Topic 6.4: Gas Exchange Flashcards
Physiological respiration definition
O2 transport to cells within tissues, where energy production occurs
Stages of respiration
a) Ventilation
b) Gas exchange
c) Respiration
Definition of ventilation
Exchange of gases between the lungs and the atmosphere (via breathing)
Definition of gas exchange
Exchange of O2 and CO2 between the alveoli and the bloodstream (via diffusion)
Definition of respiration
Process by which ATP is produced from organic molecules
Structures of the respiratory system (10)
a) Nasal cavity
b) Pharynx
c) Larynx
d) Trachea
e) Bronchi
f) Bronchioles
g) Alveoli
h) Intercostal muscles
i) Diaphragm
j) Abdominal muscles
Steps of respiratory system (4)
a) Air passes through the nose and the pharynx to the trachea.
b) Air travels down the trachea until it divides into two bronchi.
c) Inside each lung, the bronchi divides into bronchioles.
d) Each bronchiole terminates with alveoli, where gas exchange with the bloodstream occurs.
Purpose of ventilation
Maintain concentration gradients of O2 and CO2 between air in alveoli and blood in adjacent capillaries.
Principles of ventilation (2)
a) Muscle contractions cause pressure changes by modifying the volume inside the thorax
b) Gases move via passive diffusion by creating these concentration gradients.
Inhaling mechanism (5)
a) Diaphragm and exterior intercostal contract
b) Abdominals and interior intercostal relax
c) Volume of the chest cavity increases
d) Pressure in lungs decrease below atmospheric pressure
e) Air flows into the lungs to equalize the pressure
Exhaling mechanism (5)
a) Diaphragm and exterior intercostal relax
b) Abdominals and interior intercostal contract
c) Volume of the chest cavity decreases
d) Pressure in lungs increases above atmospheric pressure
e) Air flows out of the lungs to equalize the pressure.
Alveoli definition
Clusters of small sacs found at the end of the bronchioles
Main features of alveoli that facilitate exchange of gases (4)
a) Thin wall (1 cell thick)
b) Spherical shape
c) Rich capillary network
d) Fluid layer
Type I pneumocytes
a) Shape
b) Function
a) Extremely thin
b) Makes up the alveolus wall, easy for diffusion.
Type II pneumocytes
a) Shape
b) Function
a) Cube-shaped
b) Secrete pulmonary surfactant to reduce surface tension and moist surface
c) Able to differentiate into Type 1 pneumocytes.
