Anatomy And Pattern Recogniton Of The Upper Respiratory System And Neck Flashcards
Summary of respiratory system
• Our cells need O2 to produce ATP. It is vital to life
• We also need to eliminate the toxic bi-product of
the cellular processes – CO2
• Our respiratory and cardiovascular system work
in collaboration to exchange and transport gases
• Failure of this process due to pathology will lead
to rapid cell death and a build-up of toxins
• Secondary functions of the respiratory system
include:
• Helps to regulate PH alongside the kidneys
• Smell receptors
• Filters and moistens inspired air
• Sound production
• Release of heat and some water
What is respiratory system divided into
Divided into:
• Upper:
• Nose (nasal cavity and paranasal sinuses)
• Pharynx
• Lower:
• Larynx
• Trachea
• Bronchi
• Lungs
• Conducting system:
• Transport of air: filter, warm, moisten
• Respiratory portion:
• Gas exchange between air and blood
Nose
• Has 3 main functions
• Warming, moistening and filtering inhaled air
• Detecting smell
• Modifying speech and sounds through resonance
• It is the only part of the respiratory system that is externally visible
• Is often divided into
• External – nose
• Internal – nasal cavity
External nose
• Muscle and skin supported by bone/ hyaline cartilage framework
• Lined internally with mucous membrane
• External opening – nares
• Bones:
- Paired nasal bones (bridge)
- Frontal bone (root)
- Maxilla
• Hyaline cartilage:
- Septal cartilage (midline)
- Lateral processes of septal cartilage
- Alar cartilages (form flared rim of nares)
• Shape of nose dependent on cartilage structure
What is Nasal cavity
- Paired spaces either side of midline
- Upper part of respiratory tract between external nares and nasopharynx thought the choanae
- Wedge-shaped (apex anteriorly)
- Formed by complex bone and cartilage framework
- Have floor, roof, and medial/lateral walls
- Separated;
• From each other by nasal septum
• From oral cavity by hard palate
• From the cranial cavity by the frontal, ethmoid, and sphenoid bone
3 regions of nasal cavity
3 regions:
Vestibule:
• Within nares/external nose
• Lined with skin
• Coarse hairs filter large particles
Respiratory:
• Largest
• Very neurovascular (capillaries warm air)
• Respiratory epithelium
Olfactory:
• Contains olfactory (smell receptors)
• Lined with olfactory epithelium
Nasal cavity
Respiratory epithelium
Secretes (1litre per day):
• Mucous
• Watery-fluid containing lysozyme (antibacterial enzyme)
• Defensins (natural antibiotics)
Cilia propel mucous and ‘foreign particles’ towards throat; swallowed and digested
. Medial wall/division between cavities called nasal septum
• Anteriorly formed by septal cartilage
• Posteriorly formed by vomer bone and perpendicular plate of ethmoid bone
Nasal cavity – lateral walls
. Three ‘shelves / scroll-like’ bony protuberances from each wall; nasal conchae (sometimes called turbinates)
• Groove inferior to each called nasal meatus
• Mucous covered
• Increase surface area and cause air turbulence meaning particles more likely to become trapped in mucous
• Also extract moisture and heat on exhaling so not lost
Paranasal sinuses
Extensions of nasal cavity; drain into lateral walls
Develop in adolescence
Four pairs named after bone in which they are found:
• Ethmoid air cells
• Sphenoid sinuses
• Maxillary sinuses (largest)
• Frontal sinuses (variable in size)
• Lined with respiratory mucosa
Help lighten skull and resonate voice
Nasal-lacimal duct also drains into lateral wall of nasal cavity
Pharynx
- Funnel shaped tube between the nasal cavity
(base of skull) and the oesophagus / larynx (C6) - Approximately 13cm long
- Composed of skeletal muscle
- Functions as
• Common pathway for food / air before splitting into the respiratory / digestive systems
• Helps form sounds as a resonating chamber
• Contains the tonsils as part of the immune system - Is subdivided into 3 regions
• Nasopharynx – at the level of the choanae in the
nasal cavity
• Oropharynx – at the level of the oral cavity and
mouth
• Laryngopharynx (or hypopharynx) – at the opening for the larynx: laryngeal inlet
Nasopharynx
. Superior to soft palate; passage of air only
• Swallowing elevates the soft palate to close the nasopharynx
• Continuous with epithelial layer of respiratory region of nasal cavity; similar role
• Pharyngeal tonsil on posterior wall; pathogens in air
• Pharyngotympanic (Eustachian) tubes open into lateral wall
• Adjacent ridge of tubular tonsils; prevent spread of infection into middle ear
Oropharynx
. Continuous with nasopharynx above at the level
of the soft palate; passage of air and food
• Continues inferiorly to level of epiglottis / hyoid bone
• Stratified squamous epithelium; protection
• Opening with oral cavity called oropharyngeal isthmus
• Closed when chewing; can still breath through nose
• Surrounded by arches called palatoglossal folds
• Inferior to this, anterior wall is formed by posterior part of tongue
• More tonsils on posterior tongue and lateral walls of oropharynx
Laryngophalynx
• Continuous with oropharynx above at the level of the hyoid bone passage of air and food
• Continues inferiorly to level of cricoid cartilage (C6) and start of oesophagus and larynx
• Continuous with oesophagus
• Stratified squamous epithelium; protection
The tonsils
. They are collections of lymphoid tissue within the nasal and oral cavities and pharynx as part of the body’s defence against disease
• The largest of these form distinct areas called tonsils
• They form a ring around the pharynx and there are 4 main areas
• Pharyngeal tonsil
• Palatine tonsil
• Lingual tonsil
• Tubal tonsil
Pharyngeal Musculature
. Arranged in two groups separated by fascia (allows passage of other structures)
• Constrictors:
- circular around cavity
- Superior, middle, and inferior
. Longitudinal:
- Vertically orientated
Larynx
• Main function of the larynx are
Breathing
Speaking making noise
Forced closure (val salva)
swallowing
• 5cm long between the laryngopharynx and trachea
• Anterior to 4-6th cervical vertebrae
• Suspended from hyoid bone superiorly
• Inferiorly linked to trachea via ligaments
• Is a framework of 9 cartilages supported and connected by fibrous membrane and intrinsic muscles
• Innervated by branches of the vagus nerve
• Mucosal lined
• Start of the lower respiratory tract, functions as:
- A sphincter to close off the lower respiratory tract; guide passage of food
- Maintain a patent airway
- To produce sound ‘Voice box’
Epiglottis
• Spoon/leaf-shaped elastic cartilage
• Anchored anteriorly on thyroid cartilage
• Projects postero-superiorly into the pharynx posterior to the tongue
• Covered in mucosal epithelium containing tastebuds
• Normally open at laryngeal inlet
• On swallowing, larynx is elevated and epiglottis occludes trachea
So how do we swallow
• Aim to close off lower respiratory tract completely
• Adduction of both vocal and vestibular folds
• Rima glottides, vestibule, and vestibule closed
• Extrinsic muscles elevate the larynx which
causes the epiglottis to close the laryngeal inlet
• Simultaneously causes the oesophagus, posteriorly, to open (attached to cricoid cartilage)
