STUDENT COPY_ Chapter 3_ The Brain and Neuroscience

Neurons

The basic functional units of the nervous system, responsible for generating electrical signals called action potentials.

Glia (neuroglial cells)

Specialized cells that maintain homeostasis, support, nourish, and protect neurons.

Action potential

Electrical signals generated by neurons that allow them to transmit information quickly.

Soma

The cell body of the neuron, responsible for maintaining the cell's life functions.

Axon

The part of the neuron that passes messages away from the cell body to other neurons, muscles, or glands.

Dendrite

Branch-like structures that receive messages from other neurons.

Synapse

The junction between the axon terminal of one neuron and the dendrite of another.

Excitatory neurotransmitters

Chemicals that increase the likelihood of an action potential in the postsynaptic neuron.

Inhibitory neurotransmitters

Chemicals that decrease the likelihood of an action potential occurring in the postsynaptic neuron.

Resting potential

The state of a neuron when it is not firing, with more sodium ions outside and more potassium ions inside.

Threshold

The level of intensity of a stimulus that must be reached for an action potential to be initiated.

Refractory period

The time after a neuron fires when it is hyperpolarized and cannot fire again until it returns to resting potential.

Frontal lobe

Responsible for higher-order thinking, decision-making, and executive functioning.

Parietal lobe

Processes sensory information such as touch; includes the somatosensory cortex.

Occipital lobe

Specializes in visual processing.

Temporal lobe

Processes auditory information and handles language comprehension.

Broca’s Area

Responsible for speech production; damage here makes it difficult to speak.

Wernicke’s Area

Responsible for speech comprehension; damage here can cause difficulty in understanding language.

Corpus callosum

The bundle of nerve fibers that connects the left and right hemispheres of the brain.

Limbic system

A group of structures involved in emotion and memory; includes the thalamus, hypothalamus, and hippocampus.

Thalamus

The brain's relay station, sending sensory information to the appropriate areas for processing.

Hypothalamus

Regulates basic drives such as hunger, thirst, and body temperature.

Pituitary gland

The master gland of the brain that releases hormones regulating growth and other processes.

Hippocampus

Plays a major role in forming new memories.

Cerebellum

Coordinates voluntary movements and balance; important for motor learning.

Reticular Activating System (RAS)

Controls sleep/wake cycles, alertness, and voluntary movements.

Dopamine

A neurotransmitter that plays a key role in reward and pleasure pathways in the brain.

Peripheral Nervous System (PNS)

Consists of all nerves and ganglia outside the brain and spinal cord.

Somatic Nervous System

Controls voluntary movements and relays sensory information to the CNS.

Autonomic Nervous System

Regulates involuntary bodily functions and is divided into the sympathetic and parasympathetic systems.

Sympathetic Nervous System

Responsible for the body's 'fight or flight' response, increasing heart rate and alertness.

Parasympathetic Nervous System

Promotes relaxation and restoration of the body after stress.

Agonists

Substances that mimic the action of neurotransmitters and increase their effects.

Antagonists

Substances that oppose the action of neurotransmitters, decreasing their effects.

Neurotransmitters

Chemical messengers that transmit signals between neurons.

Dopamine

A neurotransmitter that plays a key role in reward and pleasure pathways in the brain.

Norepinephrine

A neurotransmitter involved in the body's 'fight or flight' response, regulating arousal and stress.

Serotonin

A neurotransmitter that regulates mood, sleep, and appetite.

Acetylcholine

A neurotransmitter involved in muscle movement and memory.

GABA (Gamma-aminobutyric acid)

An inhibitory neurotransmitter that helps to regulate anxiety and stress.

Glutamate

An excitatory neurotransmitter involved in learning and memory.

Endorphins

Neurotransmitters that act as natural pain relievers and contribute to feelings of pleasure.

Histamine

A neurotransmitter involved in immune responses and regulation of sleep.