Exam 4 Notes Lesson 16 The Brain 23 11 2011 09 46 00 The Medulla Oblongata Allows brain and spinal cord to communicated Coordinates complex autonomic reflexes Controls visceral functions Nuclei in the Medulla o Autonomic nuclei control visceral activities cardiovascular respiratory reflexes o Sensory and motor nuclei of cranial nerves o Relay stations along sensory and motor pathways The Pons Sensory and motor nuclei of cranial nerves V VI VII VIII Nuclei involved with respiration o Apneustic center and pneumotaxic center Modify respiratory rhythmicity center activity Nuclei that process and relay information to and from cerebellum Ascending descending and transverse tracts o Transverse fibers axons Link nuclei of pons with opposite cerebellar hemisphere The Cerebellum Functions include o Adjustment of postural muscles o Fine tunes conscious and subconscious movements Structures of cerebellum o Arbor Vitae tree of life high branched internal white matter Cerebellar nuclei embedded in arbor vitae relay information to Purkinje Cells o Purkinje Cells large branched cells found in cerebellar cortex Receive input from up to 200 000 synapses o Ataxia damage from trauma or stroke Disturbs muscle coordination Intoxication temporary impairment Disorders The Midbrain Structures o Tectum processes visual and auditory sensations o Tegmentum affects limb position and muscle tone o Reticular activating system component of the reticular formation in the midbrain Important for alertness and attentiveness The Diencephalon Consists of cortex Integrates sensory information and motor commands o Thalamus filters ascending sensory info for primary sensory Info on touch pressure pain temp proproception Left Right Thalamus separated by the Third Ventricle o Epithalamus roof of diencephalon Pineal Gland found in posterior epithalamus Secretes melatonin which is important in the regulation of day night cycle and reproductive function o Hypothalamus Eight Functions Provide subconscious control of skeletal muscle Controls autonomic function Coordinates activity of nervous and endocrine systems Secrete hormones Antidiuretic Hormone ADH by supraoptic Oxytocin OT OXT by paraventricular nucleus nucleus Produce emotions and behavioral drive The feeding and thirst centers Coordinates voluntary and autonomic functions Regulate body temp preoptic area Control circadian rhythms day night cycles Suprachiasmatic nucleus Infundibulum narrow stalk that connects hypothalamus to pituitary gland Mamillary bodies process olfactory and other sensory info control reflex eating movements Tuberal Area located between the infundibulum and mamillary bodies Help control pituitary gland function The Limbic System Functional Group that o Establishes emotional states such as rage fear pain sexual o Links conscious functions of cerebral cortex with autonomic arousal pleasure functions of brain stem o Facilitates memory storage and retrieval Consists of regions of the cerebrum and diencephalon The Cerebrum the largest part of the brain Controls all conscious thought and intellectual functions Processes somatic sensory and motor information Gray matter in cerebral cortex and basal nuclei White matter deep to basal cortex o Association Fibers connections within one hemisphere o Commissural Fibers bands of fibers connecting two hemispheres o Projection Fibers connect cerebrum with lower areas Pass through diencephalon Link Cerebral cortex with Dienscephalon brain stem cerebellum and spinal Internal capsule all ascending and descending cord projection fibers Structures o Gyri of neural cortex increase surface area increase number of cortical neurons o Longitudinal Fissure separates cerebral hemispheres o Lobes divisions of hemispheres divided by sulcus Central sulcus divides the anterior frontal lobe from the posterior parietal lobe Lateral Sulcus divides frontal lobe from temporal lobe Parieto occipital Sulcus divides parietal lobe from occipital lobe Three Functional Principles o Each cerebral hemisphere receives sensory info from and sends motor commands to the opposite side of the body Left hemisphere to right side of the body visa versa o Hemispheres have different functions despite like structures o Correspondence between a specific function and a specific region of cerebral cortex is not precise Motor and Sensory Areas of the cortex o Central sulcus separates motor and sensory areas o Motor Areas Precentral gyrus of frontal lobe primary motor cortex directs voluntary movements Postcentral gyrus of parietal lobe primary sensory cortex receives somatic sensory info Touch pressure pain vibration taste temp Special Sensory Cortexes o Visual cortex information from sight receptors o Auditory cortex information from sound receptors o Olfactory cortex information from odor receptors o Gustatory cortex information from taste receptors Association Areas o Sensory association areas monitor and interpret arriving information at sensory areas of cortex Visual Association Area interprets visual cortex activity Auditory Association Area monitors auditory cortex Somatic Motor Association Area Premotor cortex coordinates motor responses learned movements o Somatic sensory association area interprets input to primary sensory cortex eg Recognizes and responds to touch General Interpretive Area AKA Wernicke s Area o Present in only one hemisphere usually the left one o Receives information from all sensory association areas o Coordinates access to complex visual and auditory memories Other Integrative Areas o Speech Center broca s area associated with general interpretive area Coordinates all vocalization functions o Prefrontal cortex of frontal lobe integrates information from sensory association areas Performs abstract intellectual activities e g predicting consequences of actions Hemispheric Lateralization o Functional differences between left and right hemispheres o Each cerebral hemisphere performs certain functions that are not ordinarily performed by the opposite hemisphere Left Hemisphere usually dominant controls Reading writing math Decision making Speech and language Right Hemisphere relates to Senses touch smell sight taste feel Recognition faces voice inflections Monitoring Brain Activity brain activity assessed by electroencephalogram EEG o Electrodes are placed on skulls patterns of electrical activity brain waves are printed out Four Categories of Brain Waves o Alpha Waves found in healthy awake adults at rest with eyes o Beta Waves
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