Chapter 1: The Mind's Machine

Integration Zone

the part of a neuron that initiates neural electrical activity

Cell Body

also called soma; the region of a neuron that is defined by the presence of the cell nucleus

Conduction Zone

the part of a neuron--typically the axon--over which the action potential is actively propagated

Axon

also called nerve fiber; a single extension from the nerve cell that carries action potentials from the cell body toward the axon terminal

Output Zone

the part of a neuron at which the cell sends information to another cell

Axon Terminal

also called synaptic bouton; the end of an axon or axon collateral, which forms a synapse with a neuron or other target cell

Motor neuron

a neuron that transmits neural messages to the muscles (or glands)

Sensory Neuron

a nerve cell that is directly affected by changes in the environment, such as light, odor, or touch

Interneuron

a nerve cell that is neither a sensory neuron nor a motoneuron; receive input from and send output to other neurons

Multipolar Neuron

a nerve cell that has many dendrites and a single axon

Bipolar Neuron

a nerve cell that has a single dendrite at one end and a single axon on the other end

Unipolar Neuron

also called a monopolar neuron; a nerve cell with a single branch that leaves the cell body and then extends in two directions; one end is the input zone, and the other end is the output zone

Presynaptic

located on the "transmitting" side of a synapse

Postsynaptic

referring to the region of a synapse that receives and responds to a neurotransmitter

Snyaptic Cleft

the space between the presynaptic and postsynaptic neurons at a synapse

Synaptic Vesicle

a small, spherical structure that contains molecules of neurotransmitter

Neurotransmitter

also called synaptic transmitter, chemical transmitter, or simply transmitter; the chemical released from the presynaptic axon terminal that serves as the basis of communication between neurons

Neurotransmitter Receptor

a specialized protein, often embedded in the cell membrane, that selectively senses and reacts to molecules of a corresponding neurotransmitter or hormone

Neuroplasticity

the ability of the nervous system to change in response to experience or the environment

Axon Hillock

the cone-shaped area on the cell body from which the axon originates

Innervate

to provide neural input to

Axon Collateral

the branch of an axon

Oligodendrocyte

a type of glial cell that forms myelin in the central nervous system

Schwann Cell

a type of glial cell that forms myelin in the peripheral nervous system?

Myelin

the fatty insulin around an axon, formed by glial cells; this sheath boosts the speed at which nerve impulses are conducted

Nodes of Ranvier

a gap between successive segments of the myelin sheath where the axon membrane is exposed

Astrocyte

a star-shaped glial cell with numerous processes (extensions) that run in all directions. Regulated blood flow.

Microglial Cells

extremely small motile glial cells that remove cellular debris from injured or dead cells

Edema

the swelling of tissue in response to injury

Gross Neuroanatomy

anatomical features of the nervous system that are apparent to the naked eye

Central Nervous System (CNS)

the portion of the nervous system that includes the brain and the spinal cord

Peripheral Nervous System (PNS)

the portion of the nervous system that includes all the nerves and neurons outside the brain and spinal cord

Nerve

a collection of axons bundled together outside of the central nervous system

Motor Nerve

a nerve that transmits information from the central nervous system to the muscles and glands

Sensory Nerve

a nerve that conveys information from the body to the central nervous system

Somatic Nervous System

a part of the peripheral nervous system that supplies neural connections mostly to the skeletal muscles and sensory systems of the body; it consists of cranial nerves and spinal nerves

Automatic Nervous System

a part of the peripheral nervous system that provides the main neural connections to glands and to smooth muscles of internal organs

Cranial Nerve

a nerve that is connected directly to the brain

Spinal Nerve

a nerve that emerges from the spinal cord

Cervical

referring to the topmost eight segments of the spinal cord, in the neck region

Thoracic

referring to the 12 spinal segments below the cervical (neck) portion of the spinal chord, corresponding to the chest

Lumbar

referring to the five spinal segments that make up the upper part of the lower back

Sacral

referring to the five spinal segments that make up the lower part of the lower back

Coccygeal

referring to the lowest spinal vertebra (also known as the "tailbone")

Sympathetic Nervous System

the part of the autonomic nervous system that acts as the "fight or flight" system; generally activating the body for action

Parasympathetic Nervous System

the part of the autonomic nervous system that generally prepares the body to relax and recuperate

Cerebral Hemisphere

one of the two halves--right or left--of the forebrain

Cerebral Cortex

the outer covering of the cerebral hemispheres, which consists largely of nerve cell bodies and their branches

Gyrus

a ridged or raised portion of a convoluted brain surface

Sulcus

a crevice or valley of a convoluted brain surface

Frontal Lobe

the most anterior portion of the cerebral cortex

Parietal Lobe

the large region of the cortex lying between the frontal and occipital lobes in each cerebral hemisphere

Temporal Lobe

the large lateral region of the cortex in each cerebral hemisphere; it is continuous with the parietal lobe posteriorly and separated from the frontal lobe by the Sylvian Fissure

Occipital Lobe

a large region of the cortex that covers much of the posterior part of each cerebral hemisphere

Sylvian Fissure

also called lateral sulcus; a deep fissure that demarcates the temporal lobe

Central Sulcus

a fissure that divides the frontal love from the parietal lobe

Corpus Callosum

the main band of axons that connects the two cerebral hemispheres

Postcentral Gyrus

the strip of parietal cortex, just behind the central sulcus, that receives somatosensory information from the entire body

Precentral Gyrus

the strip of frontal cortex, just in front of the central sulcus, that is crucial for motor control

Gray Matter

areas of the brain that are dominated by cell bodies and are devoid of myelin; mostly receives and processes information

White Matter

a light-colored layer of tissue, consisting of mostly myelin-sheathed axons, that lies underneath the gray matter of the cortex; mostly transmits information

Neural Tube

an embryonic structure with subdivisions that correspond to the future forebrain, midbrain, and hindbrain

Forebrain

the frontal division of the neural tube, containing the cerebral hemispheres, the thalamus, and the hypothalamus

Midbrain

the middle division of the brain

Hindbrain

the rear division of the brain, which in the mature vertebrate contains the cerebellum, pons, and medulla

Telencephalon

the anterior part of the fetal forebrain, which will become the cerebral hemispheres in the adult brain

Diencephalon

the posterior part of the fetal forebrain, which will become the thalamus and hypothalamus in the adult brain

Brainstem

the region of the brain that consists of the midbrain, the pons, and the medulla

Nucleus

here, a collection of neuronal cell bodies within the central nervous system

Tract

a bundle of axons found within the central nervous sytem

Pyramidal Cell

a type of large nerve cell that has roughly a pyramid shaped cell body and is found in the cerebral cortex

Cortical Column

one of the vertical columns that constitute the basic organization of the cerebral cortex

Basal Ganglia

a group of forebrain nuclei, including the caudate nucleus, globus pallidus, and putamen, found deep within the cerebral hemispheres

Caudate Nucleus

one of the basal ganglia; it has a long extension or tail

Putamen

one of the basal ganglia

Globus Pallidus

one of the basal ganglia

Limbic System

a loosely define, widespread group of brain nuclei that innervate each other and form a network

Amygdala

a group of nuclei in the medial anterior part of the temporal lobe

Hippocampus

a medial temporal lobe structure that is important for learning and memory

Fornix

a fiber tract that extends from the hippocampus to the mammillary body

Cingulate Gyrus

a strip of cortex, found in the frontal and parietal midline, that is part of the limbic system and is implicated in many cognitive functions

Olfactory Bulb

an anterior projection of the brain that terminates in the upper nasal passages and, through small openings in the skull, provides receptors for smell

Thalamus

the brain regions that surround the third ventricle

Hypothalamus

Part of the diencephalon, lying ventral to the thalamus

Tectum

the dorsal portion of the midbrain consisting of the inferior and superior colliculi

Superior Colliculi

paired gray matter structures of the dorsal midbrain that process visual information

Inferior Colliculi

paired gray matter structures of the dorsal midbrain that process auditory information

Tegmentum

the main body of the midbrain, containing the substantia nigra, periaqueductal gray, part of the reticular formation, and multiple fiber tracts

Substantia Nigra

a brainstem structure that innervates the basal ganglia and is a major source of dopaminergic projections

Periaqueductal Gray

a midbrain region involved in pain perception

Reticular Formation

an extensive region of the brainstem, extending from the medulla through the thalamus, that is involved in sleep and arousal

Cerebellum

a structure located at the back of the brain, dorsal to the pons, that is involved in the central regulation of movement, and in some forms of learning

Pons

the portion of the brainstem that connects the midbrain to the medulla

Medulla

the posterior part of the hindbrain, continuous with the spinal cord

Meninges

the three protective membranes--dura mater, pia mater, and arachnoid--that surround the brain and spinal cord

Dura Mater

the outermost of the three meninges that surround the brain and spinal cord

Pia Mater

the innermost of the three meninges of the brain and spinal cord

Arachnoid

the thin covering (one of the three meninges) of the brain that lies between the dura mater and the pia mater

Cerebrospinal Fluid (CSF)

the fluid that fills the cerebral ventricles

Meningitis

an acute inflammation of the meninges, usually caused by a viral or bacterial infection