Chapter 20 - AP

Coverings of the Brain and Spinal Cord

• The dura mater is the layer of the meninges that serves as the inner periosteum of the cranial bone
• The pia mater is the innermost layer of the meninges
• The falx cerebelli separates the two hemispheres of the cerebrum
• The layer of the meninges adhering to the outer surface of the brain is the pia mater

Introduction to the Central Nervous System

• The main divisions of the central nervous system are the brain and spinal cord

Meningitis

• Meningitis refers to inflammation of the meninges

Fluid Spaces

• Cerebrospinal fluid is not found in the subdural space
• There are four ventricles in the brain
• The fourth ventricle is located where the cerebellum attaches to the brainstem

Formation and Circulation of Cerebrospinal Fluid

• Cerebrospinal fluid is formed by filtration of blood in the choroid plexuses
• Cerebrospinal fluid circulates through the ventricles, into the central canal and is absorbed back into the blood in the subarachnoid space

Structure of the Spinal Cord

• If the ventral nerve root of a spinal nerve is destroyed, a person would lose willed movement
• If the dorsal root ganglia of the spinal nerve is destroyed, a person would lose sensory perception
• The spinal cord does not have anterior and posterior grooves that almost divide the cord into symmetrical halves

Functions of the Spinal Cord

• Impulses sent over the lateral corticospinal tracts could result in voluntary movement, especially of the hands, fingers, feet, and toes of the opposite side
• The nerve fibers of the spinothalamic tract are sensory.

Somatic Motor Pathways in the Central Nervous System

• The lateral corticospinal tract fibers do not mostly inhibit the lower motor neuron.

Brain Structure

• The brain has six major divisions
• The brainstem does not include the cerebellum
• Going from superior to inferior, the structures of the brainstem are the midbrain, pons, and medulla oblongata

Medulla Oblongata

• The pyramids are formed in the medulla

Vital Centers

• Several "vital centers" are located in the medulla

Functions of the Brainstem

• The vomiting reflex is mediated by the medulla

Functions of the Cerebellum

• The cerebellum acts with the cerebrum
• The part of the brain that assists in the maintenance of balance is the cerebellum
• The white matter of the cerebellum is called the arbor vitae.

Thalamus

• Impulses from the thalamus play a part in arousing or alerting the cerebrum.

Hypothalamus

• The hypothalamus can directly influence or inhibit the release of hormones from the pituitary gland.
• Regulation of motor activity is not a function of the hypothalamus.

Pineal Gland

• The part of the brain that releases the hormone melatonin is the pineal gland
• The body's biological clock is controlled by the pineal body.

Functional Areas of the Cortex

• Audition is a function of the temporal lobe
• Areas specializing in language functions are found in the left cerebral hemisphere in about 90% of the population.
• A lesion in the cerebral cortex might result in motor deficits, sensory deficits or intellectual impairment

Integrative Functions of the Cortex

• The part(s) of the cerebrum associated with anger, fear, and sorrow is (are) the limbic system
• Broca's area is integral to articulating words

The Electroencephalogram (EEG)

• The type of brain wave associated with deep sleep is delta
• A person who is awake, alert, and attentive would have a predominance of beta waves
• Zeta is not a brain wave measurement

Functions of the Cerebellum

• The cerebellum does not control cardiac function, but coordinates control of muscle action, helps control posture and controls skeletal muscles to maintain balance

Integrative Functions of the Cortex

• Impulses from the reticular activating system play a part in arousing or alerting the cerebrum

Cerebral Tracts and Basal Nuclei

• The corpus callosum connects the cerebral hemispheres