M9S2 Conducting Portion Flashcards
What is the conducting portion
-carries air to and from lungs without contributing to gas exchange
-air condition and denfense important aspects to this area
What anatomical structures make up conducting portion
Paranasal sinuses
Nose and naval cavity
Pharynx
Larynx
Trachea
Primary bronchi
End of conducting portion
Paranasal sinuses
-collection of air filled spaces within bones of skull communicating with nasal cavity
-aid in conditioning of air (warming and humidifying), defense against pathogens and act as resonance chambers for speech
-paired sinuses so TWO OF EACH and named after bone of skull that contains it
-lined with respiratory tract epithelium, again contributing to its function of defence and conditioning
What causes a cold
When epithelial lining of sinuses become inflamed or swollen due to infection, pressure can build up due to blockage of mucous and result in sinus cold or headache
Nose and nasal cavity
-first line of defence against invading pathogens and debris, trapping them in coarse hair and mucus
-air enters the vestibules (openings) of nostrils and passed into nasal cavity where conditioned
Nasal cavity boundaries
-they surround the cavity and are bony structures
1. Roof
-bone in skull called ethmoid
2. Floor
-composed of hard palate (roof of mouth)
3. Medial wall
-makes up nasal septum
-septum composed of the vertical bones in skull and separates two halves of nasal cavity
4. Lateral wall
-contains structures known as nasal conchae
-structures create turbulence in air as it passes through cavity, allowing for conditioning and catching debris
5. Anterior
-anterior boarder of cavity
-made by nares, which opening between nose and nasal cavity
6. Posterior
-posterior boarder opening to nasopharynx (choanae NOT CONCHAE WHICH IS SOMETHING ELSE) where nasal cavity connects to pharynx
Nasal cavity histology
1. Respiratory tract epithelium (RTE)
-covers most nasal cavity
-role in protecting from airborne debris and microorganisms and conditions air
2. Olfactory Epithelium
-lines roof of nasal cavity, which contains sensory receptors for smell
-composed of Pseudostratified ciliated columnar epithelium and bipolar olfactory receptor neurons
The pharynx
-muscular tube connecting nasal cavity and larynx in respiratory system
-connect oral cavity with esophagus in digestive system
Components of pharynx
-3 components:
1. nasopharynx
-most superior aspect of pharynx
2. oropharynx
-middle aspect
-part of respiratory and digestive system
-muscular tube passes air from nasopharynx and food from oral cavity into laryngopharynx
3.laryngopharynx
-most inferior part
-involves both digestive and respiratory system, passing both food and air into respiratory systems
Histology of pharynx
-regions of pharynx have different histology due to varying functions
-nasopharynx = mostly RTE as mailing respiratory function
-oropharynx and laryngopharynx = stratified squamous epithelium as need durability when swallowing food
The larynx
-organ that produces sound
-aka voice box
-made up of variety of cartilage, ligaments and associated muscles
-sits anterior to esophagus, connecting pharynx with trachea and preventing food from entering in trachea
Cartilage in larynx
-made of many cartilages that serve to protect, attach and aid in function of vocal cords
1. Epiglottis
-large spoon shaped
-elastic cartilage
-function to prevent food from passing into trachea (windpipe)
-during swallowing, it flips downwards and covers opening of trachea
2. Thyroid cartilage
-shelf shaped hyaline cartilage
-provides attachment for many muscles as well as vocal cords
-if protrudes from neck = Adams apple
3. Cricoid cartilage
-complete ring of hyaline cartilage
-narrow anteriorly and broad posterior
-functions as attachment for muscles and vocal cords
Vocal cords
-small ligaments attached to laryngeal cartilages that vibrate when air forced out of lungs
-when cords vibrate, sound produced (vibration)
-different sounds made by altering tension on cords
-true vocal cords (ligaments that produce sound) are protected by membranous flaps called false vocal cords
How they work:
-open when breath so air pass through, come together when make noise, cover when swallow b y epiglottis (fluid through = cough
-stretch larger on higher notes, on lower notes thicken and shorten
The trachea (windpipe)
-extends from larynx to approximately level of T4/T5 where splits at junction called carina
-function is conduction of air to lungs
Structure
-made of 15-20 C-shaped cartilaginous rings, which incomplete posteriorly
-rings function to keep airway open
-cartilaginous rings connected posteriorly by trachealis muscles
Histology of trachea
1. Mucous
-lined with RTE in order to clear debris or pathogens that make it into lower respiratory tract
2. Submucosa
-lies between mucous and adventitia
-made up of loose (areolar) collective tissue, containing large vessels and nerves as well as mucus secreting glands
3. Adventitia
-outer layer of connective tissue surrounding trachea
-encloses the “C-shaped” cartilaginous rings made of hyaline cartilage
-rings make trachea flexible and durable, which important as organs in thoracic cavity shift with movement of breathing
Primary bronchi
-splitting of trachea results in 2 primary bronchi, left and right
-both have same function and histological features as trachea
-each primary bronchus enters its respective lung on the medial side at the hilus
-right primary bronchus is wider, shorter and more vertical than left so more likely for foreign objects
End of conducting portion
-characterized by bronchi diving into smaller and smaller tubes
-moving from the larger diameter, thick walled tubes -> smaller diameter and thin walled tube for GAS EXCHANGE
-corresponding change in histology as move down tree
Divided by: primary bronchi, secondary bronchi, tertiary bronchi, terminal bronchioles
After inhaled air reaches the terminal bronchioles, where does the air travel next
Respiratory portion
