biology-reviewer-nervous-system

Nervous System

The complex network of nerves and cells that transmit signals between different parts of the body.

Monitoring changes

The function of the nervous system to use sensory receptors to monitor changes occurring inside and outside the body.

Interpretation of sensory input

The process of the nervous system to process and interpret sensory input to make decisions.

Effects responses

The function of the nervous system to activate muscles or glands to produce a response.

Mental activity

The brain's role in controlling mental activities such as consciousness, thinking, and memory.

Homeostasis

The ability of the nervous system to help maintain a constant internal environment by stimulating or inhibiting other systems.

Central Nervous System (CNS)

The division of the nervous system that includes the brain and spinal cord.

Peripheral Nervous System (PNS)

The division of the nervous system that includes the nerves extending from the brain and spinal cord.

Neuroglia

Supporting cells in the CNS that support, insulate, and protect neurons.

Astrocytes

Star-shaped cells in the CNS that form a barrier between capillaries and neurons and help protect neurons from harmful substances.

Microglia

Spiderlike phagocytes in the CNS that dispose of debris, including dead brain cells and bacteria.

Ependymal cells

Glial cells that line the central cavities of the brain and spinal cord and help circulate cerebrospinal fluid.

Oligodendrocytes

Glia that wrap their extensions around nerve fibers to produce myelin sheaths.

Schwann cells

Cells in the PNS that form myelin sheaths around nerve fibers.

Satellite cells

Cells in the PNS that act as protective cushioning cells.

Cell body

The metabolic center of a neuron that contains the nucleus and other organelles.

Processes

Armlike fibers of a neuron that convey messages towards or away from the cell body.

Axon hillock

The conelike region of a neuron's cell body where the axon originates.

Axon Terminals

The ends of axons that contain vesicles with neurotransmitters.

Synaptic cleft

The tiny gap between axon terminals and the next neuron.

Myelin sheaths

Fatty coverings that protect and insulate nerve fibers and increase the transmission rate of nerve impulses.

Nodes of Ranvier

Gaps in the myelin sheath along nerve fibers.

Sensory neurons

Neurons that carry impulses from sensory receptors to the CNS.

Motor neurons

Neurons that carry impulses from the CNS to muscles and glands.

Interneurons

Neurons that connect motor and sensory neurons in neural pathways.

Multipolar neuron

Neurons with several processes extending from the cell body.

Bipolar neurons

Neurons with two processes - an axon and a dendrite.

Unipolar neurons

Neurons with a single process that divides into central and peripheral branches.

Thalamus

The relay station for sensory impulses passing upward to the sensory cortex.

Hypothalamus

The autonomic nervous system center that regulates body temperature, water balance, and metabolism.

Mammillary bodies

Reflex centers involved in the sense of smell.

Epithalamus

The roof of the third ventricle that contains the pineal body and choroid plexus.

Midbrain

The part of the brain stem composed of cerebral peduncles and corpora quadrigemina.

Pons

The rounded structure below the midbrain that contains nuclei involved in the control of breathing.

Medulla Oblongata

The most inferior part of the brain stem that contains nuclei regulating vital visceral activities.

Reticular Formation

A diffuse mass of gray matter involved in motor control of visceral organs and consciousness.

Cerebellum

The part of the brain responsible for precise timing of skeletal muscle activity and balance.

Dura Mater

The outermost layer of the meninges that encloses the brain and spinal cord.

Falx Cerebri

A fold of the inner dural membrane that attaches the brain to the cranial cavity.

Tentorium Cerebelli

A fold of the inner dural membrane that separates the cerebellum from the cerebrum.

Arachnoid Mater

The middle layer of the meninges that spans the subarachnoid space and attaches to the innermost membrane.

Pia Mater

The innermost meningeal layer that tightly clings to the surface of the brain and spinal cord.

CSF

Cerebrospinal fluid that forms a watery cushion around the brain and spinal cord, protecting them from trauma.

Choroid Plexus

Clusters of capillaries that form CSF from the blood.

Lumbar Tap

A procedure to obtain a sample of CSF for testing, which requires the patient to remain lying down to prevent a spinal headache.

Blood-Brain Barrier

A protective barrier that regulates the exchange of substances between the blood and the brain.

Spinal Cord

A continuation of the brain stem that provides a two-way conduction pathway to and from the brain and serves as a reflex center.

Meninges

Protective coverings of the brain and spinal cord.

Spinal Nerves

31 pairs of nerves that arise from the spinal cord and serve the body areas close by.

Cauda Equina

A collection of spinal nerves at the inferior end of the vertebral canal that resembles a horse's tail.

Dorsal Horns

Posterior projections of the spinal cord that contain interneurons.

Ventral Horns

Anterior projections of the spinal cord that contain cell bodies of motor neurons of the somatic nervous system.

Sensory Tracts

Tracts that conduct sensory impulses to the brain.

Motor Tracts

Tracts that carry impulses from the brain to skeletal muscles.

Nerve

A bundle of neuron fibers found outside the central nervous system.

Mixed Nerves

Nerves carrying both sensory and motor fibers.

Sensory Nerves

Nerves that carry impulses toward the central nervous system.

Motor Nerves

Nerves that carry only motor fibers.

Cranial Nerves

12 pairs of nerves that primarily serve the head and neck.

Nerve Plexuses

Networks formed by the combination of ventral and dorsal roots of the spinal cord.

Autonomic Nervous System (ANS)

A specialized group of neurons that regulate cardiac muscle, smooth muscles, and glands.

Sympathetic Division

The division of the ANS that mobilizes the body during extreme situations.

Parasympathetic Division

The division of the ANS that allows the body to "unwind" and conserve energy.

Nerve Impulse

The electrical signal transmitted by neurons.

Depolarization

The change in polarity of a neuron's membrane due to an influx of sodium ions.

Repolarization

The restoration of a neuron's membrane to its polarized state after depolarization.

Saltatory Conduction

The faster conduction of nerve impulses in myelinated fibers, where the impulse jumps from node to node.

Resting Membrane Potential

The electrical conditions of a resting neuron's membrane, with the inside being more negative than the outside.

Action Potential

The long-distance signal initiated by a depolarization that propagates along the entire length of an axon.

Repolarization

The process in which potassium ions diffuse out of the cell, restoring the negative charge on the inside of the membrane and the positive charge on the outside surface.

Communication of Neurons at Synapses

The process by which neurons transmit signals at synapses.

Arrival

The point at which the action potential reaches the axon terminal.

Fusion

The process in which the vesicle containing neurotransmitter fuses with the plasma membrane.

Release

The act of neurotransmitter being released into the synaptic cleft.

Binding

The attachment of neurotransmitter to a receptor on the receiving neuron's end.

Opening

The state in which the ion channel is open, allowing the flow of ions.

Closing

The state in which the ion channel is closed, preventing the flow of ions.