Anatomy & Physiology

Anatomy & Physiology Study Guide hormones, produce emotions and behavioral drives, coordinate voluntary and autonomic functions, regulate body temperature, and coordinate circadian cycles of activity. • The thalamus is the final relay point for ascending sensory information and coordinates the activities of the basal nuclei and cerebral cortex. The limbic system is a group of tracts and nuclei with various functions: • The limbic system, or motivational system, includes the amygdaloid body, cingulate gyrus, dentate gyrus, parahippocampal gyrus, hippocampus, and fornix. The functions of the limbic system involve emotional states and related behavioral drives. The cerebrum, the largest region of the brain, contains motor, sensory, and association areas: • The cortical surface contains gyri (elevated ridges) separated by sulci (shallow depressions) or fissures (deeper grooves). The longitudinal fissure separates the two cerebral hemispheres. The central sulcus separates the frontal and parietal lobes. Other sulci form the boundaries of the temporal and occipital lobes. • The white matter of the cerebrum contains association fibers, commissural fibers, and projection fibers. • The basal nuclei include the caudate nucleus, globus pallidus, and putamen; they control muscle tone and coordinate learned movement patterns and other somatic motor activities. • The primary motor cortex of the precentral gyrus directs voluntary movements. The primary sensory cortex of the postcentral gyrus receives somatic sensory information from touch, pressure, pain, vibration, taste, and temperature receptors. • The general interpretive area receives information from all the sensory association areas. It is present in only one hemisphere—generally the left. • Association areas, such as the somatic sensory association area, visual association area, and somatic motor association area (premotor cortex), control our ability to understand sensory information and coordinate a motor response. • The speech center regulates the patterns of breathing and vocalization needed for normal speech. • The prefrontal cortex coordinates information from the secondary and special association areas of the entire cortex and performs abstract intellectual functions. • The left hemisphere typically contains the general interpretive and speech centers and is responsible for language-based skills. The right hemisphere is typically responsible for spatial relationships and analyses. • Brain activity is measured using an electroencephalogram. Alpha waves appear in healthy resting adults; beta waves occur when adults are concentrating; theta waves appear in children; and delta waves are normal during sleep. • We have 12 pairs of cranial nerves. Except for CN I and CN II, each nerve attaches to the ventrolateral surface of the brain stem near the associated sensory or motor nuclei. • The olfactory nerves (CN I) carry sensory information responsible for the sense of smell. The olfactory afferents synapse within the olfactory bulbs. Achieve Page 140 of 368 ©2018