Lecture 4- Upper Resp. System + Neck Flashcards
What does the respiratory system consist of?
→ upper:
Nose (nasal cavity and paradisal sinuses)
Pharynx
→ lower:
Laynx
Trachea
Branchi
Lungs
Conducting system:
Transport of air, filer, warm, moisten
Respiratory portion
Gas exchange between air and blood
Functions of the nose and what Is IT divided into
3 function:
→ warming, moistering+ filtering inhaled air
→ detecting smell
→ modifying speech+ sounds through resonance
Often divided into:
External-nose
Internal- nasal cavity.
What is the external nose?
What bones make it up?
Muscle and skin supported by bone/hyaline cartilage framework
Lined internally with mucous membrane
Ext-opening- nares
Bones:
Paired nasal bones (bridge)
Frontal bone (root)
Maxilla
Hyaline cartilage in the external nose
→ septal cartilage (midline)
→ lateral processes of septal cartilage
→ alar cartilages (form flared rim of nares)
Shape of nose dependent on cartilage structure
What is the nasal cavity?
What Is IT separated from?
Pained spaces either side of midline
→ wedge shaped apex ( 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 bones
What are the 3 regions of the nasal cavity
→ vestibule
Within nares / ext. Nose
Lined with skin
Coarse hairs filter large particles
→respiratory:
Largest
Very neurovascular (capillaries warmair)
Respiratory epithelium
→ olfactory:
Contains olfactory (smell receptors)
Lined with olfactory epithelium
what is the respiratory epithelium and its role?
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
what is the nasal cavity, what is it formed by?
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
what is the paranasal sinuses, when does it develop?
Extensions of nasal cavity; drain into lateral walls
Develop in adolescence
name 4 pairs of sinuses named after the bone in which they are found
Ethmoid air cells
Sphenoid sinuses
Maxillary sinuses (largest)
Frontal sinuses (variable in size)
what are some features of the paranasal sinuses
Lined with respiratory mucosa
Help lighten skull and resonate voice
Naso-lacimal duct also drains into lateral wall of nasal cavity
what is the pharynx, how long is it and what is it composed of?
Funnel shaped tube between the nasal cavity (base of skull) and the oesophagus / larynx (C6)
Approximately 13cm long
Composed of skeletal muscle
what are the functions of the pharynx?
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
what 3 regions is the pharynx sub divided into?
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
what is the 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 (or fauces) isthmus
Closed when chewing; can still breath through nose
Surrounded by arches called palatoglossal folds
Inferior to this, anterior wall is formed by posterior (pharyngeal) part of tongue
More tonsils on posterior tongue (lingual) and lateral walls of oropharynx (palatine)
Laryngopharynx
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
what are 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
what 4 main tonsils form a ring around the pharynx
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
Stacked like cups
Join posteriorly at pharyngeal raphe
Sequentially contract to propel food into oesophagus
Longitudinal:
Vertically orientated
Named according to origin;
Stylopharyngeus
Salpingopharyngeus
Palatopharyngeus
Insert on constrictors/fascia
Elevate pharynx during swallowing and pull wall over bolus to help propulsion
whats the main function of the 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
what are some features of the larynx?
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
unattached posteriorly
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 - like a trap door!
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)
The Neck
Extends from
Anteriorly
Inferior border of the mandible to the manubrium
Posteriorly
Posterior occipital protuberance to C7/T1 disc space
what 4 components is the neck often divided into?
Visceral;
Anterior
Contains parts of digestive and respiratory systems
Also contains several endocrine glands
Vertebral;
Posterior
Contains vertebrae and related muscles
Also contains spinal cord and nerves
Left / right Vascular; Lateral
Contains major vessels and vagus nerve (CN X)
Separated by surrounding layers of cervical fascia
c3/c4 surface anatomy
Superior border of thyroid cartilage (palpable)
Bifurcation of common carotid artery
C5/C6 surface anatomy
Indentation of cricoid cartilage / first tracheal ring (palpable)
Inferior border of pharynx / larynx
Superior limit of trachea / oesophagus
what are the 2 types of muscles of the neck?
-superficial - closer to the surface of the skin
-deep- lies closer to bone or internal organs
Thyroid gland
Lies anteriorly in the midline of the neck
There are 2 lobes and in total is approximately 5cm long.
It is part of the endocrine system and is key to several metabolic functions including:
Production of thyroxine, calcitonin and tri-idothyronine
Assists in protein, fat and carbohydrate production, heat production and calcium regulation
Parathyroid glands
These are bilateral glands (4) in the posterior aspect of the thyroid gland
Secrete parathyroid hormones. This increases blood calcium levels.
Calcium is needed for
Muscle contraction
Transmission of nerve impulses
Blood clotting
Normal enzyme actions
