Central Nervous System Lecture Review

Flashcards covering key vocabulary terms and definitions related to the Central Nervous System, including brain regions, structures, functions, cranial nerves, spinal cord, and reflexes, based on Dr. Garza Decanini's lecture notes.

Central Nervous System (CNS)

Consists of the brain and spinal cord.

Neural Tube

Embryological structure from which the brain and spinal cord begin.

Gray Matter

Composed of cell bodies and dendrites; forms the cortex and deep nuclei of the brain.

White Matter

Composed of myelinated axons; forms tracts deep within the brain.

Cerebral Hemispheres

Form the superior part of the brain, derived from the telencephalon, and account for 80% of brain mass.

Diencephalon

One of the four adult brain regions, containing the thalamus, hypothalamus, and epithalamus.

Brain Stem

Consists of the midbrain, pons, and medulla oblongata; controls autonomic behaviors necessary for survival.

Cerebellum

The second largest brain structure, involved in motor coordination, motor learning, posture, and balance.

Gyri

Ridges on the surface of the cerebral hemispheres.

Sulci

Shallow grooves on the surface of the cerebral hemispheres.

Fissures

Deep grooves on the surface of the cerebral hemispheres, such as the longitudinal and transverse cerebral fissures.

Longitudinal Fissure

Separates the two cerebral hemispheres.

Transverse Cerebral Fissure

Separates the cerebrum and cerebellum.

Central Sulcus

Separates the precentral gyrus (motor control) of the frontal lobe and the postcentral gyrus (somatesthetic sensation) of the parietal lobe.

Frontal Lobe

Responsible for voluntary motor functions, motivation, planning, mood, emotion, social judgment, decision making, and aggression.

Parietal Lobe

Primary site for receiving and interpreting signals of general senses, understanding speech, and formulating words.

Occipital Lobe

The principal visual center of the brain.

Temporal Lobe

Involved in hearing, smell, learning, and some aspects of visual interpretation.

Insula

A deep lobe involved in memory, olfactory, gustatory, auditory, and pain information.

Ventricles

Fluid-filled chambers in the brain, continuous with each other and the central canal of the spinal cord, filled with cerebrospinal fluid (CSF) and lined by ependymal cells.

Cerebrospinal Fluid (CSF)

Fluid found in and around the brain and spinal cord that reduces brain weight by 97% and protects it from trauma.

Choroid Plexuses

Structures that hang from the roof of each ventricle and produce CSF, lined by ependymal cells.

Arachnoid Granulations

Structures through which CSF returns to the blood.

Basal Nuclei (Ganglia)

Masses of gray matter deep in the cerebrum primarily involved in control of movement, and secondarily in cognition and emotion.

Substantia Nigra

A midbrain structure that releases dopamine to the corpus striatum; its degeneration causes Parkinson disease.

Cerebral Lateralization (Dominance)

Specialization of cortical function where some tasks are performed better by one side of the brain, such as language in the left hemisphere or visual-spatial skills in the right.

Corpus Callosum

A structure that facilitates communication between the two cerebral hemispheres.

Broca's Area

Located in the left inferior frontal region, responsible for motor speech.

Broca's Aphasia

A condition characterized by slow, poorly articulated speech with no impairment in understanding.

Wernicke's Area

Located in the left superior temporal region, involved in language understanding.

Wernicke's Aphasia

A condition characterized by the production of rapid speech with no meaning, often called 'word salad'.

Aphasias

General term for speech problems.

Limbic System

A group of brain regions (including cingulate gyrus, amygdaloid body, hippocampus, hypothalamus, thalamus) responsible for emotional drives such as aggression, fear, feeding, and sex drive.

Hippocampus

A critical component for acquiring new information and consolidating short-term memory into long-term memory.

Consolidation (Memory)

The conversion of short-term memory into more stable long-term memory.

Nondeclarative (Implicit) Memory

Memory of simple skills, or 'how to do things'.

Declarative (Explicit) Memory

Memory of things that can be verbalized.

Working Memory

The ability to keep information in your head for a short time, a type of short-term memory.

Thalamus

Paired oval masses in the diencephalon that sort, edit, and relay ascending sensory input, and are involved in emotion, memory, and motor activities.

Hypothalamus

The main visceral control center of the diencephalon, regulating body temperature, hunger, satiety, water balance, thirst, and endocrine system function.

Epithalamus

Part of the diencephalon that includes the pineal gland, which secretes melatonin to regulate circadian rhythm.

Midbrain

The superior part of the brain stem, including nuclei for cranial nerves III and IV, corpora quadrigemina, substantia nigra, and red nucleus.

Corpora Quadrigemina

Paired dorsal dome-like protrusions in the midbrain, consisting of superior colliculi (visual reflexes) and inferior colliculi (auditory relays).

Pons

The middle part of the brain stem, composed of conduction tracts and containing respiratory control centers, and where cranial nerves V to VIII begin or end.

Reticular Formation

A network of nuclei in the brain stem involved in sleep, consciousness, respiration, pain modulation, cardiovascular control, motor control, and habituation.

Medulla Oblongata

The most inferior part of the brain stem, through which all nerve fibers connecting the brain to the spinal cord pass, and where the decussation of the pyramids occurs.

Decussation of the Pyramids

The cross-over point in the medulla oblongata where nerve fibers connecting the brain to the spinal cord switch sides.

Spinal Cord

A cylinder of nervous tissue extending from the foramen magnum to L1-L2, serving as the 'information highway' between the brain and the lower body.

Posterior (Dorsal) Horns

Sections of the gray matter in the spinal cord that receive sensory input.

Anterior (Ventral) Horns

Sections of the gray matter in the spinal cord containing the large somas of somatic motor neurons.

Lateral Horns

Additional pairs of gray matter columns found in thoracic and superior lumbar segments of the spinal cord, associated with the autonomic nervous system.

Central Canal

A CSF-filled canal in the middle of the gray commissure of the spinal cord, lined with ependymal cells.

Posterior (Dorsal) Root

A branch of the spinal nerve that carries sensory nerve fibers.

Anterior (Ventral) Root

A branch of the spinal nerve that contains motor neuron axons, extending to effectors.

Funiculi

Six columns (posterior, lateral, and anterior) into which the white matter of the spinal cord is arranged.

Ascending Tracts

Fiber tracts in the white matter of the spinal cord that carry sensory impulses upwards to the brain.

Descending Tracts

Fiber tracts in the white matter of the spinal cord that carry motor impulses downwards from the brain.

Corticospinal (Pyramidal) Tracts

Descending tracts that originate in the cerebral cortex and control primarily the muscles of the axial skeleton.

Extrapyramidal Tracts

Descending tracts that originate in the brain stem and are controlled by motor circuits of the corpus striatum, substantia nigra, and thalamus.

Cranial Nerves

Twelve pairs of nerves that arise directly from nuclei in the brain, part of the Peripheral Nervous System (PNS).

Olfactory Nerve (I)

Purely sensory nerve responsible for the sense of smell.

Optic Nerve (II)

Purely sensory nerve responsible for vision, arising from the retinas.

Oculomotor Nerve (III)

Motor nerve that innervates extrinsic muscles for voluntary eye movements.

Trochlear Nerve (IV)

Motor nerve that innervates extrinsic muscles for voluntary eye movements.

Trigeminal Nerve (V)

The largest cranial nerve, with three divisions (ophthalmic, maxillary, mandibular), involved in sensory input from the face and motor control for chewing.

Abducens Nerve (VI)

Motor nerve that innervates extrinsic muscles for voluntary eye movements.

Facial Nerve (VII)

Mixed nerve with sensory components for taste (anterior 2/3 of tongue) and motor components for facial expression and secretion from lacrimal and salivary glands.

Vestibulocochlear Nerve (VIII)

Mostly sensory nerve with vestibular branch for detecting linear and angular movements and cochlear branch for hearing.

Glossopharyngeal Nerve (IX)

Mixed nerve with sensory function for taste (posterior 1/3 of tongue) and motor function for swallowing (stylopharyngeus muscle) and parotid salivary glands.

Vagus Nerve (X)

A widespread mixed nerve with sensory input from various internal organs and motor fibers to the palate, pharynx, and autonomic motor fibers to internal organs.

Accessory Nerve (XI)

Entirely motor nerve that innervates the trapezius and sternocleidomastoid muscles.

Hypoglossal Nerve (XII)

Entirely motor nerve that innervates the muscles that move the tongue.

Spinal Nerves

Thirty-one pairs of nerves that arise directly from the spinal cord, part of the Peripheral Nervous System (PNS).

Mixed Nerves

Nerves that consist of both afferent (sensory) and efferent (motor) fibers, conducting signals in two directions.

Mechanoreceptors

Receptors that respond to touch, pressure, vibration, and stretch.

Thermoreceptors

Receptors sensitive to changes in temperature.

Photoreceptors

Receptors that respond to light energy.

Chemoreceptors

Receptors that respond to chemicals, such as those involved in smell, taste, or changes in blood chemistry.

Nociceptors

Receptors sensitive to pain-causing stimuli, such as extreme heat/cold, excessive pressure, or inflammatory chemicals.

Exteroceptors

Receptors that respond to stimuli arising outside the body, like those in the skin for touch, pressure, pain, vibration, and temperature.

Interoceptors (Visceroceptors)

Receptors that respond to stimuli arising in internal viscera and blood vessels, sensitive to chemical changes, tissue stretch, and temperature changes.

Proprioceptors

Receptors that respond to stretch in skeletal muscles, tendons, joints, ligaments, and connective tissue, informing the brain of body movements.

Reflex

Quick, involuntary, stereotyped reactions of glands or muscles to stimulation.

Inborn (Intrinsic) Reflex

An unlearned, unpremeditated, and involuntary reflex built into neural anatomy, regulated by the brain stem and spinal cord (e.g., root reflex, suck reflex).

Learned (Acquired) Reflex

A reflex that results from practice or repetition.

Reflex Arc

The neural pathway that mediates a reflex, consisting of a receptor, sensory neuron, integration center, motor neuron, and effector.

Monosynaptic Reflex

A reflex arc involving a single synapse in the integration center.

Polysynaptic Reflex

A reflex arc involving multiple synapses and interneurons in the integration center.

Somatic Reflexes

Reflexes that activate skeletal muscle.

Autonomic Reflexes

Reflexes that activate visceral effectors like smooth or cardiac muscle and glands.