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
Blood supply of pharynx
Branch of external carotid artery
Larynx
Between CIV-CVI, between laryngopharynx superiorly and trachea inferiorly
Cartilaginous skeleton (mainly hyaline cartilage) connected by laryngeal muscles, membranes, and ligaments
3 paired cartilages (arytenoid, corniculate, cuneiform)
3 unpaired cartilages (thyroid, cricoid, epiglottis)
Thyroid cartilage
Largest
Made by 2 plates attached anteriorly forming laryngeal eminence (Adam’s apple), and open posteriorly; forms right angle in males, and wider angle in females
Connected to hyoid bone via superior horn and thyrohyoid membrane
Connected to cricoid cartilage by inferior horn and cricothyroid membrane
Cricoid cartilage
Most inferior
Ring shaped with laminae facing posteriorly (wider than anterior side)
Laminae articulates with arytenoid cartilage superiorly
Inferior border connects to first cartilage ring of trachea via cricotracheal ligament
Epiglottis
Leaf shaped cartilage
Only one made up of elastic cartilage
Attached to interior side of laryngeal eminence
Wide part is behind the tongue
Closes entrance to larynx during swallowing
Arytenoid cartilage
Pyramidal cartilage that articulate with cricoid cartilage inferiorly
Has 2 processes for attachment of intrinsic larynx muscles (muscular process) and vocal ligaments (vocal process)
Corniculate cartilage
Above arytenoid cartilage
Contained with aryepiglottis fold between arytenoid cartilage and epiglottis
Cuneiform cartilage
Embedded between mucous membrane
Contained with aryepiglottis fold between arytenoid cartilage and epiglottis
Vestibule
Larynx above vestibular fold
Ventricle
Laryngeal space between vocal folds
Infraglottic region
Larynx below true vocal fold
Ligaments in larynx
Stretched between thyroid and arytenoid cartilage
Vestibular ligaments - superior, do not vibrate during phonation, form vestibular (false vocal) folds
Vocal ligaments - inferior, vibrates during phonation, form vocal (true) folds
Glottis
Vocal folds with rima glottidis (fissure between right and left vocal folds)
Nerve supply of larynx
Mucosal membrane and intrinsic muscles of larynx - CNX
Blood supply of larynx
Superior thyroid branch of external carotid and thyrocervical branch of subclavian arteries
Trachea
Fibrocartilage tube, 12cm in length, 2.5cm in diameter
Starts at CVI - TIV-TV at carina (divides it to L/R bronchi)
Composed of 20 incomplete hyaline cartilage rings; the posterior wall is attached by fibromuscular membrane to esophagus to facilitate downward movement
Esophagus is posterior
Thyroid gland and manubrium of sternum is anterior
Bronchi
R primary bronchus is shorter, wider and higher compared to the L primary bronchusN
Nerve supply of trachea
Cervical sympathetic chain and vagus nerve
Blood supply of trachea
Subclavian arteries
Lungs
Spongy structure on either side of the mediastinum separated by heart, and posterior mediastinal structures
Half cone shaped structure in pleural cavity with root attaching to mediastinum
Has apex, 3 surfaces (inferior, lateral, medial), and 3 borders (anterior, posterior, inferior)
Surfaces of lung
Apex - above rib 1, into the root of the neck
Inferior/diaphragmatic surface/base - concave; sits on diaphragm
Lateral/costal surface - convex; related to ribs, intercostal muscles, sternum
Medial/mediastinal surface - concave; related to middle and posterior mediastinal structure; contains hilum; has deep fissures that divide lungs into lobes
Hilum of lung
Located at the center of the medial surface
Includes primary bronchi, pulmonary vessels, bronchial vessels, lymphatic vessels, nerves - forms the root
1 pulmonary artery carries deoxygenated blood from R ventricle to lung, and 2 pulmonary veins that carry oxygenated blood from lung to L atrium
Borders of lung
Anterior border - sharp; on L lung has cardiac notch (provides point of access to heart), below cardiac notch is lingula; separates medial and lateral surface
Posterior border - round; related to thoracic region of vertebral column; separates medial and lateral surface
Inferior border - sharp; separated medial and lateral surface; crosses ribs 6, 8, 10 anteriorly, laterally and posteriorly
Right lung
Larger and heavier since middle mediastinum bulge towards the L side
Shorter and wider than L lung due to liver under diaphragm
Divided into 3 lobes (superior, middle, inferior) by oblique and horizontal fissure
Left lung
Divided into 2 lobes (superior, inferior) by oblique fissure
Lingula of L lung equivalent to middle lobe on R lung
Bronchopulmonary segments
Lobes of the lung are divided into bronchopulmonary segments
Both R and L lungs have 10 bronchopulmonary segments
Bronchial tree
Afteer the hilum, primary bronchi divides into secondary (lobar) bronchi and tertiary (segmental) bronchi
Tertiary divides to produce bronchioles, terminal bronchioles, and respiratory bronchioles
Bronchioles: smallest airways that do not carry any cartilage
Respiratory bronchiole: carry alveoli (respiratory system that is involved in gas exchange for air and blood); clusters of alveoli make up alveolar sacs
Nerve supply of lungs
Lung tissue: innervated by afferent and efferent branches of pulmonary plexus (at bifurcation of trachea) by vagus nerves (constricts bronchioles) and sympathetic nerves from T1-T4 (dilates bronchioles)
Visceral pleura: sympathetic nerves from T1-T4
Parietal pleura: somatic nerves supply walls of thoracic cavity (phrenic, upper intercostal)
Blood supply of lungs
Bronchial arteries from thoracic aorta through hilum
Pleura of lung
Each lung is surrounded by 2 layers of serous membrane = pleura
Parietal pleura: in touch with wall of thoracic cavity, lines inner surface of ribs and muscles between ribs
Visceral pleura: in touch with lungs
Pleural cavity: between 2 layers of pleura to keep surfaces moist and facilitate movement between lungs and chest wall
Costodiaphragmatic recess
Gutter formed by parietal pleura reflects on inner surface of chest wall covering superior surface of diaphragm, and costal parts
Lowest party of pleural cavity
At level of rib 6, 10, 12 anteriorly, laterally, posteriorly
Fluid accumulates when a person is standing
