Chapter 13: Anatomy of the Nervous System

distinct halves

distinct halves

It separates the cerebrum into two ________, a right and left cerebral hemisphere.

Superior

________ to the chain ganglia are three paravertebral ganglia in the cervical region.

Deep

________ within the cerebrum, the white matter of the corpus callosum provides the major pathway for communication between the two hemispheres of the cerebral cortex.

direct pathway

The ________ is the projection of axons from the striatum to the globus pallidus internal segment (GPi) and the substantia nigra pars reticulata (SNr)

inner surface of the

It is anchored to the ________ cranium and vertebral cavity.

neural plate

Molecular signals induce cells in this region to differentiate into the neuroepithelium, forming a

neural groove

forms, visible as a line along the dorsal surface of the embryo.

neural fold

The ridge-like edge on either side of the neural groove is referred as the

neural tube

As the neural folds come together and converge, the underlying structure forms into a tube just beneath the ectoderm called the

The prosencephalon (pros

= "in front") is the forward-most vesicle, and the term can be loosely translated to mean forebrain

The mesencephalon (mes

= "middle") is the next vesicle, which can be called the midbrain

neural crest

which runs lateral to the neural tube.

prosencephalon (pros- = “in front”)

is the forward-most vesicle, and the term can be loosely translated to mean forebrain.

mesencephalon (mes- = “middle”)

is the next vesicle, which can be called the midbrain.

rhombencephalon

The third vesicle

telencephalon and the diencephalon

The prosencephalon enlarges into two new vesicles

neuraxis

The neural tube establishes the anterior–posterior dimension of the nervous system, which is called the

cephalic flexure

There is a major curve between the brain stem and forebrain, which is called the

• cerebral cortex

wrinkled portion

longitudinal fissure

There is a large separation between the two sides of the cerebrum called the

cerebral hemisphere

It separates the cerebrum into two distinct halves, a right and left

corpus callosum

provides the major pathway for communication between the two hemispheres of the cerebral cortex.

basal nuclei

are responsible for cognitive processing, the most important function being that associated with planning movements.

basal forebrain

contains nuclei that are important in learning and memory.

limbic cortex

is the region of the cerebral cortex

limbic system

a collection of structures involved in emotion, memory, and behavior.

gyrus

(plural = gyri) is the ridge of one of those wrinkles

sulcus

(plural = sulci) is the groove between two gyri.

lateral sulcus

that separates the temporal lobe from the other regions is one such landmark.

parietal lobe and frontal lobe

which are separated from each other by the central sulcus.

occipital lobe

which has no obvious anatomical border between it and the parietal or temporal lobes on the lateral surface of the brain.

parietooccipital sulcus

From the medial surface, an obvious landmark separating the parietal and occipital lobes is called the

somatosensation

meaning the general sensations associated with the body.

postcentral gyrus

the primary somatosensory cortex, which is identified as Brodmann’s areas 1, 2, and 3.

proprioception and kinesthesia

which are the senses of body position and movement.

precentral gyrus

is the primary motor cortex.

premotor area

is responsible for thinking of a movement to be made.

Broca’s area

is responsible for the production of language, or controlling movements responsible for speech; in the vast majority of people, it is located only on the left side.

prefrontal lobe

which serves cognitive functions that can be the basis of personality, short-term memory, and consciousness.

subcortical nuclei

Beneath the cerebral cortex are sets of nuclei

hippocampus and amygdala

are medial-lobe structures that, along with the adjacent cortex, are involved in long-term memory formation and emotional responses.

caudate, putamen, and globus pallidus

which are located deep in the cerebrum.

striatum

The caudate and putamen are called the

direct pathway

is the projection of axons from the striatum to the globus pallidus internal segment (GPi) and the substantia nigra pars reticulata (SNr).

indirect pathway

is the projection of axons from the striatum to the globus pallidus external segment (GPe), then to the subthalamic nucleus (STN), and finally to GPi/SNr.

substantia nigra pars compacta

which projects to the striatum and releases the neurotransmitter dopamine.

olfaction

or the sense of smell, which connects directly with the cerebrum.

epithalamus

which contains the pineal gland

subthalamus

which includes the subthalamic nucleus that is part of the basal nuclei.

Thalamus

The thalamus is a collection of nuclei that relay information between the cerebral cortex and the periphery, spinal cord, or brain stem.

Brain Stem

The midbrain and hindbrain (composed of the pons and the medulla) are collectively

tectum and tegmentum

from the Latin words for roof and floor

inferior colliculus

is the inferior pair of these enlargements and is part of the auditory brain stem pathway.

superior colliculus

is the superior pair and combines sensory information about visual space, auditory space, and somatosensory space

Pons

comes from the Latin word for bridge.

Medulla

is the region known as the myelencephalon in the embryonic brain.

reticular formation

is related to sleep and wakefulness, such as general brain activity and attention

The Cerebellum

is the “little brain.” It is covered in gyri and sulci like the cerebrum, and looks like a miniature version of that part of the brain.

inferior olive

Sensory information from the periphery, which enters through spinal or cranial nerves, is copied to a nucleus in the medulla known as the

anterior median fissure

anterior midline

posterior median sulcus

posterior midline

Ascending tracts

of nervous system fibers in these columns carry sensory information up to the brain

descending tracts

carry motor commands from the brain.

posterior columns

Between the two posterior horns of gray matter are the

anterior columns

Between the two anterior horns, and bounded by the axons of motor neurons emerging from that gray matter area, are the

lateral columns

The white matter on either side of the spinal cord, between the posterior horn and the axons of the anterior horn neurons, are the

orthostatic reflex

is a reaction to this change in body position, so that blood pressure is maintained against the increasing effect of gravity (orthostatic means “standing up”).

carotid canal

The internal carotid artery enters the cranium through the

vertebral arteries

which are protected as they pass through the neck region by the transverse foramina of the cervical vertebrae.

basilar artery

which gives rise to branches to the brain stem and cerebellum.

superior sagittal sinus

runs in the groove of the longitudinal fissure, where it absorbs CSF from the meninges.

sigmoid sinuses

which then connect to the jugular veins.

meninges

which protect the brain

dura mater

is a thick fibrous layer and a strong protective sheath over the entire brain and spinal cord. It is anchored to the inner surface of the cranium and vertebral cavity.

arachnoid mater

is a membrane of thin fibrous tissue that forms a loose sac around the CNS.

arachnoid trabeculae

which looks like a spider web, giving this layer its name.

pia mater

a thin fibrous membrane that follows the convolutions of gyri and sulci in the cerebral cortex and fits into other grooves and indentations.

ventricles

are the open spaces within the brain where CSF circulates.

central canal

There are four ventricles within the brain, all of which developed from the original hollow space within the neural tube, the

interventricular foramina

third ventricle by two openings

fourth ventricle

which is the space between the cerebellum and the pons and upper medulla.

choroid plexus

Cerebrospinal fluid is produced within the ventricles by a type of specialized membrane called a

enteric nervous system

Many of the neural structures that are incorporated into other organs are features of the digestive system; these structures

dorsal (posterior) root ganglion

The most common type of sensory ganglion is a

sympathetic chain ganglia

constitute a row of ganglia along the vertebral column that receive central input from the lateral horn of the thoracic and upper lumbar spinal cord.

prevertebral ganglia

which are located outside of the chain but have similar functions.

terminal ganglia

that receive input from cranial nerves or sacral spinal nerves and are responsible for regulating the parasympathetic aspect of homeostatic mechanisms.

epineurium

The outer surface of a nerve is a surrounding layer of fibrous connective tissue called the

perineurium

Within the nerve, axons are further bundled into fascicles, which are each surrounded by their own layer of fibrous connective tissue called

endoneurium

Individual axons are surrounded by loose connective tissue called the

olfactory nerve

and optic nerve are responsible for the sense of smell and vision

oculomotor nerve

is responsible for eye movements by controlling four of the extraocular muscles.

trochlear nerve and the abducens nerve

are both responsible for eye movement, but do so by controlling different extraocular muscles.

trigeminal nerve

is responsible for cutaneous sensations of the face and controlling the muscles of mastication.

facial nerve

is responsible for the muscles involved in facial expressions, as well as part of the sense of taste and the production of saliva.

vestibulocochlear nerve

is responsible for the senses of hearing and balance.

glossopharyngeal nerve

is responsible for controlling muscles in the oral cavity and upper throat, as well as part of the sense of taste and the production of saliva.

vagus nerve

is responsible for contributing to homeostatic control of the organs of the thoracic and upper abdominal cavities.

spinal accessory nerve

is responsible for controlling the muscles of the neck, along with cervical spinal nerves.

hypoglossal nerve

is responsible for controlling the muscles of the lower throat and tongue.