Psychobiology - Chapter 3: Anatomy of the Nervous System

Textbook: Biopsychology - Pinel and Barnes (Chapter 3)

Central nervous system (CNS)

The portion of the nervous system within the skull and spine

Peripheral nervous system (PNS)

The portion of the nervous system outside the skull and spine

Somatic nervous system (SNS)

The part of the peripheral nervous system that interacts with the external environment

Afferent nerves

Nerves that carry sensory signals to the central nervous system

Efferent nerves

Nerves that carry motor signals from the central nervous system to the skeletal muscles or internal organs

Autonomic nervous system (ANS)

The part of the peripheral nervous system that participates in the regulation of the body's internal environment

Sympathetic nerves

Those motor nerves of the autonomic nervous system that project from the central nervous system in the lumbar and thoracic region areas of the spinal cord

Parasympathetic nerves

Those autonomic motor nerves that project from the brain to the sacral region of the spinal cord

Cranial nerves

The 12 pairs of nerves extending from the brain (e.g., optic nerves, olfactory nerves, and vagus nerves)

Glial cells

Several classes of nonneural cells of the nervous system

Oligodendrocytes

Glial cells that myelinate axons of the central nervous system; also known as oligodendroglia

Myelin

A fatty insulating substance

Myelin sheaths

Coverings on the axons of some neurons that are rich in myelin and increase the speed and efficiency of axonal conduction

Schwann cells

The glial cells that compose the myelin sheaths of PNS axons and promote the regeneration of PNS axons

Microglia

Glial cells that respond to injury or disease by engulfing cellular debris and triggering inflammatory responses

Astrocytes

Large, star-shaped glial cells that play multiple roles in the central nervous system

Golgi stain

A neural stain that completely darkens a few of the neurons in each slice of tissue, thereby revealing their silhouettes

Nissl stain

A neural stain that has an affinity for structures in neuron cell bodies

Electron microscopy

A microscopy technique used to study the fine details of cellular structure

Anterior

Toward the nose end of a vertebrate

Posterior

Toward the tail end of a vertebrate or toward the back of the head

Dorsal

Toward the surface of the back of a vertebrate or toward the top of the head

Ventral

Toward the chest surface of a vertebrate or toward the bottom of the head

Medial

Toward the midline of the body

Lateral

Away from the midline of the body of a vertebrate, toward the body's lateral surfaces

Superior

Toward the top of the primate head

Inferior

Toward the bottom of the primate head or brain

Proximal

Close to something

Distal

Far from something

Horizontal sections

Any slices of brain tissue cut in a plane that are parallel to the top of the brain

Frontal sections

Any slices of brain tissue cut in a plane that is parallel to the face; also termed coronal sections

Sagittal sections

Any slices of brain tissue cut in a plane that is parallel to the side of the brain

Cross section

Section cut at a right angle to any long, narrow structure of the central nervous system

Gray matter

Portions of the nervous system that are gray because they are composed largely of cell bodies and unmyelinated interneurons

White matter

Portions of the nervous system that are white because they are composed largely of myelinated axons

Dorsal horns

The two dorsal arms of the spinal gray matter

Meninges

The three protective membranes that cover the brain and spinal cord (singular meninx)

Dura mater

The tough outer meninx

Arachnoid membrane

The meninx that is located between the dura mater and the pia mater and has the appearance of a gauzelike spiderweb

Subarachnoid space

The space beneath the arachnoid membrane, which contains many large blood vessels and cerebrospinal fluid

Pia mater

The delicate, innermost meninx

Cerebrospinal fluid (CSF)

The fluid that fills the subarachnoid space, the central canal, and the cerebral ventricles

Central canal

The small cerebrospinal fluid-filled channel that runs the length of the spinal cord

Cerebral ventricles

The four cerebrospinal fluid-filled internal chambers of the brain: the two lateral ventricles, the third ventricle, and the fourth ventricle

Choroid plexuses

The networks of capillaries that protrude into the ventricles from the pia mater and produce cerebrospinal fluid

Blood-brain barrier

The mechanism that impedes the passage of toxic substances from the blood into the brain

Ventral horns

The two ventral arms of the spinal gray matter

Dorsal root ganglia

Structures just outside the spinal cord that are composed of the cell bodies of dorsal root axons

Brain stem

The part of the brain on which the cerebral hemispheres rest; in general, it regulates reflex activities that are critical for survival (e.g., heart rate and respiration)

Myelencephalon (medulla)

The most posterior of the five major divisions of the brain; the medulla

Reticular formation

A complex network of about 100 tiny nuclei that occupies the central core of the brain stem from the posterior boundary of the myelencephalon to the anterior boundary of the midbrain. Sometimes referred to as "little net" or as the reticular activating system.

Metencephalon

One of the five major divisions of the brain; it includes the pons and cerebellum

Pons

The metencephalic structure that creates a bulge on the ventral surface of the brain stem

Cerebellum

A metencephalic structure that is thought to participate in the storage of memories of learned sensorimotor skills

Mesencephalon

One of the five major divisions of the brain; it is composed of the tectum and tegmentum

Tectum

The dorsal surface of the midbrain; the roof

Inferior colliculi

The structures of the tectum that receive auditory input from the superior olives

Superior colliculi

Two of the four nuclei that compose the tectum; they receive major visual input

Tegmentum

The ventral division of the mesencephalon; it includes part of the reticular formation, substantia nigra, and red nucleus

Periaqueductal gray

The gray matter around the cerebral aqueduct, which contains opiate receptors and activates a descending analgesia circuit

Cerebral aqueduct

A narrow channel that connects the third and fourth ventricles

Substantia nigra

The midbrain nucleus whose neurons project via the nigrostriatal pathway to the striatum of the basal ganglia; it is part of the mesotelencephalic dopamine system

Red nucleus

A structure of the sensorimotor system that is located in the tegmentum of the mesencephalon

Diencephalon

One of the five major divisions of the brain; it is composed of the thalamus and hypothalamus

Thalamus

The large two-lobed diencephalic structure that constitutes the anterior end of the brain stem; many of its nuclei are sensory relay nuclei that project to the cortex

Massa intermedia

The neural structure located in the third ventricle that connects the two lobes of the thalamus

Sensory relay nuclei

Those nuclei of the thalamus whose main function is to relay sensory signals to the appropriate areas of cortex

Lateral geniculate nuclei

The six-layered thalamic structures that receive input from the retinas and transmit their output to the primary visual cortex

Medial geniculate nuclei

The auditory thalamic nuclei that receive input from the inferior colliculi and project to primary auditory cortex

Ventral posterior nuclei

A thalamic relay nucleus in both the somatosensory and gustatory systems

Hypothalamus

The diencephalic structure that sits just below the anterior portion of the thalamus

Pituitary gland

The gland that dangles from, and is controlled by, the hypothalamus

Optic chiasm

The X-shaped structure on the inferior surface of the diencephalon; the point where the optic nerves decussate

Decussate

To cross over to the other side of the brain

Contralateral

Projecting from one side of the body to the other

Ipsilateral

On the same side of the body

Mammillary bodies

The pair of spherical nuclei that are located on the inferior surface of the hypothalamus

Telencephalon

The most superior of the brain's five major divisions

Cerebral cortex

The layer of neural tissue covering the cerebral hemispheres of humans and other mammals

Neurons

Cells of the nervous system that are specialized for the reception, conduction, and transmission of electrochemical signals

Multipolar neuron

A neuron with more than two processes extending from its cell body

Unipolar neuron

A neuron with one process extending from its cell body

Bipolar neuron

A neuron with two processes extending from its cell body

Interneurons

Neurons with short axons or no axons at all, whose function is to integrate neural activity within a single brain structure

Nuclei

The DNA-containing structures of cells; also, clusters of neuronal cell bodies in the central nervous system (singular nucleus)

Ganglia

Clusters of neuronal cell bodies in the peripheral nervous system (singular ganglion)

Tracts

Bundles of axons in the central nervous system

Nerves

Bundles of axons in the peripheral nervous system

Fissures

The large furrows in a convoluted cortex

Sulci

Small furrows in a convoluted cortex

Gyri

The cortical ridges that are located between fissures or sulci

Longitudinal fissure

The large fissure that separates the two cerebral hemispheres

Cerebral commissures

Tracts that connect the left and right cerebral hemispheres

Corpus callosum

The largest cerebral commissure

Central fissure

The large fissure that separates the frontal lobe from the parietal lobe

Lateral fissure

The large fissure that separates the temporal lobe from the frontal lobe

Frontal lobe

The most anterior of the four cerebral lobes

Parietal lobe

One of the four cerebral lobes; it is located just posterior to the central fissure

Temporal lobe

One of the four major cerebral lobes; it lies adjacent to the temples and contains the hippocampus and amygdala

Occipital lobe

The most posterior of the four cerebral lobes; its function is primarily visual