Lesson 4.2 - The Nervous System

Neuron

A nerve cell that transmits information through electrical and chemical signals.

Dendrites

The branched projections of a neuron that receive signals from other neurons.

Axon

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

Myelin Sheath

A fatty layer that insulates the axon, increasing the speed of nerve impulse transmission.

Neurotransmitter

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

Cerebrum

The largest part of the brain, responsible for higher brain functions such as thought and action.

Cerebellum

A part of the brain that coordinates movement and balance.

Brain Stem

The part of the brain that controls basic life functions such as breathing and heart rate.

Peripheral Nervous System

The part of the nervous system outside the brain and spinal cord, including sensory and motor nerves.

Central Nervous System

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

Somatic Nervous System

The part of the peripheral nervous system associated with the voluntary control of body movements via skeletal muscles.

Autonomic Nervous System

The part of the peripheral nervous system that controls involuntary bodily functions such as heart rate and digestion.

Reflex Arc

A neural pathway that controls a reflex action, involving sensory neurons, inter neurons, and motor neurons.

Thalamus

A brain structure that acts as a relay station for sensory and motor signals to the cerebral cortex.

Hypothalamus

A brain region controlling various functions, including temperature regulation, thirst, hunger, and the sleep-wake cycle.

Glial Cells

Non-neuronal cells in the nervous system that support and protect neurons.

Action Potential Threshold

The level of depolarization that must be reached for an action potential to occur.

Repolarization

The process of restoring the membrane potential to its resting state after an action potential.

Neural Plasticity

The ability of neurons to change their connections and behavior in response to experience.

Cortex

The outer layer of the brain associated with higher-level processes such as thought and concentration.