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Unformatted text preview: turation declines
markedly and oxygen is released (to the tissues). 4. (a) Fetal Hb has a higher affinity for oxygen than
adult Hb (it can carry 20-30% more oxygen).
(b) This higher affinity is necessary because it
enables oxygen to pass from the maternal Hb to
the fetal Hb across the placenta. 5. (a) The Bohr effect.
(b) Actively respiring tissue consumes a lot of oxygen
and generates a lot of carbon dioxide. This lowers
tissue pH causing more oxygen to be released
from the hemoglobin to where it is required. 6. Myoglobin preferentially picks up oxygen from Hb and
is able to act as an oxygen store in the muscle. 7. Any two of: Hemoglobin, which picks up H+
generated by the dissociation of carbonic acid.
Bicarbonate alone (from this dissociation), and
combined with Na+ (from the dissociation of NaCl).
Blood proteins. ✓ 2 Bronchus ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✗ ✗ ✓ ✓ ✗ very
little ✓ 3
5 5. Bronchioles gradually
Alveoli ✗ ✗ The lack of surfactant and high surface tension in
the alveoli result in the collapse of the lungs to an
uninflated state after each breath. Breathing is
difficult and labored, oxygen delivery is inadequate
and, if untreated, death usually follows in a few
hours. Measuring Lung Function (page 163)
1. 2. 3. (a) Taller people generally have larger lung volumes
(b) Males have larger lung volumes and capacities
(c) After adulthood, lung volume and capacity
declines with age. Children have smaller lung
volumes and lung capacities than adults.
(a) Forced volume is a more useful indicator of
impairment of lung function than a tidal volume
because people use only a small proportion of
their lung volume in normal breathing.
(b) Spirometry can be used to measure the extent of
recovery of lung function after treatment. (a)
(f) Tidal volume
Expiratory reserve volume
Total lung capacity vol:
L 4. G: Tidal volume is increasing as a result of exercise. 5. PV: 15 x 400 = 6000 cm3 o...
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This document was uploaded on 01/28/2014.
- Winter '13