Lecture 1 Flashcards
What is the main purpose of the respiratory system?
To get air in and out.
Why is the air not suitable to go straight into our bloodstream?
An unsterile environment is not key for our system. Thus the rest system is important for cleaning and moistening the air.
What is the anatomical division of the respiratory system?
Upper Respiratory Tract.
Lower Respiratory Tract.
What makes up the upper respiratory tract?
From nasal vestibule to pharynx.
What makes up the lower respiratory tract?
From larynx to alveoli.
Why is treatment harder for a LRTI compared to URTI?
It is harder to defend against pathogens. So you get diseases such as pneumonia in a LRTI.
What is the functional division of the respiratory system?
Conducting zone.
What makes up the conducting zone of the respiratory system?
Nasal vestibule to terminal bronchioles.
What makes up the respiratory zone of the respiratory system?
Respiratory bronchioles to alveoli.
Where are the pseudo stratified columnar cells located?
Nasal cavity to the bronchi.
What is the function of the peusodstratified columnar ciliated epithelium?
There is a protective function, where the cilia (motile) beat the layer of mucus to the back of the throat to be swallowed or spit out.
Where are the goblet cells located?
Nasal cavity to the bronchi.
What is the function of the goblet cells?
Produce mucus acutely (quick response i.e. hay fever).
Where are basal cells located?
In the base of the basement membrane.
What is the function of basal cells?
To act as stem cells.
Where are club cells found?
Bronchioles.
What is the function of club cells?
They are cuboidal cells that secrete a watery substance which is important for: hydration and anti-microbial secretion.
What is the function of small granule cells?
These are endocrine cells which secrete histamine.
What is the function of brush cells?
These are sensory cells which produce a nervous response.
Where are Type I pneumocytes found?
In the alveoli.
What is the function of Type I pneumocytes?
Thin squamous cells which allow for a thin flat area -> small blood/air membrane.
Where are Type II penumocytes found?
In the alveoli.
What is the function of Type IIpneumocytes?
Secrete surfactant; which decreases the surface tension within the alveoli.
Where are macrophages found?
In the alveoli.
What is the function of macrophages?
They are defence cells which are wandering in the air space. They attack any pathogens deep in the respiratory zone.
Where is cartilage located?
Trachea and bronchi.
What is the function of cartilage?
Keep the airways patent (open).
Where are the elastic fibres located?
All the way through the tract.
What is the function of the elastic fibres?
Provides elasticity “compliance”.
Where is the collagen located?
Lamina propria (and inter-alveolar septa).
What is the function of collagen?
Provides tension.
Where is the smooth muscle located?
Walls of the airways to the alveolar ducts and bronchioles.
What is the function of the smooth muscle?
More specifically the bronchioles control the tone of the airways, so essentially the flow by constricting or relaxing the muscle.
Why is mucus important?
Helps keep airways hydrated. If cells desiccate they will die.
How many sources of mucus are there?
- Goblet cells.
2. Sero-mucus glands in the submucosa.
What do the glands produce?
Combination of sticky thick mucus - polysaccharides.
How does mucus work?
Biphasic way to help the cilia move.
Where does the cilia beat in the rest tract?
The ones in the LRT beat up to the pharynx, the ones in the nasal cavity beat to the pharynx.
How does the cilia beat?
On the top layer is the thick mucus which captures the particles i.e. pathogens. On the bottom layer there is a watery sol layer. Cilia then have the ability to move in a whip-like structure.
What happens when you have conditions like cystic fibrosis?
Mucocilary escalator has a trouble beating.
What is the function of the respiratory system?
- Area for gas exchange.
- Protection:
- of respiratory surfaces.
- against invading pathogens. - Sound protection.
- Control of blood volume, blood pressure and pH.
What is primary ciliary dyskinesia?
Also known as immotile cilia syndrome. It is a genetic disorder - where there is defective dynein.
What are the symptoms of ciliary dyskinesia?
- Chronic sinus and lung infections: bronchiectasis, pneumonia.
- Ear infections - hearing loss.
- Fertility problems.
- Headaches, hydrocephalus.
What is the diagnosis for primary ciliary dyskinesia?
- Ultrastructural microscopy - look at dynein.
- Measure cilia beat frequency.
- Nitric oxide.
- Genetic testing.
How do you manage primary ciliary dyskinesia?
- Antibiotics.
- Sinus and lung drainage.
- No cure as yet.
What is chronic rhinosinusitis?
Chronic inflammation within the nasal cavity. Constant streaming of mucus. Hard to know what the sources is. You end up changing your epithelium as you blow your nose.
What happens in chronic rhinosinusitis?
Massive hyperplasia of the airway - a lot of goblet cells. Chronic facial pain is common.
How do you treat chronic rhinosinusitis?
Surgeons can snip some of the cone bones to reduce the SA in the nasal cavity that is producing all the mucus.
What does the air need to undergo before reaching the capillaries?
- Filtering - get rid of pathogens.
- Warming.
- Humidifying - saturate it with water.
Where does the air hit first?
The vibrissae (nasal coarse hairs). This allows for debris to get caught.
Where does the air hit second?
The concae (made up of inferior, superior and middle turbinate bones).
What does the concae do?
It slows down the flow of air by swirling it and it throws big articles onto the mucus layer. It also humidifies the air via serous secretions.
What do the capillaries do?
The rich capillary network sits under the cell layer and warms up the air.
How do we protect the epithelium layers?
The nasal cycle.
What is the nasal cycle?
The inferior turbinates undergo alternating swelling with a mean duration of 2.5 hours. During the congested period the cilia beat frequency will drop, allowing the accumulation of mucus and reestablishment of moisture.
What is empty nose syndrome?
Where a person has turbinectomies. They will suffer from chronic nasal dryness and paradoxical obstruction - feeling of a stuffy nose and suffocation.
Describe the anatomy of the trachea?
10cm long.
Larynx to around T4/5.
C-shaped cartilage ring (important for keeping airway open) and connected by smooth muscle called Trachealis (provides flexibility when there is a big bolus of food). respiratory epithelium lines it.
Describe the histology of the trachea?
Inside the lumen have respiratory epithelium (pseudo stratified columnar ciliated cells), goblet cells and basal cells. Glands, smooth muscles and cartilage.
What is the function of the trachea?
Large open tube that is apart of the conducting zone.
Describe the anomy of the bronchus?
There are cartilage plates (to keep the airways open) and there are glands and smooth muscle (not quite continuous) and respiratory epithelium.
Describe the histology of the bronchus?
In the larger bronchi there is respiratory epithelium and the smaller bronchi we get the transition to columnar ciliated and goblet cells.
What is the function of the bronchus?
Conducting zone and conditioning and important branching (feed all area of the lung).
Describe the anatomy of the bronchioles?
[Find the bronchioles at 15 branching]
They are
Describe the histology of the bronchioles?
Now there is cuboidal ciliated epithelium and club cells and smooth muscle.
What is the function of the bronchioles?
Control flow into the alveoli via the contraction/relaxation of the smooth muscle.
What is the terminal bronchiole?
The last bronchiole of the conducting zone.
