Nervous Tissue and Nervous System Fundamentals

Vocabulary flashcards covering the structural and functional divisions of the nervous system, neuron anatomy and classifications, receptor types, neuroglia cells, and nerve repair mechanisms based on Chapter 12 lecture notes.

Neurons

The basic functional cells of the nervous system responsible for communication between cells.

Neuroglia

Support cells that protect and maintain the physical and biochemical structure of neurons.

Central Nervous System (CNS)

Anatomical division consisting of the brain and spinal cord, responsible for integrating, processing, and coordinating sensory information and motor commands.

Peripheral Nervous System (PNS)

Anatomical division composed of all nervous tissue outside the CNS and ENS that carries sensory information to the CNS and motor commands to peripheral tissues.

Enteric Nervous System (ENS)

An extensive network of neurons and nerve fibers within the walls of the digestive tract that operates locally outside the CNS.

Afferent Division

The functional division of the PNS that brings sensory information from receptors to the CNS.

Efferent Division

The functional division of the PNS that carries motor commands from the CNS to peripheral target organs called effectors.

Effectors

Target organs of the efferent division, such as muscles, glands, and adipose tissue, that respond to motor commands.

Somatic Nervous System (SNS)

Subdivision of the efferent PNS that controls skeletal muscle contractions, including both voluntary actions and involuntary reflexes.

Autonomic Nervous System (ANS)

Subdivision of the efferent PNS that automatically regulates smooth muscle, cardiac muscle, glandular secretions, and adipose tissue.

Perikaryon

The cytoplasm surrounding the nucleus within the cell body (soma) of a neuron.

Neurofibrils

Bundles of neurotubules extending into the axon and dendrites from the perikaryon to provide structural support.

Nissl Bodies

Clusters of rough endoplasmic reticulum and free ribosomes in the perikaryon that synthesize neurotransmitters and give neural tissue a gray appearance.

Axon Hillock

The thickened region of the neuron cell body where the initial segment of the axon originates.

Telodendria

Fine terminal branch extensions at the end of an axon that terminate in axon terminals.

Synapse

The specialized site where a neuron communicates with another cell.

Anterograde Transport

The forward movement of cellular materials from the neuron cell body down to the axon terminal, driven by kinesin using ATP.

Retrograde Transport

The backward movement of materials or debris from the axon terminal back to the neuron cell body, driven by dynein using ATP.

Anaxonic Neurons

Small neurons with many dendrites but no obvious axon, found in the brain and special sense organs.

Bipolar Neurons

Neurons featuring two distinct processes: one main dendrite branch and one axon with the cell body positioned between them.

Unipolar Neurons

Neurons in which the dendrite and axon continuous and fused, with the cell body lying off to one side.

Multipolar Neurons

Neurons featuring two or more dendrites and a single axon; the most common structural neuron type in the CNS.

Ganglion

A collection of neuron cell bodies located in the peripheral nervous system.

Interoceptors

Sensory receptors that monitor internal conditions and organ systems, sensing stretch, pressure, and pain.

Exteroceptors

Sensory receptors that gather external environmental information including touch, temperature, pressure, sight, smell, taste, balance, and hearing.

Proprioceptors

Sensory receptors that monitor the position and movement of skeletal muscles and joints.

Interneurons

Neurons situated between sensory and motor neurons within the CNS and autonomic ganglia that integrate sensory information and coordinate motor responses.

Astrocytes

The largest and most numerous CNS neuroglia, responsible for forming the blood-brain barrier, providing structural support, repairing damage, guiding development, and controlling the interstitial environment.

Ependymal Cells

Neuroglial cells that line the central canal of the spinal cord and ventricles of the brain, functioning to produce, monitor, and circulate cerebrospinal fluid (CSF).

Oligodendrocytes

CNS neuroglia with cytoplasmic extensions that wrap around axolemmas to form myelin sheaths around multiple axons.

Microglia

The smallest and least numerous CNS neuroglia, acting as phagocytes to engulf cellular debris, waste products, and pathogens.

Satellite Cells

PNS neuroglia that surround neuron cell bodies in ganglia to regulate the local interstitial fluid environment.

Schwann Cells

PNS neuroglia responsible for forming myelin sheaths or neurolemma around peripheral axons.

Wallerian Degeneration

The process in the PNS by which Schwann cells and macrophages clean up debris and guide the repair of a damaged axon along its original path.