Brain Facts: Vocabulary Review

Flashcards based on Chapters 1 and 2 of the Brain Facts primer, covering brain anatomy, neural communication, and developmental processes.

Cerebrum

The largest part of the human brain, which is associated with higher order functioning, including the control of voluntary behavior, thinking, perceiving, planning, and understanding language.

Cerebral Cortex

The outermost layer of the cerebrum, often referred to as gray matter, which is folded into grooves to increase surface area for neurons.

Corpus Callosum

A bundle of fibers that bridges the right and left hemispheres of the brain, allowing for communication between the two.

Frontal Lobe

The subdivision of the cerebral cortex responsible for initiating and coordinating motor movements, higher cognitive skills (such as problem solving and planning), and personality.

Parietal Lobe

The subdivision of the cerebral cortex involved with sensory processes, attention, and language; damage to the left side can impair the ability to understand spoken or written language.

Occipital Lobe

The subdivision of the cerebral cortex responsible for processing visual information, including the recognition of shapes and colors.

Temporal Lobe

The subdivision of the cerebral cortex that helps process auditory information and integrates information from other senses; it also plays a role in short-term memory and emotional responses.

Forebrain

A section of the brain that includes the cerebral cortex, the thalamus, the hypothalamus, and the basal ganglia.

Thalamus

The structure that prioritizes and passes most sensory information on to the cerebral cortex.

Hypothalamus

The control center for appetites, defensive and reproductive behaviors, and sleep-wakefulness.

Cerebellum

A structure in the hindbrain consisting of two hemispheres that helps control movement and cognitive processes requiring precise timing, as well as Pavlovian learning.

Central Nervous System (CNS)

One of the two major divisions of the nervous system, composed of the forebrain, midbrain, hindbrain, and spinal cord.

Peripheral Nervous System (PNS)

One of the two major divisions of the nervous system, consisting of nerves and small concentrations of gray matter called ganglia.

Somatic Nervous System

The part of the nervous system made up of neurons connecting the CNS with parts of the body that interact with the outside world.

Autonomic Nervous System

The part of the nervous system consisting of neurons connecting the CNS with internal organs; it is divided into the sympathetic and parasympathetic systems.

Sympathetic Nervous System

The branch of the autonomic nervous system that mobilizes energy and resources during times of stress and arousal.

Parasympathetic Nervous System

The branch of the autonomic nervous system that conserves energy and resources during relaxed states, including sleep.

Neuron

The basic working unit of the brain, specialized to transmit information to other nerve cells, muscle, or gland cells; the mammalian brain contains between $100\text{ million}$ and $100\text{ billion}$ of these cells.

Axon

An extension of the neuron that can range in length from a fraction of an inch to $3\text{ feet}$ or more; it transmits electrical impulses to other neurons, muscles, or glands.

Dendrites

Extensions from the neuron cell body that are designed to receive messages from other neurons via synapses.

Myelin Sheath

An insulating layer made by glia (oligodendrocytes in the brain and Schwann cells in the PNS) that increases the speed of electrical signals along an axon by up to $100\times$.

Ion Channels

Selectively permeable, water-filled molecular tunnels in the cell membrane that allow electrically charged atoms to enter or leave the cell, creating an electrical current.

Action Potential

A dramatic reversal in electrical potential that occurs on a cell's membrane, switching it from a negative to a positive charge to transmit a signal along an axon.

Neurotransmitters

The brain's chemical messengers, released at nerve terminals, that diffuse across synapses to bind to receptors on target cells.

Acetylcholine (ACh)

The first neurotransmitter identified, used by neurons to cause muscle contraction and to control heart rate; it is also critical for attention, memory, and sleep.

GABA (gamma-aminobutyric acid)

An amino acid neurotransmitter that inhibits the firing of neurons; its activity is increased by benzodiazepines and anticonvulsant drugs.

Glutamate

An amino acid neurotransmitter that serves as an excitatory signal, activating receptors such as $N\text{-methyl-d-aspartate}$ (NMDA) which are involved in learning and memory.

Dopamine

A catecholamine neurotransmitter present in three circuits, regulating movement, cognition/emotion, and the endocrine system; deficits in this chemical are linked to Parkinson's disease.

Norepinephrine

A neurotransmitter involved in learning, memory, heart rate, and blood pressure regulation; it is released during acute stress to enhance arousal.

Serotonin

A neurotransmitter involved in sleep quality, mood, depression, and anxiety; it can be manipulated by drugs such as fluoxetine to relieve depression.

Peptides

Short chains of amino acids, such as enkephalin and endorphins, that can act as neurotransmitters and are often released in response to stress to minimize pain.

Trophic Factors

Small proteins in the brain necessary for the development, function, and survival of specific groups of neurons.

Neural Induction

The process by which signaling molecules from the mesoderm trigger certain ectoderm cells to become nerve tissue.

Migration

The journey of new neurons to their proper position in the brain, beginning $3$ to $4$ weeks after human conception.

Growth Cones

Enlargements on the axon's tip that actively explore the environment to seek out precise destinations during neural development.

Apoptosis

Programmed cell death that occurs during development when neurons fail to receive sufficient trophic factors.

Plasticity

The ability of the brain to modify itself and adapt to environmental challenges by changing its neural connections.

Long-Term Potentiation (LTP)

A long-lasting increase in the strength of a synaptic response following stimulation, serving as a critical mechanism for memory storage.

Neurogenesis

The process by which the brain generates new nerve cells, occurring notably in the adult hippocampus.

Nociceptors

Sensory fibers that respond to painful thermal, mechanical, or chemical stimulation by transmitting signals to the spinal cord.

Homeostasis

The normal equilibrium of body function, which stress threatens to disrupt.

Glucocorticoids

Stress hormones, such as cortisol, released by the adrenal glands to mobilize energy into the bloodstream and mediate the body's response to challenges.