SRJC Anatomy 1 – Nervous System & Neural Tissue Vocabulary

Vocabulary flashcards covering key terms related to the nervous system’s structure, function, and cellular makeup.

Nervous System

Body system that receives sensory input, integrates information, and produces motor output for rapid coordination of body activities.

Information Flow (nervous system)

Pathway of sensory (afferent) input → central processing in CNS → motor (efferent) output to effectors.

Anatomical Organization (4 organs)

Brain, spinal cord, nerves, and ganglia.

Functional Organization

Central Nervous System (CNS) for integration and Peripheral Nervous System (PNS) for sensory input and motor output.

Neuron

Excitable cell that generates and conducts electrical impulses; basic structural and functional unit of the nervous system.

Nerve

Bundle of axons in the PNS enclosed by connective tissue sheaths.

Tract

Bundle of axons within the CNS having a common origin and destination.

Gray Matter

Regions rich in neuronal cell bodies (cortex, nuclei, horns) where synaptic processing occurs.

White Matter

Regions rich in myelinated axons that transmit signals over distances within the CNS.

Axon

Long nerve fiber that carries impulses away from the neuron’s cell body.

Dendrite

Branching neuron process that receives incoming signals and conveys them to the cell body.

Central Nervous System (CNS)

Composed of the brain and spinal cord; site of integration and control.

Peripheral Nervous System (PNS)

All nervous tissue outside the CNS—nerves and ganglia—that connects the body to the CNS.

Sensory Division

Afferent pathways that carry information from receptors toward the CNS.

Motor Division

Efferent pathways that carry commands from the CNS to effectors (muscles & glands).

Afferent

Conducting toward a reference point; sensory.

Efferent

Conducting away from a reference point; motor.

Somatic Nervous System

Subdivision that supplies skeletal muscles; usually under voluntary control.

Visceral (Autonomic) Nervous System

Subdivision that supplies cardiac muscle, smooth muscle, and glands; involuntary control.

General Senses

Senses with receptors widely distributed throughout the body (e.g., touch, pain, temperature).

Special Senses

Highly localized senses (vision, hearing, equilibrium, taste, smell) with specialized organs.

Ganglion

Collection of neuron cell bodies in the PNS.

Nucleus (nervous system)

Collection of neuron cell bodies within the CNS.

Spinal Nerves

31 pairs of mixed nerves emerging from the spinal cord that supply specific body regions.

Cranial Nerves

12 pairs of nerves that arise directly from the brain and primarily innervate the head and neck.

Myelinated Fiber

Axon wrapped by multiple layers of myelin, providing fast saltatory conduction.

Unmyelinated Fiber

Axon lacking a myelin sheath; conducts impulses more slowly.

Neuroglia (Glial Cells)

Supporting cells of nervous tissue that protect, nourish, and insulate neurons.

Neurolemma (Sheath of Schwann)

Outer cytoplasmic layer of a Schwann cell in the PNS essential for axonal regeneration.

Multipolar Neuron

Neuron with one axon and multiple dendrites; the most common structural type, especially in CNS.

Bipolar Neuron

Neuron with one axon and one dendrite; found in special sense organs like the retina and olfactory epithelium.

Unipolar (Pseudounipolar) Neuron

Sensory neuron whose single process splits into peripheral and central branches.

Interneuron

Neuron located entirely within the CNS that relays signals between sensory and motor neurons.