Respiratory Basics I & II Flashcards
What are the basic functions of the respiratory system
Gas exchange
Regulate blood pH
Contain receptors of smell, produces sound, excretes small amounts of water and heat
Blood reservoir
Metabolic functions e.g secretion of surfactant which aids lung expansion
Describe the function of conducting zone and name the areas
Passageway for air for nose, nasal cavity, trachea, bronchi, terminal bronchioles.
Conducting zone warms air, humidifies air, filters air where mucus traps inhaled particles and cilia (to provide protection) moves it
Macrophages ingulf bacteria
Describe the function of the respiratory zone and name the areas
Location for gas diffusion and exchange
In the respiratory bronchioles, alveolar ducts, sacs and alveoli
What is an ideal site of gas exchange
Alveoli which is spongy mass budding from walls of respiratory bronchioles, alveolar ducts and sacs. 1 cell thick. Extensive blood perfusion.
Name the histology of alveolar
P1 - type I pneumocytes
p2 - type II pneumocyte
M - alveolar macrophage
C - capillary
E - capillary endothelial cells
How to calculate ventilation
size of each breath (tidal volume) X breath rate/min
What are the respiratory dead spaces
Anatomical dead space: Volume of conducting airways since air doesn’t reach airways
Physiological dead space: Volume of respiratory system not used in gas exchange as they are not ventilated despite being perfused
How does air flow in and out of the lungs
Gas flow from high to low
Pressure in lungs must be lower than atmospheric pressure for air entry
Mechanical forces caused by muscular movements change thoracic volume and sets up pressure gradients
What are the 2 sites for respiratory pressure changes
Intrapulmonary pressure which is alveolar pressure and be positive or negative due to muscular movements
Intrapleural pressure which is pleural space pressure. Is sub-atmospheric due to elastic lung recoil and the desire of the ribs to spring out
What is Boyles law
pressure is inversely proportional to volume
What is Charles law
Pressure is proportional to temp
What is daltons law
Total pressure exerted in the mixture is the sum of their partial pressures
What is Henrys law and how to calculate content
Number of gas molecules dissolved in a liquid is proportional to the partial pressure of gas molecules.
solubility X gas partial pressure = content
Describe the muscles of respiration involved in quiet breathing (eupnea)
Diaphragm: 75%
-Phrenic nerves cause it to contract lower than 1cm. Thoracic vertical diameter increase allowing 0.5L air entry per breath
External intercostal muscles: 25%
The muscle lift and increase chest.
‘Bucket-handle’ movement
Describe the muscles of forced inspiration (hypernea)
Phrenic nerves cause it to flatten and lower by 10cm which increases air entry to 2-3L
Accessory muscles recruited
Sternocleomastoids elevate sternum
Scalenes elevate first 2 ribs
