Chapter 13 – Anatomy of the Central Nervous System

Vocabulary flashcards summarizing key terms from Chapter 13 – Anatomy of the Central Nervous System, covering embryologic development, major brain regions, protective structures, cerebrospinal fluid, blood-brain barrier, cranial and spinal nerves, and related disorders.

Endoderm

Innermost embryonic germ layer that forms the lining of the digestive and respiratory tracts and associated organs.

Mesoderm

Middle embryonic germ layer that becomes muscle, bone, connective tissue, and much of the circulatory system.

Ectoderm

Outer embryonic germ layer that gives rise to skin and the entire nervous system.

Neural Tube

Hollow ectoderm-derived tube that develops into the brain (anterior end) and spinal cord (posterior end).

Prosencephalon

Primary brain vesicle also called the forebrain; later forms the telencephalon and diencephalon.

Mesencephalon

Primary brain vesicle also called the midbrain; remains undivided in the secondary stage.

Rhombencephalon

Primary brain vesicle also called the hindbrain; develops into the metencephalon and myelencephalon.

Telencephalon

Secondary brain vesicle that forms the cerebrum.

Diencephalon

Secondary brain vesicle that becomes the thalamus, hypothalamus, epithalamus, and subthalamus.

Metencephalon

Secondary brain vesicle that gives rise to the pons and cerebellum.

Myelencephalon

Secondary brain vesicle that forms the medulla oblongata.

Cerebrum

Largest brain region; responsible for conscious thought, memory, and voluntary movement.

Cerebral Cortex

Wrinkled outer layer of gray matter covering the cerebrum.

Cerebral Medulla

Inner white-matter region of the cerebrum containing myelinated axons.

Hippocampus

Temporal-lobe structure crucial for formation of new memories.

Basal Nuclei (Basal Ganglia)

Deep cerebral gray-matter nuclei involved in planning and regulating motor activity.

Limbic System

Interconnected structures that govern emotion, motivation, and memory.

Amygdala

Almond-shaped limbic nucleus that processes fear and initiates fight-or-flight responses.

Precentral Gyrus

Frontal-lobe ridge housing the primary motor cortex.

Postcentral Gyrus

Parietal-lobe ridge containing the primary somatosensory cortex.

Central Sulcus

Prominent groove separating frontal and parietal lobes.

Motor Homunculus

Body map on the precentral gyrus showing cortical representation of voluntary movement.

Sensory Homunculus

Body map on the postcentral gyrus representing tactile sensation distribution.

Frontal Lobe

Cerebral lobe for voluntary motor control, planning, and personality.

Parietal Lobe

Cerebral lobe that processes somatosensory information and spatial awareness.

Temporal Lobe

Cerebral lobe for auditory processing, language comprehension, and memory storage.

Occipital Lobe

Posterior cerebral lobe devoted to visual reception and interpretation.

Association Fibers

White-matter tracts connecting cortical areas within the same hemisphere.

Commissural Fibers

Axon bundles, such as the corpus callosum, that connect the two hemispheres.

Projection Fibers

White-matter tracts linking the cerebrum with lower brain regions and spinal cord.

Substantia Nigra

Midbrain nucleus that produces dopamine; degenerates in Parkinson’s disease.

Parkinson’s Disease

Degenerative disorder caused by dopaminergic neuron loss in the substantia nigra, leading to tremor and rigidity.

Thalamus

Largest diencephalic structure; major sensory relay (except olfaction) and mood filter.

Hypothalamus

Diencephalic center controlling autonomic functions, endocrine activity, and homeostasis.

Subthalamus

Diencephalic motor control region located inferior to the thalamus.

Epithalamus

Posterior diencephalic region containing the pineal gland and habenula.

Pineal Gland

Epithalamic endocrine gland that secretes melatonin and helps regulate circadian rhythms.

Habenula

Epithalamic relay involved in visceral and emotional reactions to odors.

Brainstem

Collective term for the midbrain, pons, and medulla oblongata.

Medulla Oblongata

Brainstem segment containing vital centers for cardiac, respiratory, and vasomotor control.

Pons

Brainstem bridge relaying signals between cerebrum and cerebellum; helps regulate sleep and breathing rhythm.

Midbrain

Smallest brainstem region; mediates auditory and visual reflexes.

Reticular Formation

Diffuse brainstem network that regulates consciousness and sleep–wake cycles.

Cerebellum

Metencephalic structure coordinating balance, posture, and fine motor activity.

Arbor Vitae

Tree-like pattern of cerebellar white matter visible in sagittal section.

Meninges

Three protective membranes—dura mater, arachnoid mater, pia mater—surrounding brain and spinal cord.

Dura Mater

Tough outer meningeal layer adhering to the skull; means “hard mother.”

Arachnoid Mater

Middle meningeal layer with web-like fibers that span the subarachnoid space.

Pia Mater

Delicate inner meningeal layer that closely follows brain contours and supports vessels.

Epidural Space

Potential (cranial) or actual (spinal) space between bone and dura; site of epidural anesthesia.

Subdural Space

Potential space between dura and arachnoid mater that can fill with venous blood in subdural hematoma.

Subarachnoid Space

CSF-filled interval between arachnoid and pia containing cerebral arteries.

Cerebrospinal Fluid (CSF)

Clear fluid produced by choroid plexus, cushioning and nourishing the CNS.

Choroid Plexus

Ependymal cell and capillary network within ventricles that produces CSF.

Lateral Ventricles

Pair of C-shaped cavities in the cerebral hemispheres where CSF production begins.

Third Ventricle

Thin midline cavity of the diencephalon connected to lateral ventricles via interventricular foramina.

Cerebral Aqueduct

Narrow channel through the midbrain that links the third and fourth ventricles.

Fourth Ventricle

Ventricle between pons/medulla and cerebellum that drains CSF to the subarachnoid space.

Hydrocephalus

Accumulation of CSF in the ventricles causing increased intracranial pressure; often treated with shunts.

Blood-Brain Barrier (BBB)

Selective vascular barrier formed by endothelial tight junctions, astrocytes, and pericytes that protects neural tissue.

Astrocyte

Star-shaped glial cell that contributes to the BBB and supports neuronal metabolism.

Pericyte

Contractile cell wrapped around capillaries; reinforces BBB integrity.

Cranial Nerves

Twelve pairs of peripheral nerves arising from the brain that provide sensory, motor, or mixed functions.

Olfactory Nerve (CN I)

Pure sensory cranial nerve conveying smell information from the nasal mucosa.

Optic Nerve (CN II)

Sensory cranial nerve transmitting visual impulses from the retina.

Oculomotor Nerve (CN III)

Motor cranial nerve controlling most extraocular muscles and pupil constriction.

Trochlear Nerve (CN IV)

Motor cranial nerve that innervates the superior oblique muscle for intorsion of the eye.

Trigeminal Nerve (CN V)

Mixed cranial nerve providing facial sensation and muscles of mastication.

Abducens Nerve (CN VI)

Motor cranial nerve that abducts the eye via the lateral rectus muscle.

Facial Nerve (CN VII)

Mixed cranial nerve controlling facial expression, lacrimation, salivation, and anterior tongue taste.

Vestibulocochlear Nerve (CN VIII)

Sensory cranial nerve with cochlear (hearing) and vestibular (balance) branches.

Glossopharyngeal Nerve (CN IX)

Mixed cranial nerve for posterior tongue taste, swallowing, and parotid salivation.

Vagus Nerve (CN X)

Mixed cranial nerve supplying parasympathetic output to thoracic and abdominal organs.

Accessory Nerve (CN XI)

Motor cranial nerve innervating sternocleidomastoid and trapezius muscles.

Hypoglossal Nerve (CN XII)

Motor cranial nerve governing tongue movements.

Spinal Nerves

Thirty-one pairs of mixed nerves emerging from the spinal cord that carry motor and sensory axons.

Cervical Plexus

Nerve network (C1–C5) that supplies neck and diaphragm via the phrenic nerve.

Brachial Plexus

Network (C5–T1) innervating the upper limb; gives rise to the median, ulnar, radial, musculocutaneous, and axillary nerves.

Lumbar Plexus

Nerve network (L1–L5) supplying the anterior and medial thigh; includes femoral and obturator nerves.

Sacral Plexus

Network (L4–S4) that forms the sciatic nerve and supplies the posterior thigh, leg, and foot.

Myelomeningocele

Severe spina bifida form with spinal cord and meninges protruding through the vertebral defect.

Meningocele

Spina bifida type where meninges herniate but spinal cord remains inside vertebral column.

Spina Bifida Occulta

Mild spinal defect with vertebral arch non-fusion but no protrusion of neural tissue.

Anencephaly

Fatal neural-tube defect characterized by absence of major portions of the brain and skull.

Hydrocephalus

Pathological enlargement of ventricular system due to impaired CSF flow or absorption.

Meningitis

Inflammation of meninges, often infectious, causing headache, fever, and neck stiffness.

Subdural Hematoma

Collection of venous blood between dura and arachnoid, typically from head injury.

Epidural Hematoma

Arterial bleed between skull and dura, frequently associated with skull fracture.

Blood–Brain Barrier Tight Junction

Protein complex sealing adjacent endothelial cells, preventing paracellular diffusion into brain tissue.

Choroid Plexus Ependymal Cell

Specialized glial cell that secretes CSF within the ventricular system.

Reticular Formation

Brainstem network regulating consciousness, attention, and autonomic control.

Arbor Vitae

“Tree of life” pattern of cerebellar white matter visible in sagittal section.

Pons

Brainstem region that relays signals between cerebellum and cerebrum and regulates REM sleep.

Medulla Cardiovascular Center

Medullary nuclei controlling heart rate and blood pressure.

Corpus Callosum

Largest commissural fiber tract linking the two cerebral hemispheres.