Introduction to the Nervous System

This set of flashcards covers essential terms and concepts related to the nervous system, including its structure, functions, and key processes.

Nervous System

A communication system that includes the central nervous system (CNS) and peripheral nervous system (PNS), responsible for processing sensory input and generating responses.

Central Nervous System (CNS)

Composed of the brain and spinal cord, it processes information and coordinates body responses.

Peripheral Nervous System (PNS)

Consists of cranial and spinal nerves; it transmits sensory information to the CNS and motor commands from the CNS to effectors.

Homeostasis

The process by which biological systems maintain stability while adjusting to conditions that are optimal for survival.

Afferent Pathway

The pathway that carries sensory information from receptors to the central nervous system.

Efferent Pathway

The pathway that carries motor commands from the central nervous system to effectors, such as muscles and glands.

Neuron

A specialized cell that transmits nerve impulses; it consists of a cell body, axon, and dendrites.

Action Potential

A rapid rise and fall in voltage or membrane potential across a cellular membrane, essential for nerve signal transmission.

Neurotransmitter

Chemical substances that transmit signals across a synapse from one neuron to another.

Sodium-Potassium Pump

A cellular mechanism that pumps sodium ions out of the cell and potassium ions into the cell, essential for establishing resting membrane potential.

Resting Membrane Potential

The electrical potential across a neuron's membrane when it is not actively sending a signal, typically around -70 mV.

Threshold

The minimum depolarization necessary to trigger an action potential in a neuron.

Reflex Arc

The neural pathway that mediates a reflex action, involving sensory neurons, interneurons, and motor neurons.

Astrocytes

Star-shaped glial cells in the brain and spinal cord that support and protect neurons and help form the blood-brain barrier.

Myelin Sheath

An insulating layer that forms around nerves, allowing for faster transmission of electrical signals along the axon.

Ependymal Cells

Glial cells that line the ventricles of the brain and the central canal of the spinal cord, involved in the circulation of cerebrospinal fluid.

Oligodendrocytes

Glial cells in the CNS that wrap around axons to form the myelin sheath, facilitating rapid signal conduction.

Schwann Cells

Cells in the PNS that form the myelin sheath around peripheral axons, aiding in signal transmission.

Interneuron

A type of neuron that connects sensory and motor pathways, primarily located in the CNS.

Neural Integration

The process by which multiple signals from different neurons are combined and interpreted to elicit a specific action.

Synapse

The junction between two neurons, where neurotransmitters are released to transmit signals from one neuron to another.

Depolarization

The process during an action potential where the membrane potential becomes more positive, typically due to the influx of sodium ions.

Repolarization

The process of restoring the membrane potential to its resting state after depolarization, usually involving the efflux of potassium ions.

Hyperpolarization

An increase in the membrane potential, making it more negative than the resting potential, typically following repolarization.