Anatomy Notes Fall 2025 - Nervous System (Video) - Vocabulary Flashcards

Vocabulary flashcards covering CNS, PNS, divisions, and autonomic functions based on the Nervous System notes.

Central Nervous System (CNS)

The brain, brainstem, and spinal cord; processes information and coordinates activity, with ascending and descending nerve traffic.

Brain

Major organ of the CNS that processes information and coordinates responses.

Brainstem

Lower part of the brain that connects to the spinal cord and regulates basic life functions.

Spinal cord

Main neural pathway between the brain and body; contains ascending and descending tracts.

Afferent nerve traffic

Nerve signals that carry sensory information toward the CNS.

Efferent nerve traffic

Nerve signals that carry motor commands away from the CNS to effectors.

Dorsal cavity

Body cavity that houses the brain and spinal cord (includes cranial and spinal cavities).

Cranial cavity

Space inside the skull that houses the brain.

Spinal column

Vertebral column enclosing and protecting the spinal cord.

Ascending tracts

Pathways that carry sensory information from body to brain.

Descending tracts

Pathways that carry motor commands from brain to body.

Peripheral Nervous System (PNS)

Nerves outside the CNS, including afferent and efferent fibers and innervation of organs.

Peripheral nerves

Bundles of axons in the PNS that connect the CNS to limbs and organs.

Innervation

Nerve supply to an organ or body part.

Sensory division

Afferent division of the PNS that carries sensory information to the CNS.

Visceral senses

Senses from internal organs (stretch, pain, temperature, chemical changes, irritation, hunger); taste and smell are special senses.

Somatic senses

Senses from the skin, muscles, and joints (touch, pain, pressure, vibration, temperature, proprioception; hearing, balance, and vision are also noted).

Motor division

Efferent division of the PNS that carries motor commands to effectors.

Efferent division

The motor division; transmits motor signals from the CNS to effectors.

Visceral (Autonomic) motor

Motor to smooth muscle, glands, and cardiac muscle; usually not conscious.

Somatic motor

Motor to skeletal muscles; conscious control; single, heavily myelinated neuron from CNS to effector.

Autonomic nervous system

Division of the PNS that controls involuntary functions; subdivides into sympathetic and parasympathetic.

Sympathetic nervous system

“Fight or flight” division; preganglionic fibers are lightly myelinated and may synapse with postganglionic fibers or the adrenal medulla.

Fight or flight

Physiological response preparing the body to confront or flee from threat; increases alertness and energy availability.

Parasympathetic nervous system

“Rest and digest” division; preganglionic fibers are lightly myelinated and postganglionic fibers are usually unmyelinated; uses acetylcholine.

Rest and digest

Autonomic state that promotes maintenance activities and energy conservation.

Preganglionic fiber

Autonomic neuron leaving the CNS to synapse on a ganglion; typically lightly myelinated.

Postganglionic fiber

Autonomic neuron from a ganglion to the effector; typically unmyelinated.

Adrenal medulla

Inner part of the adrenal gland; receives sympathetic preganglionic input and releases epinephrine and norepinephrine.

Epinephrine

Hormone/neurotransmitter released by the adrenal medulla; amplifies sympathetic responses.

Norepinephrine

Neurotransmitter released by most sympathetic postganglionic neurons; also a hormone when released by the adrenal medulla.

Acetylcholine (ACh)

Neurotransmitter used at somatic neuromuscular junctions and at parasympathetic synapses; also released by preganglionic autonomic neurons.

Acetylcholine at effector

ACh released at effector synapses such as the NMJ or parasympathetic postganglionic synapses.

Somatic effect

Stimulatory effect on skeletal muscles; usually voluntary.

Autonomic effect

Effect on smooth muscle, glands, or cardiac muscle; can be excitatory or inhibitory depending on receptors.

One-neuron pathway

Somatic motor pathway: CNS to effector via a single, heavily myelinated neuron.

Two-neuron pathway

Autonomic motor pathway: CNS to effector via a preganglionic and a postganglionic neuron.

Effector organs

Tissues that respond to neural signals (smooth muscle, glands, cardiac muscle).

Skeletal muscle

Voluntary muscle controlled by the somatic nervous system.

Smooth muscle

Involuntary muscle in the walls of hollow organs; innervated by autonomic nerves.

Cardiac muscle

Involuntary heart muscle; innervated by autonomic nerves.

Glands

Secretory organs that receive autonomic innervation.

Myelination

Insulating layer around axons; increases conduction velocity; in the PNS provided by Schwann cells.

Lightly myelinated axon

Axon with a thin myelin sheath; typical for preganglionic autonomic neurons.

Unmyelinated axon

Axon lacking a myelin sheath; typical for postganglionic autonomic fibers.