Lecture 14: Overview and URT Flashcards
What are the four structures of the upper respiratory tract?
Nose
Nasal Cavity
Paranasal sinuses
Pharynx
What are the six structures of the lower respiratory system?
Larynx
Trachea
Bronchus
Bronchioles
Respiratory bronchioles
Alveoli
What are the three other main components of the respiratory system?
- Thoracic cavity
- Joints
- Respiratory muscles
What are the four main zones or cavity that make up the respiratory system and where can they be found?
- Conducting zone:
- Nose to bronchioles (basically most of the respiratory system)
- Ensures air is warm, clean moist - Nasal cavity:
- found behind the nose
- main function is Olfaction (smell) - Oral cavity:
- mouth area
- is a Passage for air and food - Respiratory zone:
- Bronchioles to alveoli (much lower section of respiratory system (lungs))
- Sites of gas exchange
What are the respected Epithelia (4) in the Respiratory System and how is it attached?
Tract lined with mucosa:
Epithelium attached via basement membrane to lamina propria (Connective Tissue)
Epithelium changes along length of tract to reflect function:
Most of the conducting region
* Respiratory epithelium
Where air & food travel
* Stratified squamous
Site of gas exchange
* Simple squamous
Olfaction
* Olfactory mucosa
Give a brief overview of the layers of the respiratory tract:
Mucosa layer: (3 parts, top to bottom)
- Epithelia
- Basement membrane
- lamina propria (connective tissue that may contain glands)
Under the mucosa is the submucosa:
- connective tissue
- depending on the region may contain glands
What is respiratory epithelium and where is it found?
Pseudostratified ciliated columnar epithelium (with goblet cells)
Found in nasal cavity, part of pharynx, larynx, trachea and bronchi
What is the role of goblet cells?
produce mucus which Traps debris and moistens air
What is the role of ciliated cells in the respiratory system?
Patterned movement pushes mucus towards the pharynx
This mucus can then be swallowed and digested by stomach acid
What are the main structures and role of the nose?
The nose is the primary passageway for air
Structure:
- The bridge of the nose is made of 2 nasal bones
- It has nasal Cartilages, which are Soft and flexible and help maintain patent (unobstructed) airway
- It has Nostrils other wise known as External nares
- the Vestibule is lined with skin
- has sebaceous glands, sweat glands and hair follicles
- Vibrissae (hairs) filter inhaled air
What are the anterior and posterior aspects of the septum?
The anterior is made of cartilage
The posterior is made of bone (ethmoid bone)
What bones make up the nasal cavity?
Roof of the cavity is formed by the ethmoid and sphenoid bones
The floor of the cavity is formed by soft and hard palates
What is the nasal conchae and what is its function?
Main function is to swirl air in the nasal cavity allowing it more time to clean, warm and moisten the air (why they are also known as turbinates = like turbines)
Has Three projections:
* Superior, middle and inferior conchae (turbinates)
- Covered by mostly respiratory epithelium
- Swirl inspired air
- Particles stick to mucosa
- allows more time for warming and humidifying of air, plus olfactory detection
What epithelium is found in the nasal cavity?
Mostly respiratory epithelium
Has a specialised area at the roof of the cavity of olfactory epithelium which contains olfactory receptors
From nasal cavity up, olfactory epithelium contains:
- Olfactory dendrites
- Olfactory support cells in amongst Olfactory receptor cells
- The receptor cells move up into olfactory nerve fibers
Briefly describe nasal mucosa:
Epithelium sits on lamina propria
- has a Thin-walled vascular plexus
- Helps warm incoming air
- When air temperature drops, plexus dilates = greater heat transfer (so warmer air)
- Nose bleeds normally originate from damage here
What are the paranasal sinuses and what are there function?
They are sinuses (normally air filled) that surround the nose
Found within frontal, sphenoid, ethmoid and maxillary bones (4 types of sinus)
Lined with respiratory mucosa which drains into the pharynx
Functions:
* Lighten skull
* Increased surface area to clean, warm, moisten air
* Sound resonance (important)
* Infected mucus can block drainage = blocked sinuses = heavy flu like head
What are the three regions of the pharynx called?
- Nasopharynx (air passage ONLY)
- Oropharynx
- Laryngopharynx
What and where is the Nasopharynx, what type of epithelium and what structure can be found within?
It is the Air passage only
It is Posterior to the nasal cavity, From internal nares to soft palate
Has respiratory epithelium
Also contains the Pharyngeal tonsils (adenoids) on the posterior wall
What prevents food from entering the nasal cavity?
Soft palate and uvula block the nasopharynx during swallowing to prevent food from entering the nasal cavity
Where do the auditory tubes drain into?
The nasopharynx
What and where is the Oropharynx, what type of epithelium and what structures can be found within?
Air and food can pass through
Posterior to oral cavity, From soft palate to hyoid bone
Has Stratified squamous epithelium = protection
against abrasion
Includes the Palatine tonsils and Lingual tonsils
What and where is the Laryngopharynx, what type of epithelium?
Air and food can pass through
From hyoid bone to opening of larynx/beginning of esophagus. Ends at the level where respiratory and digestive tracts diverge
Has Stratified squamous epithelium = protection
against abrasion
Where in the URT would you find stratified squamous epithelium?
Nasal vestibule, oropharynx and laryngopharynx
Why does your nose run on a cold day?
In cold temperatures, cilia will stop beating. With nothing to help move the mucus towards the pharynx, it can ‘dribble’ out of your nose.
Why do we cough up mucus when we are unwell?
Normally produce 1-2L of mucus a day. When we’re sick, the body produces more, so we cough to help the cilia move the mucus
Why do smokers cough?
Cigarette smoke paralyses and destroys cilia. This leads to mucus accumulation and coughing to try and dislodge it.
