Nervous part 3

Cerebral hemispheres

Collectively called the cerebrum. This is the Most superior part of the brain and larger than the other parts combined. As these grow, they enclose and obscure most of the brain stem.

Gyri

Elevated ridges on the surface of the cerebral hemisphere.

Sulci

Shallow grooves on the cerebrum.

Fissures

Deep grooves on the cerebrum.

Superficial cortex

Outer region of the cerebrum which looks gray in fresh brain tissue.

Internal area

Region of the cerebrum comprised of white matter.

Basal nuclei

Islands of gray matter situated deep within the white matter of the cerebrum. Helps regulate voluntary motor activities by modifying instructions sent to the skeletal muscles by the primary motor cortex.

Primary somatic sensory area

Part of the cerebral cortex located in the parietal lobe posterior to the central sulcus. Impulses travelling from the body's sensory receptors are localized and interpreted in this area of the brain. This allows us to recognize pain, differences in temperature, or a light touch.

Primary motor area

Part of the cerebral cortex that allows us to consciously move our skeletal muscles and controls body areas having the finest motor control, that is, the face, mouth, and hands. Located anterior to the central sulcus in the frontal lobe.

Pyramidal or corticospinal tract

The major voluntary tract that descends to the spinal cord. This is formed from the axons of the motor neurons of the primary motor area.

Broca's area

A specialized cortical area involved in our ability to speak. It is found in the primary motor area, specifically at the precentral gyrus in the left hemisphere and is also called motor speech area.

Anterior association area

Anterior part of the frontal lobes, involved in higher intellectual reasoning and socially acceptable behavior.

Posterior association area

Encompasses part of the posterior cortex. This area plays a role in recognizing patterns and faces, and blending several different inputs into an understanding of the whole situation.

Wernicke's Area

Located within the posterior association area, specifically at the junction of the temporal, parietal, and occipital lobes. This area is the sensory speech area and allows us to understand words.

Cerebral white matter

Composed of fiber tracts carrying impulses to, from, or within the cortex.

Association fiber tracts

Tracts that connect areas within a hemisphere.

Projection fiber tracts

Tracts that connect the cerebrum with lower CNS centers, such as the brain stem.

Corpus callosum

A large fiber tract that connects the cerebral hemispheres. It arches above the structures of the brain stem and allows the cerebral hemispheres to communicate with one another.

Commissures

Are fiber tracts that connect the cerebral hemispheres to each other.

Internal capsule

A tight band of projection fibers that passes between the thalamus and the basal nuclei.

Diencephalon

Also called the interbrain. It sits atop the brain stem and is enclosed by the cerebral hemispheres.

Thalamus

A major structure in the diencephalon that encloses the third ventricle, is a relay station for sensory impulses passing upward to the sensory cortex. As impulses surge through here, we have a crude recognition of whether the sensation we are about to have is pleasant or unpleasant.

Hypothalamus

Makes up the floor of the diencephalon. It is an important autonomic center because it plays a role in regulating body temperature, water balance, and metabolism. it is also the center for many drives and emotions, making it part of the limbic system

Epithalamus

Forms the roof of the third ventricle. Important parts of this are the pineal gland and the choroid plexus of the third ventricle.

Choroid plexus

Knots of capillaries within each of the four ventricles, and along with the ependymal cells lining the ventricles, form the cerebrospinal fluid.

Brain stem

About the size of a thumb in diameter and approximately 3 inches long. Its structures are the midbrain, pons, and medulla oblongata. has many small gray matter areas. These nuclei produce the rigidly programmed autonomic behaviors necessary for survival. some are associated with the cranial nerves and control vital activities such as breathing and blood pressure

Midbrain (mesencephalon)

A relatively small part of the brain stem, extends from the mammillary bodies to the pons inferiorly.

Cerebral aqueduct

Tiny canal that travels through the midbrain and connects the third ventricle of the diencephalon to the fourth ventricle below.

Cerebral peduncles

The anterior part of the midbrain and are bulging fiber tracts that convey ascending and descending impulses.

Corpora quadrigemina

Dorsal part of the midbrain and are four rounded protrusions which serve as reflex centers involved with vision and hearing.

Pons

Rounded structure that protrudes just below the midbrain. This means 'bridge,' and this area of the brain stem is mostly fiber tracts.

Medulla oblongata

Is the most inferior part of the brain stem and merges into the spinal cord below. contains many nuclei that regulate vital visceral activities. It contains centers that control heart rate, blood pressure, breathing, swallowing, and vomiting, among others

Reticular formation

Extends throughout the entire length of the brain stem and is a diffuse mass of gray matter. its neurons are involved in motor control of the visceral organs

Reticular activating system (RAS)

A special group of reticular formation neurons and plays a role in consciousness and the awake/sleep cycle. It also filters out weak sensory inputs going to the brain and spinal cord daily

Cerebellum

Projects dorsally from under the occipital lobe of the cerebrum and provides the precise timing for skeletal muscle activity and controls our balance.

Ataxia

Damaged cerebellum where movements become clumsy and disorganized and patients appear drunk.