Chapter 1 - Structure and Function (The Mind's Machine)

Neuron

The basic unit of the nervous system, each composed of receptive extensions called dendrites, an integrating cell body, a conducting axon, and a transmitting axon terminal

glial cells

nonneuronal brain cells that provide sturctural, nutrional, and other types of support to the brain

synapse

the cellular location at which information is transmitted from a neuron to another cell

input zone

the part of a neuron that receives information from other neurons or from specialized sensory structures

dendrite

an extension of the cell body that receives information from other neurons

integration zone

the part of a neuron that initiates neural electrical activity

cell body

the region of a neuron that is defined by the presence of the cell nucleus. Also called soma

conduction zone

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

axon

a single extension from the nerve cell that carries action potentials from the cell body toward the axon terminals

axon collateral

a branch of an axon

output zone

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

axon terminal

the end of an axon or axon collateral, which forms a synapse on a neuron or other target cell and thus serves as the output zone. Also called synaptic bouton

motor neuron

a neuron that transmits neural messages to 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; interneurons 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 at the other end

unipolar 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 neurotransmitter

presynaptic membrane

the specialized membrane of the axon terminal of the neuron that transmits information by releasing neurotransmitter

synaptic cleft

the space between the presynaptic and postsynaptic neurons at a synapse

postsynaptic membrane

The specialized membrane on the surface of the neuron that receives information by responding to neurotransmitter from a presynaptic neuron.

synaptic vesicle

a small, spherical structure that contains molecules of neurotransmitter

neurotransmitter

the chemical released from the presynaptic axon terminal that serves as the basis of communication between neurons

neurotransmitter receptor

a specialized protein that selectively senses and reacts to molecules of a corresponding neurotransmitter or hormone

neuropasticity

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

axonal transport

The transportation of materials from the neuronal cell body toward thet axon terminals, and from the axon terminals back toward the cell body

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 insulation around an axon, formed by glial cells. This sheath boosts the speed at which nerve impulses are conducted.

node 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

microglial cells

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

edema

a general term referring to swelling of any body tissue, including the brain

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

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

the 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

autonomic nervous system

the part of the peripheral nervous system that provides the main neural connections to the internal organs

cranial nerve

a nerve that is connected directly to the brain

spinal nerve

a nerve that emerges from the spinal cord

cervical

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

thoracic

reffering to the 12 spinal segments below the cervical (neck) portion of the spinal cord, in the torso

lumbar

reffering to the five spinal segments in the upper part of the lower back

sacral

reffering to the five spinal segments in the lower part of the back

coccygeal

reffering to the lowest spinal vertebra (the coccyx or "tailbone")

sympathetic nervous system

the part of the autonomic nervous system that generally prepares the body for action

parasympathetic nervous system

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

saggital plane

the plane that divides the body or brain into right and left portions

coronal plane

the plane that divides the body or brain into front and back parts

horizontal plane

the plane that divides the body of brain into upper and lower parts

medial

in anatomy, toward the middle

lateral

in anatomy, toward one side

ipsilateral

in anatomy, pertaining to a location on the same side of the body

contralateral

In anatomy, pertaining to a location on the opposite side of the body.

superior

in anatomy, above

inferior

in anatomy, below

basal

"toward the base" or "toward the bottom" of a structure

anterior

in anatomy, toward the head end of an organism

posterior

in anatomy, toward the tail end of an organism

proximal

in anatomy, near the trunk or center of an organism

distal

in anatomy, toward the periphery of an organism or toward the end of a limb

afferent

carrying action potentials toward the brain, or toward one region of interest from another region of interest

efferent

carrying action potentials away from the brain, or away from one region of interest toward another region of interest

dorsal

in anatomy, toward the back of the body or the top of the brain

ventral

in anatomy, toward the belly or front of the body, or the bottom of the brain

gray matter

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

white matter

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

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 of valley of a convoluted brain surface

frontal lobe

the most anterior portion of the cerebral cortex

parietal lobe

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

temporal lobe

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

Sylvian fissure

a deep fissure that demarcates the temporal lobe. Also called lateral sulcus

central sulcus

a fissure that divides the frontal lobe 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 posterior to the central sulcus, that receives somatosensory information from the entire body

precentral gyrus

the strip of frontal cortex, just anterior to the central sulcus, that is crucial for motor control

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 brain responsible for hearing and sight; location where pain is registered; includes temporal lobe, occipital lobe, and most of the parietal lobe

hindbrain

the read 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

a collection of neuronal cell bodies within the central nervous system

tract

a bundle of axons found within the central nervous system

pyramidal cell

A type of large nerve cell that has a roughly pyramid-shaped cell body; 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 caudate nucleus, globus pallidus, and putamen, found deep within the cerebral hemispheres.

limic system

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