Unit 2 Nervous System Vocabulary

Comprehensive key vocabulary terms and definitions covering Unit 2 Nervous System lecture notes.

Nervous System

An extensive network of cells that carries information to and from all body parts.

Neuron

A specialized cell in the nervous system that sends and receives messages.

Dendrites

Branch-like structures that receive messages from other neurons.

Soma

The cell body of a neuron that maintains life in the cell.

Axon

Part of a neuron that carries messages to other cells.

Myelin

Substance coating the axon that protects and speeds up messages; its deterioration leads to MS (Multiple Sclerosis).

Nerves

Bundles of axons coated in myelin that travel through the body.

Spinal Cord

Structure carrying messages from brain to body and body to brain.

Afferent Neurons (Sensory)

Neurons that send messages from senses to the spinal cord.

Efferent Neurons (Motor)

Neurons that send messages from the spinal cord to muscles and glands.

Interneurons

Neurons that connect sensory (afferent) and motor (efferent) neurons.

Neuroplasticity

The ability of the brain to change the structure and function of cells in response to major trauma.

Peripheral Nervous System (PNS)

All nerves that are not in the brain and spinal cord; allows the brain to communicate with senses.

Somatic Nervous System

Part of the PNS made up of nerves that carry info from senses to the CNS, which then sends messages to voluntary body muscles (motor pathway).

Reticular Formation

Neurons in the middle of the medulla and pons that play a role in arousal, alertness, and sleep.

Cerebellum

Part of lower brain that coordinates involuntary rapid, fine motor movements.

Limbic System

Mid-brain structures located under the cortex.

Thalamus

Structure in the limbic system that relays information from lower part of the brain to the cortex.

Hypothalamus

Structure responsible for motivational behavior (sex, food, fight, flee).

Hippocampus

Structure responsible for formation and storage of long-term memories.

Amygdala

Structure responsible for fear responses.

The Cortex

Outermost part of brain made up of tightly packed neurons $\frac{1}{10}\text{ inch}$ thick; responsible for high thought processes, interpretation, and sensory output.

Excitatory Synapse

Synapse where neurotransmitters cause the receiving cell to fire.

Inhibitory Synapse

Synapse where neurotransmitters cause the receiving cell to stop firing.

Reuptake

Process of cleaning the synapse where neurotransmitters are taken back into the synaptic vesicles.

Acetylcholine

Neurotransmitter that enables muscle action, learning, and memory (associated with Alzheimer's).

Dopamine

Neurotransmitter that influences movement, learning, attention, and emotion.

Serotonin

Neurotransmitter that affects mood, hunger, sleep, and arousal.

Norepinephrine

Neurotransmitter that helps control alertness, arousal, and mood.

GABA

Major inhibitory neurotransmitter involved in sleep.

Glutamine

Major excitatory neurotransmitter involved in memory, learning, and nervous system development.

Endorphins

Inhibitory neural regulators involved in pain relief.

axon terminal

branch at the end of an axon that releases neurotransmitters to communicate with other neurons.

synaptic knob

rounded areas at the end of axon terminal

synaptic vesicles

small membrane-bound structures in the axon terminal that store neurotransmitters before their release.

neurotransmitters

chemical messengers that transmit signals across a synapse from one neuron to another.

synapse

microscopic fluid filled space between knob of one cell and dendrites of the next cell

Hindbrain

lower part of brain

Medula

Top of spinal cord, lowest part of brain responsible for life, breathing, heart rate.

Pons

Bridge between lower and upper parts of brain plays a role in dreams and coordination