GAP Ch12 The Nervous System and Nervous Tissue

Nervous System

The system that consists of the brain, spinal cord, and nerves, responsible for transmitting signals throughout the body.

Central Nervous System (CNS)

The part of the nervous system comprising the brain and spinal cord.

Peripheral Nervous System (PNS)

The part of the nervous system that includes all the nerves outside the central nervous system.

Neurons

The primary functional cells of the nervous system that transmit signals.

Glial Cells (Neuroglial Cells)

Cells that support and protect neurons in the nervous system.

Gray Matter

Regions of the nervous system that contain many neuron cell bodies.

White Matter

Regions of the nervous system that are primarily composed of axons.

Axon

A long, slender projection of a neuron that conducts electrical impulses away from the cell body.

Myelin

A lipid-rich substance that insulates axons to increase the speed of electrical signal transmission.

Action Potential

An electrical signal that travels along the axon of a neuron.

Synapse

The junction between two neurons where communication occurs.

Nucleus (in CNS)

A localized collection of neuron cell bodies in the central nervous system.

Ganglion (in PNS)

A cluster of neuron cell bodies in the peripheral nervous system.

Tract

A bundle of axons within the central nervous system.

Nerve

A bundle of axons in the peripheral nervous system.

Optic Nerve

A nerve transmitting visual information from the eye to the brain.

Optic Tract

The bundle of axons that continues from the optic chiasm into the brain.

Sensory Division

The part of the nervous system responsible for receiving stimuli from the environment.

Integration

The processing of sensory information in the brain.

Motor Response

The actions produced by the nervous system after processing sensory input.

Somatic Nervous System

The part of the nervous system that controls voluntary movements.

Autonomic Nervous System

The part of the nervous system that controls involuntary functions.

Enteric Nervous System

A unique part of the peripheral nervous system that governs the function of the gastrointestinal system.

Dendrites

Branch-like extensions of a neuron that receive signals from other neurons.

Interneurons

Neurons that relay signals between sensory and motor neurons.

Astrocytes

Star-shaped glial cells that support neurons and contribute to the blood-brain barrier.

Microglia

Small glial cells that act as the immune cells of the central nervous system.

Ependymal Cells

Glial cells that produce cerebrospinal fluid (CSF).

Schwann Cells

Glial cells in the peripheral nervous system that produce myelin.

Satellite Cells

Glial cells in the peripheral nervous system that support neuronal cell bodies.

Blood-Brain Barrier (BBB)

A selective barrier that protects the brain from certain substances in the blood.

Cerebrospinal Fluid (CSF)

Fluid that cushions the brain and spinal cord and removes waste.

Nervous Tissue

The specialized tissue that makes up the nervous system, consisting of neurons and glial cells.

Neurotransmitters

Chemical substances that transmit signals across a synapse.

Dorsal Root

The nerve root that carries sensory information into the spinal cord.

Ventral Root

The nerve root that carries motor information from the spinal cord to muscles.

Thalamus

A part of the brain that acts as a relay station for sensory information.

Descending Tract

The pathway along which motor signals travel down from the brain to the spinal cord.

Ascending Tract

The pathway along which sensory signals travel up from the spinal cord to the brain.

Neuromuscular Junction

The synapse between a motor neuron and a muscle fiber.

Sensation

The process of receiving stimulation from both the external and internal environments.

Stimulus

An environmental change that is detected by sensory receptors.

Reflex Arc

The neural pathway that mediates a reflex action.

Action Potential Propagation

The process by which an action potential travels along an axon.

Neuroplasticity

The ability of the nervous system to change and adapt as a result of experience.

Homeostasis

The process by which biological systems maintain stability while adjusting to conditions.

Peripheral Nervous System Components

Includes sensory and motor neurons that connect the CNS to the rest of the body.