Chapter 14: The Brain and Cranial Nerves Flashcards

Question

Notable Structures of the Midbrain

Answer 1

Cerebral aqueduct * Surrounded by central gray substance * Role in pain awareness Tectum * Posterior to cerebral aqueduct * Superior and inferior colliculi * Visual and auditory reflexes Cerebral peduncles * Anterior to cerebral aqueduct * Anchor cerebrum to brainstem * Divided into three regions

Answer 2

Tegmentum * Houses red nucleus * Tracts connect to cerebellum * Participate in fine motor control Substantia nigra * Motor center * Inhibits thalamus and basal nuclei * Suppress unwanted movement Cerebral crus * Connect cerebrum to pons * House corticospinal tracts

Answer 3

Superior colliculi * Control extrinsic eye muscle * Direct gaze * Track moving objects * Move eyes and head due to visual stimuli * Connected to other visual control nuclei Inferior colliculi * Relays information from inner ear to thalamus and other brain regions * Sensitive to time delays between sounds between ears (sound location) * Process pitch fluctuations * Turn head in reflexive responses to sound * Startle reflex to noise

Answer 4

Network of grey matter * Housed between tracts and distinct nuclei * > 100 neural networks * Passes through all regions of brainstem and upper spinal cord * Connections to cerebrum Networks have numerous functions * Sensory and motor

Answer 5

Motor cortex neurons synapse with reticular formation nuclei * Form reticulospinal tracts: alter muscle tension * Balance, posture, muscle tone Relays sensory signals to cerebellum * Visual, auditory, vestibular * Required for cerebellum’s role as motor coordinator * Gaze centers allow eyes to track motion and fix on objects Central pattern generators produce rhythmic signals * Breathing and swallowing

Answer 6

Cardiovascular control * Via cardiac and vasomotor centers * Alters cardiac output and blood pressure Pain modulation * Route for pain signals from lower body to cerebral cortex * Descending analgesic tracts can block pain sensation Sleep and consciousness * Reticular activating system (RAS) * Level of control over which sensations reach cerebrum * Role in stages of consciousness: alertness, sleep * Damage can lead to permanent coma Habituation * Reticular activating system (RAS) * Brain ignores unimportant, repetitive stimuli * Novel or important stimuli are still attended too

Answer 7

Second largest region of brain * 10% of brain’s mass * 50% of brain’s neurons * Component of hindbrain * Numerous granule cell neurons Distinctive Purkinje cells * Highly branched dendrites in single plane

Answer 8

Divided into hemispheres * Connected by vermis * Covered by folia separated by sulci Each hemisphere divided into lobes * Anterior and posterior * Divided by primary fissure Grey matter * Cerebellar cortex: receives input * Deep nuclei: handles output White matter * Arbor vitae

Answer 9

* Connect cerebellum to brainstem * Contain bundles of nerve fibers Superior: midbrain * Output from cerebellum Middle: pons * Input from rest of brain Inferior: medulla oblongata * Input from spine

Answer 10

* Region is still poorly understood * General function appears to be evaluation of sensory input Cerebellar lesions affect a number of functions * Sensory, motor, linguistic, emotional, other nonmotor functions Possible involvement with: * Tactile sensation * Spatial perception * Timekeeping * Predicting path of moving object * Hearing * Language output * Planning/scheduling * Emotion and impulse control

Answer 11

* Important for motor coordination * Aids in learning motor skills * Maintain muscle tone and posture * Smooths muscle contractions * Coordinates eye and body movements * Coordinates motion of different joints

Answer 12

Receives information from * Cerebrum * Eyes and inner ears * Proprioceptors in joints and muscles Cerebrum initiates movement * Sends “plan” to cerebellum Cerebellum compares “plan” to actual movements * Via Purkinje cells Errors stimulate deep nuclei * Send information to thalamus and brainstem * Information sent to motor association area * Information sent to reticulospinal and vestibulospinal tracts * Error corrected

Answer 13

Inferior to cerebrum * Deep to cerebral hemispheres * Component of forebrain * Superior to brainstem Divided into * Epithalamus * Thalamus * Hypothalamus

Answer 14

Paired, oval masses * Joined by interthalamic adhesion (medial) * 4/5ths of diencephalon * Laterally: protrude into lateral ventricles * Medially: protrude into third ventricle Composed of 23 nuclei * Divided into five groups

Answer 15

Sensation * Ascending sensory neurons synapse with thalamic nuclei * General and special senses * Thalamus processes information * Some information sent on to cerebrum * Information sent to corresponding cortical region Motor control * Relays signals from cerebellum to cerebrum * Feedback loops between cerebral cortex and basal nuclei Memory and emotion * Nuclei associated with limbic system

Answer 16

* Inferior and anterior to thalamus Runs from optic chiasm to mammillary bodies * Mammillary nuclei relay limbic signals to thalamus * Makes up walls and floor of third ventricle * Pituitary gland attached via infundibulum * Divided into nuclei

Answer 17

Hormone secretion * Produces oxytocin and antidiuretic hormone * Produces regulatory hormones which control anterior pituitary gland * Influence on metabolism, growth, stress response, reproduction Autonomic effects * Integrating center for the autonomic nervous system * Sends descending fibers to brainstem * Influence heart rate, blood pressure, GI tract secretion and motility, etc. Thermoregulation * Integrating (control) center for negative feedback loop * Monitors body temperature * Activates mechanisms to control temperature Regulation of food intake * Monitors blood nutrient level * Receptors for hormones that influence hunger and satiety * Receptors for hormones that influence body mass Regulation of water intake * Osmoreceptors monitor concentration of blood * Promotes thirst and drinking * Release of ADH Sleep and circadian rhythms * Part of reticular formation * Nuclei regulate sleep/waking rhythms * Controls 24-hour circadian rhythm Memory * Mammillary nuclei lie in pathway between hippocampus and thalamus * Lesions cause memory defects Emotional behavior and sexual response * Centers for anger, fear, aggression, contentment, pleasure * Centers for sexual drive, copulation, orgasm

Answer 18

Smallest portion of diencephalon * Posterior * Forms roof of third ventricle Contains pineal gland * Produces melatonin * Possible role in circadian rhythms * Possible role in mood and sexual maturation Contains habenula * Relays signals from limbic system to midbrain * Connects limbic system to rest of brain

Answer 19

Largest region of brain * Encompasses diencephalon * Component of forebrain Extensively folded compared to other animals * Increases surface area

Answer 20

Two hemispheres * Divided by longitudinal cerebral fissure * Connected by corpus callsoum * Separated from cerebellum via transverse cerebral fissure Divided into five lobes * Divided by sulci Surface covered by raised gyri * Divided by sulci

Answer 21

Frontal lobe * Most anterior/rostral * Runs to central sulcus Parietal lobe * Most superior lobe of brain * Begins at central sulcus * Extends to parieto-occipital sulcus Occipital lobe * Most posterior/caudal * Begins at parieto-occipital sulcus Temporal lobe * Lateral, horizontal * Separated from parietal lobe by lateral sulcus Insula * Deep to other lobes * Deep to lateral sulcus

Answer 22

White Matter * Permits communication between different regions * Majority of cerebral volume * Divided into tracts Gray Matter * Responsible for neural integration * Three locations * Cerebral cortex * Basal nuclei * Limbic system

Answer 23

Association tracts * Connect regions within a hemisphere * Short fibers: gyri within lobe * Long fibers: lobes within hemisphere Commissural tracts * Connect hemispheres through commissures * Most pass through corpus callosum Projection tracts * Connect cerebrum with rest of body * Ascending and descending

Answer 24

* Gray matter * Lines outer cerebrum * Thin (2 - 3 mm) * 40% of brain’s mass Complex anatomy * Divided into layered regions * Specialized neurons * Stellate cells and pyramidal cells

Answer 25

Gray matter * Lateral to thalamus * Paired in each hemisphere Receive input from * Cerebral cortex * Substantia nigra (inhibitory) Send output to * Thalamus * Relays signals to cerebral cortex and midbrain Confirmed structures * Caudate nucleus * Putamen * Globus pallidus

Answer 26

* Determine onset and cessation of voluntary movements * Rhythmic, repetitive movements of hips and shoulders during walking Highly practiced, learned motor behaviors * Typing a shoe , writing, etc. Lesions cause dyskinesias * Movement disorders * Note: these are only some selected functions in motor control

Answer 27

* Gray matter Structures found in a ring * Around corpus callosum and thalamus All components are paired * Present in both hemispheres * Emotion and learning

Answer 28

Structures interconnected via fiber tracts * Permits feedback between components Confirmed structures * Cingulate gyrus * Hippocampus * Amygdala Other components * Mammillary bodies * Some hypothalamic nuclei * Some thalamic nuclei * Basal nuclei (portions) * Prefrontal and orbitofrontal cortex

Answer 29

Roles in emotion * Amygdala and hypothalamus * Emotions originate here * Amygdala can link sensations to emotional responses * Output to hypothalamus and brainstem: alters motor responses * Output to prefrontal cortex: permits conscious expression of emotions Memory * Hippocampus Houses gratification and aversion centers * Linked to stimuli * Roles in shaping behavior * More likely to repeat pleasurable experiences * Less likely to repeat unpleasant experiences

Answer 30

Difficult to correlate specific function with a specific region * Boundaries are indistinct, overlap exists * Areas may have multiple functions * Functions may be distributed (over many areas) * Typically divided into functional areas

Answer 31

Due to tracts decussating * Receive information from opposite side of body * Control effectors on opposite side of body Hemispheres specialized for some different functions * Cerebral (hemispheric) lateralization * Functions may complement one another Typically both hemispheres are used for all tasks * Communicate via commissural tracts Left Hemisphere (Usually) * Categorical hemisphere * Break info into fragments * Linear analysis of info * Spoken and written language * Sequential and analytic reasoning * Posterior language area * Motor speech area Right Hemisphere (Usually) * Representational hemisphere * Integrated, holistic perception of info * Imagination and insight * Artistic and musical skill * Perception of patterns and spatial relationships * Sensory comparison * Affective language area

Answer 32

Sensory areas * Primary sensory cortex * First receive sensory information * Permits conscious awareness of sensation Motor areas * Primary motor cortex * Voluntary control of skeletal muscle Association areas * Interpret information * Involved with cognition * Range of mental processes by which knowledge is acquired and used

Answer 33

Postcentral gyrus * Parietal lobe Demonstrates somatopy * Body regions correspond to specific brain regions * Permits spatial discrimination of stimuli More cortex dedicated to some areas * Corresponds to sensitivity * Sensory homunculus Function * Conscious perception of general senses

Answer 34

Primary visual * Posterior occipital lobe Primary auditory * Superior temporal lobe and insula Primary gustatory * Inferior postcentral gyrus Primary olfactory * Medial temporal lobe, inferior surface of frontal lobe

Answer 35

Precentral gyrus * Frontal lobe * Demonstrates somatopy More cortex dedicated to some areas * Corresponds to motor control * Number of muscles and motor units * Motor homunculus Function * Voluntary control of skeletal muscle

Answer 36

* Always located close to primary sensory cortex for sensation * Integrates and interpret sensory information * Store memories

Answer 37

* Frontal lobe, anterior to precentral gyrus Plans motor movements * Degree and sequence of contractions * Plan transferred to primary motor area for execution

Answer 38

Posterior language area (Wernicke) * Posterior to lateral sulcus * Receives input from visual, auditory, and somatosensory areas * Recognition of written and spoken language * Formulates speech, transmits to motor speech area * Damage: fluent aphasia Motor speech area (Broca) * Inferior prefrontal cortex * Receives plan for speech from posterior language area * Creates motor plan for speech, sends to primary motor area * Possible roles in language comprehension * Damage: nonfluent aphasia

Answer 39

Area opposite posterior language area * Recognizes emotional context of another’s speech * Damage impedes this ability Area opposite motor speech area * Add emotional content to spoken words * Damage results in aprosody (flat, emotionless speech)

Answer 40

* Anterior portion of frontal lobe Frontal lobe integrates information * From sensory and motor regions * From other association area Associated with cognition and higher functions * Judgement, planning, decision making, conscience, reasoning, mood, etc. * Conscious control of emotional expression * Damage personality disorders, loss of inhibition, inability to control expression of emotions

Answer 41

* Storage and recall of information Neural level: * Relies upon formation and modification of synapses * Memory trace (engram): pathway of synapses associated with memory * Synaptic plasticity: synapse added, removed, modified * Synaptic potentiation: transmission becomes easier with repetition and learning Involves multiple processes * Learning: acquiring new information * Memory proper: storage and retrieval * Forgetting: eliminating unwanted or trivial information

Answer 42

Immediate memory: what just happened * Duration: seconds * Comprehension of flow of events Short term-memory (STM) * Duration: seconds to hours * Small information capacity * Can be forgotten quickly * Recitation allows better retention Long-term memory (LTM) * Duration: years to a lifetime * Large information capacity * Modification of synapses or adding more NT channels

Answer 43

Hippocampus transfers memories from STM to LTM * Referred to as memory consolidation * Does not store memory! Long term memories stored in cerebral cortex * Within appropriate region Other regions associated with memory * Cerebellum: learning motor skills * Amygdala: emotional memory

Answer 44

Anterograde amnesia * Inability to form new memories * Can result from hippocampus damage Retrograde amnesia * Inability to recall stored LTM

Answer 45

* 12 pairs Numbered from I – XII * Anterior (rostral) to posterior (caudal) * Peripheral nervous system Associated primarily with structures of the head and neck * Vagus nerve is a notable exception * Sensory, motor, or mixed (both)

Answer 46

Olfactory Nerve I (S) * Olfaction Optic Nerve II (S) * Vision Oculomotor Nerve III (M) * Somatic and autonomic motor functions of eye * Innervates four of six eye muscles Trochlear Nerve IV (M) * Eye movements * Innervates one eye muscle Trigeminal Nerve V (B) * Three branches * Sensory: general senses of face * Motor: mastication Abducens Nerve VI (M) * Eye movements * Innervates one eye muscle Facial Nerve VII (B) * Sensory: taste * Motor: facial expressions, secretion from salivary and lacrimal glands Vestibulocochlear Nerve VIII (S) * Hearing and equilibrium Glossopharyngeal Nerve IX (B) * Sensation (taste, general senses) from tongue, throat, outer ear * Muscles of tongue and pharynx, salivary glands * Chemoreceptors and baroreceptors in cardiovascular system Vagus Nerve X (B) * Control of cardiac, pulmonary, digestive, urinary functions * Parasympathetic division Accessory Nerve XI (M) * Swallowing, movement of neck and shoulder muscles Hypoglossal Nerve XII (M) * Movements of tongue

Chapter 14: The Brain and Cranial Nerves Flashcards

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