Respiratory Systems Flashcards
(39 cards)
What is internal respiration?
Metabolism
Energy being made available to cells
What is external respiration?
Delivery of oxygen to tissues and cells
Removal of carbon dioxide
How does gas move across biological membranes?
Diffusion
Define partial pressure.
Pressure of a single gas in a gas mixture
What are physical factors influencing the rate of diffusion?
Partial pressure gradient Diameter of the gas molecules Temperature Solubility of the gas in liquid Thickness of the gas exchange surface Surface area of the gas exchange surface
What does a respiratory system consist of?
Specialised body surfaces for gas exchange
Mechanisms to ventilate the environmental face of this surface
Mechanisms to perfuse the internal face of this surface
What is the primary role of a respiratory system?
Meet the metabolic demands of the organisms
What is ventilation?
Convection of respiratory medium over the gas exchange surfaces (active or passive)
What is the purpose of ventilation?
Maintain partial pressure gradient at respiratory system
Fresh oxygen delivered and carbon dioxide removed
What is the intrapleural pressure at rest (with respect to atmospheric pressure)?
Negative with respect to atmospheric pressure
When does ventilation occur?
When active muscle force is applied to the relaxed respiratory system
Is inspiration active or passive?
Active process
In inspiration, what changes?
Volume of thorax increases
Diaphragm contracts
External intercostal muscles contract
As the volume of the thorax increases, the intrapleural pressure … ?
Falls
What is Boyle’s law?
P1 x V1 = P2 x V2
pressure x volume is constant
As the volume of the thorax increases, what happens to alveoli and alveolar pressure?
Alveoli expand
Air flows into lungs until alveolar pressure equals atmospheric pressure (before it was negative wrt atmospheric pressure)
Is expiration largely passive or active?
Passive
What happens in expiration?
Elastic recoil of lungs and chest wall reduces volume of thorax (passive mechanism) Intrapleural pressure rises Alveoli recoil Alveolar pressure > atmospheric pressure Air expelled from lungs
Air moves … from a region of … to … pressure
Air moves passively from a region of high to low pressure
Pressure-volume graph:
Why does the curve deviate to the right in inspiration?
Because of resistive forces which oppose airflow
Pressure-volume graph:
Why does the curve deviate to the left in expiration?
Resistive forces assist airflow
Describe ventilation in birds.
Birds lung volume changes less than in mammals
Air moves through lungs from interconnected air sacs
Sacs do not participate in gas exchange
Describe ventilation in frogs.
Air forced into lungs
Lungs emptied by abdominal contraction
Describe air movement in insects.
Airways penetrate each body segment, allowing diffusion
Abdominal muscles pump air through tracheae
