separates nasal and oral cavity
Lateral wall: nasal conchae (superior, middle, inferior); formed by maxillary, palatine, ethmoid, lacrimal bones and inferior nasal concha
Medial wall: nasal septum (ethmoid and vomer bone, septal cartilage)
Nasal conchae
Bony curved shells on lateral wall of nasal cavity
Increases surface area, covered with respiratory epithelium
Produces mucus to keep nasal cavity moist to filter air, add moisture, and regulate temperature
Under each shell are nasal meatuses (superior, middle, inferior) which receive paranasal sinuses and nasolacrimal duct
Paranasal sinus
Air filled space, opens to lateral wall of nasal cavity
Frontal sinus - in frontal bone
Sphenoid sinus
Maxillary sinus - largest, 15mL
Ethmoidal sinus
Lined with respiratory epithelium
Lightens skull, resonates voice, enhances efficiency of filtration, humidification, thermoregulation
Sinusitis
When too much mucous is produced when sick, drainage is interrupted causing inflammation of the sinuses
Leads to increase pressure in the sinus
Solution: restore drainage (saline rinse, steaming, anti-inflammatory drugs, antibiotics)
Nerve supply in nasal cavity
CNI (olfactory nerve) through the ethmoid bone
Maxillary division of CNV for general sensation of mucus membrane of nasal cavity and paranasal sinus
Blood supply in nasal cavity
Maxillary branch of external carotid artery supplies nasal cavity and paranasal sinus
Pharynx
12-15cm muscular tube for air (between nasal cavity and larynx) or food (between oral cavity and esophagus)
Part of respiratory and digestive system
Starts at base of skull to esophagus at CVI
Subdivided into nasopharynx, oropharynx, and laryngopharynx
Nasopharynx
Behind nasal cavities above soft palate
Pharyngeal tonsil (1) on roof of nasopharynx to produce antibodies
Auditory/eustachian/pharyngotympanic tubes are on lateral wall and connect to middle ear to equalize pressure between middle ear and pharynx; normally closed, but can temporarily open; easy to transmit infection to the middle ear
Oropharynx
Behind oral cavity extends from soft palate to superior epiglottis
Palatine tonsils on lateral wall between palatoglossal and palatopharyngeal folds
Laryngopharynx
Behind larynx from epiglottis to osophagus
Muscles of pharynx
Constrictors or levators to constrict or lift pharynx
Constrictors are more powerful and begin the peristalsis movement; also prevents entrance of foreign objects into the pharynx (gag reflex)
Nerve supply in pharynx
Mucosal membranes: Nasopharynx - maxillary division of CNV Oropharynx - CNIX Laryngopharynx - CNX Intrinsic muscles (constrictor and levators): CNX
Foreign objects are picked up by CNIX (general sense of pharynx) which goes to the brainstem and passes it to the motor aspect of CNX to constrict the muscle