Brain: Glossary

Brain Structure & Anatomy

• Amygdala – A part of the limbic systemA group of brain structures responsible for emotions and memory. involved in processing emotions, particularly fear and pleasure.
• Arbor vitae – The tree-like white matterThe outer portion of the spinal cord made of myelinated nerve fibers that transmit signals. structure in the cerebellumThe brain region responsible for balance, coordination, and fine motor control. that aids in coordination.
• Basal nucleiClusters of neurons in the CNS responsible for processing information. – Clusters of neuronsThe functional cells of the nervous system that transmit signals. in the brain that help regulate movementA fundamental property of life involving motion of the body or its parts. and coordination.
• Brainstem – The lower part of the brain that connects to the spinal cordThe central nervous system structure that relays signals between the brain and body. and controlsVariables that remain constant to ensure a fair test. vital functions.
• Caudate nucleusThe control center of the cell that contains DNA and directs cellular activities. – A structure in the basal nucleiClusters of neurons in the brain that help regulate movement and coordination. involved in motor processes and learning.
• Cerebellar hemispheres – The two halves of the cerebellum responsible for coordinating movements.
• Cerebellum – The brain region responsible for balance, coordination, and fine motor control.
• Cerebral cortex – The outermost layer of the brain, responsible for higher-order thinking and processing.
• Cerebral hemispheres – The two halves of the brain, each controlling the opposite side of the body.
• Cerebral lateralization – The specialization of brain functions between the left and right hemispheres.
• Cerebral peduncle – Large bundles of nerve fibers connecting the brainstemThe lower part of the brain that connects to the spinal cord and controls vital functions. to the cerebrumThe largest part of the brain, responsible for thought, memory, and voluntary movements..
• Cerebrum – The largest part of the brain, responsible for thought, memoryThe ability to store and recall information., and voluntary movements.
• Choroid plexus – Structures within the ventricles that produce cerebrospinal fluid(CSF) – A fluid that cushions and nourishes the brain and spinal cord. (CSF).
• Corpus callosum – The large bundle of nerve fibers connecting the two cerebral hemispheresThe two halves of the brain, each controlling the opposite side of the body..
• Corpus striatum – A part of the basal nuclei involved in movement and reward processing.
• Diencephalon – A brain region that includes the thalamusThe brain’s relay center, sending sensory information to the cerebral cortex., hypothalamusA small but vital brain region controlling hormones, temperature, and autonomic functions., and epithalamusA part of the diencephalon that includes the pineal gland and regulates sleep..
• Epithalamus – A part of the diencephalonA brain region that includes the thalamus, hypothalamus, and epithalamus. that includes the pineal glandSmall brain structure that secretes melatonin. and regulates sleep.
• Falx cerebelli – A fold of dura materThe thick, outermost layer of the meninges that protects the spinal cord. that separates the two halves of the cerebellum.
• Falx cerebri – A fold of dura mater that separates the two cerebral hemispheres.
• Fourth ventricle – A cavity between the brainstem and cerebellum that contains CSF.
• Frontal lobe – The brain region responsible for decision-making, personality, and voluntary movements.
• Hippocampus – A structure in the temporal lobeThe brain region responsible for processing sound and memory. essential for memory formation.
• Hypothalamus – A small but vital brain region controlling hormones, temperature, and autonomic functions.
• Infundibulum – The stalk connecting the hypothalamus to the pituitary glandEndocrine gland at the brain’s base controlling many hormones..
• Insula – A deepAway from the surface of the body. brain region involved in taste, emotions, and visceral functions.
• Lateral ventricles – Large CSF-filled cavities within the cerebral hemispheres.
• Lentiform nucleus – A component of the basal nuclei involved in movement regulation.
• Limbic system – A group of brain structures responsible for emotions and memory.
• Medulla oblongata – The lowest part of the brainstem controlling vital functions like breathing and heart rate.
• Midbrain – The upper portion of the brainstem involved in visual and auditory processing.
• Occipital lobe – The brain region responsible for visual processing.
• Parietal lobe – The brain region responsible for sensory perception and spatial awareness.
• Pallidus – Part of the basal nuclei that helps regulate voluntary movement.
• Pons – A part of the brainstem that connects the cerebrum to the cerebellum and helps regulate breathing.
• Putamen – A part of the basal nuclei involved in motor control.
• Red nucleus – A midbrainThe upper portion of the brainstem involved in visual and auditory processing. structure involved in motor coordination.
• Reticular formation – A network of neurons in the brainstem that regulate alertness and consciousness.
• Substantia nigra – A midbrain structure involved in movement and dopamineA catecholamine neurotransmitter involved in motor control, motivation, and reward. production.
• Temporal lobe – The brain region responsible for processing sound and memory.
• Tentorium cerebelli – A dura mater fold that separates the cerebellum from the cerebrum.
• Thalamus – The brain’s relay center, sending sensory information to the cerebral cortexThe outermost layer of the brain, responsible for higher-order thinking and processing..
• Third ventricle – A narrow cavity in the diencephalon that contains CSF.
• Vermis – The central part of the cerebellum that helps control posture and balance.

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2. Nervous System Pathways & Functions

This category includes nerve pathways, reflexesAutomatic responses to stimuli., and specialized brain functions.

• Association areas – Brain regions that integrate sensory input and coordinate responses.
• Association tractsBundles of nerve fibers in the CNS that carry signals between brain regions. – Nerve pathways connecting different areas within the same hemisphere.
• Cardiac center – A brainstem region that controls heart rate.
• Central canal – A small CSF-filled channel running through the spinal cord.
• Central sulcus – A groove separating the frontalForehead bone; forms the front part of the skull and roof of the orbits. Smooth and curved. and parietal lobes.
• Commissural tracts – Nerve pathways that connect the two hemispheres of the brain.
• Fissure – A deep groove in the brain’s surface.
• Frontal association area – A brain region involved in decision-making and problem-solving.
• Homunculus – A map of sensory or motor control in the brain, representing different body parts.
• Interventricular foramen – The opening connecting the lateral ventriclesLarge CSF-filled cavities within the cerebral hemispheres. to the third ventricleA narrow cavity in the diencephalon that contains CSF..
• Longitudinal fissureA deep groove in the brain’s surface. – A deep groove separating the left and right hemispheres of the brain.
• Lower motor neuronsNeurons that carry outgoing information from the CNS to effector organs. – Nerve cellsThe basic structural and functional units of life. that directly stimulate muscles to contract.
• Memory – The ability to store and recall information.
• Memory consolidation – The process of strengthening memories for long-term storage.
• Motor association (premotor) area – A brain region involved in planning movements.
• Motor language area – Also called Broca’s area, responsible for speech production.
• Nuclei – Clusters of neurons in the CNSComposed of the brain and spinal cord; integrates and processes information.  responsible for processing information.
• Osmoreceptors – Sensory receptorsProteins located on the surface or inside cells that bind specific molecules (e.g., neurotransmitter that detect changes in fluid balanceThe maintenance of proper fluid volume and distribution in the body..
• Postcentral gyrus – The area of the parietal lobeThe brain region responsible for sensory perception and spatial awareness. responsible for processing sensory input.
• Posterior speech area – Also called Wernicke’s area, responsible for language comprehension.
• Precentral gyrus – The area of the frontal lobeThe brain region responsible for decision-making, personality, and voluntary movements. responsible for voluntary movements.
• Primary motor area – A region in the precentral gyrusThe area of the frontal lobe responsible for voluntary movements. controlling voluntary muscle movements.
• Primary somatosensory cortex – A region in the postcentral gyrusThe area of the parietal lobe responsible for processing sensory input. that processes touch and sensation.
• Projection tracts – Nerve pathways connecting the cerebrum to lower brain structures and the spinal cord.
• Pyramidal cells – Large neurons in the cerebral cortex involved in voluntary motor control.
• Respiratory centers – Brainstem regions that regulate breathing.
• Rostral caudal – Directional terms describing movement from the front to the back of the brain.
• Somatosensory association area – A brain region that processes touch-related information.
• Tracts – Bundles of nerve fibers in the CNS that carry signals between brain regions.
• Transverse fissure – A deep groove separating the cerebrum from the cerebellum.
• Upper motor neurons – Neurons that originate in the brain and control lower motor neuronsNerve cells that directly stimulate muscles to contract..
• Vasomotor center – A brainstem region that regulates blood pressureThe force exerted by gases in the respiratory system, affecting airflow and gas exchange. by controlling blood vessel diameter.

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3. Protective Structures & Support Cells

This category includes the brain’s protective membranes, fluid-filled spaces, and supporting cells.

• Arachnoid granulations – Structures that absorb cerebrospinal fluid into the venous system.
• Arachnoid mater – The middle layer of the meninges(singular: meninx) – Protective membranes surrounding the spinal cord and brain. that surrounds the brain and spinal cord.
• Blood-brain barrier – A selective barrier that prevents harmful substances from entering the brain.
• Cerebrospinal fluid (CSF) – A fluid that cushions and nourishes the brain and spinal cord.
• Circumventricular organ (CVO) – Brain regions with a weakened blood-brain barrierA selective barrier that prevents harmful substances from entering the brain. for monitoring blood chemistry.
• Dura mater – The tough outer layer of the meninges.
• Dural sinusesAir-filled spaces in the skull that lighten it and help humidify air. – Venous channelsProtein passages in the cell membrane that allow specific molecules to pass through. that drain blood from the brain.
• Ependymal cells – Glial cells that produce and circulate cerebrospinal fluid.
• Meningeal layer of dura materThe inner layer of the dura mater. – The inner layer of the dura mater.
• Meninges (singular meninx) – The three protective membranes covering the brain and spinal cord.
• Periosteal layer of dura materThe outer layer of the dura mater. – The outer layer of the dura mater.
• Pia mater – The thin, inner membrane of the meninges.
• Subarachnoid spaceThe space between the arachnoid and pia mater, filled with CSF. – The space between the arachnoid and pia materThe thin, innermost layer of the meninges that closely adheres to the spinal cord., filled with CSF.