respiratory system Flashcards
what are the features of the upper respiratory tract?
nasal cavity / pharynx / larynx
what is the function of the nasal cavity?
nasal cavity = filtration of air / conduction of air / smell / warming of air
what is the function of the pharynx?
pharynx = allow air to pass through your windpipe / food and rink through oesophagus / vocal production
what is the function of the larynx?
larynx = voice generation / conduction of air / protection of lower airways / separation of digestive tracts
what are the main anatomical structures in the upper respiratory tract?
nasal cavity / pharynx (and its three subdivisions) / larynx / thyroid cartilage / cricoid cartilage / hyoid bone
describe the nasopharynx
- it goes from the choanae to the soft palate
- the pharyngeal tonsil (adenoid) is located here
- the eustachian tube is located here
describe the oropharynx
- b/w the palate and superior border of the epiglottis
- palate tonsil is located here
- has the palatopharyngeal arch
describe the laryngopharynx
- connects the oropharynx and oesophagus
- posterior to the larynx until inferior border cricoid
describe the nasal cavity
- divided by septum
- septum removed -> 3 conchae (superior and middle which is part of the ethmoid bone / inferior which is a bone in its own right)
- septum removed -> 3 meatus (inferior, middle, superior)
- roof has CN1
- the lateral walls connect to the paranasal sinuses
- nasolacrimal duct ends at the inferior meatus
what are the 4 paranasal sinuses?
maxillary, frontal, ethmoidal, sphenoid
describe the hyoid bone
connects the pharynx, larynx, and mandible via membranes and muscles
describe the pharynx
made of pharyngeal constrictor muscles
describe the thyroid cartilage
- largest cartilage
- laryngeal prominence
- posteriorly open
- connected to the cricoid cartilage, epiglottis and vocal ligaments
describe the cricoid cartilage
- signet ring structure
- complete ring
- connected to thyroid and arytenoid cartilages (mvmt of arytenoid cartilages change width of rima glottidis)
what features are included in the lower respiratory tract?
trachea all the way to the lungs
what are the functions of the lower respiratory tract
transport of air / cleaning / gas exchange ONLY at the alveoli
what are the main anatomical structures in the lower respiratory tract
trachea, muscles (e.g diaphragm and intercostal), lungs (pleura, bronchi, bronchioles)
describe the trachea
has abt 20 cartilaginous semicircular rings that are connected by CT and muscle which assist in moving the neck
describe the muscles during breathing
the diaphragm does the majority of the work while muscles like the sternocleidomastoid and pectoralis are accessory muscles
describe the lungs
- contains pleura (two layers which connect at the hilum = visceral and parietal / between the two layers there is pleural fluid)
- contains bronchi (left [more oblique / aorta passes] and right [straight / azygos vein passes] main bronchus branching off of the carina
- left lung has 2 lobes
- right lung has 3 lobes
- alveoli = largest surface area in body that is exposed to outer environment
voluntary breathing pathway
cortex > corticospinal tract > discharge of motor neurons to diaphragm and intercostal muscles
involuntary breathing
medulla > pacemaker cells > discharge of motor neurons to diaphragm and intercostal muscles
what are the 3 walls of airway tubes
mucosa, submucosa, adventitia
what does the mucosa consist of
epithelium, basement membrane, lamina propia (loose CT)
what does the submucosa consist of
fibrous CT, hyaline cartilage, large veins
what does adventitia consist of
CT
respiratory epithelium in the mucosa of the trachea consist of…
- pseudostratified columnar w ciliated cells, goblet cells, and basal cells
- CT (which has seromucous glands, smooth muscle and hyaline cartilage)
describe the lamina propia
- loose CT beneath the epithelium
- has defence cells
- has elastic fibres
- has seromucous glands
- has mucosal venules
what are the functions of respiratory mucosa
- trap particles w secretions from goblet cells
- humidify air
- warm air
- removal of pathogens
describe the adventitia
outermost CT layer of wall > hold tube in place
describe alveolar epithelium
- type 1 alveolar cell > squamous for exchange
- type 2 alveolar cell > cuboidal for surfactant release
- alveolar macrophage
What is ventilation
Mechanical process of moving air in and out of airways
Anatomy of ventilation
Muscles, bones, joints, membranes, extra cellular structures
Control of ventilation
Nerves > sensors and processors and efferent phrenic/intercostal nerves
4 components of respiration
Pulmonary ventilation diffusion of O2 and CO2 b/w alveoli and pulmonary circulation, gas transport, gas exchange within body tissue
Mechanics of pulmonary ventilation
Two ways lungs expand to alter volume > contraction of diaphragm to lengthen chest cavity / elevation of ribs to increase anteroposterior diameter of chest cavity
Normal quiet breathing
Diaphragm lengthen + contract to increase chest cavity
Forced breathing
Diaphragm involved BUT ALSO external intercostal for inspiration and abdominal recti and internal intercostals for expiration
Air modification
Inspiration
- warming (surfaces of nasal septum and conchae)
- humidification
- filtration (mucous coating of airways)
Expiration
- expired gas passing over cooler upper airway mucosa leads to return of some of its heat
- water reclaimed by process of condensation
Components of blood air barrier
Alveolar type 1 epithelial cells, basement membrane, endothelial cell, plasma, erythrocyte membrane
Gas transport
- O2 transported in blood dissolved or bound to haemoglobin (cooperative binding)
- CO2 transported in blood dissolved or converted to bicarbonate or bound to proteins
- N2 rapidly dissolves in blood
- unloading of O2 in capillaries facilitates loading of CO2 = haldane effect
Gas exchange in tissue
PO2 low in tissues and PCO2 high in> drives diffusion
