Chapter 13: Anatomy of the Nervous System

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.