BIO 234: Chapter 10 - Nervous System Architecture, Cellular Components, and Neural Processing

Vocabulary practice flashcards covering Chapter 10 (Nervous System) lecture notes, focusing on structural and functional classifications of neurons, neuroglia, impulse conduction, synaptic mechanisms, and related neurological disorders.

Nervous System

An organ system composed of neural tissue, blood vessels, and connective tissue that maintains homeostasis, exerts precise control over bodily functions, and provides awareness of internal and external events.

Central Nervous System (CNS)

The division of the nervous system consisting exclusively of the brain and spinal cord.

Peripheral Nervous System (PNS)

The division of the nervous system composed of cranial nerves, spinal nerves, and ganglia located outside the brain and spinal cord.

Ganglia

Clusters of neuron cell bodies located outside the brain and spinal cord within the peripheral nervous system.

Nerves

Bundles of axons located specifically within the peripheral nervous system (PNS).

Tracts

Bundles of axons located specifically within the central nervous system (CNS).

Neurons

Specialized nerve cells that react to physical and chemical changes, receive input via dendrites, and conduct output in the form of impulses down axons.

Neuroglia

Non-neuronal supporting cells that nourish neurons, send and receive chemical messages, greatly outnumber neurons in the brain, and assemble to form protective barriers.

Blood-Brain Barrier

A protective cellular structure formed by neuroglia in the brain that shields delicate brain tissue from chemical fluctuations in the bloodstream.

Synapse

A functional connection between a neuron and the specific cell with which it communicates.

Synaptic Cleft

The narrow intercellular gap separating a neuron from the cell it communicates with at a synapse.

Neurotransmitters

Biological messenger molecules that convey information across the synaptic cleft from a presynaptic neuron to a postsynaptic cell.

Sensory Function

The nervous system function where sensory receptors detect internal or external environmental changes and generate impulses conducted along peripheral nerves to the CNS.

Integrative Function

The nervous system function wherein sensory input is gathered by the CNS to create sensations, memories, or thoughts and make decisions on appropriate responses.

Motor Function

The nervous system function in which neurons conduct impulses from the CNS to effectors outside the nervous system to act upon integrated decisions.

Effectors

Responsive structures outside of the nervous system, including muscles and glands, that execute motor functions directed by impulses from the CNS.

Somatic Nervous System

The motor subdivision that communicates voluntary instructions originating in the CNS to skeletal muscles, resulting in muscle contraction.

Autonomic Nervous System

The motor subdivision that transmits involuntary, subconscious instructions from the CNS to cardiac muscle, smooth muscle, and glands to maintain homeostasis.

Neuron Cell Body

The core structure of a neuron containing granular cytoplasm, a large spherical nucleus, mitochondria, lysosomes, Golgi apparatus, endoplasmic reticulum, microtubules, and neurofilaments.

Neurofilaments

Cytoskeletal fibers within the neuron cell body that form a supportive network and extend as a bridge into the axon.

Axon

A single elongated neuronal process that arises from the axon hillock and transmits electrical impulses, biochemicals, and organelles away from the cell body.

Axon Hillock

The specialized, slightly elevated region of the neuron cell body from which a single axon arises.

Axon Terminal

The specialized ending found at the branch terminus of an axon that interfaces with the synaptic cleft to release neurotransmitters.

Dendrites

Multiple, highly branched receptive processes of a neuron that receive input from other neurons and direct it toward the cell body.

Dendritic Spines

Tiny, thorn-like projections located along dendrites that serve as specialized physical contact points for synaptic inputs from other neurons.

Schwann Cells

PNS neuroglia that encase large axons of peripheral neurons in lipid-rich myelin sheaths, remove excess ions and neurotransmitters, and assist in peripheral axon regeneration.

Oligodendrocytes

CNS neuroglia, smaller than astrocytes, that form in rows and produce myelin sheaths around axons of the brain and spinal cord.

Nodes of Ranvier

Narrow, unmyelinated gaps along an axon situated between successive myelin sheath wrappings.

White Matter

Regions within the nervous system characterized by an abundance of myelinated axons, appearing white due to the myelin coating.

Multipolar Neuron

A neuron with a single axon and many dendrites extending from its cell body; the most common structural type in the brain and spinal cord, as well as autonomic ganglia and parts of the eye.

Bipolar Neuron

A structural type of neuron featuring two processes arising from opposite ends of the cell body (one axon and one dendrite); found in specialized regions of the eyes, nose, and ears.

Unipolar Neuron

A structural type of neuron with a single process extending from the cell body that divides into two branches functioning as a single axon; typically located in ganglia.

Sensory (Afferent) Neurons

Predominantly unipolar neurons whose dendrites serve as sensory receptors, conducting impulses from peripheral body parts to the brain or spinal cord.

Motor (Efferent) Neurons

Multipolar neurons that transmit nerve impulses away from the brain or spinal cord to effectors such as skeletal muscle, cardiac muscle, smooth muscle, and glands.

Interneurons

Multipolar neurons residing entirely within the brain or spinal cord that form links between neurons, relaying and funneling sensory input into appropriate processing areas.

Astrocytes

Star-shaped CNS neuroglia located between neurons and blood vessels that provide support, aid glucose and potassium metabolism, form the blood-brain barrier, produce scar tissue after injury, and connect via gap junctions.

Microglia

Small, scattered CNS neuroglia that support neurons, phagocytize bacteria and cellular debris, and proliferate during inflammation caused by disease or injury.

Ependyma

Ciliated cuboidal or columnar CNS neuroglia that line the spinal cord central canal and brain ventricles, forming a porous layer that permits diffusion between brain interstitial fluid and cerebrospinal fluid (CSF).

Satellite Cells

Small, cuboidal PNS neuroglia that surround neuron cell bodies within ganglia to provide nutritional support and clear excess ions and neurotransmitters.

Peripheral Axon Regeneration

The repair process in the PNS wherein the distal injured axon degenerates, macrophages remove debris, and the proximal axon develops sprouts that grow into a tube of remaining Schwann cells to re-form a myelin sheath.

Presynaptic Neuron

The neuron that conducts a nerve impulse toward a synapse to transmit a signal to another cell.

Postsynaptic Neuron

The neuron or recipient cell that receives input across a synapse following neurotransmitter release.

Synaptic Transmission

The one-way process in which a presynaptic impulse triggers synaptic vesicles in the axon terminal to release neurotransmitters that bind postsynaptic receptors, eliciting excitatory or inhibitory actions.

Saltatory Conduction

The rapid mechanism of impulse propagation along myelinated axons in which electrical depolarization jumps from one Node of Ranvier to the next.

Neuronal Pools

Functional groups of interconnected neurons in the CNS that synapse together to receive input, process it, and generate a coordinated output.

Convergence

A neural circuitry pattern in which impulses from $2+$ presynaptic axons synapse onto a single postsynaptic neuron, enabling summation of input from multiple sources.

Divergence

A neural circuitry pattern in which impulses from a single presynaptic neuron reach multiple postsynaptic neurons, allowing widespread amplification of signals.

Migraine Aura

A neurological visual phenomenon characterized by shimmering images in the peripheral visual field that typically precedes or accompanies a migraine headache.

Transcranial Magnetic Stimulation (TMS)

A non-invasive treatment under study for acute and chronic migraines wherein a patient holds a device to the back of the head to deliver magnetic energy pulses to the brain.

Multiple Sclerosis (MS)

A progressive autoimmune disorder of the CNS affecting $2.5\text{ million}$ people worldwide in which white blood cells attack myelin-producing cells, causing inflammation, demyelination, and muscular atrophy.

Scleroses

Hard, fibrous scars formed in the brain and spinal cord due to the immune destruction of myelin sheaths in Multiple Sclerosis, blocking neurons from conducting impulses.

Huntington's Disease

An incurable neurodegenerative condition with onset typically between $30\text{--}50\text{ years old}$ caused by microglia releasing a toxin that damages neurons, characterized by cognitive impairment and uncontrollable dancelike movements.