Spinal Cord & Spinal Nerves - Vocabulary Flashcards

Vocabulary flashcards covering key terms and concepts from the Spinal Cord and Spinal Nerves lecture (Ch. 9).

Central nervous system

The brain and spinal cord.

Somatic nervous system

Division of the peripheral nervous system that controls voluntary skeletal muscles.

Autonomic nervous system

Division of the peripheral nervous system that regulates involuntary functions (glands, smooth and cardiac muscle).

Dendrite

Neuron process that receives impulses from other neurons.

Axon

Neural process that conducts impulses away from the cell body.

Myelin sheath

Insulating layer around some axons that speeds nerve impulse conduction.

Schwann cells

Glial cells that form myelin in the peripheral nervous system.

Oligodendrocytes

Glial cells that form myelin in the central nervous system.

Neurilemma

Outer layer of the axon in the PNS; aids repair of damaged axons.

Sensory (afferent) neuron

Neuron that carries information from receptors to the CNS.

Motor (efferent) neuron

Neuron that carries information from the CNS to muscles.

Astrocytes

Glial cells that help form the blood-brain barrier and support neurons.

Microglia

CNS phagocytes that protect the brain and spinal cord.

Ependymal cells

Glial cells that line ventricles and produce cerebrospinal fluid (CSF).

Resting membrane potential

Baseline electrical charge of a resting neuron (about -70 mV).

Sodium (Na+)

Ion that rushes into the cell during depolarization.

Potassium (K+)

Ion that leaves the cell during repolarization.

Saltatory conduction

Conduction that jumps from node to node along myelinated axons.

Synaptic cleft

Gap between neurons at a synapse.

Acetylcholine (ACh)

Neurotransmitter released at neuromuscular junctions.

Serotonin

Neurotransmitter involved in mood regulation.

Dopamine

Neurotransmitter associated with reward and movement.

Norepinephrine

Neurotransmitter involved in alertness and sympathetic signaling.

Dorsal horn

Spinal cord region that processes sensory information.

Ventral horn

Spinal cord region that contains motor neurons.

Cerebrospinal fluid (CSF)

Fluid that cushions the CNS and circulates nutrients; produced by ependymal cells.

Ascending tracts

Spinal tracts that carry sensory information to the brain.

Descending tracts

Spinal tracts that carry motor commands from the brain.

Dorsal root ganglion

Cluster of cell bodies of sensory neurons located in the dorsal root ganglion.

Dorsal root

Spinal nerve root that carries sensory (afferent) fibers into the CNS.

Ventral root

Spinal nerve root that carries motor (efferent) fibers away from the CNS.

Dermatome

Region of skin innervated by one spinal nerve.

Reflex arc

The simplest structural pathway of a reflex: receptor → sensory neuron → CNS → motor neuron → effector.

Stretch reflex

Knee-jerk reflex; a spinal reflex caused by muscle stretch.

Sympathetic

Division of the autonomic nervous system that prepares the body for 'fight or flight'.

Parasympathetic

Division of the autonomic nervous system that conserves energy and promotes 'rest and digest'.

Norepinephrine (postganglionic)

Neurotransmitter released by sympathetic postganglionic neurons.

Nicotinic and Muscarinic receptors

Receptors that respond to acetylcholine (ACh) in the CNS and at neuromuscular junctions.

Alpha and Beta receptors

Subtypes of adrenergic receptors that respond to norepinephrine/epinephrine.

Multiple sclerosis

Demyelination of CNS neurons.

ALS (Amyotrophic Lateral Sclerosis)

Degeneration of motor neurons leading to muscle weakness and atrophy.

Poliomyelitis

Viral disease that destroys motor neurons and may cause paralysis.

Sciatica

Pain radiating along the sciatic nerve.

Guillain-Barré syndrome

Acute autoimmune demyelination of the peripheral nervous system.