Central Nervous System Lecture Notes Flashcards

This set covers essential vocabulary from Chapter 12 of Human Anatomy and Physiology, focusing on the structures, functions, development, and protective mechanisms of the Central Nervous System.

Sensory Functions

The detection of sensations within and outside the body, primarily performed by the peripheral nervous system (PNS).

Integrative Functions

Decision-making processes carried out exclusively by the central nervous system (CNS).

Motor Functions

The stimulation of muscle cell contractions or gland secretions, performed by the PNS.

Brain Weight

A soft, whitish-gray organ residing in the cranial cavity that weighs between $1,250–1,450\,\text{g}$, with a brain weight to body weight ratio that is equal between males and females.

Neuroplasticity

The phenomenon where a person's socialization influences the development of neural networks, which can explain perceived intelligence differences between sexes.

Cerebrum

The enlarged, superior portion of the brain responsible for higher mental functions, including learning, memory, personality, cognition, and conscience.

Diencephalon

The central core of the brain responsible for processing, integrating, and relaying information, as well as maintaining homeostasis of biological rhythms.

Cerebellum

The posterior, inferior portion of the brain important for the planning and coordination of movement, especially complex activities.

Brainstem

The portion of the brain that connects to the spinal cord and controls basic involuntary processes such as the rate and depth of breathing.

Spinal Cord Dimensions

A long, tubular organ measuring about $43–46\,\text{cm}$ in length and about $0.65–1.25\,\text{cm}$ in diameter.

White Matter

Nervous tissue containing myelinated axons; in the brain, it forms bundles called tracts.

Gray Matter

Nervous tissue made up of neuron cell bodies, dendrites, and unmyelinated axons; in the brain, clusters of these cell bodies are called nuclei.

Neural Tube

A hollow structure that completely forms by the fourth week of development, giving rise to the primary brain vesicles and the spinal cord.

Primary Brain Vesicles

The initial three enlargements of the neural tube: the forebrain, midbrain, and hindbrain.

Sulci and Fissures

Shallow grooves (sulci) and deep grooves (fissures) on the cerebrum surface, such as the longitudinal fissure that separates the cerebral hemispheres.

Gyri

Elevated ridges that cover the surface of the cerebrum.

Insulas

Cerebral lobes visible only when the frontal, parietal, and temporal lobes are pried apart at the lateral fissure.

Neocortex

The evolutionarily most recent part of the cerebral cortex, composed of six layers and responsible for conscious processes.

Primary Motor Cortex

Located in the precentral gyrus of the frontal lobe; houses upper motor neurons that plan and execute voluntary movement.

Primary Somatosensory Cortex ($S1$)

Located in the postcentral gyrus of the parietal lobe; interprets incoming somatic sensory stimuli such as touch and temperature.

Broca’s Area

An association area in the anterolateral frontal lobe responsible for the production of language, grammar, and syntax.

Wernicke’s Area

An association area in the temporal and parietal lobes responsible for language comprehension and linking words to their symbolic meaning.

Basal Nuclei

Clusters of cell bodies including the caudate nucleus, putamen, and globus pallidus that inhibit involuntary movement and initiate voluntary movement.

Commissural Fibers

White matter fibers that connect the right and left cerebral hemispheres, with the largest group being the Corpus Callosum.

Limbic System

A functional brain system including the hippocampus and amygdala that participates in memory, learning, emotion, and behavior.

Thalamus

The egg-shaped central region of the diencephalon that acts as the main entrance to the cerebral cortex for sensory and motor information.

Hypothalamus

The region of the diencephalon that acts as the boss of the autonomic nervous system and regulates survival functions like thirst, hunger, and sleep/wake cycles.

Pineal Gland

A structure in the epithalamus that secretes melatonin to help regulate the sleep/wake cycle.

Arbor Vitae

The branching pattern of white matter within the cerebellum.

Midbrain (Mesencephalon)

The superior portion of the brainstem containing the Substantia Nigra and the superior and inferior colliculi.

Medulla Oblongata

The inferiormost part of the brainstem containing the pyramids, where motor fibers decussate (cross over).

Reticular Activating System (RAS)

A system of fibers within the reticular formation that arouses the cerebral cortex from sleep and maintains alertness.

Vasopressor Center

Nuclei in the pons and medulla that increase the rate and force of heart pumping and constrict blood vessels to raise blood pressure.

Pyrogens

Chemicals secreted by immune cells or bacteria that cause the hypothalamus to increase the body's normal temperature range, resulting in fever.

Orexins

Neurotransmitters secreted by the lateral hypothalamic area during fasting that induce hunger and help maintain wakefulness.

Suprachiasmatic Nucleus (SCN)

The biological clock in the hypothalamus that regulates circadian rhythms by signaling the pineal gland to produce melatonin.

Electroencephalogram (EEG)

A test measuring the electrical activity of the brain, identifying brain waves such as Beta, Theta, and Delta waves.

REM Sleep

Rapid eye movement sleep characterized by dreaming and brain waves that resemble those of an awake person.

Stupor and Coma

States of altered consciousness involving diminished cortical activity (stupor) or unarousable unconsciousness (coma).

Aphasia

A language deficit, either Broca's (inability to produce speech) or Wernicke's (inability to understand language).

Declarative Memory

The memory of things readily available to consciousness, such as facts, phone numbers, or quotes.

Long-Term Potentiation (LTP)

The mechanism of encoding long-term declarative memories by increasing the strength of synaptic connections between neurons.

Cranial Meninges

Three protective membranes surrounding the brain: the Dura Mater, Arachnoid Mater, and Pia Mater.

Cerebrospinal Fluid (CSF)

A clear liquid formed by choroid plexuses that cushions the brain, removes waste, and maintains temperature.

Blood Brain Barrier

A protective property of brain capillaries that uses tight junctions and astrocytes to limit what substances can enter the brain's extracellular fluid.