The Nervous System: The Brain and Cranial Nerves

Vocabulary practice flashcards covering brain divisions, protective structures, functional cerebral areas, diencephalon, brain stem, limbic system, and the 12 cranial nerves.

Cerebrum

The most superior and largest part of the brain, consisting of left and right hemispheres.

Diencephalon

The central portion of the brain located between the two cerebral hemispheres and superior to the brain stem; includes the thalamus and hypothalamus.

Brain Stem

The region spanning between the diencephalon and spinal cord; composed of the midbrain, pons, and medulla oblongata.

Pia mater

The innermost meningeal layer made of delicate connective tissue; attached to the nervous tissue of the brain and spinal cord, following all contours and holding blood vessels.

Arachnoid

The middle meningeal layer that forms the subarachnoid space where cerebrospinal fluid (CSF) circulates.

Dura mater

The thickest and toughest outermost layer of the meninges; around the brain it consists of two layers with the outer layer fused to the cranial bones.

Subarachnoid space

The space formed by the arachnoid layer that contains circulating cerebrospinal fluid (CSF).

Dural sinuses

Venous channels formed where the two layers of the dura mater separate, providing drainage for blood coming from brain capillaries.

Cerebrospinal Fluid (CSF)

A clear liquid that circulates in and around the brain and spinal cord to support nervous tissue, cushion shocks, carry nutrients, and transport waste.

Choroid plexus

A network of ependymal cells and blood vessels located within all four ventricles that manufactures cerebrospinal fluid (CSF).

Gyri

Elevated folds on the arranged surface of the cerebral cortex.

Sulci

Shallow grooves separating the raised gyri of the cerebral cortex.

Central sulcus

An important landmark lying between the frontal and parietal lobes of each cerebral hemisphere, positioned at right angles to the longitudinal fissure.

Lateral sulcus

A landmark curving along the side of each hemisphere that separates the temporal lobe from the frontal and parietal lobes.

Corpus callosum

An important band of white matter at the bottom of the longitudinal fissure that serves as a bridge permitting impulses to cross between the right and left hemispheres.

Frontal Lobe

The cerebral lobe lying anterior to the central sulcus; contains the primary motor area, prefrontal cortex, and Broca area.

Broca area

The motor speech area located within the prefrontal cortex in one cerebral hemisphere; damage to it hinders expressing ideas in words.

Parietal Lobe

The cerebral lobe occupying the superior part of each hemisphere posterior to the central sulcus; contains the primary somatosensory area.

Temporal Lobe

The cerebral lobe containing the auditory receiving area, auditory association area, Wernicke area, and olfactory area.

Wernicke area

The speech comprehension area located in the temporal lobe; damage causes difficulty understanding the meaning of speech.

Occipital Lobe

The cerebral lobe lying posterior to the parietal lobe that contains the visual receiving and visual association areas.

Thalamus

Part of the diencephalon consisting of masses of gray matter that sort out nearly all sensory impulses and direct them to specific areas of the cerebral cortex.

Hypothalamus

The diencephalon region acting as the control center for negative feedback loops in homeostasis, controlling body temperature, food intake, water balance, autonomic divisions, and the pituitary gland.

Midbrain

The superior portion of the brain stem containing four rounded bodies that serve as reflex centers for eye and ear movements.

Pons

The portion of the brain stem meaning 'bridge', composed largely of myelinated nerve fibers connecting the cerebellum with the rest of the nervous system and integrating respiration reflexes.

Medulla Oblongata

The inferior portion of the brain stem between the pons and spinal cord containing respiratory, cardiac, and vasomotor centers, as well as crossing motor fibers resulting in contralateral control.

Limbic System

A neuronal coordinating network between the prefrontal cortex and autonomic brain regions that helps control behavior and emotional responses.

Cingulate gyrus

The portion of the cerebral cortex looping over the corpus callosum that associates emotions with memories.

Hippocampus

A sea horse-shaped structure located under the lateral ventricles that enables storage of new memories and learning.

Amygdala

Two clusters of nuclei deep in the temporal lobes that coordinate emotional responses to stimuli.

Basal Nuclei

Interconnected motor networks (also called basal ganglia) that modulate motor inputs and facilitate practiced, routine motor tasks.

Reticular Activating System (RAS)

A component of the reticular formation that sends impulses to the cerebral cortex to keep a person awake and attentive.

Special sensory impulses

Sensory impulses for smell, taste, vision, and hearing that originate in special sense organs in the head.

General sensory impulses

Sensory impulses for pain, touch, temperature, deep muscle sense, pressure, and vibrations.

Somatic motor impulses

Nerve impulses that control skeletal muscles.

Visceral motor impulses

Nerve impulses that control glands, smooth muscle, and cardiac muscle.

Olfactory nerve (I)

Sensory cranial nerve I that carries smell impulses from receptors in the nasal mucosa toward the brain.

Optic nerve (II)

Sensory cranial nerve II that carries visual impulses from the eye to the brain.

Oculomotor nerve (III)

Motor cranial nerve III that controls contraction of most eyeball muscles and carries parasympathetic fibers to constrict the pupil.

Trochlear nerve (IV)

Motor cranial nerve IV that supplies one eyeball muscle.

Trigeminal nerve (V)

Mixed cranial nerve V, known as the great sensory nerve of the face and head; carries impulses from the eye, upper jaw, and lower jaw.

Abducens nerve (VI)

Motor cranial nerve VI that sends motor impulses to control an eyeball muscle.

Facial nerve (VII)

Mixed cranial nerve VII that controls muscles of facial expression, carries taste sensation, and stimulates salivary and lacrimal glands.

Vestibulocochlear nerve (VIII)

Sensory cranial nerve VIII that carries sensory impulses for hearing and equilibrium from the inner ear toward the brain.

Glossopharyngeal nerve (IX)

Mixed cranial nerve IX carrying general sensory fibers from the posterior tongue/pharynx, controlling swallowing muscles, and stimulating the parotid gland.

Vagus nerve (X)

The longest mixed cranial nerve (meaning 'wanderer') that supplies most thoracic and abdominal organs and carries motor impulses to the larynx and pharynx.

Accessory nerve (XI)

Motor cranial nerve XI with two branches that controls muscles in the neck and larynx.

Hypoglossal nerve (XII)

Motor cranial nerve XII, the last of the 12 cranial nerves, carrying impulses that control the muscles of the tongue.