KN 232 - Week 8 Structure List: Nervous System Anatomy

Vocabulary practice flashcards covering the anatomical structures, cellular components, and gross brain anatomy from the KN 232 Week 8 Structure List.

Neuron

The structural unit of the nervous system. Collectively, neurons receive information, conduct electrical signals, and release neurotransmitters.

Cell body (perikaryon or soma)

The main part of the neuron; its plasma membrane encloses the cytoplasm, and it contains the nucleus. Receives input from dendrites, initiates some graded potentials, and conducts these potentials toward the axon.

Nucleus

An organelle located inside the cell body that contains DNA and controls cell activities.

Nucleolus

A dense region inside the nucleus that produces components needed to make ribosomes.

Mitochondria

Organelles found in the cell body that produce ATP to supply energy for cellular activities.

Chromatophilic substance (Nissl bodies / rough ER)

Structures composed of free and bound ribosomes in the cell body that synthesize proteins.

Dendrites

Short, unmyelinated processes that branch off the cell body to receive input and transfer it to the cell body.

Axon

A long process extending from the cell body that attaches at the axon hillock and ends in terminal branches. Conducts action potentials and releases neurotransmitters at synaptic knobs.

Axolemma

The plasma membrane surrounding the axon that conducts action potentials as voltage-gated channels open sequentially along the membrane.

Axon hillock

The triangular region of the cell body where the axon attaches. Incoming signals are summed here; if threshold is reached at the initial segment, an action potential is generated.

Myelin

Several layers of glial-cell membrane wrapped around an axon; its high lipid content gives it a glossy-white appearance. Insulates the axon and allows faster action-potential propagation.

Schwann cells (neurolemmocyte)

Elongated, flat glial cells that wrap around axons in the peripheral nervous system (PNS) to form myelin, allowing faster action-potential propagation.

Nodes of Ranvier (neurofibril node)

Gaps between adjacent myelin-wrapped segments of an axon that allow action potentials to be regenerated along the axon, supporting faster conduction.

Oligodendrocytes

Glial cells in the central nervous system (CNS) with extensions that wrap around axons, forming myelin around portions of multiple axons.

Terminal branches (telodendria)

Branches at the end of an axon that lead to synaptic knobs, which release neurotransmitters to communicate with other cells.

Axon terminal (synaptic knob / terminal bouton)

The enlarged tip at the end of a telodendrion that releases neurotransmitters from synaptic vesicles.

Vesicle (synaptic vesicle)

A small sac inside a synaptic knob that contains neurotransmitters; it releases neurotransmitters when an arriving action potential triggers calcium entry into the synaptic knob.

Neurotransmitter

A chemical messenger synthesized by neurons and stored in vesicles in synaptic knobs. It is released, binds to receptors on a target cell, and triggers a physiological response.

Brain

An organ of the central nervous system that processes information and helps coordinate responses to sensory input.

Cerebrum

A major region of the brain consisting of two cerebral hemispheres; involved in conscious sensation, voluntary movement, memory, and other higher functions.

Cerebral hemispheres

The left and right halves of the cerebrum, separated by the longitudinal fissure. They contain the cerebral lobes and areas involved in processing sensory information and controlling movement.

Frontal lobe

A lobe located toward the front of the cerebrum that contains the primary motor cortex, which controls voluntary skeletal muscle movement.

Precentral gyrus (Primary motor cortex)

A ridge of the frontal lobe located just anterior to the central sulcus that controls voluntary skeletal muscle movement.

Parietal lobe

A cerebral lobe behind the frontal lobe that processes somatic sensory information, such as touch and body position.

Postcentral gyrus (Primary somatosensory cortex)

A ridge of the parietal lobe located just posterior to the central sulcus that receives and processes sensory information from the body, including touch.

Occipital lobe

A lobe situated at the back of the cerebrum that processes visual information.

Temporal lobe

A cerebral lobe on the side of the brain, located below the lateral sulcus; involved in hearing, memory, and language processing.

Brainstem

A region connecting the brain with the spinal cord that includes the midbrain, pons, and medulla oblongata. Relays information and helps regulate essential involuntary functions.

Cerebellum

A brain region located behind the brainstem and beneath the posterior cerebrum that helps coordinate movement, balance, posture, and motor control.

Arbor vitae

The tree-like branching pattern of white matter inside the cerebellum that carries signals within the cerebellum and between it and other nervous system regions.

Vermis

The narrow midline region connecting the two cerebellar hemispheres that helps coordinate posture and movements of the trunk.

Fissures / sulci

Grooves on the brain's surface that mark boundaries between brain regions; sulci are generally shallower, while fissures are deeper.

Central sulcus

A groove between the frontal and parietal lobes that separates the precentral gyrus (primary motor cortex) from the postcentral gyrus (primary somatosensory cortex).

Lateral sulcus

A prominent groove on the side of the cerebrum that separates the temporal lobe from portions of the frontal and parietal lobes.

Longitudinal fissure

The deep groove between the left and right cerebral hemispheres that separates the cerebrum into its two hemispheres.

Transverse fissure

A deep groove between the cerebrum and cerebellum that marks the boundary between these two brain regions.

Parieto-occipital sulcus

A groove marking the boundary and separation between the parietal and occipital lobes, most clearly seen on the medial brain surface.

Pons

A rounded region of the brainstem that relays signals and contributes to the regulation of breathing.

Medulla oblongata

The lowest part of the brainstem, continuous with the spinal cord, that helps regulate vital involuntary functions, including breathing, heart rate, and blood pressure.