Basic Physiology Of Respiration Flashcards
(23 cards)
What does 10cm H20 equate to in low?
1 kPa
What is atmospheric pressure?
Approximately 101 kPa
What is partial pressure?
Partial pressure is the concentration of gas expressed as a part of the dry atmospheric pressure. Atmospheric pressure = 101kPa (6.3kPa is water vapour) therefore dry atmospheric pressure = 94.7kPa
How do you calculate partial pressure of Nitrogen if there is 79% nitrogen in the air?
PN2 79x94.7/100 =149.626 74.8kPa
What is respiration?
The movement of oxygen to the cells and the removal of carbon dioxide from the cells
What are the 4 processes of respiration?
Ventilation – Movement of air into & out of the lungs
External Respiration – Gas exchange between blood and air-filled chambers of the lungs
Transport of Gases – Cardio-vascular circulation
Internal Respiration – Gas exchange between systemic blood and the tissue cells
What are the organs of the respiratory system?
Nose, nasal cavity, pharynx, trachea, bronchi, bronchioles, and the alveoli
What are the two zones of the respiratory system and what to they do?
Conducting and respiratory zones. The conducting zones transport, cleanse, warm and humidify the incoming air.
Gas exchange with the blood occurs in the respiratory zones. It does NOT occur in the conducting zones
What are the functions of the nose?
Providing an airway for respiration
Moistening and warming air
Filtering inspired air
Serving as a resonating center for speech
Housing the olfactory receptors
What are the functions of the nasal cavity?
Produces over 1 litre of mucus per day
Contains lysozyme.
Traps inspired dust, bacteria, and debris.
High H2O content of mucus humidifies inward air
Ciliary current moves mucus to pharynx for swallowing
Cold temps disable these cilia ↑ runny nose
Rich network of capillaries and veins underlie the nasal epithelium and warm incoming air
What are the functions of the larynx?
The larynx is closed by the epiglottis during swallowing.
In addition to opening and closing the glottis for speech, the vocal folds can act as a sphincter during conditions such as coughing and sneezing
What is dead space?
Some of the inspired air never reaches the respiratory zone and isn’t exchanged.
This volume of air which can occupy the volume of the entire conducting zone is about 150mL. This is called the anatomical dead space.
If some of the alveoli are damaged – their volume is alveolar dead space.
Total DS = Anatomical DS + Alveolar DS
What are the three layers of the trachea?
Mucosa, du mucosa and adventitia
What does the trachea divide into?
Left and right main bronchus
Smoking destroys respiratory cilia - necessitated coughing for mucus propulsion
How does the main bronchus prevent the airway collapsing?
It is supported by cartilaginous rings
What does the left and right main bronchi divide into?
These divide into three lobes in the right lung and two lobes in the left lung. All contain cartilage, as the airways branch further the cartilage is lost and always become known as bronchioles
What is the respiratory zone?
Behind at the transition of terminal bronchioles to respiratory bronchioles which transition alveolar ducts which lead to terminal clusters of thin walled alveoli called alveolar sacs
What is Fick’s law?
It states that the amount of gas moving across a sheet of tissue is proportional to the area of the sheet, but inversely proportional to its thickness. Therefore for efficient diffusion the gas membrane must be extremely thin and cover a large surface area
What is the thickness of the alveoli membrane ?
0.5 microns
What is the diameter of alveoli?
0.2mm in diameter
How does diffusion occur?
Each alveolus is surrounded by a network of capillaries approximately 10 micron in diameter, wide enough for a RBC to pass through
Factors that can influence the diffusion of CO2 and O2 across the respiratory membrane
Partial pressure gradients & solubilities
Matching of alveolar ventilation with pulmonary perfusion
Thickness and surface area of the respiratory membrane
