Pathology Exam 6 Nervous System (elise)

What type of beam demonstrates air-fluid levels indicative of underlying inflammatory disease or fracture?

horizontal beam

What is the ability of an imaging system to differentiate between two nearby structures, which is important to detect the sharpness of structure edges of the smallest parts?

spatial resolution

What is the ability of the imaging system to distinguish various shades of gray among structure tissues?

contrast resolution

How can the divisions of the nervous system be classified?

by location or by the type of tissue supplied by the nerve cells in the division

What does the central nervous system consist of?

the brain and spinal cord

What does the peripheral nervous system (PNS) consist of?

12 pairs of cranial nerves, 31 pairs of spinal nerves, autonomic nerves, and ganglia

What system consists of afferent and efferent neurons?

the peripheral nervous system (PNS)

What conducts impulses from peripheral receptors to the CNS?

afferent (sensory) neurons

what conducts impulses away from the CNS to the peripheral effectors?

Efferent (motor) system

What supplies the striated skeletal muscles?

somatic nervous system

What supplies smooth muscle, cardiac muscle, and glandular epithelial tissue?

autonomic nervous system

What is the basic unit of the nervous system?

neuron or nerve cell

What does a neuron consist of?

a cell body and two types of long, threadlike extensions

Where does a single axon lead?

from the cell body

Where does one or more dendrites lead?

towards the cell body

Axons are insulated by a fatty covering called what?

myelin sheath

What does the myelin sheath do?

increases the rate of transmission of nerve impulses

Deterioration of this fatty myelin sheath is a characteristic abnormality in what?

multiple sclerosis

In involuntary reactions, the impulse conduction route to and from the CNS is termed what?

a reflex arc

Impulses pass from one neuron to another at a junction called what?

synapse

What is a chemical reaction in which the termini of the axon release a neurotransmitter that produces an electrical impulse in the dendrites of the next axon?

transmission of the synapse

What is the largest part of the brain?

cerebrum

What does the cerebrum consist of?

two cerebral hemispheres

The surface of the cerebrum is highly convoluted with elevations called what?

gyri

What are the low shallow grooves called in the cerebrum?

sulci

What do the deeper grooves called fissures divide?

each cerebral hemispheres into lobes

What is the outer portion of the cerebrum termed?

cortex

What does the cortex consist of?

a thin layer of gray matter where the nerve cell bodies are concentrated

What does the inner layer of the cerebrum consist of?

white matter, which is composed of the nerve fiber tracts

What is the cerebral cortex responsible for?

receiving sensory information from all parts of the body and for triggering impulses that govern all motor activity

Just _________ to the central sulcus, the cerebral cortex has specialized areas to receive and precisely localize sensory information from the ___.

posterior, PNS

Visual impulses are transmitted to what portion of the brain?

posterior

Where are olfactory (smell) and auditory impulses recieved from?

the lateral portions

Where is the primary motor cortex in relation to the central sulcus?

anterior

Where does the premotor cortex lie in relation to the primary motor cortex?

anterior

What controls the movement of muscles by stimulating groups of muscles that work together?

the premotor cortex

The two cerebral hemispheres are connected by a mass of white matter called what?

the corpus callosum

Deep within the white matter are a few islands of gray matter that are collectively called what?

basal ganglia

What structures help control position and automatic movements and consist of the caudate nuclei, the pallidus, and the putamen?

basal ganglia

what lies between the cerebrum and the spinal cord?

the brainstem

What is the brainstem composed of from the top to the bottom?

midbrain (mesencephalon), the pons, and the medulla

In addition to performing sensory, motor, and reflex functions, the brainstem contains what?

the nuclei of the 12 cranial nerves and the vital centers controlling cardiac, motor, vasomotor, and respiratory function

Centers in the medulla are responsible for such non-vital reflexes such as what?

vomiting, coughing, sneezing, hiccupping, and swallowing.

What is the second largest part of the brain?

cerebellum

Where is the cerebellum located?

just below the posterior portion of the cerebrum

What two large masses is the cerebellum composed of?

the cerebellar hemispheres and a central section (vermis)

What does the vermis resemble?

a worm coiled on itself

what lies between the cerebrum and the mid brain?

diencephalon

What primarily functions as a relay station that receives and processes sensory information of almost all kinds of sensory impulses before sending this information on to the cerebral cortex?

thalamus

what is a tiny complex structure that functions as a link between the mind and body and is the site of "pleasure" or "reward" centers for such primary drives as eating, drinking, and mating?

hypothalamus

What plays a major role in regulating the body's internal environment by coordinating the activities of the autonomic nervous system and secreting the releasing hormones?

hypothalamus

What lies within the vertebral column and extends from its junction with the brainstem at the foramen magnum to approximately the lower border of the first lumbar vertebra?

spinal cord

What is the basic function of the spinal cord?

to conduct impulses up the cord to the brain (ascending tracts) and down the cord from the brain to the spinal nerves (descending tracts)

What are the outer bony coverings of the skull encasing the brain and vertebrae surrounding the spinal cord?

meninges

what is between the layers of the meninges & delicate cobweb like

arachnoid membrane

What separates the two cerebellar hemispheres?

falx cerebelli

CSF is formed by the filtration of plasma from blood into what?

the choroid plexuses

Obstruction of the CSF circulation results in what?

hydrocephalus

What is acute inflammation of the pia mater and arachnoid, two of the membranes covering the brain and spinal cord?

meningitis

What is most commonly caused by haemophilus influenzae in neonates and young children and by meningococci and pneumococci in adolescents and young adults?

bacterial meningitis (pyogenic)

what may be caused by mumps, poliovirus, and occasionally herpes simplex?

viral meningitis

a chronic form of meningitis can be caused by what?

tuberculous infection

What is the most common form of meningitis?

Bacterial Meningitis (pyogenic)

What is necessary to determine the cause of meningitis?

a spinal tap

what produces symptoms ranging from mild headache and fever to severe cerebral dysfunction, seizures, and coma?

encephalitis

Encephalitis caused by what is an often fatal fulminant process?

herpes simplex

what are usually a result of chronic infections of the middle ear, paranasal sinuses, or mastoid air cells, or of systemic infections?

brain abscesses

The organisms that most commonly cause brain abcesses are what?

streptococci

What is a suppurative process in the space between the inner surface of the dura and the outer surface of the arachnoid?

subdural empyema

Approximately 25% of intracranial infections are what?

subdural empyema's

What is the most common cause of subdural empyema?

the spread of infection from the frontal or ethmoid sinuses

Where is the most common location of a subdural empyema?

over the cerebral convexity, the base of the skull is usually spread

What is the modality of choice in evaluating the patient with suspected subdural empyema?

MRI

What is almost invariably associated with osteomyelitis in a cranial bone originating from an infection in the ear or paranasal sinuses?

epidural empyema

Subdural and epidural empyemas should be treated how?

as medical emergencies

What is most commonly caused by direct extension of a suppurative process from the paranasal sinuses, mastoid air cells, or scalp?

osteomyelitis of the skull

How does osteomyelitis appear radiographically?

as multiple small, poorly defined areas of lucency

How do intracranial neoplasms manifest clinically?

as seizure disorders or gradual neurologic deficits

What percent of CNS tumors are primary lesions, with others representing metastases?

50%

What are the most primary malignant brain tumors?

gliomas (consist of glial cells)

How do gilomas spread?

by direct extension and can cross from one cerebral hemisphere to the other through white matter tracts, such as the corpus callosum.

What are highly malignant lesions that are predominantly cerebral, although similar tumors may occur in the brainstem, cerebellum, or spinal cord.

giloblastomas

what are slow-growing tumors that have an infiltrative character and can form large cavities or pseudocysts?

astrocytomas

what most commonly arise from the walls of the forth ventricle, especially in children, and usually from the lateral ventricles in adults?

ependymomas

what are rapidly growing tumors, disseminating throughout the spinal fluid, which develop in the posterior portion of the vermis in children and rarely in the cerebellar hemisphere in adults?

medulloblastomas

what are slow-growing lesions that usually arise in the cerebrum and have a tendency to calcify?

oligodendrocytomas

What are tumors that arise from arachnoid lining cells, are attached to the dura, and are almost always benign?

meningioma

What tumors typically occur in elderly adults with a female pre-dominance and generally are asymptomatic?

meningiomas

What are slowly growing benign tumors that may occur as solitary lesions or as part of the syndrome of neurofibromatosis?

acoustic neuroma

what tumors arise from schwann cells in the vestibular portion of the auditory (eighth cranial) nerve.

acoustic neuroma

what type of tumor originates in the auditory canal and extends into the cerebellopontine angle cistern?

acoustic neuroma

What are tumors that almost all of which arise in the anterior lobe, constitute more than 10% of all intracranial tumors?

pituitary adenomas

What are benign tumors that contain both cystic and solid components and usually occur in patients younger than 20 years of age?

craniopharyngioma

Where do craniopharyngioma's generally originate?

above the sella turcica, depressing the optic chiasm and extending up into the third ventricle

What are the most common tumors of the pineal gland?

germinomas and teratomas

what tumors occur predominately in males younger than 25 years of age and may be associated with precocious puberty?

pineal tumors

What tumors typically compress the midbrain from above and lift the splenium of the corpus callosum?

pineal tumors

What are tumors that arise from remnants of the notochord (the embryotic neural tube)?

Chondromas

What are the most common sites for chondromas?

the clivus and the lower lumbosacral region

What produce the clinical picture of multiple cranial palsies on one or both sides combined with a retropharyngeal mass and erosion of the clivus?

chondromas