Chapter 16: The Nervous System — Pathways and Higher-Order Functions

Vocabulary flashcards covering key nervous system pathways and higher order functions from the lecture notes.

tract

Nerve pathways called tracts that connect the CNS and PNS; tracts include ascending and descending pathways and are named to indicate origin and destination.

ascending pathway

A sensory pathway that carries information from peripheral receptors toward the brain.

posterior column pathway

An ascending sensory pathway that carries proprioception, fine touch, pressure, and vibration from the body to the brain.

spinothalamic pathway

An ascending sensory pathway that transmits pain and temperature sensations.

spinocerebellar pathway

An ascending sensory pathway that transmits proprioceptive information to the cerebellum.

first order neuron

The neuron that carries sensory information from the receptor to the central nervous system.

second order neuron

An interneuron located in the spinal cord or brain stem that relays signals to the thalamus or cerebellum.

third order neuron

A neuron that carries information from the thalamus to the cerebral cortex.

fasciculus gracilis

A posterior column tract that carries proprioception, fine touch, pressure, and vibration from the inferior half of the body.

fasciculus cuneatus

A posterior column tract that carries proprioception, fine touch, pressure, and vibration from the superior half of the body.

lateral spinothalamic tract

A spinothalamic tract that transmits pain and temperature sensations to the brain.

anterior spinothalamic tract

A spinothalamic tract that transmits crude touch and pressure sensations.

nucleus gracilis

Nucleus in the medulla oblongata that processes signals from the lower body; axons cross over via the medial lemniscus.

nucleus cuneatus

Nucleus in the medulla oblongata that processes signals from the upper body; axons cross over via the medial lemniscus.

medial lemniscus

A tract formed by crossing second order neurons that carries signals to the thalamus from both nuclei.

spinocerebellar posterior tracts

Proprioceptive pathways to the cerebellum; typically on the same side.

spinocerebellar anterior tracts

Proprioceptive pathways to the cerebellum; fibers may cross and cross again within the cerebellum, reaching the same or opposite side.

corticospinal pathway

A major descending motor pathway for conscious control of skeletal muscles; includes lateral and anterior corticospinal tracts.

corticobulbar tracts

Descending motor tracts from the primary motor cortex to brainstem nuclei controlling cranial nerves.

medial pathway

Group of motor pathways that subserve subconscious regulation of balance and muscle tone, including vestibulospinal, tectospinal, and reticulospinal tracts.

lateral pathway

Group of motor pathways including the rubrospinal tract for subconscious upper limb movement and tone.

vestibulospinal tracts

Medial pathway tracts that regulate balance and posture and coordinate head and body movements.

tectospinal tracts

Medial pathway tracts that regulate reflex head and neck movements in response to visual and auditory stimuli.

reticulospinal tracts

Medial pathway tracts that regulate reflex activity and muscle tone.

rubrospinal tracts

Lateral pathway tracts that influence subconscious regulation of upper limb movement and tone.

upper motor neuron

Neuron within the CNS that synapses with lower motor neurons to control skeletal muscles.

lower motor neuron

Neuron from the CNS to an effector; motor neuron of the somatic nervous system or autonomic system.

preganglionic neuron

Autonomic neuron located in the CNS that synapses on a ganglionic neuron in an autonomic ganglion.

ganglionic neuron

Postganglionic autonomic neuron that innervates an effector organ.

somatic nervous system

Part of the peripheral nervous system that controls skeletal muscles.

autonomic nervous system

Part of the peripheral nervous system that regulates visceral organs through preganglionic and ganglionic neurons.

pyramids of the medulla oblongata

Folded regions in the medulla where corticospinal fibers cross to the opposite side.

general interpretive area

Integrative cortical region that receives input from all sensory association areas; usually in the left hemisphere and involved in language.

speech center

Brain region that regulates patterns of breathing and vocalization for language.

prefrontal cortex

Integrative area that coordinates information from association areas and performs abstract intellectual functions.

hemispheric specialization

Functional differences between the left and right cerebral hemispheres, such as language versus spatial processing.

memory

Process of accessing stored information acquired through experience.

memory consolidation

Conversion of a short term memory into a long term memory; supported by the amygdaloid body and hippocampus.

amygdaloid body

Limbic system structure essential to memory consolidation and emotional processing.

hippocampus

Limbic system structure essential to memory consolidation and forming new memories.

reticular activating system

Network in the brainstem that maintains arousal and attention by modulating cortical activity.

reticular formation

Nuclei network in the brainstem involved in the RAS and various autonomic and motor functions.

states of awareness

Levels of consciousness such as conscious states, delirium, dementia, confusion, somnolence, vegetative state, and coma.

aging changes in the nervous system

Common age related changes include reduced brain size, fewer neurons, decreased blood flow, and altered synaptic organization.

Brodmann's areas

Functional areas of the cerebral cortex defined by Brodmann numbering, often cited in relation to language and other functions.