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Unformatted text preview: e reduced by (a and b any two of):
• Sweating (cooling by evaporation) • Reducing activity • Behavioural mechanisms such as removing clothing or seeking shade • Increasing blood flow to skin (leads to increased radiation from the skin
surface). 2. (a) Hypothalamus: Monitors temperature changes in
the body and coordinates appropriate responses
to counteract the changes.
(b) Skin: Detects changes in skin temperature and
relays the information to the hypothalamus.
In response to input from the hypothalamus,
muscles and capillaries in the skin act as
effectors to bring about an appropriate
(c) Nervous input to effectors: (from hypothalamus)
brings about (through stimulation of muscles)
an appropriate thermoregulatory response (e.g.
raising hairs, constricting blood vessels).
(d) Hormones: Mediate a change in metabolic
rate through their general action on body cells
(epinephrine and thyroxine increase metabolic
rate). Endoscopy allows exploration of organs and
tissues without extensive surgery. This is useful for
diagnosing the exact nature and location of problems
(e.g. blocked fallopian tubes or roughened areas of
cartilage in a knee joint). Explanatory note: Once a
problem is diagnosed, surgery can be performed if
necessary, using very small incisions and specialized
surgical tools that cause minimal tissue damage
(endoscopes are used for viewing during the surgery). 5. Thermoregulation (page 45) Whereas X-rays pass through a person and expose
photographic film, radionuclide scanning involves the
introduction of the radionuclide into the body where
it is differentially absorbed by different tissues. These
tissues then emit radiation which is detected by a
gamma camera. 4. The Integumentary System (page 43)
1. (a) and (b) any of in any order:
– Thermoregulation: cooling by sweating,
vasodilation, and hair flattening, conserving heat
by vasoconstriction and hair erection.
– Skin contains sensory receptors to enable
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This document was uploaded on 01/28/2014.
- Winter '13