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Chapter 2. Prehension

Chapter 2. Prehension

Chapter 2. Prehension

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<strong>Chapter</strong> 7 - Opposition Space Phases 297<br />

Somatic Motor System Autonomic Motor Systen<br />

/.<br />

(mechanoreceptors J<br />

/ I CONTA<br />

COMPLIANCE fl<br />

DEFORMATION<br />

FRICTION ADHESION<br />

FRICTION<br />

HEAT<br />

to/ Is\<br />

slip slip<br />

too much lubrication dry and smooth<br />

good grip<br />

boundary lubrication<br />

Figure 7.5 In using an opposition space, the hand generates<br />

appropriate forces along the opposition vector@) for grasping and<br />

manipulative stability, using the muscles (somatically innervated<br />

sensorimotor system) in parallel with the eccrine sweat glands<br />

(autonomically innervated sudomotor system). There is a complex<br />

interplay between the muscles, mechanoreceptors (joint, muscle,<br />

skin), and sweat glands (likely vasodilators also). Healthy<br />

sweating provides boundary lubrication of the palmar surface of<br />

the hand, adhesion, and good grip. With contact, the skin is<br />

deformed, activating mechanoreceptors, and creating heat through<br />

friction. Both of these may lead to secretions by the sweat<br />

glands.

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