Brain Structure, Organization, and Functions

Vocabulary terms and comprehensive definitions covering neuroanatomy, brain functional regions, meninges, ventricles, and cranial vasculature based on Biology 2230 Lecture 14.

Somatic Sensory Division

The subdivision of the PNS sensory division where sensory neurons carry signals from muscles, bones, joints, the skin, and special sense organs to the central nervous system.

Visceral Sensory Division

The subdivision of the PNS sensory division where sensory neurons carry incoming signals from internal organs (viscera).

Somatic Motor Division

The motor subdivision of the PNS in which lower motor neurons transmit voluntary motor signals directly to skeletal muscles.

Visceral Motor Division (Autonomic Nervous System)

The efferent branch of the PNS composed of sympathetic and parasympathetic neurons that carry involuntary motor signals to viscera.

Dura Mater

The thick, tough, superficial layer of cranial meninges composed of abundant collagen that protects the brain and stabilizes the dural venous sinuses.

Arachnoid Mater

The web-like middle meninx that features a subarachnoid space filled with cerebrospinal fluid (CSF).

Pia Mater

The thin, highly vascularized deepest cranial meninx that adheres directly to the surface contours of the brain and spinal cord.

Falx Cerebri

A longitudinal dural fold located within the longitudinal fissure that anchors the superior sagittal, inferior sagittal, and straight sinuses.

Tentorium Cerebelli

Lateral sheets of dura mater that separate the cerebrum from the cerebellum and hold the transverse and sigmoid sinuses in place.

Cerebrum

The largest brain division, composed of two contralateral hemispheres responsible for higher mental functions, sensory perception, and the planning and initiation of movement.

Longitudinal Fissure

The deep external groove along the midsagittal plane that separates the right and left cerebral hemispheres.

Cerebral Cortex

The outer surface layer of the cerebrum, comprised of unmyelinated gray matter organized into five lobes.

Cerebral White Matter

The deep interior regions of the cerebrum containing myelinated axons that relay signals between cortical areas and lower CNS centers.

Basal Nuclei

Islands of gray matter embedded deep within the cerebral white matter that assist in regulating motor output messages to skeletal muscles.

Prefrontal Cortex

The anterior region of the frontal lobe that processes intellect, cognition, recall, personality, and working memory.

Premotor Cortex

The region of the frontal lobe located anterior to the primary motor cortex that plans and coordinates voluntary motor movements.

Primary Motor Cortex

The cortex located in the precentral gyrus of the frontal lobe that transmits voluntary motor commands to effectors.

Primary Somatosensory Cortex (S1)

The cortex located in the postcentral gyrus of the parietal lobe that receives general sensory information from the body.

Occipital Lobe

The posterior region of the cerebral cortex dedicated to receiving and interpreting visual signals originating from the retinas.

Temporal Lobe

The cerebral lobe positioned inferior to the lateral sulcus that processes auditory information (pitch, volume, location) and olfaction (smell).

Insula

The deep cerebral lobe hidden beneath the frontal, parietal, and temporal lobes that processes gustatory (taste), vestibular (equilibrium), and visceral sensory stimuli.

Corpus Callosum

The broad, C-shaped tract of white matter that connects and facilitates communication between the right and left cerebral hemispheres.

Thalamus

Egg-shaped bilateral nuclei of the diencephalon that sort, edit, and relay sensory and motor signals to and from the cerebral cortex (excluding olfaction).

Hypothalamus

The inferior region of the diencephalon connected to the pituitary gland via the infundibulum; regulates body temperature, hunger, thirst, sleep-wake cycles, and endocrine hormone secretion.

Epithalamus

The dorsal region of the diencephalon that forms the roof of the third ventricle and houses the pineal gland.

Pineal Gland

An endocrine organ in the epithalamus that secretes melatonin to regulate sleep patterns.

Midbrain

The most superior section of the brainstem, positioned between the diencephalon and pons, containing the corpora quadrigemina and the cerebral aqueduct.

Corpora Quadrigemina

Four rounded reflex centers located on the dorsal midbrain that coordinate visual and auditory reflexes.

Pons

The prominent bulge of the brainstem between the midbrain and medulla oblongata that regulates breathing depth and rate and relays motor signals between the cerebrum and cerebellum.

Medulla Oblongata

The conical inferior portion of the brainstem that connects to the spinal cord at the foramen magnum; serves as an autonomic reflex center controlling heart rate, blood pressure, respiration, swallowing, coughing, and vomiting.

Cerebellum

The brain division dorsal to the pons and medulla that monitors body position and posture and coordinates the force, direction, and extent of skeletal muscle contractions.

Arbor Vitae

The branched, tree-like appearance of white matter located internally within the cerebellum.

Ventricles

A linked system of four hollow fluid-filled chambers within the brain that produce and circulate cerebrospinal fluid.

Cerebral Aqueduct

A slender channel through the midbrain that connects the third ventricle to the fourth ventricle.

Internal Carotid Arteries

Paired arteries passing through the carotid canal of the temporal bone that supply the majority of oxygenated blood to the brain.

Vertebral Arteries

Paired vessels ascending through the transverse foramina of cervical vertebrae that pass through the foramen magnum and merge to form the basilar artery.

Basilar Artery

A single midline vessel formed by the union of the right and left vertebral arteries along the anterior surface of the brainstem.

Cerebral Arterial Circle (Circle of Willis)

An arterial anastomosis surrounding the sella turcica and pituitary gland that provides collateral circulatory pathways to prevent ischemia if a feeder vessel is occluded.

Cerebrovascular Accident (CVA)

Damage to brain tissue resulting from an interruption in blood supply, caused by either an arterial clot (ischemia) or a ruptured vessel (hemorrhage).

Sigmoid Sinuses

S-shaped dural venous sinuses receiving blood from the transverse and cavernous sinuses that drain into the internal jugular veins via the jugular foramina.