ch 13 and 14 – Flashcards
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cerebrum
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Two large hemispheres on superior aspect of brain Center of: intelligence and reasoning thought, memory, and judgment voluntary motor, visual, and auditory activities
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cerebrum composition
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longitudinal fissure: deep cleft tracts: form white matter connecting regions corpus callosum: provides main method of communication between hemispheres
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cerebral lateralization
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differences between hemispheres; regions of brain responsible for speech in left hemisphere..
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What is the function of the corpus callosum?
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It provides the main method of communication between the cerebral hemispheres.
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five lobes of cerebrum
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frontal, parietal, temporal, and occipital insula, not visible at surface (fifth lobe)
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frontal lobe
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voluntary motor functions concentration and verbal communication decision making, planning, and personality
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parietal lobe
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postcentral gyrus -general sensory functions
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temporal lobe
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involved with hearing and smell
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occipital lobe
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-processing visual information -storing visual memories
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insula
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-memory -interpretation of taste
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Which lobe of the cerebrum forms the superoposterior part of the hemisphere and is involved with general sensory functions?
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parietal lobe
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Which lobe of the cerebrum forms the anterior part of the hemisphere and is involved with voluntary motor functions, planning and concentration, and personality?
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frontal lobe
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functional areas of cerebrum
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motor area sensory area association area
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motor area
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control voluntary motor function -Primary motor cortex located in precentral gyrus of lobe control voluntary skeletal muscle activity project contralaterally (opposite side) within brainstem or spinal cord
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motor speech area
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broca area controls muscular movement for vocalization
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frontal eye field
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regulates eye movements needed for reading and binocular visions
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sensory areas
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-primary somatoasensory cortex: housed in the post central gyrus -primary visual cortex primary auditory cortex primary olfactory cortex primary gustatory cortex
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primary somatoasensory cortex
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recieves somatic sensory info from proprioceptors, touch, pressure, pain and tempurature has sensory homunculus: inidcates amount of sensory info collected in a region
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primary visual cortex
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receives and processes incoming visual information
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primary auditory cortex
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receives and processes auditory information
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primary olfactory cortex
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provides conscious awareness of smells
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primary gustatory cortex
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involved in processing taste information
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Association areas
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Process and interpret data or coordinate motor response premotor cortex: responsible for coordinating skilled motor activities
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Somatosensory association area
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integrates sensory information determines texture, temperature, pressure, and shape of objects
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Visual association area
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helps process visual information helps us identify things we see
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Auditory association area
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interprets characteristics of sound stores memories of sound heard in the past
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functional brain regions
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integrates information from individual association areas ie. wernickes
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Wernicke area
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typically located only in left hemisphere involved in recognizing, understanding, and comprehending spoken and written language
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gnostic area
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integrates somatosensory, visual, and auditory information of association areas provides comprehensive understanding of current activity
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What role does the primary motor cortex play?
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control of voluntary skeletal muscle activity
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What association area allows us to identify known objects with our eyes closed?
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somatosensory association area
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Hemisphere specialization
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Called cerebral lateralization Categorical hemisphere represational hemisphere: constant contact thru commissures, correlated with handedness
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What are the primary functions of the left cerebral hemisphere? The right?
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The left hemisphere is specialized for language abilities, and sequential and analytical reasoning tasks. The right hemisphere is involved in visuospatial relationships, imagination, artistic skill, and pattern perception.
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epilepsy
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neurological disorder ; neurons transmitting AP to fast
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cerebrovascular accident (CVA or stroke)
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reduced blood supply to the brain. brief episode= transient ischemic attack (TIA)
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diencephalon
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part of prosencephalon
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components of dencephalon
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epithalamus, thalamus, and hypothalamus provides the relay and switches for sensory and motor pathways, controls visceral activitires
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epithalamus
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Posterior portion: houses pineal gland and habenular nuclei has pineal gland: secretes melatonin and regulates circadian rhythm
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What is the function of the pineal gland?
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The pineal gland secretes melatonin, which helps regulate the day-night cycles (circadian rhythm).
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What is the function of the habenular nuclei?
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The habenular nuclei help relay signals from the limbic system to the midbrain and are involved in visceral and emotional responses to odors.
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Thalamus functions
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Principal and final relay point for incoming sensory information Processed and projected to primary somatosensory cortex Information filter e.g., "filters out" sounds in a busy cafeteria while you study
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What is the general function of the thalamus?
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The thalamus is the final relay point for incoming sensory information that is processed and projected to the primary somatosensory cortex. It acts as an information filter.
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hypothalamus
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Anteroinferior region of the diencephalon Infundibulum
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hypothalamus functions
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Master control of the autonomic nervous system Master control of the autonomic nervous system: antidiuretic horm and oxytocin Regulation of body temperature Control of emotional behavior Control of food intake Control of water intake Regulation of sleep-wake rhythms
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Brain Disorders diencephalon
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headache cerebral palsy encephalitis huntington disease parkinson disease: caused by decrease dopamine
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Brainstem
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From superior to inferior: midbrain pons medulla oblongata
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Components of midbrain
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substantia niagra tectum
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substantia niagra
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houses neurons producing dopamine
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tectum
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contains two pairs of sensory colliculi (tectal plate) -superior colliculi(visual) and inferior colliculi(auditory)
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What parts of the midbrain contain paired visual and auditory sensory nuclei?
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The tectum, in the posterior region of the midbrain dorsal to the cerebral aqueduct, which contains the superior colliculi and inferior colliculi.
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What is the function of the substantia nigra?
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The substantia nigra helps control movement, emotional response, and ability to produce pleasure and pain.
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Components of pons
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Middle cerebellar peduncles Pontine respiratory center helps regulate skeletal muscles of breathing
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Medulla oblongata
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Most caudal part of the brainstem Continuous with spinal cord inferiorly All tracts between brain and spinal cord passing through here -crossing over occurs here
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Autonomic nuclei of medulla
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Cardiac center: vasomotor center medullar respiratory center
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cardiac center
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regulates heart's rate and strenght of contraction
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vasomotor center
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controls blood pressure alters diameters of arterioles
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medullar respiratory center
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regulates respiratory rate
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other nuclei in medulla
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involved in courghing, sneezing, salviation, swallowing, gagging, vomiting
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What are the three main autonomic centers located in the medulla?
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The cardiac center regulates heart rate and strength of contraction. The vasomotor center controls blood pressure. The medullary respiratory center regulates respiratory rate.
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Cerebellum
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Second largest part of the brain Produces fine control over muscular actions Stores memories of movement patterns
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The superior, middle, and inferior cerebellar peduncles connect the cerebellum to which parts of the brainstem respectively?
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Midbrain, pons, and medulla
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cerebellar functions
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Coordinates and "fine-tunes" skeletal muscle movements stores memories of previously learned movements regulates activity along voluntary and involuntary motor paths adjusts movements initiated by cerebrum
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more cerebellar functions
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Helps maintain equilibrium and posture Receives proprioceptive information from muscles and joints helps maintain awareness of body's position and muscle tone Continuously receives input from sensory and motor pathways Monitors muscular activity
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Variety of drugs impairing cerebellar function
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leads to: disturbance of gait loss of balance and posture inability to detect proprioceptive information
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Limbic system
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Collectively process and experience emotions
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limbic system componenets
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cingulate gyrus parahippocampal gyrus: associated with hippocampus hippocampus amygladoid body olfactory bulbs, tracts, and cortex fornix
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hippocampus
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assists in storing memories and forming long-term memory -Key memory center
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amygdaloid body
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involved in several aspects of emotion, especially fear can help store emotions depending on emotional context
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olfactory bulb,s tracts, and cortex
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process odors that can provoke emotions
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fornix
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thin tract of white matter connects hippocampus with other limbic structures
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What are the main functions of the limbic system?
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The limbic system is involved with processing and experiencing emotions
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reticular formation
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projects vertically thru core of midbrain, pons, and medulla -has motor and sensory component motor: regulates muscle tone sensory:process visual, auditory, and touch stimuli, not active during day
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consciousness
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Includes awareness of sensation and voluntary motor activities -alertness to sleep
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How is the reticular activating system related to the reticular formation?
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The reticular activating system is the sensory component of the reticular formation, responsible for alerting the cerebrum to incoming sensory information.
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fainting
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brief loss of consciousness
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stupor
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arousable only to extreme stimuli
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coma
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deep and profound unconsciousness alive but unable to respond to environment
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persistent vegetative state
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person without thinking and awareness of environment
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electroencephalogram EEG
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diagnostic test where electrical activity of the brain is measured -plots types of brain waves
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higher order mental functions
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include learning, memory, and reasoning
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memory
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requires higher order mental functions
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types of memory
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sensory: lasts for seconds short term long term secondary tertiary
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short term
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brief, seconds to hours
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long term
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can be converted from short-term memory if information repeated termed encoding may exist for limitless periods of time -stored primarly in association areas
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Conversion of short-term to long-term memory
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hippocampus required for formation of short-term memory
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alzheimer disaese
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leading cause of dementia no cure, some medications to slow course
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amnesia
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partial or complete memory loss
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The spinal cord
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Provides a vital link between brain and rest of body Exhibits some functional independence from the brain
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Spinal cord and spinal nerves
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Pathway for sensory and motor nerve signals Responsible for reflexes, quickest reactions to stimulus
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Dermatomes
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Specific segment of skin supplied by single spinal nerve All spinal nerves except C1 Can indicate potential damage to one or more spinal nerves Involved in referred visceral pain --pain from one organ referred to a dermatome
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shingles
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Reactivation of chickenpox infection Rash and blisters along the dermatome
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spinal cord Conduction pathways characteristics
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Travel through white matter of the spinal cord Tract (axon bundle) and nucleus (collection of neuron cell bodies) sensory pathways motor pathways contrallateral ipsilateral
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sensory pathways
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ASCENDING pathways receptors ascending to the brain somatosensory pathways viserosensory pathways
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motor pathways
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DESCENDING pathways from brain TO muscles
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contralateral
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relationship to opposite side
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ipsilateral
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same side
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What are the three characteristics common to most nervous system pathways?
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Most pathways decussate while traveling through the white matter of spinal cord, consist of paired tracts, and are composed of two or three neurons working together.
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decussate
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cross over
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primary neuron in sensory pathway
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first neuron in chain -posterior root ganglia of spinal nerves
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secondary neuron in sensory pathway
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interneuron within posterior horn of spinal cord or brainstem nucleus
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tertiary neuron
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interneuron residing in thalamus
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What are the locations and functions of primary, secondary, and tertiary neurons in sensory pathways?
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Primary neurons: posterior root ganglia of spinal nerves. They project to secondary neurons. Secondary neurons: posterior horn of spinal cord or brainstem nucleus. They project to thalamus or cerebellum. Tertiary neurons: within thalamus. They project to the primary somatosensory cortex.
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Motor pathways
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Descending pathways in the brain and spinal cord only looking at motor pathways controlling skeletal muscle in this chapter
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motor pathway spinal cord components
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upper motor neuron and lower motor neuron
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upper motor neuron
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housed within cerebral cortex or nuclei within brainstem
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lower neuron
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housed within anterior horn of spinal cord or brainstem cranial nucleus always excitatory
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What are the locations and functions of upper and lower motor neurons in motor pathways?
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Upper motor neurons are found within the cerebral cortex or a nucleus within the brainstem. They synapse on lower motor neurons or interneurons. Lower motor neurons are found within the anterior horn of the spinal cord or a brainstem cranial nerve nucleus. They project to skeletal muscles to be innervated.
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Reflex properties
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Rapid, pre-programmed, involuntary reactions of muscles or glands Stimulus required to initiate response
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What are the main properties of a reflex?
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stimulus required to initiate a response to sensory input rapid response requiring few neurons pre-programmed and involuntary response
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reflex arc
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neural wiring of a single reflex
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5 steps of reflex arc
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1. Stimulus activates a receptor. 2. Nerve signal travels through sensory neuron to the CNS. 3. Information from the nerve signal is processed by interneurons. 4. The motor neuron transmits a nerve signal to an effector. 5. effector responds to the nerve signal from the motor neuron
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reflex types
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ipsilateral reflex arcs contral lateral " " monosynaptic reflex polysynaptic relfex
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ipsilateral reflex arc
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both receptor and effector organs on same side of spinal cord
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contralateral reflex arc
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sensory impulses from receptor on opposite sides of spinal cord
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monosynsaptic reflex arc
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simplest of all reflexes ie. patellar reflex
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polysnaptic reflex arc
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more complex neural pathways -always involves at least 1 interneuron withdrawal reflex
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What are the five steps involved in activation of a reflex?
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Stimulus activates a receptor. Nerve signal travels through to the CNS. Information from the signal is processes by interneurons. Motor neuron transmits a nerve signal to an effector. Effector responds to nerve signal.
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stretch reflex
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Monosynaptic reflex Regulates skeletal muscle length muscle spindle: only at distal regions, detects changes in muscle reciprocal inhibition
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biceps reflex
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monosynaptic stretch reflex initiate muscle contraction and flex elbow joint
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Golgi tendon reflex
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Prevents muscles from contracting excessively Polysynaptic reflex Results in muscle lengthening Occurring in response to tension at Golgi tendon organ
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reflex path of golgi tendon
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protects muscle and tendon from excessive damage
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reciprocal activation of golgi tendon
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stimulation of alpha motor neurons of antagonistic muscles; stretch reflex may be nullified by golgi tendon reflex under extreme tension
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Crossed-extensor reflex
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Often in conjunction with withdrawal reflex Reflex path
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What are the four common spinal reflexes?
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Stretch reflex Golgi tendon reflex Withdrawal reflex Crossed-extensor reflex
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Reflex variations
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Used to test specific muscle groups and spinal nerves may signal damage to nervous system or muscles
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reflex variations: hypoactive reflex
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reflex diminished or absent -damage to segment of spinal cord
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clonus
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rhythmic oscillations between flexion and extension -may indicate damage
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hyperactive
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abnormally strong response clonus -damage in brain or spinal cord
