Nervous Tissue and Nervous System Fundamentals

A comprehensive set of vocabulary flashcards covering key terms and concepts from the lecture on nervous tissue and the nervous system.

Homeostasis

The maintenance of a stable internal environment in the body, regulated mainly by the nervous and endocrine systems.

Nervous System

The body system that detects changes, integrates information, and coordinates responses through electrical and chemical signals.

Central Nervous System (CNS)

Comprises the brain and spinal cord; integrates sensory information and issues motor commands.

Peripheral Nervous System (PNS)

All nervous tissue outside the CNS, including cranial and spinal nerves, ganglia, and sensory receptors.

Sensory Input

Detection and transmission of internal and external changes to the CNS via afferent pathways.

Integration

Analysis, storage, and decision-making functions performed by the CNS.

Motor Output

Transmission of excitatory or inhibitory commands from the CNS to effectors via efferent pathways.

Afferent Pathway

Neural route that carries sensory information from receptors toward the CNS.

Efferent Pathway

Neural route that carries motor commands from the CNS to muscles or glands.

Neuron

Highly specialized, non-dividing cell that conducts nerve impulses and forms the circuitry of the nervous system.

Neuroglia (Glial Cells)

Supporting cells that nourish, protect, and maintain neurons and can divide throughout life.

Cell Body (Soma)

The metabolic and genetic center of a neuron containing the nucleus and most organelles.

Dendrite

Branched neuronal process that receives incoming signals and conveys them toward the cell body.

Axon

Long neuronal process that propagates action potentials away from the cell body toward other cells.

Nissl Bodies

Rough endoplasmic reticulum clusters in neurons responsible for protein synthesis.

Axon Hillock

Cone-shaped region of the cell body where the axon originates and action potentials are initiated.

Schwann Cell

PNS glial cell that forms the myelin sheath around axons.

Oligodendrocyte

CNS glial cell that myelinates multiple axons.

Myelin Sheath

Multilayered lipid-protein covering that insulates axons and speeds impulse conduction.

Node of Ranvier

Gap between myelin segments where action potentials are regenerated.

Unipolar Neuron

Neuron with a single process that splits into peripheral and central branches; common in sensory neurons.

Bipolar Neuron

Neuron with one axon and one dendrite; found in retina, inner ear, and olfactory epithelium.

Multipolar Neuron

Neuron with one axon and multiple dendrites; most common type in CNS.

Synapse

Junction where a neuron communicates with another cell; can be electrical or chemical.

Electrical Synapse

Synapse using gap junctions for direct ion flow; found in cardiac and some smooth muscle.

Chemical Synapse

Synapse with a synaptic cleft where neurotransmitters relay the signal in one direction.

Neuromuscular Junction (NMJ)

Chemical synapse between a motor neuron and a skeletal muscle fiber using acetylcholine.

Acetylcholine (ACh)

The primary neurotransmitter at neuromuscular junctions.

Astrocyte

Star-shaped CNS glial cell that maintains the blood–brain barrier and regulates the extracellular environment.

Microglia

Small CNS glial cells that act as phagocytes removing debris and pathogens.

Ependymal Cell

CNS glial cell lining ventricles and central canal; produces and circulates cerebrospinal fluid.

Satellite Cell

PNS glial cell that surrounds neuronal cell bodies in ganglia, providing support and regulation.

Myelination

Process of forming a myelin sheath around axons, performed by Schwann cells in the PNS and oligodendrocytes in the CNS.

Sensory Receptor

Specialized structure that detects stimuli; classified by structure, stimulus type, and location.

Free Nerve Ending

Unencapsulated receptor detecting pain, temperature, and some touch.

Encapsulated Nerve Ending

Receptor ending enclosed in connective tissue capsule, detecting pressure, vibration, etc.

Proprioceptor

Receptor that provides information about body position and movement.

Ganglion

Collection of neuronal cell bodies located in the PNS.

Nucleus (Neuroanatomy)

Cluster of neuronal cell bodies located within the CNS.

Nerve

Bundle of axons in the PNS surrounded by connective tissue.

Tract

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

Somatic Nervous System (SNS)

PNS division that controls voluntary skeletal muscle activity and conveys sensory information from skin, muscles, and joints.

Autonomic Nervous System (ANS)

PNS division regulating involuntary activities of smooth muscle, cardiac muscle, and glands.

Sympathetic Division

ANS branch that prepares the body for 'fight-or-flight' responses.

Parasympathetic Division

ANS branch that conserves energy and promotes 'rest-and-digest' activities.

Enteric Nervous System

Intrinsic neural network of the gastrointestinal tract that controls digestive functions independently or with ANS input.