Study Guide: Central Nervous System Structure and Function (Chapter 12)

Cerebrum

White Matter vs. Gray Matter

The cerebrum consists of regions of white matter and gray matter, each with distinct functions and locations.

• Gray matter: Contains neuron cell bodies, dendrites, and unmyelinated axons; found in the cerebral cortex and basal nuclei.

• White matter: Composed of myelinated axons; responsible for communication between different brain regions.

• Example: The cerebral cortex is primarily gray matter, while the corpus callosum is white matter.

Ventricles of the Brain

The brain contains interconnected cavities called ventricles that produce and circulate cerebrospinal fluid (CSF).

• The third ventricle is connected to the fourth ventricle via the cerebral aqueduct.

Cerebral Hemispheres

The cerebral hemispheres are divided by the longitudinal fissure and connected by commissural fibers.

• Longitudinal fissure: Separates the left and right hemispheres.

• Transverse cerebral fissure: Separates the cerebrum from the cerebellum.

• Corpus callosum: Major commissural fiber connecting the hemispheres.

Cerebral Cortex Functional Areas

The cerebral cortex contains specialized areas responsible for motor, sensory, and association functions.

• Primary motor cortex: Controls voluntary movements.

• Premotor cortex: Plans movements.

• Broca's area: Controls speech production.

• Frontal eye field: Controls voluntary eye movements.

Sensory Areas

Sensory areas process incoming sensory information.

• Primary somatosensory cortex: Receives sensory input from the body.

• Somatosensory association area: Interprets sensory information.

• Association areas: Integrate and interpret information from multiple sensory inputs.

• Example: The visual association area interprets visual stimuli.

Lateralization

Lateralization refers to the specialization of certain functions in one hemisphere of the brain.

• Left hemisphere: Language, math, logic.

• Right hemisphere: Visual-spatial skills, intuition, emotion.

Basal Nuclei

The basal nuclei are deep gray matter structures involved in movement regulation.

• Striatum: Composed of the caudate nucleus and putamen.

• Function: Regulate voluntary motor activities and inhibit unnecessary movements.

Diencephalon

Thalamus

The thalamus acts as a relay station for sensory and motor signals to the cerebral cortex.

• Function: Filters and directs sensory information.

Hypothalamus

The hypothalamus regulates homeostasis and controls the endocrine system.

• Functions: Controls autonomic nervous system, regulates body temperature, hunger, thirst, and circadian rhythms.

• Example: The hypothalamus controls the release of hormones from the pituitary gland.

Epithalamus & Pineal Gland

The epithalamus includes the pineal gland, which secretes melatonin.

• Melatonin: Hormone involved in regulating sleep-wake cycles.

Brainstem

Midbrain

The midbrain contains nuclei and tracts involved in vision, hearing, and motor control.

• Periaqueductal gray matter: Involved in pain modulation.

• Corpora quadrigemina: Contains superior and inferior colliculi.

• Superior colliculus: Visual reflex center.

• Inferior colliculus: Auditory reflex center.

• Substantia nigra: Functionally connected to the basal nuclei; involved in movement.

Pons

The pons relays signals between the cerebrum and cerebellum and regulates breathing.

• Function: Controls respiratory rhythm and relays information.

Medulla Oblongata

The medulla oblongata controls vital autonomic functions and houses important nuclei.

• Fourth ventricle: Located within the medulla.

• Choroid plexus: Produces cerebrospinal fluid.

• Pyramids: Contain motor tracts.

• Vital functions: Regulates heart rate, blood pressure, and respiration.

Cerebellum

Coordination and Communication

The cerebellum coordinates voluntary movements and communicates with higher brain centers.

• Function: Ensures smooth, balanced muscular activity.

• Example: The cerebellum helps maintain posture and balance during movement.

Key Terms and Definitions

• Gray matter: Neuron cell bodies and dendrites.

• White matter: Myelinated axons.

• Ventricle: Fluid-filled cavity in the brain.

• Basal nuclei: Deep brain structures regulating movement.

• Thalamus: Sensory relay station.

• Hypothalamus: Homeostasis regulator.

• Pineal gland: Melatonin secretion.

• Midbrain: Vision, hearing, motor control.

• Pons: Breathing, communication.

• Medulla oblongata: Autonomic control.

• Cerebellum: Coordination.

Summary Table: Major Brain Regions and Functions

Region	Main Function	Key Structures
Cerebrum	Higher cognitive functions, voluntary movement	Cortex, basal nuclei, corpus callosum
Diencephalon	Sensory relay, homeostasis, endocrine control	Thalamus, hypothalamus, pineal gland
Brainstem	Autonomic functions, reflexes	Midbrain, pons, medulla oblongata
Cerebellum	Coordination, balance	Cerebellar cortex, deep nuclei

Additional info: Some details, such as the specific nuclei and their functions, were inferred based on standard Anatomy & Physiology curriculum for the central nervous system.