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Unformatted text preview: d Antigen Antibody
type Heart size increases because (like any muscle) it gets
bigger with work. The larger size also means it pumps
a greater volume of blood more efficiently. 4. Self-recognition is undesirable:
– During pregnancy. Note: Some features of the
self-recognition system are disabled to enable
growth (to full term) of what is essentially a large
– During tissue and organ grafts/transplants
from another human (allografting) or a nonhuman animal (xenografting). Note: Such grafts
are usually for the purpose of replacing rather
than repairing tissue (e.g. grafting to replace
damaged heart valves). For these grafts, tissuetyping provides the closest match possible
between recipient and donor. The self-recognition
system must also be suppressed indefinitely by
immunosuppressant drugs. Anatomy and Physiology 2. (b) This self-recognition system allows the body
to immediately identify foreign tissue e.g. a
pathogen, and mount an immune attack against it
for the protection of the body’s own tissues. 22
contrast, non-specific resistance refers to defense
against any type of pathogen.
3. Anatomy and Physiology 4. 5. The leukocytes (white blood cells) involved in the
second line of defense are the monocytes (which
mature as macrophages) and the granulocytes
(eosinophils, neutrophils, and basophils), so-called
because of the granular appearance of their
cytoplasm. Their roles are:
– Eosinophils produce antimicrobial substances,
including proteins toxic to certain parasites.
Eosinophils also show some phagocytic
– Basophils release heparin (an anticoagulant) and
histamine which is involved in inflammation and
– Neutrophils and macrophages are phagocytic,
actively engulfing and destroying foreign material
Functional role for (b)–(i) as follows:
(b) Destroys pathogens directly by engulfing them.
(c) Trap pathogens on sticky mucus and cilia move
the trapped microbes out towards the mouth &
(d) Some secretions (sebum) have a pH...
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- Winter '13