Central Nervous System Lab

Central Nervous System (CNS)

Brain and spinal cord; integrates sensory input and coordinates motor output

Brain

Control center of CNS; responsible for consciousness, memory, learning, sensation, and voluntary movement

Spinal Cord

Conducts signals to and from brain; reflex center

Cell Body (Soma)

Contains nucleus and organelles; metabolic center of neuron

Axon

Conducts action potentials away from cell body

Axon Hillock

Site where action potentials are initiated

Dendrites

Receive signals and transmit them toward the soma

Neurilemma

Outer layer of Schwann cell in PNS; essential for axon regeneration

Myelin

Lipid covering around axon that increases conduction speed

Nodes of Ranvier

Gaps in myelin sheath that allow saltatory conduction

Synaptic Knobs

Swollen ends of axon terminals that release neurotransmitters

Dura Mater (Brain)

Tough outer meningeal layer protecting brain

Periosteal Layer

Outer layer of cranial dura attached to skull

Meningeal Layer

Inner dura layer forming dural folds

Superior Sagittal Sinus

Venous sinus that drains blood from brain

Arachnoid Mater

Middle meningeal layer; web-like

Subarachnoid Space

Space containing CSF and major blood vessels

Pia Mater

Thin inner meningeal layer tightly adhering to brain

Cerebrospinal Fluid (CSF)

Cushions brain and spinal cord; provides nutrients and waste removal

Gray Matter (Brain)

Contains neuron cell bodies; site of processing

White Matter (Brain)

Contains myelinated axons; conducts impulses

Cerebral Hemispheres

Largest brain region; higher cognitive functions

Central Sulcus

Separates frontal and parietal lobes

Precentral Gyrus

Primary motor cortex; voluntary skeletal muscle control

Postcentral Gyrus

Primary somatic sensory cortex; receives sensory input

Longitudinal Fissure

Separates right and left hemispheres

Frontal Lobe

Voluntary motor control, planning, personality

Broca’s Area of frontal

Motor speech area; speech production

Primary Motor Cortex of frontal

Initiates voluntary movement

Premotor Cortex of frontal

Plans and coordinates learned movements

Prefrontal Association Area

Personality, judgment, decision making

Parietal Lobe

Processes sensory information

Primary Sensory Cortex of Parietal lobe

Receives touch, pain, temperature input

Somatic Sensory Association Area

Interprets sensory input

Wernicke’s Area

Language comprehension and interpretation

Temporal Lobe

Hearing, smell, memory

Auditory Cortex

Processes sound

Gustatory Cortex

Processes taste

Olfactory Cortex

Processes smell

Occipital Lobe

Vision

Visual Cortex

Processes visual information

Basal Nuclei

Regulate motor control and muscle tone

Association Tracts

Connect areas within same hemisphere

Commissural Tracts

Connect two hemispheres (corpus callosum)

Corpus Callosum

Major commissural tract connecting hemispheres

Projection Tracts

Connect cerebrum with lower CNS regions

Fornix

Connects hippocampus to other brain regions; memory processing

Hippocampus

Memory formation and learning

Olfactory Bulbs

Receive sensory input for smell

Thalamus

Sensory relay station to cerebral cortex

Intermediate Mass

Connection between right and left thalamus

Hypothalamus

Maintains homeostasis; controls autonomic and endocrine systems

Mammillary Bodies

Relay stations for memory

Pituitary Gland

Master endocrine gland controlled by hypothalamus

Infundibulum

Connects hypothalamus to pituitary gland

Optic Chiasm

Crossing of optic nerves

Epithalamus

Contains pineal gland; regulates circadian rhythms

Pineal Body

Secretes melatonin

Midbrain

Visual and auditory reflex centers

Cerebellum

Coordinates balance and fine motor movement

Pons

Relays information between cerebrum and cerebellum; regulates breathing

Medulla Oblongata

Controls vital autonomic functions (heart rate, breathing, BP)

Lateral Ventricles

CSF-filled cavities in cerebral hemispheres

Third Ventricle

CSF cavity in diencephalon

Cerebral Aqueduct

Connects third and fourth ventricles

Fourth Ventricle

CSF cavity between pons and cerebellum

Central Canal

CSF-filled canal in spinal cord

Arachnoid Granulations

Reabsorb CSF into venous blood

Choroid Plexus

Produces CSF

Dura Mater (Spinal Cord)

Outer meningeal layer of spinal cord

Epidural Space

Space between dura and vertebrae containing fat and vessels

Arachnoid Mater (Spinal Cord)

Middle meningeal layer

Subarachnoid Space (Spinal Cord)

Contains CSF

Pia Mater (Spinal Cord)

Inner meningeal layer attached to cord

Posterior Median Sulcus

Shallow groove on posterior spinal cord

Anterior Median Fissure

Deep groove on anterior spinal cord

Central Canal (Spinal Cord)

Contains CSF

Posterior Horn

Sensory processing region of gray matter

Lateral Horn

Autonomic motor neurons (T1–L2)

Anterior Horn

Somatic motor neurons

Posterior Column

Sensory ascending tracts

Lateral Column

Ascending and descending tracts

Anterior Column

Motor descending tracts

Cervical Enlargement

Supplies nerves to upper limbs

Lumbar Enlargement

Supplies nerves to lower limbs

Conus Medullaris

Tapered end of spinal cord

Cauda Equina

Bundle of spinal nerves below conus medullaris

Terminal Filum

Anchors spinal cord to coccyx

Posterior (Dorsal) Root

Carries sensory input into spinal cord

Posterior Root Ganglion

Contains sensory neuron cell bodies

Anterior (Ventral) Root

Carries motor output from spinal cord

Cervical Plexus

Nerve network supplying neck and diaphragm

Brachial Plexus

Supplies upper limb

Lumbar Plexus

Supplies anterior thigh

Sacral Plexus

Supplies posterior thigh and lower limb