Neuroscience Exam 2

Olfactory nerve I

Responsible for the sense of smell; damage causes loss of smell, originated in the forebrain, sensory fibers

Optic nerve II

Transmits visual information from the retina to the brain, originates in the diencephalon and is a sensory fiber

Cculomotor nerve III

Controls most eye movments, eyelid elevation, and pupil constriction, originated in the midbrain, and is a motor fiber

Trochlear nerve IV

Moves the eye downward and inward using the superior oblique muscle, originated in the midbrain and is a motor fiber

Trigeminal Nerve V

Provides facial sensation and controls muscles of mastication, originates in the pons and is both sensory and motor fibers

Abducens Nerve VI

Controls lateral eye movement via the lateral rectus muscle, originates in the pons, and is a motor fiber type

Facial Nerve VII

Controls facial expression, taste on the anterior 2/3 of tongue, and tear/saliva secretion. Originates in the pons and is both sensory and motor fibers.

Vestibulochochlear nerve VIII

Responsible for hearing and balance, originates at the pons and medulla junction and is a sensory fiber

Glossopharyngeal nerve IX

Controls taste on the posterior 1/3 of tongue, swallowing, and gag reflex. Originates in the medulla and is both sensory and motor fibers.

Vagus nerve X

Controls voice, swallowing, and autonomic regulation of the heart and digestive tract. Originates in the medulla and is both sensory and motor fibers.

Accessory nerve XI

Controls neck and shoulder movement, originates in the medulla and spinal cord and is a motor fiber.

Hypoglossal nerve XII

Controls tongue movement for speech and swallowing. It originates in the medulla and is a motor fiber.

Diencephalon location

Located between cerebral hemispheres and brainstem; includes thalamus, hypothalamus, epithalamus, and subthalamus

Diencephalon function

relays sensory and motor signals to the cortex

Thalamus

Major relay station for sensory and motor information; regulates consciousness and alertness.

Cerebral Dominance

The hemisphere specialized for specific functions; left for language, right for spatial and emotional processing.

Corpus Callosum

Large bundle of white matter connecting both hemispheres; enables communication between sides of the brain.

Central Sulcus

Separates the frontal and parietal lobes; divides motor and sensory cortices.

Lateral Sulcus

Seperates temporal lobe from the frontal and parietal lobes. Associated with auditory and language functions.

Cerebrum

Largest part of the brain; made up of two hemispheres including cortex, white matter, and basal nuclei.

Brodmann’s Areas

Numbered regions of the cerebral cortex identified by structure and function.

Prefrontal Cortex

Areas 9-12, 46, 47. Responsible for decision-making, planning, and emotional regulation.

Brocas Area

Areas 44, 45. Controls motor planning for speech production; damage causes expressive aphasia.

Premotor Cortex

Area 6. Plans and sequences movements; damage causes motor apraxia.

Primary Motor Cortex

Area 4. Controls voluntary movement; damage causes contralateral paralysis.

Primary Sensory Cortex.

Areas 3, 1, 2. Processes touch, pressure, and proprioception; damage causes sensory loss.

Somatosensory Association Cortex

Areas 5, 7. Integrates sensory information for recognition; damage causes astereognosis

Angular Gyrus

Area 39 . Involved in reading, writing, and math; damage causes alexia, agraphia, or acalculia.

Supramarginal Gyrus

Area 40. Supports phonological processing and language comprehension; damage causes comprehension deficits.

Primary Auditory Cortex

Area 41, 42. Processes hearing; damage causes cortical deafness.

Wernicke’s Area

Area 22. Comprehends spoken and written language; damage causes receptive aphasia.

Midddle and Inferior Temporal Areas

Areas 20, 21, 37, 38. Responsible for object recognition and semantic memory; damage causes visual agnosia.

Tonotopic Organization

Auditory cortex is arranged by frequency, with different tones mapped to specific cortical regions.

Association Fibers

Connect cortical regions within the same hemisphere.

Superior Occipitofrontal Fasciculus

Connects frontal and occipital lobes within the same hemisphere.

Superior Longitudional Fasciulus

Connects frontal, parietal, and occipital lobes; includes the arcuate fasciculus for language.

Arcuate Fasciculus

Connects Broca’s and Wernicke’s areas; essential for repeating and comprehending speech.

Inferiror Occipitofrontal Fasciculus

Connects frontal lobes to occipital and temporal regions.

Uncinate Fasciculus

Connects frontal and temporal lobes; involved in emotional and memory processing.

Frontal Aslant Tract

Connects Broca’s area with supplementary motor regions; involved in speech initiation.

Comminssural Fibers

Connect the two hemispheres (e.g., corpus callosum).

Projection Fibers

Connect cortex to lower brain centers and spinal cord.

Corticopetal Fibers

Carry sensory information toward the cortex.

Corticofugal Fibers

Carry motor commands away from the cortex.

Internal Capsul

Major projection fiber tract with anterior limb, genu, and posterior limb; carries motor and sensory fibers.

Corona Radiata

Fan-shaped continuation of the internal capsule spreading into the cortex.

Skeletal System

Skull and vertebrae that protect the brain and spinal cord.

Meninges

Three layers (dura, arachnoid, pia) that protect and cushion the CNS.

Dura Mater

Tough outer layer covering the brain and spinal cord.

Arachnoid Mater

Middle, web-like layer where cerebrospinal fluid (CSF) flows.

Pia Mater

Thin inner layer that adheres directly to brain surface.

Ventricular system

Four interconnected ventricles that produce and circulate CSF.

Meningitis

Inflammation of the meninges, often caused by infection.

Hydrocephalus

Excess buildup of CSF in the ventricles causing pressure on the brain.

Arterial System

Carries oxygenated blood from the heart to the brain; divided into anterior and posterior circulatory systems.

Anterior Circulatory System

Originates from the common carotid arteries, which branch into the internal and external carotid arteries.

Posterior Circulatory System

Originates from the subclavian arteries and gives rise to the vertebral arteries that merge into the basilar artery.

Common Carotid Arteries

Major arteries on each side of the neck that split into internal and external carotid arteries.

Internal Carotid Arteries

Branch of the common carotid that supplies oxygenated blood to the brain.

External Carotid Arteries

Branch of the common carotid that supplies blood to the face, pharynx, and tongue.

Subclavian Arteries

Arteries below the clavicle that give rise to the vertebral arteries, supplying the posterior brain.

Vertebral Arteries

Arteries that ascend through the cervical vertebrae and merge to form the basilar artery; part of the posterior circulation.

Anterior Cerebral Artery (ACA)

Supplies the cingulate gyrus, corpus callosum, superior frontal gyrus, supplementary motor area, medial primary motor and sensory cortices, and superior parietal lobe.

Middle Cerebral Artery (MCA)

Supplies the prefrontal cortex, Broca’s area, premotor cortex, primary motor and sensory cortices, parietal lobes, auditory cortex, Wernicke’s area, and superior/middle temporal lobes (language regions).

Posterior Cerebral Artery (PCA)

Supplies the inferior and midline temporal lobe, hippocampus, parahippocampal gyrus, entire occipital lobe, and thalamus.

Circle of Willis

A circular network of arteries at the brain’s base connecting the carotid and vertebral systems; provides collateral circulation if a major artery is blocked.

Function of Circle of Willis

Maintains continuous blood flow even if one artery is obstructed; damage below the circle = minimal deficits, above the circle = more severe damage.

Venous System (Brain Veins)

Drains deoxygenated blood and metabolic waste from the brain through venous sinuses, returning blood to the heart for reoxygenation.

Venous Sinuses

Large collecting veins within the dura mater that channel blood from the brain back toward the jugular veins and heart.

Aneurysm

A balloon-like bulge in an artery caused by a weakened vessel wall; may rupture and cause a hemorrhagic stroke.

Stroke (Cerebrovascular Accident)

A sudden interruption in the brain’s blood supply leading to loss of brain function.

Ischemic Stroke

Caused by a blockage that prevents blood flow to brain tissue

Thrombosis

Stationary clot that blocks an artery

Embolism

Traveling clot that lodges in a brain artery

Hemorrhagic Stroke

Caused by the rupture of a blood vessel, leading to bleeding within or around the brain.

Transient Ischemic Attack (TIA)

“Mini-stroke” — temporary blockage of blood flow; symptoms resolve within 24 hours but signal high risk for a future stroke.

Arteriovenous Malformation (AVM)

A congenital tangle of arteries and veins that disrupts normal blood flow and may rupture, causing hemorrhage.