By which mechanism, oxygen is transported from lungs to cells?
Diffusion
Facilitated diffusion
Transpiration
Osmosis
A large proportion of oxygen is left unused in the human blood even after its uptake by the body tissues.
This O2
raises the PCO2 of blood to 75mm of Hg
is enough to keep oxyhaemoglobin
helps in releasing more O2 to the epithelial tissues
acts as a reserve during muscular exercises
Which fact suggests that most oxygen is transported from lungs to the tissues combined with haemoglobin rather than dissolved in blood plasma?
Oxygen carrying capacity of whole blood is much higher than that of plasma and oxygen content of blood leaving the lungs is greater than that of blood entering the lungs
Haemoglobin can combine with oxygen
Oxyhaemoglobin can dissociate into haemoglobin and oxygen
Increase in carbon dioxide concentration decreases the oxygen affinity of haemoglobin
Exchange of gases in man takes place in
trachea
bronchus
alveoli
All of these
Amount of CO2 in expired air is about
0.04%
0.03%
4.5%
2.1%
During inspiration, the diaphragm
expands
shows no change
contracts and flattens
relaxes to become dome-shaped
Pick the correct statement.
The contraction of internal intercostal muscles lifts up the ribs
The RBCs transport oxygen only
The thoracic cavity is anatomically an air tight chamber
Healthy man can inspire approximately 500mL of air per minute
After a deep inspiration and maximum expiration, the capacity of lungs is known as
vital capacity
tidal volume
IRV
ERV
During normal respiration without any effort the volume of air inspired or expired is called
reserve volume
residual volume
None of these
Which of the following respiratory organs are present in spiders and scorpions?
Book lungs
Gills
Gill books
Lungs