Resp 1 Flashcards
D: Internal respiration
the intracellular mechanisms which consume O2 and produce CO2
D: External respiration
The sequence of events which lead to the exchange of O2 and CO2 between the external environment and the cells of the body
What are the 4 steps to external respiration?
Ventilation, Gas exchange between air in alveoli and the blood, Transport of O2 and CO2 in the blood between lungs and tissues and exchange of O2 and CO2 between blood and tissues
Boyle’s Law
at any constant temperature the pressure exerted by a gas varies inversely with volume of gas (as the volume of gas increases the pressure the gas exerts decreases)
What is the intrapleural fluid cohesiveness?
water molecules in the intrapleural fluid are attracted to each other and resist being separated so the membranes tend to stick together
What is negative intrapleural pressure?
the sub-atmospheric intrapleural pressure creates a pressure gradient across the entire lung wall and chest wall hence the lungs are forced to expand out and the chest is forced to squeeze inwards
Inspiration is a —— process it depends on muscle ——-, it’s major inspiratory muscles are the ——- and ———- ——– muscles
active, contraction, diaphragm and external intercostal muscles
Which nerve controls the diaphragm?
The Phrenic nerve from cervical 3,4 and 5
When the lung size increases air will enter the lungs until
intra-alveolar pressure = atmospheric pressure
The accessory muscles of inspiration are
the sternocleidomastoid, scalenus and pectoral
These contact for forceful inspiration
Expiration is
a passive process caused by the relaxation of the inspiratory muscles
During expiration air leaves down the pressure gradient until
the intra-alveolar pressure=atmospheric pressure
Muscles involved in active expiration are
abdominal muscles and internal intercostal muscles
What is pulmonary surfactant?
the substance which reduces the alveolar surface tension, it is a complex mixture of lipids and proteins secreted by type II alveoli. It intersperses between the water molecules in the alveoli lowering the tension
What would happen if there was no surfactant lining the alveoli?
The alveoli would collapse due to the attraction of the water molecules - surface tension and this would stop you being able to breathe
