Respiratory Flashcards
(143 cards)
How much air do you normally inhale per breath?
500mL
12-15 breaths/minute= 6-8L/min total ventilation
How much O2 enters the body per minute?
250mL
How much CO2 is expired per minute?
200mL
How many times does the airway divide between the trachea and alveolar sacs?
23 times
What are the first 16 divisions of the airways?
The conducting zones- dead space = 150mL per breath
What are the last 7 divisions of the airways?
Transitional and respiratory zones- for gas exchange = 350mL per breath= alveolar ventilation
Is anatomical dead space = physiological dead space?
In a normal person, yes
How is gas moved in the alveolar region?
Chiefly by diffusion
Where do you find type I and type II pneumocytes?
They line the alveoli
What are type I pneumocytes?
They are flat, large cytoplasmic extensions and are the primary lining of the cells. Simple squamous epithelial cells
What are type II pneumocytes?
They are granular pneumocytes, thicker and have numerous lamellar inclusion bodies. They secrete surfactant
What are the other cells present in the lungs?
Macrophages, lymphocytes, plasma cells, APUD cells, mast cells
What is the volume of the conducting zone?
About 150mL
What is the volume of the lung excluding the conducting zone during resting conditions?
About 2.5-3L
How do you distinguish a respiratory from a terminal bronchiole?
Respiratory bronchioles have alveoli lining the walls
What is the predominant mode of gas flow in the respiratory bronchioles?
Diffusion rather than convection
How many alveoli are there and how big are they?
300million, 0.3mm
What makes the alveolar structure stable?
Surfactant- lowers the surface tension
How are large particles filtered out of the airways?
By the nose
How are particles that reach the airway removed?
By the mucus escalator which is propelled by millions of tiny cilia
Where does the mucus in the airway come from?
From mucous glands and goblet cells in the bronchial walls?
How are particles that reach the alveoli removed?
They are engulfed by macrophages and then material from the alveoli is removed from the lung via lymphatics
What is the blood supply to the lungs?
Mainly from RV- 5L/min
Additionally from bronchial circulation from aorta- this supplies conducting airways down to terminal bronchioles
What is the mean pressure in the pulmonary artery at rest
~15mmHg