Physiology 1 Flashcards
External Respiration Definition
Sequence of events that leads to the exchange of O2 and CO2 between the external environment and cells of the body
How many steps in external respiration?
4
4 steps of external respiration?
Ventilation
Gas exchange between alveoli
Gas transport in the blood
Gas exchange at tissue level
Internal Respiration Definition?
Intra-cellular mechanism which consumes O2 and produces CO2
Ventilation
Mechanical process of moving air between the atmosphere and the alveolar sacs
Gas exchange between alveoli
The exchange of O2 and CO2 between the air in the alveoli and the blood in the pulmonary capillaries
Gas transport in the blood
The binding and transport of O2 and CO2 in the circulating blood
Gas exchange at tissue level
The exchange of 02 and CO2 between blood in the systematic capillaries and the body cells
4 body systems involved in external respiration
Respiratory
Circulatory
Nervous
Haematology
Boyles Law?
At any constant temperature the pressure exerted by a gas varies inversely with the volume of the gas
(As volume of gas increases the pressure exerted by the gas decreases)
What must happen to intra-alveolar pressure for air to flow into the lungs during inspiration?
Must become lower than atmospheric pressure
Intra-alveolar pressure before inspiration?
Equivalent to atmospheric pressure
Why do thorax and lungs expand in Inspiration
Contraction of Inspiratory muscles
2 forces that hold the lungs and thoracic wall in close opposition?
Intrapleural Fluid cohesiveness- water molecules attract each other, pleural membranes stick together
Negative intraplueral pressure- transmural pressure gradient across lung and chest walls
3 pressures important in ventilation?
Atmospheric pressure
Intra-alveolar pressure
Intra-pleural pressure