The Nervous System - Part 1: General Organization, Spinal Cord, and Spinal Nerves

Vocabulary flashcards covering key terms from the Nervous System lecture notes.

Central Nervous System (CNS)

Brain and spinal cord; integrates, processes, and coordinates sensory data and motor commands.

Peripheral Nervous System (PNS)

Nervous tissue outside the CNS; links the CNS to receptors and effectors.

Afferent division

Part of the PNS that carries sensory information toward the CNS.

Efferent division

Part of the PNS that carries motor commands away from the CNS to effectors.

Receptors

Specialized cells or nerve endings that monitor stimuli and trigger responses.

Special sensory receptors

Receptors for smell, taste, vision, balance, and hearing.

Visceral sensory receptors

Receptors that monitor internal organs and body systems.

Somatic sensory receptors

Receptors that monitor skin, muscles, joints, and body surfaces.

Chemoreceptors

Receptors that respond to chemical changes (e.g., taste, smell, pH, osmolarity).

Nociceptors

Receptors that detect pain.

Mechanoreceptors

Receptors that respond to mechanical stimuli such as touch, vibration, pressure, and joint position.

Thermoreceptors

Receptors that detect changes in temperature.

Photoreceptors

Receptors that detect light for vision.

Somatic nervous system

Division of the PNS that controls voluntary skeletal muscle movements.

Autonomic nervous system (ANS)

Division of the PNS that regulates involuntary functions of viscera.

Parasympathetic division

ANS subdivision associated with rest-and-digest activities.

Sympathetic division

ANS subdivision associated with fight-or-flight responses.

Somatic motor pathway

Voluntary pathway controlling skeletal muscles; involves motor neurons from the CNS.

Primary motor cortex

Brain region that initiates voluntary movements; contains the motor homunculus.

Spinal nerve

Mixed nerve formed by the dorsal and ventral roots; carries sensory and motor information.

Dorsal root

Sensory root carrying afferent fibers into the spinal cord.

Dorsal root ganglion

Cluster of sensory neuron cell bodies in the dorsal root.

Dorsal horn

Posterior gray matter region that processes incoming sensory information via interneurons.

Ventral root

Motor root carrying efferent information away from the spinal cord.

Ventral horn

Anterior gray matter region containing motor neuron cell bodies.

White matter

Myelinated axons forming tracts that carry signals up and down the spinal cord.

Gray matter

Region of neuron cell bodies and synapses in the spinal cord.

Central canal

CSF-filled canal running through the spinal cord.

Dura mater

Outermost, tough protective meningeal layer.

Arachnoid mater

Middle meninx; subarachnoid space contains CSF.

Pia mater

Innermost, delicate meninx in contact with the spinal cord.

Subarachnoid space

Space between arachnoid and pia containing CSF.

Epidural space

Space outside the dura; contains fat and blood vessels; site for epidural anesthesia.

Lumbar puncture

Procedure to withdraw CSF by inserting a needle into the subarachnoid space in the lower lumbar region.

Epidural anesthesia

Anesthetic delivered into the epidural space; analgesic diffuses beyond the dura.

Spinal nerves (31 pairs)

31 pairs of mixed nerves; cervical nerves exit above corresponding vertebrae; others exit below.

Cervical plexus

Network supplying the head, neck, and shoulder.

Brachial plexus

Network supplying the upper limb.

Lumbar plexus

Network supplying the lower abdomen, groin, thighs, knees, and calves.

Sacral plexus

Network supplying the pelvis, buttocks, genitals, thighs, calves, and feet.

Lumbosacral plexus

Combined network of the lumbar and sacral plexuses.

Dermatomes

Skin areas innervated by sensory fibers from a single spinal nerve.

Shingles dermatome distribution

In shingles, skin eruptions follow a single spinal nerve's dermatomal area.

Referred pain

Visceral pain perceived in the skin or muscles served by the same spinal segment.

Cauda equina

“Horse’s tail” of spinal nerve roots below the conus medullaris.

Endoneurium

Connective tissue wrapping around individual nerve fibers.

Perineurium

Connective tissue wrapping around a fascicle of nerve fibers.

Epineurium

Outer protective connective tissue wrapping around the entire nerve.

Nerve plexus

Network of interwoven nerves formed by ventral rami; four major types: cervical, brachial, lumbar, sacral.

Fascicle

A bundle of nerve fibers wrapped by perineurium.

Unipolar neuron

Sensory neuron with a single process (dendrite and axon fused) often located in dorsal root ganglia.

Multipolar neuron

Motor neuron with multiple dendrites and a single axon.

Phantom limb

Perceived sensation of a limb that has been amputated.

Motor homunculus

Cortical map showing the body parts controlled by the primary motor cortex.

Sensory homunculus

Cortical map showing the distribution of sensory input on the primary somatosensory cortex.