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Unformatted text preview: viral infection. In
patients disadvantaged (immune suppressed) by their
disorder, this could severely undermine their health.
Retroviruses infect only dividing cells, so uptake can be poor.
Viruses may not survive if attacked by the host’s immune system.
If they do not integrate into the chromosome, the inserted genes may only function sporadically. Autoimmune Diseases (page 155) Monoclonal antibody therapies are called targeted
therapies because they target only the cells with the
specific antigens for the antibody involved - no others. Gene Therapy (page 153)
1. the recipient's untreated cells. Biozone International 2009 Photocopying Prohibited 27
The Human Respiratory System (page 161)
1. (a) The structural arrangement (lobes, each with its
own bronchus and dividing many times before
terminating in numerous alveoli) provides an
immense surface area for gas exchange.
(b) Gas exchange takes place in the alveoli. 2. Respiratory membrane is the layered junction
between the alveolar cells, the endothelial cells
of the capillaries, and their associated basement
membranes. It provides a surface across which gases
can freely move. (b) The CO2 is the product of cellular respiration in
the tissues. Note: Some texts give a value of
4.0% for exhaled air (100X the CO2 content of
(c) The dead space air is not involved in gas
exchange therefore retains a higher oxygen
content than the air that leaves the alveoli air. This
raises the oxygen content of the expired air. Gas Transport in Humans (page 165) Completed table: Hemoglobin binds oxygen reversibly, taking up oxygen
when oxygen tensions are high (lungs), carry oxygen
to where it is required (the tissues) and release it. Region Cartilage Ciliated
tissue 1 Trachea ✓ ✓ ✓ ✓ 3. (a) As oxygen level in the blood increases, more
oxygen combines with hemoglobin. However, the
relationship is not linear: Hb saturation remains
high even when blood oxygen levels fall very low.
(b) When oxygen level (partial pressure) in the blood
or tissues is low, hemoglobin sa...
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- Winter '13