403
CHAPTER ELEVEN
Nervous System II
Hemisphere Dominance
Both cerebral hemispheres participate in basic functions,
such as receiving and analyzing sensory impulses, control-
ling skeletal muscles on opposite sides of the body, and stor-
ing memory. However, one side usually acts as a
dominant
hemisphere
for certain other functions.
TABLE
11.5
|
Functions of the Cerebral Lobes
Lobe
Functions
Frontal lobes
Association areas carry on higher intellectual processes
for concentrating, planning, complex problem solving,
and judging the consequences of behavior.
Motor areas control movements of voluntary skeletal
muscles.
Parietal lobes
Sensory areas provide sensations of temperature, touch,
pressure, and pain involving the skin.
Association areas function in understanding speech and
in using words to express thoughts and feelings.
Temporal lobes
Sensory areas are responsible for hearing.
Association areas interpret sensory experiences and
remember visual scenes, music, and other complex
sensory patterns.
Occipital lobes
Sensory areas are responsible for vision.
Association areas combine visual images with other
sensory experiences.
Parietal lobe
Sensory area
Central sulcus
Motor area
Frontal lobe
Salivation
Vocalization
Mastication
Longitudinal
fissure
Facial
expression
Swallowing
Thumb,
fingers,
and hand
Forearm
Arm
Trunk
Pelvis
Thigh
Leg
Foot and
toes
Lips
Upper
face
Tongue and
pharynx
Hand, fingers,
and thumb
Forearm
Arm
Neck
Trunk
Pelvis
Thigh
Leg
Foot and
toes
Genitals
Teeth and
gums
(a) Motor area
(b) Sensory area
Longitudinal
fissure
FIGURE 11.18
Functional regions of the cerebral cortex. (
a
) Motor areas that control voluntary muscles (only left hemisphere shown). (
b
) Sensory
areas involved with cutaneous and other senses (only left hemisphere shown).
Tests indicate that the left hemisphere is dominant in 90% of right-
handed adults and in 64% of left-handed ones. The right hemisphere
is dominant in 10% of right-handed adults and in 20% of left-handed
ones. The hemispheres are equally dominant in the remaining 16%
of left-handed persons. As a consequence of hemisphere dominance,
the motor speech area on one side almost completely controls the
motor activities associated with speech. For this reason, over 90% of
patients with language impairment stemming from problems in the
cerebrum have disorders in the left hemisphere.
previous page 433 David Shier Hole's Human Anatomy and Physiology 2010 read online next page 435 David Shier Hole's Human Anatomy and Physiology 2010 read online Home Toggle text on/off