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Unformatted text preview: ically.
Increased capacity of the muscle to oxidize fats,
which allows glycogen to be used at a slower
Increased myoglobin content in the muscle,
which stores oxygen and aids oxygen delivery to
An increase in the number of capillaries
surrounding muscle fibers increases oxygen
delivery and removal of wastes.
An increase in the size and density of
mitochondria in the muscle.
An increase in the concentration and activity
of Krebs cycle enzymes improves capacity for
An increase in fiber size which can accommodate
an increase in mitochondria, myoglobin, and
glycogen storage. 1. (a) Sensory: Reception of internal and external
(b) Integrative: Interpretation of sensory messages.
(c) Motor: Initiation and coordination of an
appropriate response to the sensory input. 2. (a) CNS: Brain and spinal cord. The brain has
ultimate control of almost all body activities
(except simple spinal reflexes). The spinal cord
interprets simple reflexes and relays impulses to
and from the brain.
(b) PNS: All nerves and sensory receptors outside
the CNS. Divided into sensory and motor
divisions. The motor division controls both
voluntary (somatic) and involuntary (autonomic)
responses. Regulates sensory reception, relays
impulses to the CNS, brings about the motor
response. 3. Separation of the motor division of the PNS into
somatic and autonomic divisions allows essential
functions to occur without conscious involvement.
In this way, the conscious part of the brain is not
overwhelmed by having to coordinate every motor
response. This improves efficiency of motor function. The Autonomic Nervous System (page 72)
1. (a) Sympathetic NS: Fibers originate from the spinal
cord in thoracic and lumbar regions. Preganglionic
fibers are short and release acetylcholine.
Postganglionic fibers are long and usually liberate
norepinephrine. The sympathetic NS is more
active when the body is preparing for action ('fight
(b) Parasympathetic NS: Fibers originate from the
brainstem and the sacral region of the spinal cord.
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This document was uploaded on 01/28/2014.
- Winter '13