Introduction, Upper Tract And Histology Flashcards
State Boyle’s law
Pressure of a gas is inversely proportional to its volume
If the temperature and number of molecules remains constant
How many divisions of the airways do we have?
23 divisions
Define the conducting airways
The first part of the airways: divisions 1 - 16 of the respiratory tract where no gas exchange occurs
Define the respiratory zone
Lower part of the airways: divisions 17 - 23 where gas exchange can occur
What is the partial pressure of oxygen in alveolar air?
13.3 kPa
How do we work out the partial pressure of a gas in a mixture?
Work out the percentage of the gas in the mixture
Find the whole pressure
Times the two together as partial pressure of a gas is directly proportional to its percentage in the mixture
What is the saturated vapour pressure at body temperature?
6.23 kPa
How do we work out the amount of oxygen dissolved in the plasma?
Solubility coefficient of oxygen multiplied by the partial pressure of oxygen
What is another word for partial pressure?
Tension
Define atmospheric pressure
The pressure exerted by the weight of the air above the earth in the atmosphere
Describe ‘the bends’
High pressure in the lungs causes nitrogen to move it a diver’s blood. A slow return to the surface allows nitrogen to return to the lungs where it is breathed out. Swimming up too quickly doesn’t give nitrogen enough time so it forms bubbles in the blood. These are very painful and can cause an air embolism.
What are the parameters of the upper respiratory tract?
External nose to the lower border of the cricoid cartilage
Where does the larynx become the trachea?
The lower border of the cricoid cartilage
What is another word for nostril?
External nare
What do we call the bony projections inside the nasal cavity and how many are there?
3 conchae/turbinates for each side of the nose
Superior, middle and inferior
What do we call the space under a concha?
Meatus
What is the function of the concha?
Allow the nasal cavity to slow the airflow by increasing the surface area over which it is passing (increased turbulence)
How do we smell?
Using the olfactory mucous membrane at the very top of the nasal cavity
What are the functions of the nasal cavity?
Filter (mucous/cilia)
Humidify
Warm
What drains into the nasal cavity?
Paranasal sinuses
Nasolacrimal duct
What are the names of the paranasal sinuses?
Frontal
Ehtmoidal
Sphenoidal
Maxillary
What is the pharynx?
A fibromuscular tube that extends from the base of the skull to C6
It allows the passage of air from the nasal cavity to the larynx
What are the 3 regions of the pharynx?
Nasopharynx
Oropharynx
Laryngopharynx
What is the Eustachian tube?
The tube that connects the nasopharynx to the middle ear
What are the functions of the larynx?
Guard air passages esp during swallowing
Maintains patent airway
Phonation
Define the glottis
The vocal cords and the space in between them
What is the rima glottidis?
The space between the 2 vocal cords
Give some examples of things that can cause laryngeal obstruction
Oedema
Foreign body
Tumour
How many lobes does each lung have?
Right = 3 Left = 2
Which parts of the respiratory tract do we class as extrapulmonary?
Nasal cavity to the primary bronchi
What epithelium lines the nasal cavity to the secondary bronchi?
Pseudostratified ciliated with goblet cells
What epithelium lines the bronchioles to the terminal bronchioles?
Simple columnar epithelium with cilia and Clara cells
No goblet cells
What epithelium lines the respiratory bronchioles to the alveolar ducts?
Simple cuboidal epithelium with Clara cells and sparse cilia
What epithelium lines the alveoli?
Simple squamous epithelium (type 1)
With a few simple cuboidal (type 2)
Describe the histology of the Olfactory regions
Particularly thick, columnar pseudostratified epithelium
No goblet cells
Microvilli
Describe the pathology of CF
Cystic fibrosis transmembrane regulator not present/working
Chloride ion transport across the membrane compromised
Not enough salt in the mucus therefore water doesn’t follow
Mucus becomes viscous
What are Clara cells?
Cells that secrete a surfactant lipoprotein which prevents the walls of the resp tract from sticking together during expiration
Also secrete abundant Clara cell protein (CC16) which is used as a serum marker for lung damage (low) and leakage across air-blood barrier (high)
New alveoli continue to develop until what age?
8 years old
Describe emphysema
Destruction of alveolar walls and permanent enlargement of air spaces
From smoking or alpha 1 anti-trypsin deficiency
Bronchioles collapse, making it difficult for the lungs to empty
What is the most organism to cause pneumonia?
Streptococcus pneumoniae
What epithelium lines the paranasal sinuses?
Respiratory - pseudostratified ciliated
