Nervous System Organization - Vocabulary Flashcards

Vocabulary flashcards covering CNS/PNS organization, spinal cord anatomy, autonomic divisions and their characteristic functions.

Central nervous system (CNS)

Brain and spinal cord; processes and relays information to and from the peripheral nervous system.

Peripheral nervous system (PNS)

All nerves outside the CNS; connects the CNS with the body and senses.

Brain

Major organ of the CNS; integrates and coordinates sensory and motor information (encompasses cerebrum, cerebellum, brainstem; also called encephalon).

Spinal cord

CNS structure that transmits information between the brain and the PNS; contains gray matter and white matter.

Gray matter

CNS tissue of neuronal cell bodies; includes the anterior (ventral) and posterior (dorsal) horns in the spinal cord.

Anterior (ventral) horns

Ventral gray matter regions containing motor neuron cell bodies.

Posterior (dorsal) horns

Dorsal gray matter regions that receive sensory input.

White matter

Myelinated axons in the CNS; forms dorsal, ventral, and lateral columns (tracts).

Dorsal columns (posterior columns)

Posterior white matter tracts carrying ascending sensory information.

Ventral columns (anterior columns)

Anterior white matter tracts containing various motor and sensory pathways.

Lateral columns

Lateral white matter tracts containing multiple ascending and descending pathways.

Final common pathway

Synaptic point where signals from many descending motor pathways converge onto motor neurons that project to muscles.

Somatic nervous system

Subsystem of the PNS that controls voluntary skeletal muscle movement via cranial and spinal nerves.

Autonomic nervous system

Part of the PNS that regulates involuntary functions; subdivides into sympathetic and parasympathetic.

Sympathetic nervous system

Autonomic system that prepares the body for 'fight or flight': increases heart rate, respiration, glucose release, sweating, pupil dilation; inhibits digestion; can relax bladder.

Parasympathetic nervous system

Autonomic system that promotes 'rest and digest': decreases heart rate, stimulates digestion, constricts pupils, contracts bladder, stimulates sexual functions.

Pupil dilation

Sympathetic effect: enlargement of the pupil via iris dilator muscle.

Pupil constriction

Parasympathetic effect: narrowing of the pupil via iris sphincter muscle.

Increased heart rate

Sympathetic effect: faster heartbeat.

Decreased heart rate

Parasympathetic effect: slower heartbeat.

Sweat gland activation

Sympathetic effect: sweating as part of the arousal/stress response.

Digestion inhibition

Sympathetic effect: slows or inhibits digestive activity.

Digestion stimulation

Parasympathetic effect: increases digestive activity.

Bladder relaxation

Sympathetic effect: relaxes the bladder to store urine.

Bladder contraction

Parasympathetic effect: contracts the bladder to expel urine.

Adrenaline release

Sympathetic effect: release of epinephrine from adrenal glands, increasing alertness and energy.

Glucose release

Sympathetic effect: stimulates glucose release to boost energy.

Sexual arousal (parasympathetic)

Parasympathetic effect that promotes arousal and reproductive functions.

Stress response

Sympathetic activation dominates during stress, preparing the body for action.